After briefly working as a puppeteer and builder for The Howdy Doody Show then working on stop-motion films (including projects with George Pal), Don Sahlin began working with Jim Henson in 1962. Henson hired Sahlin to create a Muppet of a dog character, Rowlf, for Purina Dog Chow commercials. Rowlf when onto become the singer’s side-kick during the four-year run of The Jimmy Dean TV show. Sahlin became Jim Henson’s primary designer and builder. Henson credited Sahlin with creating the distinctive Muppet “look.”
In addition to working on the Muppets, Sahlin provided special and visual effects for Henson’s Oscar-nominated short film from 1965, “Time Piece.”
At about seven minutes and 30 seconds into “Time Piece,” you see a small rocket launched.
The rocket and its launch pad may have looked familiar to readers of Estes’s Model Rocket News.
In the June, 1965, issue of MRN, Don Sahlin is listed of the winner of
Long ago, Estes Industries published a newsletter called Model Rocket News. This was long before I got into the hobby.
This kept model rocketeers (mostly children in those days, though a lot of the information was very sophisticated, involving advanced mathematics and physics) up to date on the latest developments in rocketry, presented ideas for science fair projects, and allowed young rocketeers to present tips, feedback and ideas to both Estes and other rocket kids around the country.
You can find issues in PDF form around the Internet (though I think a complete collection still eludes us).
I recently downloaded as many of these as I can find. I enjoy reading them, because even though they are from the early days of model rocketry, and even though some of the information is no longer relevant (parts or motors which no longer exist), there are still good ideas in the Model Rocket News, and still tidbits to learn from. And much of the basic rocketry information continues to be true. And I appreciate them as historical documents.
And they have rocket plans!
Some of these were submitted by Model Rocket News readers - some of the kids who were designing rockets in those days had some pretty interesting designs, and you can still make them today.
Some of the designs were free rocket plans from Estes.
Tonight, I was reading Volume 3, Number 2, from April/May 1963, and I saw something surprising: A free plan for a rocket I'm very familiar with: Estes Industries Rocket Plan No. 13: Big Bertha.
It seems that before it was a classic Estes kit, the Big Bertha was a classic Estes free design. This might not be a surprise to longtime rocketeers, but to a n00b like me, it was a cool discovery.
It looks much like it does today, with a few minor differences.
The nose cone was made of balsa (which you can still find at Jonrocket.com or Balsa Machining Service or a number of online rocket parts vendors around the Internet), and motor mounts were made a little differently then. Also, instead of a motor hook, the original Bertha design used a friction fit, requiring you to wrap a bit of masking tape around the motor before inserting it into the rocket for a snug, secure fit.
Also, at least according to the drawing, the nose cone was slightly pointy.
You can find the full edition of Volume 3, Number 2 Model Rocket News here, including a full-sized plan which you can print out and build. You'll also get a glimpse into the early days of Estes Industries operations, complete with mail-order procedures.
"Chute Release is designed to be extremely easy to use. As a first step, you attach the tether to one of the parachute shroud lines (so that you don’t lose your Chute Release). Then, you gather the bottom of your parachute together and wrap the (rubber) band around it and snap the pin into the other side of chute release. That holds your parachute closed until you want it to open. Then you use the buttons to set an altitude. You can pack your chute however you like after that, including rolling it up." So as I understand it - The parachute does eject as normal but the Chute Release holds your parachute closed, wrapped in a rubber band. The reefed chute acts as a closed drogue. When the Chute Release unit senses the preset altitude, the rubber band is released and the parachute fully opens. "A nice benefit of Chute Release is that you can use a larger chute than you normally would. You can choose your chute to give a soft landing without worrying as much about how far it will drift on winds aloft. It won’t fit in every rocket. Practically speaking, the smallest rocket tube that it will fit will be the 41mm (1.64″) BT-60 (Big Bertha) size tubes, and perhaps the international 40mm FAI size. Unless/until we can design a smaller Chute Release, we’ll market this as more of a medium-to-high power product, for motors F-K, since that’s a range that reaches higher altitudes and still usually relies on simple motor ejection." In a word - BRILLIANT! Less drift, and no need for a complicated second BP ejection charge. To see the product development, CLICK HERE
In May, I went to launch some rockets with Chad. I took along several I'd built but never flown before. It was breezy, and I lost a few. Against my better judgment, I put the Quest Quadrunner on the launch pad.
This beauty of a rocket from Quest Aerospace is a four-motor cluster capable of pretty high altitudes for a model rocket. It took me a long time and some heartache to build, but in the end it turned out really beautiful.
I installed four standard EC6-7 motors in the rocket. But clusters are tricky. The trick is getting all the motors to ignite at once. Estes motors (or "engines") all come with igniters, but they're not as reliable as you want for a cluster rocket.
There are a couple problems that prevent Estes igniters from being ideal for clusters. One is their size - they're pretty small and don't have much reach. But the main problem is that they require too much current.
Getting one Estes igniter to fire is one thing, but when you have the current from your launch controller split between two or more igniters, the total current reaching each igniter tip is less and less. What can then happen is that sometimes one motor might fire, and take the rocket with it, ripping out the other igniters before the other motors light.
Quest Aerospace has a much better igniter for this job. It's called the Q2G2 igniter.
These were off the market for a while, but they're back. The supply still can't quite meet the demand, but they are on the market.
Two things make this igniter much better for cluster rockets.
The first, is that the igniter has a black pyrogen on the tip.
This is a flammable substance. When the igniter tip heats up, the pyrogen creates a small flash or flame, aiding in the motor's ignition.
Estes igniters used to have a pyrogen, but they stopped making them like that in the last year. I still have a few, but I save them for special occasions.
But what makes the Q2G2 an even better igniter for cluster ignition is that they are low current igniters. That means it takes much less electric current to make the tips hot enough to ignite the rocket motors. You can send the same amount of current through several Q2G2 igniters as through one Estes igniter, and they will all fire pretty much simultaneously.
I put the Quadrunner on the pad, inserted the safety key into my launch controller, counted nervously down from 5, pressed the ignition button... And there was this loud puffing sound signifying ignition.
And then the rocket just sat there. Fortunately! I'm sure I would have lost it otherwise!
But what had happened?
As you can see in the above photos, the Q2G2 comes packed in a little red straw. This is actually what keeps the igniter installed in the motor before ignition. This is a different method than the plastic plug method seen in the Estes igniter photos.
Quest Q2G2 installed in an Estes C6-7 motor
I really like the straw method. It allows you to insert the igniter until you can really feel that it's in contact with the propellant.
I looked at the rocket. The Q2G2 igniters - all of them - had slipped downward a little inside their straws. The straws were blackened, and the puff of the pyrogen had actually ejected them from the nozzles of the rocket motors without igniting any of the propellant.
OK, so that saved me losing a beautiful rocket on its first flight.
On other occasions, I've used multiple Q2G2 igniters successfully, but only after fiddling around with them, then placing the rocket gingerly on the pad, hoping nothing would disturb the igniters before I pressed the launch button. Then I'd have to rush to launch the rocket before any of them fell out.
Rushing is not a good idea with rockets.
I've got a big launch coming up in a large field, and I'd love to see the Quadrunner finally take flight, and have a reliable ignition system securely in place.
If you've had trouble keeping your Q2G2 igniters staying in place, here's a way to prevent them falling out.
The problem isn't the straw. It fits into the nozzle of the rocket motor just fine. The problem is that the igniter itself can pass too easily through the straw, slipping out before you press the launch button.
Here's what you do:
Cut a very small bit of masking tape.
Wrap the masking tape around the twisted part of the Q2G2 igniter. You don't want to cover the pyrogen head, obviously, and you want to leave the free ends of the igniter free to bend them in whatever direction you need to to hook the leads up to the launch controller.
You want just enough masking tape around the twisted part of the igniter so that it can still pass all the way through the straw and come into contact with the propellant, but that it will have enough of a friction fit that it won't fall out.
Now the igniter is securely installed. Don't worry - it isn't "stuck." When the motor ignites, it will eject the straw and the igniter. But it will ensure you get reliable ignition on as many motors you have in your cluster rocket!
Note: These pictures are for illustration only. You should not install the igniters in your rocket motors until you are on the flying field, preparing for launch!
I didn't anticipate writing a post on this kit but now am even more fascinated with it. I hope to fly it this coming weekend and will fill in a flight report shortly thereafter.
This is a four stage rocket! Others may contest this fact but it has one booster and three parallel- staged sustainers. 3 + 1 = 4. That's my story and I'm sticking to it. The components are interesting for Estes. It has a plastic manifold to direct the blow-through from the booster to the three sustainers and the body sections are made from white foam. The foam dings easily but makes for a quick build and a light rocket. For several reasons including laziness, I didn't spend a lot of time finishing the rocket.
The booster section consists of a motor tube, a metal retainer clip, a short foam body, a two part plastic manifold, a dowel, and three, two piece, die-cut fins. These fins, and one fin on each sustainer, have to be glued together. This wasn't a problem per se but I would have rather had them as a single piece. I assume this was done to save a skosh of balsa stock.
The foam body was done nicely and made the rest of the assembly easy. It holds the retainer snugly and aligns the fins perfectly.
The two part manifold requires some plastic cement and attached easily to the motor tube. It also holds the dowel that forms the launch rod for the sustainers.
Oh yeah, there is also a balsa standoff and a launch lug. The standoff also fits nicely in slot in the foam body.
Each sustainer consists of a foam body, a long section of BT-5, a motor block, a launch lug, three balsa fins (one of which is two-part so that's 4 pieces of balsa each), a two-piece plastic nose cone and a standard Estes rubber band shock cord.
Again, I like the foam bodies. I won't sweat the dings and it does a great job aligning all the parts.
The motor block goes in with a spacer and the shock cord via a tri-fold mount. I generally don't use these but did so in this case. I especially don't like them in BT-5's since I can't get them far enough in not to interfere with the recovery components. These sustainers use tumble recovery so there is little chance of snagging.
The lugs are cut from a longer section and are staggered between the three sustainers so they will all fit over the dowel on the booster. The engines protrude a quarter inch or so and slide into the plastic manifold. I think the whole thing is pretty slick. The only issue I see is that the body sections do not fit very snugly at the nose end. Others have been concerned about this and some have held them together with a small amount of tape.
Because of the foam parts, you need to be careful with the type of paint that you use. I chose Krylon H2O for the booster and Testor's spray enamel for the sustainers. I left the manifold and nose cones in their native black plastic. The kit comes with a slew of waterslide decals. I may put them on someday. This is actually one kit that I would have liked to have had peel and stick decals.
As mentioned earlier, the booster used a standard clip. On the sustainers, the motors are retained with a wrap of tape around them and the lower body. I haven't done this yet and am not sure what this wrap will do to the fit between the motors and the manifold Time will tell. You then add some wadding, stuff in the shock cord, put the cones on, and slide them all together.
I continued to ponder why the Perfectflite PNUT flown in Probe-18 on Saturday had ground level at -65 feet. I am not an electronics type of guy, so I did what any nerd seeking enlightenment would do - I contacted tech support:
Sir, I experienced my first ever anomaly with a Perfectflite altimeter at this past Saturday’s launch. In brief, it seemed to think ground level was at -65 feet, and underreported the altitude by that amount (as compared to another altimeter in the same payload section). I have a post describing this on my blog:
and have attached the data file to this email. Any insight/help you can give would be greatly appreciated. Kind regards, Bill Cooke
Perfectflite responded in a day with this very informative post, which gives a lot of insight into the workings of the PNUT:
Hi Bill The Pnut does not start recording at T = 0 & Alt = 0. After you turn it on and wait for the init procedure, it constantly samples pressure and fills several circular buffers. One buffer records the last 32 altitude readings (MSL, or above sea level, not ground level) to provide pre-launch data. The other buffer stores averages of the contents of the first buffer to track the ground elevation which can change due to weather variations if the rocket sits on the pad for an extended time. The averaging also minimizes the impact of sensor drift and wind gusts.
The altimeter detects launch when the current altitude reading is 100 feet higher than the averaged ground elevation (this launch detect threshold is changeable from the download software, 100' is the default). The program then copies the last 29 readings into the flight memory and continues sampling and recording data from that point. So the bottom line is that you get about 1.4 seconds of data preceding the 100 foot altitude point, which will not necessarily mean that T=0 on the graph will be at altitude = 0. If the rocket takes off quickly, you will have a number of altitude = 0 readings stored before the curve starts upward. Similarly, if the rocket has a slow ascent, the T=0 altitude will be greater than 0. With a 100 foot launch detect, as long as the rocket's average speed is above about 70 FPS you will be assured of getting data extending back to the liftoff point.
The above is just an explanation of the fact that T = 0 and altitude = 0 do not coincide (so we can record and display some pre-liftoff data), it has nothing to do with explaining your anomaly.
The second buffer averages the MSL readings from several seconds prior to the current point in time back to about 26 seconds prior to the current time. The produces the stabilized ground elevation that the altimeter later uses to convert MSL readings to AGL (above ground level) readings. Because the average is based on a "moving window" that is updated continuously, effects of sensor drift and weather variations are essentially eliminated. Because it is an averaged value based on a large number of samples, noise due to wind gusts or other anomalies is also reduced. If you just sampled the ground elevation once when the altimeter was turned on and the rocket sat on the pad for 30 minutes before launch (not uncommon...) then the sensor drift and weather issues could be quite large. If you just take a single sample every so often to update the ground elevation (without averaging), then a wind gust at that particular point can shift the ground elevation significantly, potentially leading to false launch detect and large errors in the ground elevation.
As soon as the altimeter detects launch (altitude greater than 100 feet and T=1.4 seconds) the ground elevation averaged from the period 3 seconds earlier to 26 seconds earlier is "locked in" and is never subject to change. The large ejection spike occurs well after that point, so it has nothing to do with the issue.
So something during the period of 3 seconds to 26 seconds prior to launch detect had an enormous impact on the ground elevation. If it was a brief event, the magnitude would have to be huge to shift the average of nearly 450 samples by 65 feet.
Is it possible that sunlight entered the payload bay's vent holes (i.e. are any lined up in such a way that this could be possible)? If your Pnut is one with the newer stainless steel covered pressure sensor (U3 on the bottom of the unit) then one of the sensor's holes should be covered with a small black piece of tape. If the tape has been dislodged, then the sensor will have a large degree of light sensitivity and a hit by direct sunlight could easily cause the issue you describe. If you have the older sensor with a white plastic cover, light sensitivity is not a problem.
Can you email a sharp closeup of the bottom of the altimeter?
Also, the difference in magnitude of the ejection spike is easily explained by the fact that the spike is very brief (less than 1 sample in duration) and the Pnut samples at 20 samples per second vs. the MicroPeak 10 sample per second. Unless the two devices were in perfect synchronization, they would be sampling different pressures due to the rapid change in pressure during the spike.
The paragraph highlighted in bold is what surprised me - a light-sensitive pressure sensor? I hauled out the PNUT and took a close look:
Bottom of PNUT altimeter (Click to enlarge).
Sure enough, there was no tape covering one of the holes (I have no idea which one is supposed to be covered). So that seems to be it - light entering the payload section and hitting the sensor caused ground level to be reset. Who would have thunk?
Perfectflite, being a class act, offer to repair and clean the altimeter if I return it to them, which I will do next week. Hard to turn down an offer like that. They also gave me a couple more tips, which I am posting below for those who may find them of use. Technical support (except for Apple Genius Bar) is good - a couple of emails yielded a plausible answer to my mystery.
Additional Perfectflite suggestions:
1) A large downward ejection spike is usually caused by ejection charge gas entering the payload bay because of insufficient sealing. Since the gas is corrosive, this can cause degradation of the electronics. Are there any holes or other possible leaks in the balsa coupler depicted in your drawing? Or is the balsa that porous?
Bill's note - nope, there are no holes or leaks in the coupler, which is a nice 1.5" length cylinder of good quality balsa. Has a nick in the bottom after this flight, but still AOK)
2) Your static ports don't need to be anywhere near as large as described on your drawing (four 1/8" holes). Four pinholes made with a standard pin would be more than enough, and using a pin is fast & clean. The smaller holes would also minimize sunlight effects and provide filtering of wind and turbulence for a smoother graph.
On YouTube, Grant Thompson show how to make a good PVC launcher. To see the video, CLICK HERE There are plenty of launcher "how-to's" out there, but this is a good visual step-by-step. What really sets it off is how it is painted. Most PVC home made launchers are left in the bare white pipe. Everything in the video looks good except for one of the launch angles. Grant is known as "The King Of Random" and has some other interesting DIY model rocket posts.
I have built a few of these before, but not for the blog. A few years ago, Bill Stine contacted me to make one for NARAM demos. That model is on the Quest website. Tim at Apogee needed one built for his catalog. That model is shown on the Apogee website. I have two unopened Magnum kits - here we go.
Here's all the parts. For a medium sized, two engine cluster model it's a great value. The current Quest retail price is $17.84 Two engine cluster rockets are great performers. No clip whips are needed. Enclosed are water slide decals and two 14" Quest parachutes. The payload capsule is very well made. This kit has an extended payload section. You could launch two eggs if you wanted.
The parts of interest, left to right: The thick walled payload tube Egg or Payload Capsule (Same as in the Quest Courier) Blue adapter ring Black nose cone coupler Thin yellow engine tubes Spring steel engine hooks Inset: Letramax laser cut "Half Moon" cluster centering rings
Two sheets of die-cut balsa are included.
These fin sheets may have come from an older kit, I don't know which one. All the fins I marked with the "X" are discarded. But save the duplicate fourth fins, the larger lower and smaller upper.
On the last cruise I worked on a new carded downscale. This time it's the Estes Yellow Jacket, Kit #2008, available from 1989 - 1998. Originally a BT-50 based model, it had a great fin design and decals.
The downscale will be made around a BT-5 tube and uses 13mm engines. No painting except for the nose cone.
You'll need the Quark style long nose cone from the BT-5 plastic nose cone package, BT-5 tubing just over 7" long, 1/8" launch lug, some cereal box cardboard, engine block, Kevlar, elastic shock cord and a streamer.
The fin and body tube skins are available on a free PDF. Email me at email@example.com and request the Yellow Jacket PDF. Print, glue and fly!
Here's the fins being cut out in my ship cabin. No white glue, a small straightedge and a glue stick.
The break-off blade knife was packed in my boots, not in my carry on luggage.
My cutting board is the back cover of the HAL Compass book. The book is basically a sales tool for future cruises. They are replaced every year. I wonder if the next cabin guest wonders about all the cut marks in the back cover.
I've mentioned this in a post before. My supply of older (black pyrogen coated) Estes igniters is running low! Time to revisit lacquer coating the new Estes Starters. While it's not an actual pyrogen, when coated this way the igniter will flame instead of just heating red hot.
I bought some cheap black fingernail polish at the Dollar Tree store. Be sure the ingredients include Nitocellulose. That's the lacquer that will burn when heated.
I used the brush attached to the cap to paint the igniter tips. Now they at least look like the old Estes igniters.
Here's an Estes clear tip Starter igniter after the launch button was pressed. I'm using my old Estes 6 volt with four AA batteries.
It's hard to capture with my digital camera, but this clear tip isn't flaring up. The bridge wire is heating and red hot, the clear coat just melts. The inset picture shows the igniter afterwards.
Here's the black lacquer coated tip after heating. After this picture was taken the tip lit and flamed like a struck match! It took about 1/2 second for the flame to start. The inset shows the black lacquer after it flamed up.
The new clear tip Estes Starters will ignite an engine when used correctly. They remind me of using bare nichome, it takes an extra second to ignite, where the older igniters were quick. You'll have the best results using a 12 volt system.
A post from TRF: From Jerry - "I love using my well used/broken in 18" JonRocket parachute. There are no more memory fold lines. It's very soft and fluffy. Even the shroud lines are super soft from all the talc and not hard and whiskery. I have had dozens of flights with this chute and it just gets better like a well worn hat or shoes."
Hi Jerry, That's good to hear! I designed those parachutes for JonRocket and BMS. They are also used in RSR amd Odd'l Rockets kits. My goal was to produce the best LPR parachute out there. The chute material is 1.5 mil thick, a bit thicker than most kit parachutes.
Three choices on diameter (12", 15" or 18") and three choices of spill hole size. They are red and white for high visibility and look a lot like the Apollo and NASA Orion mission chutes. This makes them perfect for both sport and scale models.
Regarding shroud lines, The best shroud lines have a high percentage of cotton. They will last longer and not easily melt like thread made with Rayon or Polyester.
When I was a kid, I found this strange book in a library - I forget the title. It was written in the 1960's, and was a kind of activity book with various crafts you could do to pretend you were living in the stone age. One of these crafts was to make a spear from a broom handle. You used colored tape to decorate it, and there you go, kid. You're a caveman!
Problem is, I could never through the darned thing straight. I thought paleolithic man must have had some secret spear-throwing technique this book didn't cover. It wasn't until I started building rockets that I thought back to that book and realized what the problem was.
. . .
There are three types of stability you may encounter in rocketry: positive stability, neutral stability, and negative stability.
In the first post, I mentioned the concepts of center of gravity (CG) and center of pressure (CP). These are both central points, of sorts, on a rocket. The CG is the balance point of the rocket (or of any object). It is an imaginary point at the center of all mass on the rocket. The rocket (or any object flying or falling through space) will rotate around this point, always, 100% of the time. The CP is the center of all aerodynamic pressure on a rocket, and is where it is due to the surface area of the rocket.
Although gravity acts on all points of a rocket equally (the motor hook is pulled toward the Earth with as much force as the nose cone), we say that gravity acts through the center of gravity. If you balance an object on your finger, at its center of gravity, it won't fall. Although gravity is pulling on the ends of the object just as much as it's pulling on the center of gravity or mass, you can hold it up just by balancing it at that point.
Similarly, although the air acts on all points of a rocket, we say that it acts through the center of pressure.
I also briefly mentioned the proper relationship between the CG and CP - that the center of gravity must be ahead of the center of pressure. If the rocket is built this way, it will fly straight up, in the direction intended. It may oscillate - wobble back and forth - a bit as it does so, the fins correcting its trajectory as it flies upward. As the fins dampen the oscillation and the rocket accelerates, it will oscillate less and less. A rocket built this way is what is known as positively stable, or, simply, stable.
In this slo-mo supercut, you can best see the slight oscillation in the Der Red Max launches. It's not very prominent, but you can see it in the smoke trail.
If a rocket is built with its center of pressure ahead of its center of gravity, it will not fly straight.It will fly erratically, flipping and flopping around the sky, and probably crashing to the ground in the process. This can be dangerous, with a larger, heavier rocket. In this case, the rocket is called negatively stable, or just unstable.
In this great video from KQED Public Television, at about 3:40, you can see what some unstable rocket flights really look like.
A neutrally stable rocket is one in which the CG and CP are at roughly the same point. A neutrally stable rocket can have a very strange flight. It won't necessarily flop around in flight, but neither will it necessarily fly straight. In fact, it will go in any direction it is pointing. That might sound like it will fly straight up as desired, but in fact, any small gust of wind, or anything which disturbs its straight flight, will change its direction. A neutrally stable rocket cannot correct its trajectory, as a stable rocket will.
An illustration of the three types of stability: positive, neutral, and negative. From Centuri Technical Information Report 30: Stability of a Model Rocket In Flight, by Jim Barrowman, 1970. We'll discuss Barrowman and his contribution to the understanding of rocket stability in the next post in this series. The oscillation depicted in the stable rocket illustration is exaggerated.
But neutral stability is interesting, because with it, we can do a little experiment to show us how we make a rocket stable. The key ingredient: fins. The fins on a rocket have two purposes.
An Experiment in Stability
Take a foot long dowel rod and balance it on your finger.The point where it balances is its center of gravity - it's the center of all its mass. The mass on one side of your finger is equal to the mass on the other side of your finger.
If you flip the dowel rod in the air, it will rotate around that balance point exactly. If you try to force it to rotate around some point closer to one end, it simply won't work.
Now try throwing the dowel like a spear straight across the room, and see if you can get the front end to stay at the front. Perhaps you can do it, but most times, it will simply point wherever. It probably won't spin fast, but it will end up turning sideways, maybe backwards. The dowel rod is neutrally stable. Can you throw it straight? Maybe, but not reliably. Because the point at which the surface area is equal is also the point at which the mass is equal on all sides, the center of gravity and center of pressure are in the same spot.
This is why I could never throw my broomstick spear straight! The center of pressure and center of gravity were essentially the same, so the spear (like a rocket) was neutrally stable!
Now take three bits of masking tape, a couple of inches long. Tape one to an end of the dowel rod, making a T shape. Then fasten the other bits of tape on the same way, so that the three pieces of tape come in contact with both the dowel rod and the sticky parts of each other. You've now made fins. They're a bit janky, but they'll do the trick.
If you re-balance the dowel rod, you may notice that the center of gravity has moved rearward just a little bit, due to the mass of the tape being added to one end. But you've also moved the center of pressure rearward, and by much more than the center of gravity. That is the first purpose of the fins - to move the center of pressure rearward.
If you now throw the dowel across the room, it will go straight, with the pointy end forward and the fins aft. The dowel is now stable!
If I'd added a bit of weight - like a clay spearhead - to the tip of my pretend spear, moving the center of gravity forward, or if I'd added some kind of fletching to the rear, moving the center of pressure aftward, or a little of both, I could have thrown the broomstick spear with no trouble.
Now, this is not because the fins are merely guiding the rocket. If that were the case, the fins could be anywhere. If you try to throw the dowel with the fins first, you cannot do it. The dowel will flip around in flight and fly fins last. If the part with the fins were your "nose cone," you'd have an unstable dowel rocket, because the CP would be ahead of the CG. This is why we do not put the fins at the front of the rocket. If we did that, we'd have a terribly unstable rocket, which would try to fly backwards.
Of course, a rocket cannot fly backwards, because it has the continual thrust of the motor coming out the back, trying to push the rocket forward. The result is that the rocket flips around all over the place, constantly trying to "correct" itself and fly with the CG ahead of the CP, but the thrust keeps pushing it in different directions.
If the fins were merely guiding the rocket, it might seem like having fins all the way up the side of the rocket would make it go straighter. Let's take a look at why that's not such a good idea.
Here's a simple design of a 4-finned rocket.
Click the pictures to enlarge.
You can see that the CG is ahead of the CP, and that the stability is positive - in this case, 1.35 caliber. We'll get more into caliber next time. For now, you can see that this is a stable rocket, and will perhaps fly over 800 feet on a C6-5 motor.
Now, what happens if we add some fins to the front end as well - in an attempt to make the rocket fly even straighter.
The rocket is now negatively stable. It's stability is -0.915 caliber. The simulation also tells us that the rocket may hit 98 feet. But it won't be pretty.
Why is this?
Let's illustrate the CG/CP relationship. Here we see a cardboard cutout of a simple rocket design - Sounder IB.
As I mentioned in Part 1, the center of gravity is indicated by the blue and white circle (really tiny in this image), and the center of pressure is the red circle with the red dot in the middle. Note that the CG is ahead of the CP.
As the rocket flies straight, assuming there's no wind coming from the side, the rocket experiences the wind coming at it straight on, flying past the body and fins at an angle of 0 degrees. This angle is known as angle of attack, and we'll talk more about it later.
For now, though, just imagine the pencil as indicating the airflow past the rocket. The thumbtack is on the center of gravity, because a free-floating object in space can only rotate around its center of gravity.
Now imagine that something disturbs the rocket in flight. It could be a gust of wind, an odd bump of plastic on the nose cone - anything. The rocket will turn slightly, so that the apparent wind is coming at it at an increased angle (of attack). The rocket is still flying upwards - how does it correct itself?
Well, as mentioned before, the air pressure acts on all parts of the rocket. But the center of pressure is the point the air pressure acts through. It is as though the air pushes right on that spot.
Because the air pressure is essentially pushing on the CP, it will cause the rocket to rotate around the CG, making it fly straight forward again. When a rocket is flying at an angle of attack above 0 degrees, the airflow over the fins creates high pressure on one side and low pressure on the other side. This creates an aerodynamic force called lift, which we'll talk about in more depth later, and straightens the rocket out. The rocket corrects its trajectory. This is the second purpose of the fins - to correct a rocket's trajectory in flight.
It may overcorrect, and flip the other direction. In that case, the air pressure once again causes the rocket to rotate around its CG, in the other direction. This is the oscillation you may notice in rocket flight.
Eventually, the fins dampen out the oscillation and it becomes less and less, until the rocket flies more or less straight up. That's a stable rocket.
But what happens if the CG is behind the CP? Using the same cutout (because it took me a lot of effort to cut it cleanly and reinforce it), let's imagine that scenario.
Maybe this is because we have a really heavy motor, or really tiny fins, or we thought it would be a good idea to put a second set of fins near the front of the rocket to provide "more guidance."
Here, I've moved the imaginary CG behind the CP.
As the rocket flies, the air pressure, acting through the CP, rotates the rocket around it's CG - this time, flipping the rocket around so that it's trying to fly backwards!
Of course, with the thrust coming out the motor, the rocket continually tries to fly forward, so the apparent wind continually changes direction, and the rocket flips and flops around in the air until it crashes.
A neutrally-stable rocket has its CG and CP at roughly the same spot. The fins cannot correct its trajectory, so it's free to fly wherever it happens to be pointing.
"Whatever... I do what I want."
Just remember: G comes before P - in the alphabet, and in your rockets.
How do you know where the CP is? And does it matter how far behind the CG you put the CP? And what if you have an unstable rocket design - what are some things you can do to fix it without throwing the whole thing out?
Well, we'll talk about that in the next couple posts in this series.
But why do we need to know this, if kits are designed to be stable in the first place?
Because I want to show you how easy it is to design your own rockets. But in order to do that, you need to understand the basics of stability. And of all the different aspects of rocketry, stability might be my favorite subject.
. . .
When I put the first part of this series on Twitter, Homer Hickam himself posted it on his Facebook page, and even commented on the blog post itself. You can imagine how thrilled I was at that!
He mentioned a couple of things which he thought might be other explanations for the lack of stability in that early flight - including non-vertical launch, poorly mixed propellant, or a poorly-machined throat nozzle. I might talk a little about those in a future post in this series - especially the non-vertical launch possibility (something he corrected in later launches, if you read the book, which I highly recommend).
Of course, this series isn't meant to be an analysis of his rockets per se - that would be nearly impossible to do for a rocket launch which took place nearly 60 years ago and was not filmed!
I mention Mr. Hickam's book (and the movie), because once you gain some understanding of the basic principles of rocketry, you can make an educated guess as to what happened when you get a weird flight. And I think that makes reading the book more fun - you can understand and appreciate some of the technical aspects of what he's talking about.
This is one of the two newer "T" engine builder's kits, The Lynx. The Lynx is brother to the other new mini engine kit, The Scorpion. I picked the Lynx over the Scorpion simply because I liked the design better.
All the parts are of high quality. One of the BT-5 Intake Tubes was a little out of round. Not a problem, you only use half the tube on the cut intake.
These are the small cooling vanes that go around the outside rear of the engine mount tube. These are tiny! I'll have to fill and prime them before gluing on the tube. Sure you don't have to do this, but filling the grain after gluing them on the engine tube would be hard.
These are the BT-5 intake tubes. Underneath them are the twin cutting templates.
While I deal with smaller, low power models, occasionally I have to transport something BIG.
I bought one of these neck rings if I ever needed to take a nap in my car. I've found a second use for it. A few years ago I had to take an Apogee Saturn V to the UPS Store to weigh in for estimated shipping charges. My home scale was too small.
The ring was placed around the body to lessen the chance of it rolling and protect the white body from the seat belts in the backseat of my car. It fit the 5 1/2" diameter body very well. This ring has also been used for 4" diameter models. Two rings (one at the front and one at the rear) would probably work best.
TIP: Before you buy a neck ring for rockets (or sleep), get one with stiff filler material. Some of them are so flimsy they offer no support at all.
Yes, I'm calling it a Centuri ST-20 tube. I like the single long tube instead of two pieces with a coupler. The Centuri kit had an ejection baffle at the two piece tube joint.
This model is based on and uses the capsule and tower molds from the old Centuri kit. The capsule has great detail. The fins are laminated balsa like the Centuri version.
The engine mount is for 18mm engines with the only recommended engine a C6-3. I've seen one fly with a C6-3. With only a 200' altitude it seems under powered. I'll probably make it a 24mm mount and fly it with C11s and D12s. I can still go "low and slow" with a 20/50 adapter.
Pieces of interest: There is only a single 15" parachute. I'll use that for the body and the capsule will descend separately on an added 12" chute. A 1 1/2" long 1/8" diameter launch lug is included. This is cut into two 1/2" lengths. You'd think a model this big and heavy would use 3/16" lugs. Brought up earlier, the red on the decal sheet looks pink. There is the MR7 and too bold a font used on the UNITED STATES. Time for a redraw and home print decals.
I'll start with the fins first. Some have asked how to sand the tapers. There'll be a few posts covering it all.
Did you ever have trouble getting shroud lines through the tight loop on a snap swivel?
Lonnie Buchanon showed me a tool he made at the last R.O.C.K. launch. TIP: The end of a stiff wire is bent in a tight, long "U" shape. Hook the "U" around the shroud line loop, feed and pull it through the swivel end. Simple and effective.
Here's a great YouTube video from Bernardotech.org on Stability and Swing Testing CLICK HERE
"A tutorial on how to design a model rocket in such a way that it will be stable and fly correctly. If you want to learn about model rocket stability, this is a good place to start." The video illustrates how a weather vane will turn into the wind. Using the same principles, a stable model rocket should fly straight. I first tried swing testing in 1969 after reading about it in the old Estes catalog "Yellow Pages" Technical Section. I wish had this video back then. My rocket slipped off the string right into a wood fence.
Mojo 1986 was selling some older Estes Model Rocket News (MRNs) on Ebay. For me, one of the most valuable pages was "The Idea Box". I did some screen grabs and will feature some older ideas that still have some value today.
"This safety cap by Hervert H. Maston of Lavonia, Georgia works well as a wind direction indicator in addition to its primary function. The tube may be a plastic straw or an LL-2D launching lug. The flag may be of red plastic tape or of painted PRM-1."
How many eyes were poked by people leaning over the launch rods? Launchers are typically low to the ground and I'm sure it has happened enough to justify including rod caps with launchers. This one is a great idea as the safety cap also works as a wind direction indicator.
I put together a PDF of a Launch Rock Safety Cap. It's a great, simple addition for your next launch day. Print, cut and glue around a launch lug.
This PDF only took up half the sheet so I added some more safety flags to choose from.
If you'd like a copy of the PDF, email me at: firstname.lastname@example.org and request the Launch Rod Safety Flag PDF
This one turned out to be one of the weirdest builds yet! The way the model was engineered was interesting but required some extra primer and sealing steps. If you were to just punch out the pieces, glue it together and paint it, you would end up with a model with many rough edges.
I picked up two of these on Ebay for a very reasonable price. In the mid to late 1970s, many Centuri kits had die-cut card stock fins instead of balsa. These two had LOTS of layered card stock.
Centuri called the Marauder fins "baffled, multi-layer" wings. Making a model like this out of balsa would have been difficult. Thick card stock construction solved many problems.
Here's all the parts.
There are four sheets of die-cut card stock in three different thicknesses.
The parts of interest: The LONG blow molded nose cone. By 1979, Centuri was steering away from the two part molded nose cones. The shock cord mount is just a small piece of card stock, maybe too small. The clay nose weight is hard but still usable. One of the two ST-7 missile launcher tubes was a dark purple color. Held up to a light it was almost translucent. I've never seen a body tube like this before.
I recently dug up and scanned a bunch of old photos for my friend's birthday and came across a few of possible interest to the rocketry community: That's me at roughly 12 or 13 years old proudly sporting tethered, fold-up Vuarnet sunglasses; one of two pairs my grandmother had generously purchased for me on her vacation in France. Note also the custom-built Aerotech fanboy shirt with velvet, iron-on lettering. On the back I had made an attempt to run a popular slogan of the time: "Aerotech Gets High On NH4CLO4" and yes that's a capital L. Gary Rosenfield expressed confusion when he first saw my shirt and, in short order, having mentally inventoried the periodic table of the elements, was unable to recall this "L"ement. He was kind about it but, as a chemical engineer now, just know that I'm cringing and yes it should have read NH4ClO4. Duh. I think that rocket was about 2.5" in diameter and ~5' tall and I called it Gaudior having recently read Madeleine L'Engle's A Swiftly Tilting Planet. I was having trouble with the motor mount diameters just now until The Google turned up this Canadian Crown Rocket Technologies (CRT) catalog [and check out the cornucopia of other retro gems on his site!]. The central motor was a 29mm F67 and the three outboard pods with individual nosecones held CRT 24mm E45 motors (with ejection charges removed). At the time the ignition method du jour for clusters involved sleeved Thermalite Fuse rigs with flashbulb initiators hence the disconcerting business end. Despite a slightly angled liftoff I was convinced the flight had gone as planned. Upon recovery, however, I sadly observed that two of the E45s had CATO'd just after liftoff so I was a semi-sad kid that day and I don't think I rebuilt Gaudior. Damned bleeding edge rocket science! :) Oh and I used to paint all my rockets so I've only become lazy on finishing in the last decade or so. Next up is Jim Jaworski prepping with a group of early high-power flyers in deep conversation I'm at far left, Gary Rosenfield can be seen just behind me, Jim Jaworski is on the ground setting up his igniter, Jerry Irvine has his back to the camera, and I don't remember the other four fellas on the right. Despite Jerry's infamy in recent decades I always found him to be an extremely intelligent and thoughtful rocketry mentor and a good friend. Now onto the flight... Jim Jaworski was in/famous for his beautifully built and finished rockets that pushed the total impulse boundaries beyond most of the group but, unfortunately, they often failed in some new way. I'm quite certain this was a J- or K-class ~2" motor with low initial thrust typical of case-bonded, progressive burn geometries of the day. Upon ignition the motor mega-chuffed the rocket off the rod then it laid horizontally on the ground awaiting additional chuffs and eventual ignition. Upon final pressure-up it then shot out horizontally across the desert in spectacularly undesirable fashion. Nobody was hurt and Jim recovered the rubble. We've come a long way with BATES grains and peak thrusts in the beginning with nice regressive traces that don't shred rockets. Someone must suffer these learning setbacks to advance our collective knowledge so... thanks, Jim! I should note that Aerotech was already employing an early BATES grain precursor where they cast propellant into a cardboard tube. Once core-drilled this "cartridge" of propellant was dropped into the phenolic liner with glass-phenolic nozzle and the forward end sealed up with delay and ejection charge. As such AT motors were bleeding edge and featured end- as well as core-burning geometry. This gave them a nice initial kick off the pad but the high aspect ratio of the cartridge produced a humped thrust trace that wasn't quite the ideal regressive burn yet. Anyway kudos to Gary!
Here’s a PDF cutting diagram. To the remarks on the diagram I’d add pretty much none of the dimensions are really critical. This is the sort of thing some people might be able to build out of scraps found in the garage, but I didn’t have what I needed so I spent somewhere under $20 ...
Textbook Rocket Launch - Space Center Houston Tomorrow
UpcyclingTextbooks.org threw out a design challenge for builders here to create launchable rockets made from old textbooks... in a week or less so that we could launch them at Space Center Houston's Earth Day Kick-Off on Saturday, April 18th... tomorrow.
Four builders here on TRF-- hcmbanjo, JumpJet, Babar, and Artapplewhite--accepted the challenge and delivered an incredible 13 textbook rockets of unique designs. Some of their builds can be seen on here in the Scratch Build forum. For those of you Houston locals, we'd love to see you for for the event and the launch 3:00pm and possibly a launch at 1:00pm also. Below is a bit of information abut what we're doing tomorrow and also a bit about Upcycling Textbooks.
A huge thanks to all our builders for their creative efforts and lightening speed turnaround to help us inspire change!
Rockets…Rockets…and more Rockets! Upcycling Textbooks @ Space Center Houston Earth Day Kick-Off Come see some though-provoking pieces crafted from… old college textbooks, including several textbook rocket ships, and a satellite! Then pick a favorite textbook piece, hop into our photo booth with your best pose and have your picture taken in front of some of NASA’s finest space images.
Check out a dozen experimental model rockets—built with discarded textbooks—including pinwheel rockets, a stealth rocket and a 1/100th scale Saturn 1B. And join us for a special launch as these one-of a kind “textbook rockets” spin and soar through the skies—some are predicted to blast several hundreds feet high.
Here's my submission -
It's called the "Speed Reader". I know - a little plain compared to John Boren's textbook Saturn 1B! The simpler design was a compromise. I only had a few days to put it together. The first package I received from Upcycling Textbooks contained a scarf and a letter thanking Grandma for taking care of the grand kids. I got my textbooks four days after that!
From Upcycling Textbooks: Upcycling Textbooks is a movement determined to advance education beyond textbooks, with more affordable, more environmentally friendly and more personalized learning tools.
If we can put a man on the moon, we can do better than textbooks. And we want something better. So, let’s use our creativity to spark innovation and fuel change. Let’s transform those old textbooks into something better and inspire people to see textbooks, learning tools and education in a new way.
What could you make from an old textbook to inspire change? A work of fine art? A top secret safe? A planter? A musical instrument? An iPad case? A solar oven? A rocket that actually blasts off? Textbooks probably never really wanted to be textbooks. So, let’s set them free and help create change. Share your piece on UpcyclingTextbooks.org. Tweet pics @UpcyclingTexbooks. Tag pictures #UpcyclingTextbooks or #UpcyclingTxtbks.
Check out other thought-provoking upcycled textbooks in the Gallery and Blog on UpcyclingTextbooks.org. Join our challenges and join a community of people who want change.
A TARC mentor from Southern California suggested a bill to modernize the state’s model rocketry regulations and bring them into compliance with national standards. Proposed by Assemblywoman Chang, the bill was supported in testimony by Ken Biba (a California TARC mentor) and Benjamin Kolland (a current TARC team captain). Their testimony helped the bill pass ...
The near-impossibility of soldering Nichrome wire poses some problems for making electrical igniters without special fluxes. Here is a step-by-step method for making electrical igniters without the use of solder. The reliability of these igniters is very high. This is not a high-speed method for making igniters, but rather a procedure to follow for making [ ...
A world record setting full scale V2 model launched at Thunda Downunder in Australia. It was a spectacular Low and Slow launch. Height – 14.04 metres. That’s over 46 feet high! Mass at lift off – 280kg or 617 lbs. Powered By CTI O motor Video of Launch on Facebook You can read more about this [ ...
This model was from Peter Alway's Home Page. I can't seem to find it now! If anybody has a link, let me know. The website had plenty of sport and scale plans including a Vostok, Saturn I and a Flying Rabbit that looks better than the old Estes Cloud Hopper.
You can get Peter Alway's books: Rockets of the WorldHERE and Scale BashHERE Both highly recommended!
There's one model that has been on my "to-do" list for a while. The SATURN IV! This is Peter's "psuedo-scale" design of a Saturn that could have existed between the Saturn 1 and Saturn V, the Saturn IV.
Full resolution plans aren't available now, I'll build from the website pages.
Could this have been the missing Saturn IV? Dick Stafford posted this on his great Original Rocket Dungeon Website. HERE
From a February 24 post, TRF member luke skywalker has posted a summary of NASA's "Big G Final Report-Logistic Spacecraft System Evolving from Gemini." This includes drawing of more cool looking rocket configurations that never were and the layout of the capsule options". Here are da' rockets." I have most of the tubes already, the largest diameter is short lengths of BT-60. The nose cone is a PNC-55AC, or the same nose cone from the Bullpup and old Arcas kit. I pulled one from the PNC-55 assortment. I don't have the 55-60 adapter rings, an order is off to BMS.
On TRF, TBSSJoe posted pictures of his new rail launcher, the base is a cheap speaker stand.
. . . "The stand is a speaker stand I purchased from Amazon for $16 shipped. Ironically the brand is 'Blast King'. CLICK HERE to see it in the aluminum finish.
Rail is a 5' maker beam 10mm. Plan on using it with the micro buttons procured from our friendly forum rail button purveyor.
The rail is bolted to a small piece of pipe that originally provided adjustable height for the stand. I am going to cut that pipe up into 6" or so pieces so I can swap out micro rails, 1010 rail, launch rods, etc.
I purchased a 98 cent drawer knob from Home Depot and ground down the provided bolt to slide into the rail. This will support my blast deflector. I'm hoping the cardboard will hold up to some G motors in my Leviathan.
Actually, that's just the template. I'm going to cut the actual deflector out of 16ga steel."
$16 for the stand $10 for the rail and $5 for hardware. My response: "Wow, that's cheap for a speaker stand! I have two stands I bought (for speakers) in the mid 1980s. Both are still going strong! The legs do open out for a wider stance and better stability. You could probably telescope a piece of aluminum pipe in one of the legs to angle the launcher. Lock it with a set screw." I don't see how to turn the rail on its side to slide the rocket down the rail. But, if the stand is aluminum it is light enough the entire stand could be picked up and held horizontal.
The Students for the Exploration and Development of Space at the University of Central Florida (SEDS-UCF) have created a Kickstarter campaign to raise funds to support their participation in NASA’s University Student Launch Initiative (USLI) competition. JonRocket.com is happy to support SEDS-UCF. We ...
If you follow the blog, you might recognize this rocket. It's my two engine cluster model called the Big Girtha. It was adapted from a Quest Big Betty kit.
I took this picture before it was launched at the Tampa TTRA monthly. Then I saw it in a EBAY listing. Maybe I should be flattered, but I'm not.
A vendor was selling his 808 "Spy" cameras using my picture. Farther down the Ebay listing is a link to my YouTube video from the flight.
I didn't buy and build the rocket, buy the camera, fly it, edit the video and post it for somebody else to make a profit. Build your own model, fly your camera and post your pictures.
Just because you can "Right Click", "Copy and Paste" doesn't mean you own or have the right to profit from somebody else's work. Don't assume "Oh, he's one of us, he won't care!" This is a business and part of my income. I wrote the vendor twice and he did pull the pictures and video link.
Early in my blogging days and near the peak of my fascination with monocopters, I found some photos of the Rotary Space Ship that was manufactured by the Brown Manufacturing Company in the '50s/60s. I was recently contacted by one Richard Moore, who has owned one since around then. He says he may be putting it up on eBay so, if anyone is interested, you should keep an eye out. If you want to make an offer before that, I can forward your contact info to him.
He was also kind enough to provide some nice photos:
From John Boren (JumpJet on TRF): "Sorry I haven't posted in this thread yet but I couldn't find it and since I seldom go to the Watering Hole section it was by chance I found this thread since it was linked in another thread.
As you can see my original question or statement if you wish to call it that instead, isn't an easy one to answer or for a company to act on. There are some common wants but for the most part everyone wants something different as their number one thing, which is common no matter what the topic is. I see more engines and parts are pretty much at the top of the list. I've flown engines here that I WISH would have made it to market, but for one reason or another they didn't. Estes isn't in the parts business so you won't see everything we use in our products sold separately. Places like BMS and Semroc supply most of this kind of stuff anyway.
By the way this is me asking the question not Estes asking me to ask the question. I am a modeler first of foremost so I pretty much would like to see just about everything everyone has mentioned but I'm also the one and only R&D guy here and what I design has to first and for most be in the best business practice for Estes and not my personal want.
Here are a few items I can comment on -
Centuri Super Kits: I knew Carl was doing them so I stayed away from them, since there's plenty of other stuff to do. More Card Stock: I use card stock in many of my designs and there's more of it to come. More Scale: There's more to come Limited production runs: This is what most of the other rocket companies do. A hundred or two hundred kits is fine for them but we have to do several thousand at a time. More Bring Backs: I'd love too, but they really don't sale any better then new stuff, so why do YES. in most cases this might be better then a simple bring back. Higher Skill Level kits: For many years Estes didn't have any skill level 4 and skill level 5 kits, now we do and there are more to come. 38mm retainer: A fellow club member tested a rapid prototype one I designed, it worked great. This won't be coming to market. RC Gliders: I wish, and I've created a few that I've posted here in the past for my personally use but were also used for testing of radio gear that could be used by Estes. Gooney Birds: I created a whole new series of these but we instead made other short BT60 models like the Estes Jet Liner Smaller kits for 29mm: It's on my personal to do list. I've got two in testing. Cluster Model kit: I would like to do at least one kit since we now have the Pro Series Launch Controller. More Electronic Stuff: Yes A3-6T : We tried, can no longer get 6 seconds of delay in the case with the black powder available Rock Sim: I don't use any type of stability software to design my models with. After the fact I do use Rock Sim to prove the margin of stability of the design for Corporate. Rubber Shock Cords: LONG LIVE RUBBER SHOCK CORDS, Down with Kevlar. Places like Apogee welcome your purchase of their Kevlar. Kevlar burns and breaks just like rubber, plus it zippers.
By the way posting positive stuff on the Estes Face Book page is the best way to maybe get more of what your looking for since more Corporate people will see these posts then just I who visit the forums. I would also ask that you leave reviews on the Estes web site on the products we sale. The New Conquest I designed has yet to have a single comment posted and it."
Most interesting for me is More Scale, Bring Backs, Info on the A3-6t engine and Rubber Shock Cords. Regarding the A3-6t: I had heard black powder takes up more room in the casing now so longer delays aren't always possible.
Some of you know that I've been dabbling in 3D printing for three-ish years. I ceaselessly admire the astonishing progress of garage-based hardware hackers using intellectual property from patents that have expired in recent years. It appears that the masses using democratized technology continue to move far faster than the corporations that developed the IP in the first place!! One new startup, 3D Printer Works, arose from a successfully funded Kickstarter campaign. I like their style and recently ordered their first product, The CreatorBot 3D, for home use: And yes of course I upgraded to the pro package with dual extruders, a heated glass build platform, acrylic enclosure to prevent drafts, and the Raspberry PI with OctoPrint to enable WiFi printing. Who wouldn't?! With a nearly unparalleled prosumer build volume of 2,592 in3 and 1 ft. x 1 ft build plate I decided that my first home project would have to be a V2 with a 24mm motor mount to take the full range of Pro24 reloads. This is the first rocket I've attempted to design in my go-to 3D package, Modo, and I'm very pleased with the initial version. I started with V2 scale profile images from the interwebs and used them as background images in Modo. I then added a cylinder and adapted the cross-sectional hoops to conform to the airframe shape. I added edge loops at the fin root locations and extruded the fins directly out from the airframe. The entire model below is previewed in Catmull-Clark Subdivision mode for maximum smoothness and that's the format I'll use to export the .stl files bound for equivalently smooth 3D printing: That black feature in the center wireframe is a hypothetical Pro24 6GXL casing as a worst case motor length. While CTI presently offers only 1, 2, 3, and 6G casings in Pro24 I do see 4, 5, and 6XL on both David Reese's Wildman West page and CTI's page so I'll assume they're forthcoming some day soon. I still need to add features like the nosecone shoulder, shock cord mounts, and rail guide(s) but the exterior form exceeds my expectations and took only about 2 hours to complete. I also used Modo's powerful and astonishingly versatile bevel tool to build both the vented motor mount and the interior walls of the airframe in a single operation set: I plan to print with ABS that flows and extrudes reliably at 230Ë�C but its glass transition temperature hovers around 105Ë�C (221Ë�F). NFPA specifies a maximum casing temperature of 200Ë�C for 160 N•s or smaller so this could be an issue. ;) As such I think that venting the motor tube inside the airframe will decrease the likelihood of structural failure due to motor casing heat. If I observe melt damage I can always add exterior vents to the airframe and maybe I'll make them whistle while I'm at it. For the first flight I'm just planning to use two diametrically opposed, wide-head wood screws and perhaps washers for motor retention. Here's a top view showing the virtual 6XL casing in it's vented motor mount: Once the model is finalized I also want to cleave it into pieces such that it can be printed in black and white using the dual extruders and according to the scale painting pattern so no painting will be required (and you know I LOVE painting!): This first design will be 3" in diameter and 24.5" long. At the limit I should be able to design and print a roughly 10" diameter V2 in four vertical segments. More on this soon as my printer should arrive in the next two weeks. Yay, 3Dp!
Addendum: The site 3DPrint.com recently published this article on Steve Jurvetson who's advocating 3D printing for hobby rocketry for many good reasons. He also gives a genial introduction to rocketry and finishes with some cool SpaceX stuff. The revolution will be webcast!!
For those of you who are old enough to remember what “catalogs” are, there’s a new one from Estes. I’ve been compiling some statistics from historical Estes catalogs. Here are some numbers from 40, 30, 20, 10, 1, and 0 years ago — numbers of kits, and percentages of the total, for each skill level: ...
Here's the big one, the The Launch Pad PERSHING MGM-31A.
It's about the same size as the old Estes Maxi-Brute Pershing at 39.75" tall.
The Estes kit was 41" tall, BT-101 at 3.938" diameter.
Lots of parts, balsa strips and nine centering rings.
Below the nose cone are the two nose cone washer weights.
There is no engine block, the model uses Aerotech engines with the rear centering ring.
The body tubes from left to right: 12" BT-60 6" BT-80 12" BT-80 21.25" BT-101 The first picture shows the 2.75" long BT-50 engine mount tube.
The Estes kit used a blow molded nose cone. This long nose cone is formed with card stock shrouds. There are three shroud pieces topped by a conical balsa nose cone. The shrouds were rolled up in the large tube.
There are plenty of card stock templates. The upper square fins are card stock over built up balsa stringers. On the lower right is the tri-fold shock cord mount.
This is a Mylar parachute, a six sided oblong shape. Dimensions are 18" wide by 30" long.
Here's another of the MPC Round 2 kits. These are not the older MPC rockets from the late 1960s but relabeled Sky model rockets from China. Sky also makes the engines imported and relabeled by Quest.
I bought this one on Ebay, a "Buy It Now" for $4.80, too good to pass up. I was a big Looney Tunes fan and thought I'd give it a shot. This'll be a quick build.
The package box is bright and seems small considering the rocket when built is over 17" tall.
Check out the "Compatible" engines - Estes or Quest A8-3, B8-3, C6-5 I've never seen a B8-3 engine.
This looks to be the same model sold through Apogee as the Sky Eagle with Porky Pig graphics. CLICK HERE
Here's the parts - Four plastic fins Pre-wrapped graphic on a convolutely (not spiral) wound tube. Convolutely wound is like the old BT-30 or how you might roll a tube from a sheet of paper around a dowel. A too short elastic shock cord A very thin paper tri-fold mount A BIG 18" parachute, too large for this sized model Fin stickers Instructions and a NAR membership flyer
Parts of interest: The engine mount tube is just 2 1/4" long, also convolutely wound. It's thin like a BT-20 but stiffer and stronger.
The fins are thin! The inset picture was taken outside to be back lit. You can see the light through the thin outside edge.
The nose cone is blow molded plastic. The surface is smooth but with a "pebbled" texture.
The model is shades of purple with a yellow fin can.
I'm sure some won't agree with this explanation. For me it explained the basics of thrust.
It's 1969, I'm in my eighth grade Science class. I thought I knew everything about model rocketry. I'd been building them for a year and probably had a few dozen flights under my belt.
I was talking to my science teacher about my new hobby. He asked: "What makes your rockets move?" I tried to explain: "The thrust gasses push against the air outside the rocket. That friction makes the rocket go up and fly."
He said: "No, no exactly." He added something like: "The model moves because the pressure inside the engine isn't even." What? I still didn't get it. (That catalog drawing with all the arrows inside the cutaway engine didn't make sense.)
He grabbed a piece of paper and pencil and drew some stick figures in a box. The box has no bottom, their feet are on the floor under the box sides. (I'll try to explain what he showed me.)
"Here's Jim and Fred in a big cardboard box. They have a bet who will break through the box first. Jim is on the left, Fred is on the right. Both are pushing hard on opposite walls of the box. First to break through their side wall wins."
"Fred (on the right) doesn't know that Jim (on the left) has installed a trick door on his side."
"With both pressing hard on their sides, Jim hits the switch and the trick door on Fred's side pops open! Which way does the box move? With the door open and the back pressure released out that door, Jim's push to the left is what moves the box!"
Flip the box vertically, imagine it's a rocket engine. "Think of the open door as the rocket nozzle. Fred's pushing effort is the escaping gas out the nozzle." It's the upward push that gives the rocket it's movement.
This was one of those "AH HA!" moments. My science teacher explained it in a way I could visualize and understand.
ROCK held its last launch of 2014 on December 6. The light winds and moderate temperature made for a great day to fly. The countdown reached zero and a rocket soared skyward more than eighty times during the day. I’ve ...
Bill Stine referred my name to Custom Rockets about building a Custom PONG kit for the Seattle Museum Of Flight rocketry display. I had one upstairs, finished and never flown! CLICK HERE The is the same model that was built on the blog. It was to sent to Custom Rockets for consideration.
At the last NARAM, submitted models were voted on to be included in the Model Rocketry display. CLICK HERE Along with the chosen NARAM models, each major rocket kit vendor will have a model from their product line. This PONG model will represent Custom Rockets.
An auspicious occasion, ladies and gentlemen. I have this evening opened up the last of the kits from 2013 still in the build pile: The Estes Xarconian Cruiser #3223. (And if you want one yourself, go buy it now! Estes is having another of its sales — no, this isn’t a holiday weekend, but apparently their ...
This Estes version is based on the old Centuri Scram Jet kit #KF-4. The Centuri kit didn't have the long continuous stabilizer. Centuri had two long separate horizontal pieces. The sub fins were missing on the Scram jet.
Pieces of Interest: The long launch lug, 1/16" thick laser cut fins, the decal sheet features the kit name not the stenciled U.S. NAVY, a thick yellow coupler/engine block, two card stock alignment templates.
We've all done it at one time or another - you realize the launch lug is missing on a finished model. You don't want to glue a new lug on and go through masking and refinishing.
Simply glue on a colored paper skin. Print up some colored rectangles in different shades. Pick the one that is closest to the finish paint already on your model. It's easiest to adhere with a glue stick. Roll (don't brush) on a coat of Future acrylic with a Q-tip. Keep the Future (here it's used as a printer ink sealant) away from the seam where it will be glued.
Scrape off some paint off the body tube where the lug will be glued. Make the scraped area smaller than the width and length of the lug. Glue on and fly!
Recently I wrote something that mentioned how the Estes A8 motors really are, for incomprehensible reasons, more like A3. I’ve been looking at some old Estes catalogs online (they’re here, also here) to get a little more information on the subject. The 1961 catalog lists an engine designated A.8–3. In those days the units were ...
Roger Smith took a great sequence showing the A10-3t engine cato in the Spudnik at last week's Bunnell Blast. CLICK HERE Scroll down about halfway and step through the sequence. It always looks different than you remembered. The Spudnik got about 10 feet in the air, the engine spins off to the right. The fireball remained below rising up the launch rod.
NEFAR hosted it’s annual two-day Bunnell Blast launch on November 8 and 9, 2014. Canopies, cars, and trucks covered the full length of the north edge of the launch site and extended around the eastern edge. Chris Michielsson debuted his ...
A black powder booster motor, one ending in “-0″, has no delay charge, no ejection charge, no clay cap. When the propellant burns through it sends hot combustion products forward where they can ignite the next stage’s motor. What if you used a non booster motor in a booster stage? What would happen? Bad things, ...
Again, this is the smaller version of the Estes R2D2 kit. The larger version had a BT-101 body with a printed wrap. This one has a plastic body.
Lots of parts, the only traditional tube and rings are inside in the engine mount.
You are given two elastic shock cords, the 1/8" x 36" long one is used.
A 1/8" x 18" shock cord is in the parachute bag but not needed.
Parts on interest from the upper left going clockwise - Two bulkhead disks are on thick die cut card stock. Only one is used. The engine mount and interior tubes are thick for Estes. No shiny layer on the larger 55 size tube. In the center is a washer weight. The centering rings were probably made for just this kit. These aren't anything I've seen before, especially the bulkhead ring on the lower right.
During Estes’s sale last December I did not buy a D-Region Tomahawk (#2037). I bought five. Well, see, it was at the top of my “wow, what a sale, let’s get this” list; a big, nice rocket for $5.49 vs. (too high!) list price $43.49? But it went out of stock sometime between “add to ...
On October 26, 2014, High school students Sanzio Angili and Dylan Whitesel of Chesterfield, Virginia, raised $20,000 for the Susan G. Komen Foundation and broke a world record by launching 3973 model rockets at one time.
Supporters sponsored the event by donating $10 for each rocket, many of which were labeled with the name of a person being honored or remembered.
The two students, along with family and friends, assembled the rockets in the months before the launch.
The rockets were launched at the Chesterfield County Fairgrounds.
I launched the SPUDNIK twice yesterday morning, both times with a A10-3t engine. Both flights were stable to about 100 feet but there was corkscrewing.
The Odd'l Rockets Sputnik (with the 3" foam ball) flys vertical without any "coning" or corkscrewing.
The problem is trying to drill out a straight 1/2" hole for the engine mount tube. If the line of thrust is off by a degree or two the rocket won't fly perfectly vertical. Add the uneven surfaces along the top and it probably won't fly without some spiraling. Drag and weight are other considerations. On both flights the model was nose down and ejected the engine at half the altitude. I know - MORE POWER! A larger engine (B6-2 or C6-3) would get it higher in the air but still doesn't solve the mount hole reaming and deflection from the uneven top surfaces.
The inset picture shows the micro clips connected to the igniter. If you have a Sputnik rocket, be sure the clips have no chance of getting caught up on the legs!
The Spudnik won't become a kit. There just isn't a way to ream out a straight hole for the engine mount tube. This isn't a loss by any means. I'm only out a few dollars for the potato and two engines. You'd be surprised how many models are built, flown and not released. I might fly it at a club launch but wouldn't want to release it for sale with the stability concerns.
This build will be a little different. At the bottom of each post I'll be keeping track of how long I take on each step. These are my personal build times, I tend to take longer on rocket building than most people. I don't keep track like this very often, it's a bigger effort to keep recorded build times.
There will be upgrades. A BT-60 model at over 21" tall should probably be D engine capable. You can always drop in a 18mm adapter for smaller fields. A payload section will be made using the upper yellow tube section.
All the parts: Yellow upper tube Nose cone Parachute with the 'spiderweb' pattern 18" rubber Shock cord Two Decal sheets Laser Cut Fins (some extra wood on the sides - hmmm . . .) Two white body tubes around 6 3/4" long Red Couplers Launch Lug 18mm Engine Mount Parts (will be 24mm)
Parts of interest: The yellow tube is a faded yellow and translucent color. The nose cone is very good, almost seam free. These are the tight red couplers that can grab using the new formula Elmer's white glue Two identical stick on "decal" sheets
Build time: Open kit and pics = 10 minutes Total build time so far = 10 minutes
I’ve uploaded a video of NEFAR’s October launch to YouTube. I flew a DJI PLantom 2 Vision quadcopter to capture the event from an aerial perspective. The video below shows low- and high-power rocket launches as seen from above as ...
This will be a quick freebie. This is a high performance, MicroMaxx rocket made from a Bic pen. Art Applewhite has designed some great saucers, spools and monocopters First stop by:
http://www.artapplewhite.com/ Check out all the spools, saucers and monocopters Look to the upper left, click on "Free Stuff" Read the Limitation of Liability, Click on "I Agree" Go to the Free Stuff page - Click on "MicroMaxx Rockets" Click on the "Bic StiC"
Print out the instructions (with fin can) on 110 lb. card stock.
You'll need a Bic StiC pen and hobby tools. Add a 1/4" dowel if you want make an coupler, Kevlar and a streamer for recovery.
After talking it up for over a year I finally flew my scratch-built Der Red Mix mark II on a full complement of seven burly Skidmark motors (as always switching to 720p in full-screen mode is the shit):
A formidable liftoff featuring loud, flaming titanium granules: And notably angled ascent: I arrived at the lake bed later than I'd have preferred but the conditions were perfect all day with light, intermittent wind and perfectly clear skies. I had prepped all the electronics two months ago so I only needed to load up the seven Skidmark motors, set up the CD3 ejection system, mount the Flip Mino camera inside, and button everything up. Upon checking in with the RSO he seemed confident in my design and flight plan but cautioned that the far pads were angled away from the spectators. He specifically asked me not to adjust the rail to a more vertical orientation (and that's some foreshadowing). Kurt Gugisberg was out at the pads and helped me to get the 30.5 pound rocket loaded up on the rail. I powered up the two Ravens, installed the air-start igniters, started the Flip camera, closed the electronics bay door, installed the central motor ignitor, and was ready to go. The ignition of the central CTI 2010K675 was instantaneous as expected and, at a 7.3:1 thrust-to-weight ratio, the ascent was expeditious. Now normally I would have set the launch angle at 1-2 degrees from vertical because this rocket is incredibly stable and there was no wind. Instead the angle I was asked not to change was closer to 4-5 degrees from vertical so the angle you see it the picture above is real. The one second air-start gaps I programmed into the altimeters seemed a bit long but the sequential pairs of 543I297, 258H180, and 176H123 Skidmarks otherwise popped as expected. By the time the H123 pair fired the rocket appeared to be approaching a horizontal flight path but, in reviewing the onboard video above, that was mostly an optical illusion. From the ground it also appeared that the ejection was 3-4 seconds too late but the video once again proves that wrong and the 'chute popped right at apogee. Unfortunately the initial launch angle essentially lobbed the rocket on an arc rather than straight up so that extra velocity at apogee served to zipper the top of my rocket rather severely. I can repair it but, from now on, I'm trusting myself to set the optimal launch angle. Once again DRMII stuck the landing: Here's the zipper damage from the energetic ejection (Grrr...): And here's the interesting thrust curve showing acceleration surges from the four motor phases in red on the left of the graph:
The altitudes from the Raven 2 (tabular, graph) and Raven 3 (tabular, graph) only differ by 10 feet (!) and average to 4,483 feet above ground level. So I'll repair the damage, shorten the air-start delays to 0.1-0.5 seconds, and fly DRMII again soon with a K815 Skidmark in the center. I'm not yet sure of the outboard motors but they'll likely max out the motor tube lengths. Thanks for reading!
"Here is my latest Monster Odd Roc. A giant squid that was reportedly pulled from Loch Ness in 1916 and trained to attack German U Boats, the secret weapon that finally did in the U Boat menace. Some say is was rocket powered instead of jet powered like its salt water cousins. It took a stern trainer from the Black Watch to train these beasties to attack any German sounds such as speech, polkas, fat ladies singing opera, and returning to the sweat sound of bag pipes. These top secret photos show the actual monster before the program was terminated after the War.
Three 24mm E mid mounted motors with flame fin action will hopefully keep her stable with ample nose weight thrown in as well. Two big fins on the front of a rocket just make it look cool. Six and Eight foot streamers should give a squirmy effect to Squidworth. The balsa tail cone in back gives it a nasty beak."
This is some great design work! I bet it'll fly stable with the upper canted engines and all the lower streamer drag. See the post thread HERE
Watching the 1988 film The Naked Gun: From the Files of Police Squad! via Amazon Prime the other night, I was surprised to see the following scroll by during the end credits:
Special Thanks to: Tripoli Rocketry Association
“Aha,” I thought, “That’s where the name came from.”
To back up and explain. The origins of “Tripoli” as the name of one of our major rocketry associations is clouded in myth and the fog of history.
I’d never really thought much about the name’s origin before. But, here was an explanation. As a contributor to the Internet Movie Database (IMDB) had done earlier, I assumed that the credit was a comedic reference to events in the film (“the scene in which the car with the villain in it crashes into a mobile scud launcher before crashing into a fireworks store”).
I imagined someone seated in a theater, finishing his popcorn as the “Naked
JonRocket.com introduced many visitors to rocketry the Orlando Maker Faire held at the Orlando Science Center on September 13 & 14. The Science Center event was a great way to generate interest in the Central Florida rocket clubs.
Roger Smith put together a continuous launch video that ran on a large screen monitor. Bracha gave out cards with information and website addresses for the local clubs and launch dates.
Many guests stopped by the table to talk about their rocket past activities. Here's some of the models on display.
This Maker Faire was more of a craft display than a Make-It, Take-it show. I was surprised how many 3D printers were at the show - all making the same little robots! The Science Center did have all it's regular hands on activities for the kids.
I told Roger I was concerned about kids picking up the rockets. Years ago at a trade show a young boy picked up a detailed rocket, yelled: "Blast Off!" and threw it across the room.
Roger made an intimidating sign. Nobody picked up the rockets.
Sometimes things go wrong. Sometimes things go really wrong. Really. The video below is a collection is a “blooper reel” of highlights from local Central Florida rocket club launches. Because of our safety codes, none of these events resulted in ...
Roger Smith has been busy with his video editor. CLICK HERE The revised Little Green man video shows an added C6-5 flight from last months Bunnell NEFAR launch. The Little Green Man is very "vocal" on this new video.
I thought I'd misplaced this one! Here's a letter I received from Mr. Estes dated February 19, 1970. I had hand written a letter to Estes (not directly to Mr. Estes) explaining my troubles getting a BP engine permit in California. Rocket engines and fireworks were tightly restricted back then.
Mr. Estes asks: If I had an area (a flying field) to launch cold powered Vashon rockets why couldn't that same place be used to fly BP model rockets? I couldn't buy BP engines without a permit. My mother made a few calls and got the Assistant California Fire Marshall to approve the family artichoke ranch for BP rockets. He drove 3 1/2 hours to Watsonville from Sacramento, the state capitol. The Fire Marshall gave us more than just a permission form, he gave me a permit to buy and sell engines! I never went into business selling engines.
The letter from Vern Estes shows how model rocket companies handled customer service in rocketry's golden age.
This was the oldest kit in my build pile, bought just under a year ago back when Shrox was for a brief time selling kits at shrockets.com. He switched over to selling plan paks, and you can still get one for the Sea Sting. As with the Photon Disruptor, I might have started building this ...
These came from Liberty Launch Systems/ROCKETS Magazine's LDRS-33 Saturday album. The rocket didn't seem to fly 100% straight but appeared to recover just fine. I'm hoping Neil will talk about it in the launch report. (Photos by Neil McGilvray, used with permission.)
In a recent post I asked: "Was there ever an Estes Alpha II? * Chris Gonnerman commented on the Alpha II: "According to CPMcGraw and BEC on YORF, the Alpha II was an educator-only kit; it had either a balsa or plastic nose cone, fins with the root edge marked by the die cutter, and an extended engine mount to which you attached the shock cord." * Bernard Cawley posted the Alpha II instruction PDF . . . You can see it HERE * Lonnie Buchanon commented: "The Alpha II was an identical kit to the Alpha, except that it had a plastic nose cone instead of balsa." I found the instructions interesting.
In the Alpha II instructions the elastic shock cord is tied underneath the top bend of the engine hook. I had never seen this method used before in an Estes kit. Personally I wouldn't want an elastic cord this close to an ejection charge. The rubber would decay very quickly.
This is the same method used in many Semroc kits, except the lower end of the shock cord is flame resistant Kevlar and not rubber. I wonder if the Alpha II was the inspiration behind the Semroc style Kevlar tie?
Last September I started drawing what I hoped would be a better LPR parachute. It turned out to be a bigger task than expected. Printing on poly sheeting is not the same as printing on paper. Flexible, rubber plates are used and the graphics are handled differently.
The parachute has a historic look. It resembles the recovery parachutes from the Apollo missions. The NASA parachutes had 64 gores, this parachute has only 32. When looking at a 18" parachute with 64 gores it can mess with your eyes and become an optical illusion.
The parachute can be made as a 12", 15" or 18" size. Shroud lines to make the 18" chute are included, you simply cut shorter lines for a smaller parachute. Three different spill holes are indicated, a 3", 4" and 5".
The reinforcement ring locations are set farther to the outside edge of the parachute. Some vendor parachutes have the ring locations too far away from the edges. The dashed cut lines are thinner, the cut lines shouldn't detract from the looks of the parachute.
Some LPR parachutes seem thin at 1 mil or one thousandth inch thick. I wanted something stronger and decided on a 1.5 mil poly sheet.
I proceeded to build my finless, induction stabilized rocket, the Inductor.
The phenolic liner from a Loki 75mm motor is the perfect size to accept 12oz aluminum soda cans...just a tad off from a 2.5" body tube. I didn't want to use the liner and briefly pondered building an 18mm rocket from BT-60. However, I ended up rolling a tube from poster board, 3M "77" spray adhesive, and using Loki casting tube as a mandrel. Quick and sticky. The spray adhesive seemed to work well...until I sprayed on some primer, which promptly caused the tube to start peeling. A little epoxy and a strip of tape took care of that.
I cut a 7.5" length for the induction tube. This fits the rule of having that tube over 2 calibers in length and allows two cans to fit. Two cans with the top and bottom lopped off, that is. I cut one end down on the taper so it would overlap the 2nd can slightly. These photos show the induction tube with the cans installed. The two small screws allow the cans to be replaceable, will ensure they stay in place and, hopefully, won't affect the airflow. On the other end are 4 popcicle sticks that will hold the upper and lower body pieces together across the air gap. The tie wraps were only used to dry fit the tubes.
This is a quick and dirty build so it required a quick and dirty nose cone. This one is made from a cap from some spray paint, a ball from a ball pit, a cardstock shoulder and some braided twine.
I didn't photograph the upper section. I made it 11" long and ended up using a 24mm mount because I found the required parts i.e. didn't have to make any rings. An E9-4 should be a good motor choice. I added a Kevlar leader and will use some good old Estes rubber band cord.
I should have some photos of the finished rocket later today, complete with its fugly paint job. I think I'll actually need some mass on the bottom to get the CG just above the air gap. Note to self...glue on the launch lug!
A few days ago, one Dean Black posted a unique finless design on Facebook (members can join the NAR group and look for Dean's name). He describes the design as "induction stabilized." He also has a .pdf describing the rocket (again, you'd have to join and ask for it). There are several criteria which must be met for this to have any chance of working. Thus, I will generally describe the rocket but will not provide details until I've flown one and can personally vouch for it.
His design is a two piece body with a central gap and no fins. The motor is in the top section. He claims two things about this design. First, the rocket will be stable as long as the motor is burning, even if it is a slow speed launch. In fact, he says it is stable with no launch rod. Second, if the lower body is shiny (i.e. made out of aluminum), it will promote the after burning of the CO in the exhaust of a a BP motor. This creates a large, more impressive exhaust plume.
I am now thinking of using hand rolled 2.5" ID tubing with a 29mm mount. I will have a recovery system (his are very light and don't have one) and will use a lug (just not to press my luck any further). Why the odd tubing? Well, I want to see that afterburn and, apparently, that won't work of the inner surface is crudded up with residue. So, I will cut up soda cans and shoot for a replaceable liner.
My plans may change up to and including their cancellation.
Here's a RockSim model I built just to get a feel for the CG.
From a 2005 post by "A Fish Named Wallyum" on YORF - Here's some background on Vern Estes and the original Big Bertha.
"Vern built this rocket to use at demonstration launches. It proved to be so popular that they later made it a free plan and then a kit. It became the largest selling rocket Estes ever made. I believe it is now also the "oldest" kit still made."
In a recent post Bernard Cawley added: "It, along with many other things that Vern and Gleda have kept or collected, will be housed by the Museum of Flight in Seattle. The Stine archive is already there.
Actually the first Big Bertha may get to the MoF sooner. It sounded like, from what Vern said last night at the NARAM-56 banquet, that it might be as soon as this year. The beginnings of the MoF's model rocketry exhibit is set to be opened around Thanksgiving this year. It will be located in the Space Gallery alongside the shuttle full fuselage trainer."
I like the "Lucky Seven decal and the well worn rounded fins!
Photo at left by Bernard Cawley, picture at right by Bill Eichelberger
For almost a decade, JonRocket.com has supported the National Association of Rocketry’s NARTREK Cadet program. The NARTREK Cadet program is designed specifically for modelers under age 18 and is open to both members and non-members of the NAR. The NARTREK ...
Jeff Taylor (FatBoy on TRF) "Steampunked" his FlisKit ACME Spitfire. The finished results are amazing! CLICK HERE
There are hundreds of rivets and plenty of cardstock trim. I especially like the shingles on the fin root edge and the Zebra wood veneers with barrel hoops on the upper section. The stand-off launch lug is hidden in the pipework on the right side.
Jeff is donating the model to the NARAM 56 auction. If I were there, I'd bid on it!
Turned 180 degrees shows more detail. Check out the screen on the lowest section shroud.
The gauges add dimension and more detail. I thought the model was finished but Jeff added a darker "wash" to make the model look aged. Truly inspirational work!
I haven't built many of the ASP (Aerospace Specialty Products) kits except for two of their Micro Maxx models. I've always liked the looks of the Corporal. This is a BT-50 based, 18mm model.
ASP also makes a BT-55, 24mm version. I picked this one up at JonRocket.com.
Parts are standard and high quality.
Parts of interest, clockwise from the upper left: The clay nose weight, vinyl roll pattern, two longer 3/16" square balsa for tunnels, a metallic orange 12", 8 sided Mylar parachute, two smaller 1/8" square balsa tunnel pieces, red motor mount tube, large screw eye and snap swivel, black vinyl for fin area roll pattern, 1/16" basswood for fins, fin pattern.
The clay weighs in at .85 oz. I don't think I'll be using all of it.
On July 14,high school students participating in PEO STRI’s Summer Engineering Internship program built and launched model rockets. ROCK members Roger Smith, Bracha Smith, Chris Michielssen, and David Ribakoff set up ROCK’s launch equipment and helped the kids prepare and ...
I have heard about Squadron Putty for years. Many builders use it to fill the seams in plastic nose cones. I've been using medium super glue on plastic nose cones with good results.
I haven't used Squadron Putty before simply because I don't build plastic models. It is primarily used to fill the joint seams on plastic kits. I recently picked up a tube at JonRocket.com. The Squadron Putty contains Toluene and dissolves some of the plastic locking the filler in the open seams. The Toluene is why the Squadron putty stays in the shallow mold lines on a nose cone.
I was curious if there was any difference between the green and white Squadron putty. After a few online searches it seems that the green putty is the original formula. Some builders say the green is coarser, the white putty is finer. Others say there is no difference except for the color. All agree the white putty covers easier when color coats are applied after filling. Some say they have similar results using the Bondo Spot and Glazing Putty.
TIP: Don't use super glue to fill gaps in a soft wood like balsa. Super glues dry too hard and you'll end up sanding more wood than the glue you set down as a filler.
I was most interested in filling the small tab gaps on the QCC Explorer intakes. Super Glue is used to assemble the intakes. After sanding, the super glue has sealed the wood and a water based filler (CWF) won't stick in the open seams. The Squadron putty has the Toluene solvent and so far has stayed in the fill areas after sanding. The dried putty sanded pretty easily with 400 grit sandpaper.
Two years ago, Shella Condino, a Texas teacher known for using rocketry to inspire and educate, received a letter from the US Immigrations Service saying, “You are not authorized to remain in the United States and to depart as soon as possible.”
A Texas congressman investigated and learned that the letter had been sent by mistake. Shella Condino now has a “Green Card” and continues to inspire her students in Presidio, Texas. Earlier this year, she once again, lead a team of kids to the Team America Rocketry Challenge finals. The team finished fourth over all in the nationwide competition.
Here's the one kit I packed for Mexico. It's small with strong tubes. I could put this into my carry-on bag for a more gentle transit on the plane. With the available skins there is no filling or painting! Perfect for an "away build".
This is a MMX downscale of one of the more popular Flis kits. When finished it'll stand 4.42" tall. The body sections are BT-5 based.
The parts going clockwise from left to right: Pattern Sheet, Clay weight Nose Block, Kevlar cord anchor nail Streamer 1/2" X 12" long, Stiff Kevlar 24" long Instructions, Laser cut ring and fin sheet Launch Lug, Engine Block BT-5 tube 5 3/16" long, BT-2.5 tube 5 1/8" long
Parts of interest: Pattern sheet for cutting tube segments, base shroud and nose cone cap, all printed on 24 lb. stock Kevlar is stiff, not braided The smallest nose block I've ever seen Thick card stock rings and fins, very clean laser cuts
If you go to the FlisKits website you can download the skins and print them at home CLICK HERE I picked the standard print, a Mercury Deadstone decor is also there. I made extras and all got a shot of clear coat.
I scanned the pattern sheet and printed up a few more to be safe.
This build may seem a little long for such a small model. Fitting all the tube angles takes some extra time. Many of the build ideas can probably be used on the larger FlisKits A.C.M.E. Spitfire.
It’s been five years since Roger and Bracha Smith took over the reigns of the online model rocketry retailer, JonRocket.com. To thank all of their customers for supporting the business, JonRocket.com is holding a sale event which runs through July ...
Thunderstorms threatened, but stayed to the east. So, only a few sprinkles of rain interrupted the June, 2014, NEFAR rocket launch. I flew my DJI Phantom 2 Vision quadcopter about a half-dozen times to record the low- and high-power launches ...
This catalog page is from the 1992 Quest Catalog. The Aurora was Quest kit #3002, a parasite boost glider. The model is 15" tall built around a sturdy 25mm Quest body tube.
The face card description says: "The boost glider is modeled after the new, top-secret successor to the SR-71 spy plane. Glider jettisons booster at 500 feet and glides back to earth while booster returns via 12 inch parachute."
I bought this one a few months back at the Orlando Hobby Spot store. They have a very limited rocketry selection but occasionally you can find an interesting older kit. The kit was marked at $7.99 for reasons I would find out during the build. During construction I found the kit was re-bagged. The balsa pieces had been broken loose from the die-cut sheet. The glider rudder strake (front end) was broken off.
Parts of interest: The one-piece fin can with integrated launch lugs. (The "launch lugs" weren't open! You couldn't slide them down a launch rod without drilling through them.) Small 5mm nose cone with adapter shoulder to the left. Launch lugs (2) Dowel for glider hook Gripper tabs for shroud line attachment
An "Important Assembly Note" was in the kit. It explained that a launch lug would have to be glued beside the closed lug molded into the fin can. Stickers!!!
This was actually Post 7 from the Estes Python build. I missed posting it and found it later in the blog drafts. This information could be applied to any tight red couplers from Estes kits. This Python kit was different - the coupler was glued into the upper tube, the lower side of the coupler slid into the lower tube.
This red adapter was really tight in its BT-55 tube. It was sanded down for a better slip fit. It took a lot of sanding to get a sliding fit that wouldn't "lock-up" when glue was added to the mix.
The instructions have you glue the coupler 1/2 the way into the upper tube. 1/2 of the coupler is only 5/8" exposed. On this model it's not much for a steady fit. I'll leave more exposed out the bottom.
1/3 of the coupler was slid into the tube and marked with a pencil. Don't glue in place yet. The coupler was removed.
After sanding the coupler for an easier fit, the surface is rough. The coupler got a coat of medium CA up to the pencil line. Below the pencil line is where it will it will be glued into (on this model) the upper tube.
The dried CA was sanded smooth with 400 grit. This makes for a smoother sliding coupler into the upper section.
The coupler ends were sanded round for easier insertion in the tubes.
"I regularly fly a Sunward Eruption that was given to No2son, who doesn't have time for rockets now. The rocket takes 4 18mm motors, so I bought 3 packs of Estes C6-7s the other night at HobbyTown USA. In opening the packs and transferring the contents to my field box, I noticed that the ignitors had white tips rather than black tips.
Today, we had a Cub Scout pack at our NAR Sport Launch and had numerous discontinuity and misfire issues. My Eruption flew fine on four of the white-tips, but my daughter's Sky Twister had discontinuity on the first, then lit properly on the second (white-tip) ignitor. It lawn-darted, but that was no fault of the ignitor.
Has anyone else had issues with the white-tip ignitors? Did anyone see anything resembling a press release or announcement that Estes was going to change their ignitors?"
The response from JumpJet (John Boren of Estes Industries) "Phil, the new igniters from Estes are called Starters. Their tips contain NO pyrogen so you must make sure the tip makes complete contact with the propellant grain. The good news is you can now order starters without paying a high hazemat fee. The bad news is you need to spend a little more time inserting the igniter to get proper ignition." John Boren The picture directly above was one I took of the new igniter the first time I'd seen one at a club launch. There are now some new engines packages with Starters at Hobby Lobby. I haven't used the new clear tip Starters yet. Most interesting is Mr. Boren's comment: "Their tips contain NO pyrogen". Not a press release, but this is the first time Estes has said anything about "no pyrogen". The webpage description says "Works just like out 2301 igniters."Or, maybe not. I guess the clear coating is more like a protective dip for the thin bridge wire at the tip of the igniter. Personally, I wouldn't try a cluster with these "Starters". I have plenty of Quest Q2G2 igniters for that. Did anybody else notice Estes has no cluster kits in their product line-up? I might be buying some pyrogen dip and making my own igniters with the cheap nichrome wire I recently bought.
In another post, Zeus-cat adds:
Some good news, Estes has gone back to putting 4 igniters in each three pack of motors. We had gobs of extra igniters at the end of the day and a few of us grabbed most of the extras.
Right now it's hard to find Quest Q2G2 igniters for sale anywhere! Even on the Quest website it says: This item is currently Out of Stock and will be available soon! The Apogee website says the Q2G2 igniters won't be available until September, 2014.
Lets hope the Quest igniters keep the pyrogen tip!
This should be a fun one . . . The parts - Clockwise from the upper left - 18" pre-assembled parachute, BT-80 slotted tube, Blow Molded Nose Cone Launch lugs Laser cut balsa fin sheets, Instructions, Engine Mount parts, Mosquito decal, Tri-fold mount, Rubber Shock Cord
Parts of interest: BT-50 heavy wall tube for engine mount Big Bertha style Blow Molded Nose Cone Two 1/4" diameter Launch Lugs NINE (yes, nine) balsa fin sheets The new Mosquito decal sheet
As I write this blog post, Amazon.com is offering the Estes Phoenix model rocket kit at more than 50% off its regular retail price of $23.99. If you are an Amazon Prime member, there is no extra charge for two-day shipping.
I was alerted to the special price by using the RocketReviews.com Rocketry Deals Finder.
A quick build for a model I'll probably lose anyway!
When I can find them, the first flight will be with a 1/4A3-3t engine.
The nose cone joint is smooth and the mask came out clean. The yellow is a good color to see against the grass field at the schoolyard. The new water slide "bug" was set on the fin. The decal draw is coming up in a blog post.
Here's the Mosquito from the 1973 Estes catalog. This is the look I was going for. My black paint went a bit higher than the catalog picture, more like the new kit scheme.
And, the Mini Mosquito from the Estes online picture. The nose cone shape is more pointed than the supplied kit nose cone. It looks like the black paint goes farther back, to the root edge of the yellow fin. The side view picture (see below) on the instruction sheet shows the black paint line stops halfway between the fins.
Look close - What's wrong with the model picture at the top of the Mini Mosquito instructions?
What's was included in the Mega Mosquito kit that is missing in the instruction art? This image was probably drawn before the kit parts were produced.
From the Odd'l Rockets Email box, a question - "Waiting to finish an Estes Mini-Max, with waterslide decals. You use the drop of liquid detergent in the water, which has worked for me. The Apogee site recommends using white glue in the soaking. apogeerockets.com/Advanced_Construction_Videos/Rocketry_Video_91. Your thoughts?" My response:
I've never heard of using white glue in the soak water!
This might work, but I've never tried it.
Decals from different vendors are so inconsistent, sometimes you can't move them once they are set down.
I wouldn't want a tough to position decal to be any more sticky!
TIP: The inconsistency is sometimes the thickness of the clear topcoat. Too thin and the printer ink dissolves. Too thick and the decal ends up looking like a peel and stick.
While I hate Krylon color paints, their clear acrylic spray still seems to be the best for clear coating a home printed decal sheet. Three coats (not too heavy) seems to be about right. It seals the printer ink and gives you the right thickness.
Home print decals are good, but never as great as a kit decal. Face it, you are not printing decals on a large press or silk screening.
As Gus (Steve) on TRF once wrote: "They are a different animal."
Most every source recommends using a very small drop of detergent soap in the soak water.
It helps break up the surface tension in the soak water. Others say it helps the decal slide on the model surface.
On response on TRF tells you: "The decals are ruined because the drop of soap breaks down the adhesive on the decal."
I've never had a problem with the small drop of dish soap in the soak water.
(Judging by the forum responses, many others haven't had a problem either.)
Wet the surface on the model with a drop of water where the decal is to go. Set the decal on the wet surface.
That water under the decal helps lubricate the surface for easier positioning.
TIP: If the decal can't be easily moved, use a wet brush to work some water into the edges. The soft brush will get some water under the decal with tearing the edges.
After the decal is in in position, don't rub over it with a paper towel. A thin decal could tear.
Roll a wet Q-tip over the decal to work out any air bubbles or water drops.
I don't brush Future acrylic all over a model to seal the decals. I've never had great results with brushing or spraying Future.
Now I dip a Q-tip in the Future and wipe off the excess. You won't need much of the Future to apply a thin, protective coat.
The wet (with Future) Q-tip is rolled over the decal and the edges.
I've never had decals peel or lift after this light sealing.
Here's another one I picked up cheap for $8.99 at a collectors store in Orlando. The Python 4 (#EST 2054/1245) was a Launchables packaged model from the Enduring Freedom missile series. Some parts were much like the recent Paveway build. The upper picture shows filler in the tube seams. I'd already started before the picture was taken.
The parts of interest: The stick on decals - I'll be drawing and printing up some water slide decals. Die cut fin conduits. These are thin card stock pieces that glue under the long tapered middle fins. Blow molded adapter. This is the same one used in the Paveway kit. There is a 20/55 adapter on the upper end, it isn't used in the kit. After it is cut off, it's never mentioned again in the instructions. The instructions also include a second fin marking guide for a smaller, upper BT-20 tube. The upper tube is a BT-55 like the lower tube. The nose cone looks a little like a small Big Bertha cone except there is a molded recessed line near the top. A single 1/4 oz. "butter pat" of clay weight. A very tight fitting red coupler. (Don't use the "New Stronger Formula" Elmer's on this one!)
Congratulations to the many TARC teams that competed in this years contest. The team from Creekview High School in Canton GA won the 12th annual competition this past weekend. lace Score Team Number Team Name City State First Place – $10,500 14.88 14344 Creekview High School (Team 1) Canton GA Second Place – $9,500 [ ...
SpaceX's just released their latest Falcon 9 model rocket kit: Falcon 9 and Fairing Flying Model Rocket Kit. It's unclear whether the body tube is the same size as its predecessor but this one features their operational payload section and flies on Estes 24mm motors (or AT, CTI for that matter).
I like the nose section but this will not be that much different than their previous kit. I'm holding out for the version that comes with landing legs...or maybe the Falcon 9 Heavy.
I'd been curious about the Chinese made MPC licensed kits. This one looks nothing like the Star Trek enterprise except for the parachute and logo. I made a Ebay bid of $.99 and won it! I feel like I only paid for shipping.
Opening the box I was surprised by the BT-60 size diameter of the body tubes.
The 18" parachute looks like the round body of the T.V Enterprise. The plastic is thick, maybe 2mm.
Stick on fin decor and a nose cone wrap that goes on right above the shoulder.
The plastic fins are very flexible and shouldn't crack.
Below the fins is the fin can and engine cap locking ring.
The tubes are convolutely wound. They look and feel like rolled thin sheet plastic! Not spiral wound but wrapped like you would roll a body tube on a card stock model.
The nose cone is blow-molded, 7 7/8" long! Directly below the nose cone is the tube connector.
The box copy describes it a a "two-tiered design". I think of two-tiered as a larger lower section and smaller upper section. Upper and lower section diameters are the same. The parts illustration on the back of the box looks like the old MPC line drawings.
The diameter is 1.58 or 40mm. When the fins are slid on and the tubes joined with the plastic connector, the model is almost 28.75" tall!
The recommended engine is a C6-5 - the package says the model weighs 3.67 oz. Maybe it'll only get 260 feet as advertised! Estes or Quest C6-5? I wouldn't use a Quest engine in this heavy model. It'll be interesting and require a lot of plastic cutting - it'll be converted for D12 engines. EDIT: I should have added - These models are not the old MPC designs from the 1970s. These models are based on the Chinese made SKY brand model rockets but in a trademarked wrapper. The MPC / Round 2 models use licensed images of the Warner Brothers cartoon characters, the rock band KISS and Star Trek. They also have some "generic" designs: Red Giant, Lunar Shuttle and G.T.S. 1. MPC / Round 2 have also brought back the old plastic MPC Vostok and Titan IIIC. Go HERE to see some of them.
You can now manage your Flight Log at Community.RocketReviews.com. Log in using your RocketReviews.com email address and password. Then click the “My Flight Log” link in the “My Account Menu.”
The Flight Log dashboard will be displayed with brief statistics about the information in your Flight Log. At the top of the dashboard is a menu bar.
Click the “Rockets” button in the menu bar to see a list of the rockets in your Flight Log. Click “Add Rocket” button to add a new rocket.
Click the “Flights” button in the menu bar to see a list of the flights in your Flight Log. Click the “Add Flight” button to add a new flight.
The new Flight Log feature in the RocketReviews.com Community uses the same database as the existing Flight Log feature at RocketReviews.com. But, it offers a much nicer interface for entering and editing flights.
Quest Aerospace is offering an X-15 kit parts pack HERE
X-15 Parts Pack includes the following parts: 2014-1010 X-15 Instructions 2014-1030 X-15 Decal 20222 X-15 Nose Cone 33030 X-15 Balsa Big Sheet 33051 X-15 Balsa Strakes To the right are all the parts needed for the complete build:
To build the complete model you'll need to add: 12" or 15" Parachute 2" Launch Lug 135 lb. Kevlar Elastic shock Cord Engine Hook BT-20/35mm Centering Rings .25 oz. Clay Weight Engine Block Motor Mount Tube 35mm Quest tube, 11" or 13"
Right now the complete kit is OOP. The parts pack listed above is whats available from Quest.
Some had unstable flights with the original model. Later in the kit run, Quest lengthened the 35mm body tube from 11" to 13". A clay weight was also added to the kit. This Quest X-15 has gone over some recommended engine changes over it's run. Toward the end of the kit run, the A6-4 was the only recommended engine. On this build I'll play it safe and use the 13" longer 35mm tube and add .25 oz. of clay in the nose cone. I may not get stellar altitudes, but it should be stable!
Round 2 has brought back the MPC Vostok and Titan IIIC plastic models HERE. The re-release kit doesn't include any parts for flight. EDIT: The larger flight fins are included. The two piece molded launch lugs are still on the molded pieces. This build is the older version from the 1970s where you could "Build To Fly" or Build To Display". I'll try to include all information needed for the flying conversion. You should be able to fit a 20mm (or BT-20 tube with a shim) in the hollow middle plastic section. The AVI folks sent this one to me. I've had it in storage for over 35 years.
The plastic parts, many are broken off the trees . Most is molded in white, there are some chrome and clear parts.
Parts needed for the flying version: A large 20" Mylar parachute, 8 shroud lines and unusable tape strips. How you gonna' fit all that into a 20mm tube? A Stine "Shock Lock" shock cord attachment 9" long 20mm heavy walled tube Two lead weights One for the Vostok, one for the Sputnik capsule, your choice Thin yellow engine compartment tube The instructions said there was a brown tube, I couldn't find it and substituted a Quest yellow tube. Two engine hooks were provided, only one is needed Four larger for flight fins. Smaller display fins were included. In the middle are the two interior halves, the 20mm tube slides inside.
3221 QCC Explorer $22.99 2271 24" Parachute $ 5.49
Estes parachute prices in 2010 were ridiculous!
That year the retail price for a 12" parachute was $8.29
Three years ago, Estes brought out the new retro print parachutes. The prices were reasonable.
In 2011 the retail price for a new retro print 12" parachute was $1.39 You wanna try a great NEW inexpensive parachute? Check out the new parachute at JonRocket.com HERE Or contact me at email@example.com for bulk prices
Here's one that took too long to get produced! The Odd'l Rockets PIGASUS kit is now available from JonRocket.com HERE Kit Features: Parachute Recovery Decals and Printed Wings and Goggles Windswept Ears and Balsa Razorback!
When Pig's Fly!
EDIT: The initial six kits at NARCON sold the first day. The second litter of five kits listed at JonRocket.com on March 17 sold out within hours. More are on the way - I hope! Anyone have a line on ST-18 tubes?
All subscribers should have received an email this morning. Their costs have gone up a lot and they don't want to have to pass a huge increase on to the subscribers. The same issue killed Extreme Rocketry, which first tried to go to mostly B&W photos. It also got High Power Rocketry, which tried to survive by going to a smaller form factor. ROCKETS' approach is the emag. It's going to be free and they provided an code to apply your remaining subscription value towards ROCKETS merchandise, such as DVD's.
I haven't read the issue so I'll refer you to the cover image for the contents. I did scan the issue and am really looking forward to the article on tube finned rockets, which appears to present a wide variety of wild configurations. I am motivated to try some already.
This is an interesting design. A definite "reflection" and nod to the Centuri Lil' Hustler. The model is a cross between the Lil' Hustler payload and body the fins look like they came from the Centuri Jaguar. This build will be a little different, two models will be built. One will have the kit Reflector fins, the second will have the Lil' Hustler style fins.
All the parts are of high quality, the BT-50 main tube seems thicker walled than older BT-50 tubes. Even the blue BT-20 engine mount tube is better quality than before. It's hard to see in the picture at the right but the recessed date stamp is in the white stripe ink area.
Here's something you never see in a face card picture - balsa grain pores! Usually the face card model picture has been retouched, the wood surfaces and paint seem impossibly smooth! This gives you an idea how some factory built models actually look in person. This is probably a pre-production build. The white stripes on the fins look like they could be a thicker trim tape, not a decal.
Future of Semroc Semroc Fans, I am sorry to say that we will be closing the company. After my father’s death and my stay in the hospital I have realized that it will be impossible to catch up. I have decided after much thought that it would be in my best interest to close the doors. This is not an easy decision after living a 10yr plus dream with my Dad. We appreciate all the loyalty that you have all shown me and my family over the years, we are forever grateful. We will always cherish the memories and friendships we have made over the years. It has made all this worthwhile. All of the current inventory is up for sale but there will not be any custom parts cut and once the kits and parts are gone there will be no more. If anyone is interested in buying out current stock please drop us an email and let us know. Again thank you all for helping me and my family live the dream!
Florida’s Space Coast hosted NARCON, the National Association of Rocketry’s annual convention, from February 28 to March 2, 2014. We made the one-hour trek from Oviedo to Cocoa Beach on Friday morning. We checked into the International Palms Resort and picked up our NARCON badges and welcome packet. Then we went across the street to [ ...
NARCON WAS A BIG SUCCESS! Everybody who attended would agree.
I had only been to NARAMs and some smaller conventions in the past. I'd forgot how great these get-togethers can be. Along with the technical sessions it's about meeting the people there. There were over 100 people attending with home states as far away as Oregon.
A lot of people from my rocketry past: Trip Barber - Past NAR President Matt Steele - (North Coast Rocketry) Richard Fox - Foxmitter
And of course - This guy!
I had that rocket nerd obligation to have him sign my Alpha. I shook his hand and made the comment: "Thanks for keeping me out of trouble during my teen years. I didn't date a lot, but I did fly rockets!" I don't think he got the gist of the joke.
I had the chance to finally meet: Wes "Dr. Zooch" Oleszewski - My Saturn V and Soyuz shelf queen models were on display at his table. Tim Van Milligan and Family- Apogee Components James and Campbell Duffy - The scale master of the Mercury Little Joe. James introduced me to his daughter Campbell. She used the blog posts to help with her Sat V build! Steve Kristal - "Gus" on TRF
My LPR build session was well attended. I don't think I shut up for a second through the entire talk. I had a lot of material to cover. I introduced the new PIGASUS! kit and showed off the new parachute. The FINTOOL was demonstrated and many were interested at how small, simple and accurate it was. I went back to the JonRocket table and sold all of the pig kits. Other vendors were already pre-ordering the new parachutes. A big day for me and Odd'l Rockets!
A tip of the hat to Pat McCarthy for a very well run event !
PIGASUS will debut at NARCON! It's about time, I haven't been able to produce new Odd'l Rockets stuff lately. Hard to believe, but banjo playing can pull you away from rocket production. This model always turns heads and is favorite with wives and girlfriends that were dragged to a launch against their will. At NARCON, JonRocket will have the kits on Saturday. My other distributors should have the pigs soon.
I'd always liked the look of the red and white parachutes used in the Apollo program. A rough count looks like there are 64 alternating red and white gores.
The Estes Saturn V kit (and the earlier Centuri version) came with parachutes like this. Many of my semi-scale and fantasy scale model kits use a supplied generic canopy. I always thought a scale model (sport models too) should descend on a scale style parachute.
Last September (when stuck in Mexico) drawings were started for what I hoped could be a better 6 sided parachute, or "parasheet".
It's considered an "all in one". The largest outside cut line is for an 18" chute, a popular size for vendors. Inside are cut lines for a 15" or 12" parachute pattern. In the middle are 3", 4" and 5" spill hole circles. TRIVIA: FSI first came out with a "Select-A-Size" parachute in the early 1970s.
The Saturn V kit parachute had 64 printed red and white "gores". But on a smaller parachute it's visually too many. The print pattern messes with your eyes like a "Hypno Disk".
The new parachute edge has rounded "gores" giving the illusion of a shroud line pulling on each one. The polyethylene is the ideal thickness. Some kit parachutes are thick or crispy. This parachute opens quickly with no sticking.
Parachute drawing and development was a real education. There are many considerations when art is transferred onto a flexible rubber printing plate. It's not the same as paper printing. This has been redrawn and tweaked too many times.
25,000 parachutes later . . . These turned out better than we had hoped! JonRocket and Balsa Machining Service are the first to get them. If you are interested in parachutes like this for your kits, please contact me. The parachutes I have are generic without a logo in the center.
EDIT: We had hoped to have two hundred of these for NARCON, but the pressman called in sick! They did run a few, I managed to sneak them out of the print shop. Roger and Bracha of JonRocket.com will have the parachute at NARCON. Stop by and check it out!
How did AeroTech squeeze nearly 83 N-sec out of a form factor that until just recently was limited to around 53 N-sec (a 56% increase)?
• High solids propellant with higher specific impulse (Isp), high density and higher burn rate to minimize throat erosion and delay grain length • Volumetrically efficient "finocyl" propellant grain design • No separate case liner, so larger diameter propellant grain • Longer propellant grain due to shorter delay and bulkhead • Slightly higher motor peak operating pressure • Relatively flat thrust curve to increase average pressure
Here's a great Shrox design introduced in the 2010 Quest catalog. I understand Shrox likes conical pointy nose cones, the older MPC Nike Smoke nose cone is used here. This design also used a Shrox standard, the 50mm intake tube underneath.
Here's all the parts: The 18" 35mm main air frame tube Two piece Nike Smoke nose cone with tip Laser cut balsa wing fins Large decal sheet 1/8" launch lug 18mm engine mount 10" long 50mm intake tube not shown (I don't know why I didn't include it in the picture)
Some parts of interest: The 35mm body tube had a discolored spot on it. Oil? I'll have to double check it when the spray paint is applied. 14" parachute has thick off-white shroud lines (replace) Thin 18mm yellow engine mount tube (replace, more on this later) Engine hook (replace with spring steel engine hook)
If you buy the standard BOB Smith super glues you'll need tips or Teflon tubing to apply it with any control. This glue is thin! If you don't use an applicator tip the glue will be all over your model, the bottle and your hands. The open nozzle by itself doesn't give enough control over the glue flow. While some prefer the applicator tips, I use the Teflon tubing. You can buy Teflon tubing in 2 foot lengths here: http://www.amazon.com/Bob-Smith-305-Teflon-Tubing/dp/B002N4R2CA
On the right the blue cap has been removed from the nozzle of the CA bottle.
At the top is a small tip to be cut off. The trick is getting it to the right size so the Teflon tube has a tight fit.
Cut the end of the long tube at an angle for easier insertion. Cut of a little of the tip and test fit the tubing. Chances are it won't fit the first cut end. Shave off a slight amount and try the tube again.
I leave the tube long until I get the angled end in the glue bottle. It took four tries, four thin slice cuts to get the nozzle opening to the right size for a friction fit.
Once it's in I'll cut it off with about 1/2" exposed. Some builders use a much longer piece. The open end can be cut at an angle for easier flow and glue application.
Once the Teflon tube is in place you won't need the blue nozzle cap anymore.
I bought this one on sale from Uncle Mike's rocket shack. An interesting design with conical stability.
Parts were of high quality. The model is BT-50 based. This is another of the better BT-50s. They seem a bit thicker walled.
The parts of interest: 12" diameter red Mylar parachute. 3" long launch lug Three small laser cut fins, 3/32" thick stock 20/55 centering ring for shroud base Tri-fold shock cord mount. I'll replace with Kevlar from the engine mount. The conical shroud printed on 65 lb. stock. I'll scan it and reprint on 110 lb. card stock.
Mountain Dew advertised their “Kickstart” flavors of soda during the 2014 Super Bowl in a commercial featuring a spectacular night launch of 400 model rockets at one time. The rockets are meant to be a “metaphor for getting you up for the night” according to Greg Lyons, Mountain Dew’s Vice-President, Created by the ad agency BBDO [ ...
I haven't built a MMX rocket in a while. They are great first launch of the day models to test the controller, rod angle and winds. This one is almost a minimum diameter and should be fast with good altitude.
Parts quality is very good. The engine mount tube is a BT-2.5, just under 2" long. The crayon tube is a 6" long BT-3. The streamer is red plastic, 1/2" X 12" long.
Clockwise from the top: The Kevlar shock cord is thin, the line in my MMX Honest John has burned through. I'll replace this line with something slightly thicker. There is plenty of clear fin material, make extra fins. The body wrap is printed on red construction paper. The four centering rings and engine block are small but very well cut. The small nail holds the shock cord in the nose cone base. Finally, the crayon balsa nose cone.
While the FlisKit crayon wrap looks great I went and redrew a Crayola crayon logo wrap. I simply wanted it to look like a Crayola.
This build was tough! How Estes could label it as a Level 2 is beyond me. The body shrouds would be impossible for a younger builder. Fitting the shroud front around the complex curves on the nose cone shoulder took too much effort. In the end, the match still isn't great. The light embossing on the shrouds almost disappear by the time you are finished. On a craftsman kit water slide decals should be supplied, not peel and stick! How about this - Kits with balsa get water slide decals. Plastic RTF or ARTF models get stickers. Is this considered a bad review? Yeah, probably.
This was one of those builds where you think: "Put a fork in it, it's done!" You could mess with it more, but after a while you want to move on.
Krylon (flat clear coat) let me down again - Never Again! It's now glossier than I would like but I can't take the chance of any more finish problems. The model got a final shot of Americana clear shot from a distance. Not a heavy finish coat for a satin finish.
I still have to glue in the engine mount and install the parachute.
The website is in German. When the page loads, hit the "Translate" button at the top to follow along in English.
There are some models that few would even attempt to build and fly. Soyuz, N1 Herkules, Bachem Natter, Juno 1, Ariane V and many others. These are of course scratch builds. Photos show the construction, with many parts formed from fiberglass.
Oh boy - this should be a fun one! Skill Level 2? No, I don't think so. More like a Skill Level 4. It's interesting to look up the Centuri Blackbird instructions at Jim Z's - HERE
This BT-50 based model looks to be a downsize of the earlier Centuri kit. The larger BT-60 Centuri version was using Estes parts at the time.
The kit parts were actually good quality. The BT-50 tubes were the best I'd seen in quite a while. The biggest downfall, the decals are peel and stick! Many of them are white so I won't be able to redraw and print decals at home.
The embossing on the card stock is faint - almost not there! Some of the die cutting is off, more on that later. I can already see how hard these will be to glue and form over the central BT-50 tube.
Here's some back story on the Flutter-By from the Semroc Spartan kit instructions: "The Stellar Spartan was the second in the Centuri Stellar Line. Originally planned for mass merchandising, the line was later changed to mail-order only, then dropped. The Spartan was an early prototype for the later Screaming Eagle which replaced it. Leftover parts from the Spartan were used for a few years on the Flutter-By until they were gone." Looking at the Spartan fin profile, you can see it's the same fin.
The "Flutter-By" - not a very macho rocket name. I had an original Centuri Flutter-By in the mid 1970s. As I remember, it performed well with A8-3 engine's.
I bought two Flutter-Bys in the recent Estes Clearance Sale. I put off buying the re-issued kit because the price was too high. Up until the sale the retail price was $14.29!!! High - considering how few parts are in the bag. In the picture above notice the laser cut lines for fin strake positions.
Parts of interest: The nose cone is longer than the Centuri version. The original was a Centuri PNC-80, 2" long. This nose cone is 3 1/4" tall. The drawn lines on the decal are thick compared to the original kit. It's missing the chrome trim included in some Centuri kits at the time.
I'll be referring to this one as a Centuri Flutter-By. I won't be using the strakes and will try to make it look a little more like the Centuri catalog picture seen HERE.
Talk about true love! Under our tree this year was a brand new six inch Gorilla Rocket motor, Reloads, Nozzle, and a kit to put it all together. Can’t wait to try it out. Looks like my first chance will be Thunderstruck 5 this spring in Indiana….. Thanks Deann! I love you.
Here's a build by request, the Estes Gyroc, # K-24 I received my first Gyroc as a Free Kit for placing a $5.00 Estes order.
Wayne Hill's Rocketry Blog gave some history: http://rocketry.wordpress.com/2006/06/06/rocket-of-the-week-662006/ "The Gyroc was originally released in 1965 and was offered as “Free with a $5.00 order” in the 1967 Estes MRN. The kit was listed asK-24and was offered through 1983." Years ago my first launch experience with the Gyroc wasn't successful. The moment it left the launcher the fin panels flipped. I didn't install the hold-down tabs correctly. The Gyroc did a tight loop and stuck itself into the dirt. I'm hoping for better luck this time.
On the upper left you see how it appeared in the 1969 Estes Catalog. As far as I know, this was one of the first helicopter kits available. I won't be attempting this paint job. It would be tough to get the spiral paint patter under the large wing fin. In later catalogs the Gyroc was painted yellow overall and used some of the black decals from the Beta kit.
The parts from left to right: The "Tape Hinge" material will be cut from the border pieces left from a stick on CD label. The "Flap Holders" will be carved from a larger craft stick. An LL-2A launch lug, 1 1/4" long BT-20D body tube, 6 1/2" long BNC-20B nose cone EB-20B engine block 1/16" thick balsa sheet (once known as BFS-20) Instructions printed from the JimZ website http://www.spacemodeling.org/JimZ/estes/k-24.pdf Elastic thread not shown
Sometimes the inside tube lip can lift. I normally would just use CA glue to strengthen the tube ends, but I'm finding the lifted ends don't stay down when set with CA. Use white glue to first set down the raised tube end. Lay a bit of white glue under the lifted seam tab.
Roll over the lifted end with a dowel.
Let dry - then use CA. Strengthen the lip with a coat of medium CA applied with a Q-tip.
I’ve uploaded photographs from the December, 2013, ROCK launch to RocketReviews.com: December 2013 ROCK Launch Photos I was having a problem with my left eye and found it difficult to take still photographs, so I let Bracha use the DSLR. ...
Via Ted Cochran on the NAR's Facebook page. How cool is this?
Ted CochranThis photo of National Association of Rocketry volunteers (along with other photos) was used as NASA test data. It was displayed on a large screen in mission control at NASA in Greenbelt, Maryland and then sent to White Sands, New Mexico where it was uplinked using lasers to the LADEE satellite as it orbited the moon. Lasers on the satellite then sent the photos back.
The laser communication test achieved a data rate of 622 megabits/second.
The Quest engines are sooty! That soot sticks and can make a nose cone fit too tight.
It's easy to remove dirt from the outside of a body tube with a damp paper towel. But I wanted to remove some accumulated crud from the inside of the body tube. The inside of the body tube could swell or come apart if you get it too wet.
For the past few years I've brushed medium CA glue around the inside end of the body tube for strength and a smoother inside surface. Before I was only covering 1/8" to 1/4" of the inside lip.
From now on I'll extend the CA coat farther down the tube a little deeper than the length of the nose cone shoulder. After you brush on the CA with a Q-tip, lightly sand with 400 grit. The CA coat seals the naked interior tube, Water can't penetrate into the card fibers. Now I can (carefully) wipe off the interior soot with a damp paper towel.
This past weekend was the N.E.F.A.R. Bunnell Blast, a two day event with a night launch on Saturday night.
The Quest AEROSPACE ONE is a great flyer adapted to an Estes D12-5. Towards the end of the thrust phase the model wiggled a bit. Altitude was near 900'. The left rear rudder fin broke off clean at the root edge on landing, an easy fix.
Rocket Rick Boyette had one of the larger upscales - The 12" diameter x 12' tall Estes Alpha. I had to leave before the flight, many were waiting for the winds to die down.
A new favorite is the CHEROKEE GOON. A little sooty after a few flights with Quest B6-4, but it's a perfect engine for this squatty. Estimated altitude was about 400'.
My two engine cluster JOLLY ROGER hadn't flown for two years. (Check out the planked ship style fin) Two C6-5s got it to an estimated 1,000'. Taped on the side is the same keychain video camera that sat in the strawberry field in Tampa for a few weeks. The video is great but no audio!
Down the rack is Dave Ribakoff setting up a rare OOP Dr. Zooch Thor Agena B for flight on a B6-4.
Everyone would agree, the highlight of day was Bracha and Roger Smith's Akavish flying spider. This was Roger's first flight with an L engine.
With the wind gusts there was some concern about the rail, only six feet was used. In the end all was stable and successful. The Akavish apogee was 990' and descended under a spiderweb parachute.
In the picture from left to right is Roger, Akavish, Marty and Oscar Pendragon the rocket dog.
Launch of the Akavish! (Roger Smith photo)
My also flown: Estes MINI SHUTTLE to about 375' with another Quest B6-4. Great textbook flight.
I’ll be in transit from Manila, Philippines to Orlando over the next day or so there may not be any blog posts. Thanks for your patience. While on the cruise I wrote an article for possible online publication about how to shape Nike style fin diamond tapers. When I get back I’ll be finishing up the Estes Xarconian Cruiser and building the new improved PIGASUS, soon to be a Odd’l Rockets kit. This model always turns heads and could be popular with rocketeer wives and girlfriends. Drawing up the instructions for the flying pig took a lot of time!
I won this one on a EBAY lot auction for a great price. I'd wanted to build it for a while. The parts are great quality, typical of FlisKits. There are two thicknesses of balsa sheeting, one 1/88" thick and one 3/32' thick. The model is BT-60 tube based.
The Kevlar seemed a little thin, it's probably fine but I'm going replace it with 150 lb. There is an addendum to the instructions to add clay weight. The clay is needed for stable flight with larger 18mm composite engines. Recommended engines are B6-4, C6-5, D10-5 and D13-7. The fin pattern sheet was folded in half though the fin marking guide. Only one copy of the shrouds is included. Fliskits usually includes a few shrouds. This is a complex shroud and I could use extras for a backup. I'll scan the sheets and print off more.
For filling body tube seams, I was mixing the CWF a little thicker than what was used for balsa grain filling. The thicker filling didn't seem to chip out of the seams when sanding to surface.
I had two separate containers of CWF, one thinner for balsa and a second a little thicker for body tube seams. In the container (with the thinner CWF for fins) I noticed the filler at the top of the tub. This is what was left when I would wipe off the excess off a brush. This filler was slightly dried and a little thicker than the filler in the bottom of the jar.
This drying filler turned out to be just right for the body tube seam filling, a bit thicker than the brushable balsa filler. I dipped just the tip of my knife into the thicker CWF at the top.
Set the blade into the seam and drag the CWF drop down the trough. The blade helps guide the CWF right into the seam. You can only do about an inch at a time, then remove the excess.
A razor blade is lightly dragged over the CWF while it is still wet. Don't press hard on the CWF, you want to leave a "skin" of filler over the seam. Don't press hard or you'll pull filler out of the seam. This will be sanded down to surface after drying with 400 grit.
TIP: It's easy to see the seams on the white tubes. On the brown tubes sometimes you can't see them.
Use a sharp pencil and draw a light line down the seam. Use the pencil line to set the CWF drop and drag it down the pencil line.
I'm aware many builders use thinned auto body filler for body tube seam filling. Right now I'm using the CWF with good results. I know it sticks better but I'm concerned about fumes from the auto body filler.
TIP: When sanding the CWF to surface, sand from side to side down the length of the tube, opposite the spiral direction. This helps leave more of the filler in the seam. If you were to sand around the tube, directly following the seam, you could knock some of the filler out of the seam trough.
Here's a rendering of the 1st cut at a RockSim model. I was scrounging around looking for something to build for the new Estes 29mm BP motors. I had an extra Quest MLAS kit and decided to convert it. There wouldn't be much room for a 'chute(s) and a fair amount of extra nose weight would be required. It already uses a heavy lag bolt for the nose weight and is not a particularly durable kit.
I found a slightly beefier tube of the same OD and somewhat arbitrarily decided to stretch it by 1.75". I also decided that I'd use the surviving fins from my high power upscale for the lower set of fins. I haven't assessed the nose weight situation but, between the larger lower fins and longer body, I hope the stock nose weight will suffice.
On the forums, some builders complain of runs after spray painting rockets.
We've all seen this illustration in kit instructions, this one from a recent Semroc Cherokee D.
DON'T PAINT YOUR MODEL IN AN UPRIGHT VERTICAL POSITION! You are just asking for drips.
Set you model horizontal, on it's side for painting.
Use a painting wand to hold onto your model. This is nothing more than a 1/2" diameter with a used 18mm engine casing on the end. You may have to add a few wraps of masking tape to get the casing to fit on tight. Lock it into the engine mount and the dowel will keep the paint away from your holding hand. For a 24mm paint wand, slip a 24m casing over the 8mm casing already on the dowel. Again, add a wrap or two of tape for a tighter fit over the 18mm casing.
Take a look at the white paint to the immediate left of the casing. That's not an illusion, you can see how thick the paint is on the dowel. I've used this painting wand many times.
Here's the casing wand in an Estes Mini Shuttle. This is how I would hold the model for spraying - horizontally. TIP: After I do my final heavier "wet" coat I slowly turn the model like a slow rotisserie. I turn the model for a minute or two. Keeping the model rotating won't allow the heavy wet paint to start pooling and make a run. Slowly rotate until the paint just starts to "skin". Runs can happen anywhere but usually gets thick at the end of the body tube .
The painting wand also gives you something to clamp onto while the model dries. I clamp the dowel into my Black and Decker Workmate. Nothing touches the rocket until it is dry.
If you can feel the body tube seams with a fingernail, the seam will show after color coats are applied.
It's hard to see the seams, especially on the white tubes. Lately I've been dragging a mechanical pencil point down the seam to see it when applying filler.
Seam filling CWF is mixed a bit thicker than the filler brushed on balsa.
I dip the tip of a dull knife in thinned CWF. One side of the blade (facing away in this picture) is wiped off on the lip of the filler jar. Drag the drop of filler down the pencil marked seam. Do an inch then dip, wipe and drag again.
It looks like a lot but you can apply seam filler down an entire body tube in a few minutes.
I've seen forum posts mentioning how CWF filler doesn't stay in the body tube seams.
Mentioned earlier - Use filler mixed slightly thicker for tube seam filling. Thicker filler has less thinned out glues. CWF used in filling balsa is thinner and brushed on. Let the filler in the seams dry thoroughly overnight before sanding. It might feel dry, damp filler won't stay in the seam.
When sanding, sand up and down the length of the body tube.
Don't sand around the tube over the seam. That can knock the filler out of the seam!
Here's a YORF thread I missed the first time around from the 2013 National Sport Launch.
Vern Estes gave a talk about his fourth chilld - Mabel, the rocket engine making machine. You'll find the transcribed PDF HERE It's recommended reading, lots of pictures and many things I hadn't heard of before.
This picture is from the YORF thread, Photo by Bernard Cauley
DECALS! Whether traditional silk screened (provided in some kits), Ink Jet or Laser printed (provided in some kits) and home printed - All have different soak times. Play it safe and scan the kit sheet decals just in case you have to print up some extras.
Don't start with the largest decal on the sheet - Not that huge wrap-around decal! Start small to get used to the soak time and how each kit decal transfers unto the model. Look over the decal position on the model. Should the decal be cut close to the printed image? Will the clear coat overhang a seam or fin edge? Plan ahead and cut out accordingly. TIP: Make that first decal a "test" decal. Cut out the kit number or vendor logo decal, one you probably wouldn't put on the model anyway. This way, if it is ruined you still have all the important decals left over.
Soak only one decal at a time! Start soaking and time how long the decal takes to slide off the backing paper. Set the first decal in the water and count to 15. Take out the decal and see if it easily slides off the backing paper. This is just to play it safe, I've had decals slide off the backing paper after sitting in the soak water after only 15 seconds! It should still be stuck on the backing paper. Soak a bit more. Set the decal on a paper towel until needed. This doesn't mean to let the decal sit for an hour. Apply it in the next few minutes.
There has been forum arguments about using a drop of dishwasher detergent in the soak water. Some say the drop of soap breaks up any beading of the water or makes the decal slide for easier positioning. Others say the drop of soap removes adhesive from the back of the decal. I've used a very small drop of soap in the water for years with no real problems. TIP: For good decal adhesion - Your paint surface should be glossy and smooth.
The picture above shows a decal floating on the surface. You can float a small decal on the surface for soaking. Try to keep the decal off the bottom of your water glass or dish. It's too hard to retrieve a small decal from the bottom of a water glass. I know, I could use less water for the small decals. I was using more water for the larger decal soaking. The larger decals tend to roll up, I needed enough water so the entire (rolled) decal had coverage.
TIP: It's much easier to hold and soak smaller decals held with tweezers. Soak for 15 seconds (1/2 average soak time) and lift out the decal. Change the position of the tweezers on the decal and soak again. Moving the tweezers to the other side of the decal allows the entire decal surface to soak.
This was a favorite, I'd built the Estes original in the early 1970s. The BT-55 tube is strong. It's a clean design with plenty of decals. I don't think it was ever launched with a D engine though. Mainly B6 and C6 engines.
This build will be a little different. It's standard construction - I'll be concentrating on posting build TIPS I'll also be keeping track of how much time it takes for each step.
Here's the parts: Great Semroc Quality Three 1/8" thick fins 12" parachute. The original kit had an 18" chute) It seems like Estes was always including a larger parachute than what was really needed. Most other parts are standard
The parts of interest: Great profile shape of the BNC-55AC nose cone BIG decal sheet, lots of pieces crowded on a half page The 5055 centering rings are cut from thick white stock. On the lower right is the 20/50 engine mount for 18mm engines. One ring is already cleanly split for the engine hook movement.
The Aerospace Projects Review Blog continues to feed us cool retro rockets/spaceships with the TRW Mars Ship. With an ICBM-like capsule, it would be assembled in-orbit, requiring 6 Saturn V flights. It would achieve artificial gravity by spinning with two sections connected by a long cable. Scott's post has several drawings. I picked the one most likely to result in a modroc, just to tempt you. Scale purist should consider purchasing an issue of Aerospace Projects Review (if it is included in one).
A few online vendors are using photos of my finished builds for their website sales. In a way I'm flattered, but I'm never given credit for the builds or picture. This blog is a business. Some finished rockets are sold to vendors and collectors. If I post a build, what gives others the right to sell their product using those images?
I always email and ask before posting someone else's work. There are a few blog posts in draft form that can't be used until I get permission.
As soon as I can figure out how to add a watermark, anyone who copies blog pictures will have my name on it. Others have used my build images, but they simply asked before doing so.
My personal images have been copied and pasted before. My favorite was a phone call I got from a angry woman. "How dare you tell me you love me! I don't even who you are anymore!" Apparently a guitar playing Casanova copied a picture of me playing the guitar and used it to meet women online! She did a web search and somehow got my home phone. After we talked on the phone she did more detective work and found his real identity and address. A carefully worded registered letter (with a threat to contact his wife!) stopped him.
Just because you can right click and "copy" doesn't give you ownership of another person's work. Every picture you find on a search has the origin address. Do the right thing and ask before you copy and paste.
Here's another one that can be made from parts from the Baby Bertha kit. This was the Estes kit #1391.
Check out the instructions at the JimZ plan site HERE
This will be a spare parts box build. The red nose cone did come from a Baby Bertha kit. It was painted red when it temporarily sat on my Ranger. A shot of primer and some white and it'll work on the Shuttle. All the patterns were copied and printed from Ninfinger's.
The instructions say the clay is 1/2" square. I'll have to check the weight.
The wings and rudder were cut from 3/32" scrap balsa. The wings are made from three pieces of balsa.
From the Space Age Industries catalog is the MINI BAT boost glider.
I built this one a few years back but have yet to launch it. Hand thrown trim glides were done, there was a ding in the nose cone. The plans are HERE
It's a short, chunky boost glider. The wing is large and a long rudder is on the underside.
The view from the back - There are small raised aerilons on the rear edge of the wing.
And straight on - First launches will be with a 1/2A3-2t. The engine mount tube is a BT-20 so the 13mm engine will be friction fit into an empty 18mm casing. Before flying there will be a few test tosses and clay weight triming.
This isn't my idea, I wish it was. I saw the Cherokee Goon on TRF, HERE John Bergsmith (Boosterdude on TRF) posted the first pictures I'd seen of this Gooney. He got the decals and fin pattern from a post from Blades HERE. Go to the second post for the decal art.
I've got pieces and parts from a Baby Bertha kit, the nose cone was painted red from another project that never got finished. The engine mount was built for pictures from the Apogee article on replaceable Kevlar.
The decal art was lifted from a Semroc (full size) Cherokee D kit. I'll redraw the decals to fit the BT-60 diameter and print up a new set.
This Cherokee Goon uses the same sized fins as the original BT-55 kit. I'll use the Semroc kit fins for a tracing pattern. EDIT: After the model was built, they could have been a little smaller!
The Baby Bertha is still one of the best deals in rocketry. Buy it with a Hobby Lobby 40% discount coupon for $6.00.
TIP: Change out to a 18" BT-60 and make a Big Bertha - OR - Add and 11" length of BT-60, a nose block and three BT-20 engine mount tubes and you can make a 3 engine cluster Ranger -OR- Go to Excelsior Rocketry HERE and check out all the Goonies. Most can be made from the parts in the Baby Bertha kit, some require additional parts, usually just 3/32" balsa.
A real classic, available from Semroc as an X Kit.
I finally got the landing pods right this time! I was never happy with my first attempts carving them out of balsa layers. The white edged "1" decal looks good against the single black fin. It was worth the extra effort.
The nose cone shoulder is well hidden behind the black bands.
There are a few decals left over, some black rounded rectangles. I'll save them for another build. This model shared many of the same decals as the two-stage Shrike kit, HERE
I found the MMX Saturn V the most interesting of the new releases from FlisKits.
Here's all the parts -
It's advertised as the "World's Smallest Flying Saturn V". I checked - the Quest MMX Saturn stands 5 3/4" tall. The FlisKit Saturn V is 4.65" tall.
Some parts of interest, clockwise from the left: Water slide decals that take care of most all of the trim. The card stock sheet with the fins and drag shroud Plastic streamer recovery Scalloped ring that forms the rear edge of the engine skirts Balsa nose cone forming the upper stages Small plastic rod for the launch escape tower.
On the back of the instruction sheet are the engine skirts. Jim Flis always gives extras on pieces that might be hard to make the first time around. Thanks Jim - a great idea for small parts.
A while back, Rocketarium came out with a LOT of scale kits! Most are BT-60 based kits and feature a new ogive plastic nose cone.
Parts are of good quality: Centering rings are laser cut plywood The balsa fins stock is hard and stiff. (Newer kits have pre-cut fins)
Parts of interest: (clockwise from left) Large tri-fold shock cord mount Clay weight Plastic nose cone Adjustable size parachute, 15", 12' and 9". 1 mil, red ink over clear Two wide spring steel engine hooks Fin attachment stickers (I'll redraw and make water slide decals) Fin Mounting Attachments (cardstock) Fin Patterns (Center)
The instructions lack an exploded drawing. David Stribling drew it up HERE Check out the PDF link in the first post. Other posts answer questions about paint patterns.
This was an early edition of the kit with fins you cut out yourself. The kit now includes pre-cut fins. My instructions were only four pages long with limited illustrations. The instructions have now been expanded and improved. Online I found six pages of instructions with more illustrations.
This is one I've looked forward to building for quite a while - The Sirius Interrogator. This is the 18mm engine version, Sirius also makes upscales of this design.
From left to right, the parts of interest: Three water slide decal sheets! Lots of decals with clean graphics. 1/16" thick balsa PRM (Paper Reinforcement Material) One printed with the fin patterns, one blank Fin Pattern sheet (for those who may not want to use the PRM) Intake Tube Cutting template 8 Sided 12" Mylar Parachute
A side note: Here's what the box looked like when it arrived! This is no fault of Sirius Rocketry! USPS did the number on the end of the box. The kit was well packed and there was no damage to the parts.
The Tampa TTRA flying field was overcast with a good chance of rain. After a short delay, flying started around noon.
The BIG GIRTHA (Re-Birtha!) just finished on this blog was flown with a cluster of two Estes C6-5 engines. Estimated altitude would be around 1,000. A slightly reefed 14" parachute brought it back close this time with no damage.
Tammy Spyker flew her Gnome with a G64-8. A very creative design, the red nose cone is the Gnome's hat!
Check out the notched centering rings in the inset picture. The fins are through the wall and also through the rings! This technique has been talked about on the forums. You'll see more of this construction in the future. Tammy's husband made the notched rings and baffle.
Big thanks go out to Brian Urban, he returned my spy cam today! He kept it safe until we met up this afternoon.
Here's Brian's four engine cluster, two D12s and two C6 engines. The fins have spin tabs sanded into the trailing edges. The silver upper body is made from Red Bull cans!
That's Bill Gibson with his Paladium Destroyer. It flew beautifully with an Estes D12-5.
To the left is Lawrence Brown's Viper. On the right is my Dr. Zooch TITAN IIIC launched with an Estes C6-5. Estimated altitude was 600'.
My also flown: Repaired Quest RAPTOR with an Estes C6-5 to an estimated height of 500'.
EDIT: This one is a challenge! The face card lists this as a Skill Level of 3. The Custom website mentions a Skill Level of 4 but no listed models have that level. This borders on the Master Modeler's Level 4, maybe a level 3 1/2. For a smaller "T" engine kit this build took a LOT of time. To paint it like the facecard you have to build and fill in subassemblies. If you are looking for a inexpensive challenge, add this one to your want list! It's an impressive design.
I bought two of the Custom P.O.N.G. kits on Ebay at a pretty good price. Shipping was cheap! There was a reason why. The kits were shipped in a padded envelope, no box! Most all the body tubes were crimped and bent. Luckily I have extra tubes and cut some new ones to size.
For a 13mm "T" engine model, this one is detailed. Lots of tubes and some very small BT-5 couplers.
The parts of interest: A 65 lb. paper shroud (I'll scan and print more on heavier stock) The pink streamer (maybe a 6" parachute might be better) The ping pong ball nose cone 8 (yes, eight) 5/50 centering rings Two yellow BT-50 sized tubes. These look like the thinner BT-50 pre-colored tubes that come on some RTF models.
Three stick on decal sheets. The model is interesting enough without the decals, but these will really dress it up.
If you didn't know, I build rockets for Model Rocket Vendors, collectors and hobbyists.
If there is a favorite model you'd like to own in it's classic catalog decor, let me know! I guarantee accuracy, (unless you specify update changes) no balsa grain or visible tube seams. Interior and exterior construction are clean.
I'd be happy to give you a quote and a realistic time frame for delivery.
The Meatball Team won the scale competition at NARAM 50. Stop by their website and find out why! You'll find Plenty of scale information and build tips. http://meatballrocketry.com The articles on how to make the Saturn 1 (or 1B) fairings are worth the trip alone! Go to Model Rocketry, then articles.
I'm sure everybody has built one of these. I built a Bullpup when I got back into the hobby a few years back. My kit was a later version with the stick-on decals. Like most, I've always hated stick-ons. I bought another and did a kit-bash to make a convincing sport scale MX-774.
This "kit" was bought from the JonRocket trailer at a recent R.O.C.K. launch. There were no instructions included, but for $5.00 I didn't pass it up.
Here's all the parts next to my original built up Bullpup.
This early kit included the water slide decals! All the die cut fins were broken off the balsa sheet. The blades were dull when these fins were cut out.
The pieces of interest - The tail cone/adapter, Yellow thrust ring spacing tube, 3.5" long engine mount tube, Too short length (16" long) of elastic, not rubber Water slide decals! (Worth the $5.00 sale price alone) 1/2 oz of melted clay nose weight Separated die-cut fins, 3/32" thick
I bought three Quest Area 51 Saucer starter kits (with launcher and controllers) for $.99 on Ebay! Shipping charges certainly brought up the price, but still a bargain for the launchers and controllers alone! We've all seen the Quest launchers before, here's some information about assembling the saucer.
Here's the upper side of the Area 51 Saucer. Metallic stickers are already in the window areas.
The engine hook was set at an angle. I thought the retainer ring would be glued down, but the hook was twisted around until it was straight. (See inset picture)
Installing the wire antenna legs is confusing. You'll never get them over the inside legs with the black corner piece at the angle on the left. That's how all three were shipped.
You've got to turn the black piece as shown in the inset picture.
I need some "non-standard" centering rings for an upcoming build. A series of three interchangeable engine mounts will be made for a Semroc Centurion. I don't use BT-20 tubes for 18mm engines, they are too thin and weak. ST-7 tubes will be used. No BT-50 tubes for the 24mm mount, again too thin. I have some thick walled BT-50 tubing. The Semroc Centurion uses a Centuri style ST-16 mainframe. Sure, I could put in a custom order, but sometimes it's quicker and cheaper to just make your own from scrap framing mats.
I don't have a circle cutting compass. I know, I should have one. These rings will be cut with a new #11 X-Acto blade.
Trace around the larger diameter tube first. You won't be able to visually center the large tube if the smaller motor mount tube circle was drawn first. Use a sharp, thin mechanical pencil.
With the larger tube diameter drawn you can center the inside tube circle inside of it. Draw and check the center circle. If it's off, erase and redraw. It might take a few tries.
TIP: Cut the smaller inside circle first! You'll want to have plenty of border material to hang onto.
Here I'm cutting a little inside the pencil line. The traced line was drawn around the outside of the tube. You have to make allowances for the thickness of the pencil line next to the outside diameter of the motor mount tube. You can always sand to a perfect friction fit.
I should have made a resolution to install a length of coupler above the engine mount on all BT-5, BT-20 and BT-50 tube models. I've been through this tube crimping too many times in the past. You can get longer couplers from many vendors. The standard 1" long coupler would be too short to reinforce the tube. You can even get 34" long coupler tubing from BMS. Cut it to the length you need.
Here's how my Custom Solar Explorer body tube looked like after the first flight! I'm not blaming the Custom Rockets company - it's just that BT-5, BT-20 and BT-50s are thin tubes. All three will crimp and buckle especially right above the internal motor mount. One hard landing and you'll see wrinkles. Pull a friction fit engine that's too tight and you'll crimp the tube.
I had to pick a location to cut the body tube to insert a long coupler. The coupler won't get rid of the wrinkle in the tube, it'll just strengthen the area above the engine mount where crimps occur.
To hide the separation line I decided to cut right along the base edge of the stick on decal. With any luck, when the tubes are re-joined the seam won't be that noticeable.
I used a new, sharp razor blade. It was difficult to cut around the leading edges of the fins.
Here's the tube after being cut.
I had to untie the Kevlar from the elastic, coil it and store it in the mount for the next step.
Both ends of the cut tube were sanded square with 400 grit on a block.
The coupler will butt-up against the forward centering ring of the engine mount. It will need to be long enough to extend past the crimped area of the upper tube.
I picked this one up at the February Orlando R.O.C.K. launch. It's originally a Custom Rockets Zero Gravity kit. I saw it in a "bargain box" at the jonrocket trailer for $5.00.
But, something was wrong - Take a look at the nose cone - Somewhere down the line it was subjected to heat and warped! The bend starts about halfway down the nose cone.
I showed it to Roger and he said: "$2.00!" Heck, for the parts alone that's a great price. I bought it, warped nose cone and all.
The parts of interest: Of course, the warped nose cone. 1/4" elastic shock cord seemed thick for a BT-50 based model. The Die Cut balsa fins. (I thought all kits had laser cut fins these days.)
The other parts were of high quality, the BT-50 was better than many I've seen in recent Estes kits. I like the Custom line of kits. Good quality at a reasonable price. Now, what can I do with that nose cone?
Here's the next project on the blog - The Estes PLASMA PROBE, Kit # 3211
Compare the Plasma Probe side by side the older Centuri Laser X Space Probe. The Laser X was Centuri's answer to the Estes Mars Snooper. The old Estes Mars Snooper and the Centuri Laser X have smaller forward fins. The colors and roll patterns are about the same. There is definately Centuri influence here.
Last year I called Lee Piester (Centuri Engineering President) and he mentioned there was a new Estes kit that looked a lot like the Laser X. This has to be the one he was referring to.
Centuri came out with the Stellar Line in the mid 1970s. The futuristic design in the series was the Photon Probe, kit # KD-16. That black and white pic on the right is from the JimZ site. The forward fins on the Laser X have been replaced with the 8 small strakes.
Next up was the Estes Solar Probe, the reissue of that design. This one is almost an copy of the Centuri Photon Probe but no dowels on the fins. Both the upper adapter and rear boat tail are card stock shrouds. All four previous models have the word "Probe" in the name.
Here's the back end from my flight worn Semroc Laser X. There aren't twelve coolant vanes on the back end of the Estes Plasma Probe. No rear card stock boat tail either.
The Laser X had 1/16" thick balsa throughout, a little thin. The Plasma Probe has 3/32" thick fins and strakes.
I bought this one off EBAY for about $10.00. In the mid 1970s I built and flew many of the MPC Miniroc series - except for the ASP and this one.
This kit was billed as a "customizer kit". It included some extra chromed plastic parts.
All the parts: That's a 12" parachute - too large for a BT-5 based model. Two sheets of decals are included. One sheet has roll patterns, the other has "United States" , numbers and the Air Force Star and Bar logo. Four die-cut balsa fins cut from 1/16" thick balsa.
There is two small booster tubes. They are thick walled, about 3/16" diameter. The two chrome nose cones fit into the tubes.
That's a Stine "Shock Lock" in the center. The cotton string is the only shock cord on the model. No elastic, just a thick cotton string.
The parachute shroud tabs will be replaced. Most of the adhesive has lost it's grip.
Here's a closeup of the chromed pieces. All were still on the trees except for the small nose cones in the previous picture.
The pieces on the left look like they were taken from a plastic car kit. The pieces on the right probably came from a Apollo based model. In an optional step you are told to use the long silver pieces on the left as a nozzle in the booster tubes. All the other pieces aren't mentioned in the instructions.
After the model was built I saw an MPC Moon Go kit on sale on Ebay. The same chrome parts were included in this larger kit. The box illustration shows the "hub cap" looking pieces at the base of two fins. Small chrome details are glued over the leading edges. The same Taurus boosters are used in the Moon Go kit.
This model was designed by Shrox when he was working for Quest. It was featured on the 2010 Quest Catalog cover with two ES-1 Escort models.
It's a larger model to be flown with 18mm engines. On any larger model over two feet tall, I usually convert them for 24mm engines. This model is 23" long with large wing fins and many details.
The motor mount, shock cords and dowel details are in a single bag.
Parts of interest: The large Intake Tube was out of round. This probably happened during storage or shipping. It's almost two inches in diameter and shouldn't be hard to reshape.
The seams (see inset) are another story. The seams are wide and deep.
From the Quest website: "The future of Presidential transport! Another visionary design by SHROX. Two big decal sheets (we couldn't fit them all on one!) really make this rocket a visual dazzler! Slow impressive lift-offs with B6-4 and C6-3 motors."
I was a little disappointed, expecting water slide decals. But, I understand the reasons behind the stick-ons. The big blue trim decals would be very hard to use if they were water slides. The two sheets have a few wrinkles. I might scan these and print out some water slide decals.
A 4FNC rocket? I always need good models for soccer field launches and I have plenty of A6-4 engines to run through. There were "gotchas" on this build and some problem solving. Many have had trouble packing the wadding and streamer in such a short body tube.
I built a clone of the Quest Cobalt a while back.
I wasn't happy with the stability and wanted to try the actual Quest kit to see where I messed up!
All the parts -
That 40mm body tube is only 4" long!
The engine mount centering rings are a thicker, stronger stock. Older Quest kits had thin rings. This is a good improvement.
The laser cut fin stock is 3/32" thick.
Some pieces of interest -
The centering rings have no notches cut for the engine hook movement.
There is no hole for the Kevlar line. The engine hook will be replaced with a spring steel hook. Below the engine hook is the "Gripper Tab" to attach the streamer to the shock cord. Self-adhesive sticker decals - oh great!
Fifty-one BP motors sure make an impressive column of fire, as seen in this photo of Boris Katan's Hell Boy 70. There are more photos on his TRF post. He reports that it hit 1,250' and both parts recovered well. In fact, the 'single use' booster is partially reusable. One of the 19 sustainer motors didn't fire but at least in my book this was totally successful. So cool!
The Dr. Zooch Saturn V gets more searches and blog hits than any other model kit! When I built my Zooch Saturn I never did a build thread. Back then I wasn't scanning the wraps. It's about time I did a full build on it!
All the small details will be made first. All I can take along with me on this long cruise - Small parts, dowels, toothpicks a break off blade knife and sandpaper. Body tubes, balsa adapters and nose cone will have to wait until I get back home.
This is all the parts!
The main body is a BT-60 tube. There's a trash bag parachute and 1/4" wide elastic for the shock cord.
The centering rings are black Letramax material.
Sorry, I didn't photograph the wrap sheet! It's really a highlight of the kit. I'll try to include it in a later post.
And the parts of interest: The smallest balsa sheet you'll ever see in a kit! There's plenty for the four small fins. Zooch always gives you an extra shroud line disk - there's seven! Enlarge the picture and read the note. Dr. Zooch (and a few other vendors) got some bad decal sheets! The paper glue on decals are supplied, just in case.
The pre-weighted adapter. The inset picture shows the wider, weighted end.
On the small end is the drilled hole for the escape tower dowel.
These LED "Finger Lights" are sold through the Publix supermarket during the Halloween season. Kids wear them for safety after dark and as part of their Halloween costume.
I actually bought these with the idea I could use these on stage. Imagine a dark stage, a fast banjo roll and colored lights. (Yeah, I know, stupid idea. I'm always looking for the next big thing.)
It didn't occur to me to use these for a night launch! It's pretty obvious, the lights have an elastic band to go over the fingers. The elastic could be slipped right over a body tube. A little tape for insurance and you have a cheap light for night launches.
Four lights for $2.00!
This is the back of the package with the catalog number and other information.
I did a quick search and they are available through many online vendors! Search under LED Finger Lights.
I tried the elastic around everything from a BT-20 to the BT-60 on my Red Max. The fit is pretty tight around the BT-60 size. Be careful the back side of the plastic light casing doesn't scratch the finish or decals. Two layers of electrical tape on the back of the housing could help prevent scratches.
On a BT-20 you'll have to add some tape over the elastic band or it might slide down the body tube during a quick boost.
"This is the "Mudd Team"'s entry into the N5800CS competition. We are flying ours at XPRS (pending no tragedies in the remaining construction process). It was designed to be such that we could build it ourselves (well, by myself mostly, but that's a different story) at Harvey Mudd College over the summer. It uses as many in-house-fabricated parts as possible, as we prefer working with our own processes and materials, especially given the ease with which the N5800 has shrugged off commercially-made nosecones/body tubes/fincans in the past."
This rocket seems ready to handle the N5800, particularly because it will use an aluminum fin can. Not only is metal superior in heat resistance and strength, but the alignment will also be better than with fins installed by hand. The nosecone will be reinforced significantly as well. My only remaining concern is the coupler used between the motor case and noscone; it is a conventional fiberglass airframe. Now spiral wound fiberglass is extremely strong, but it is still conventional. I think it is the weak link in the project thus far. With some reinforcing ribs it would be more likely to survive the flight. I look forward to hearing more about this project.
The original Estes Midget kit was one of the first rockets I ever built. In 1969 I thought $1.25 was a great price for a two stage rocket!
Before I start on this one - This build is not the recently released Retro Repro Midget kit from Semroc and not the original Estes kit. This is a clone kit I picked up off EBAY. I thought the price was good, under $10.00. The new Semroc kit is only $10.00!
I should have waited for the Semroc repro! There was too many things that needed fixing to get it close. Here's the parts I received. There are two 1 3/4" long 18mm casings I cut for 13mm engine adapters. I got this idea after reading over the Semroc Midget instructions online. When I received this kit, I thought - How ridiculous! This model can't be flown with current 13mm "T" engines. It was a clone of the old "S" (for short, 1 3/4" long) engine model. So it sat in the build pile until I saw how Semroc adapted 18mm engine casing adapters. A simple solution.
ï»¿The strange thing is, these fins were laser cut by Semroc! I could assume most all the other parts were also from Semroc.
The clone kit didn't include a parachute or a proper shroud. I wrote a note to the producer of the kit and a new Estes 12" parachute was sent.
The 20/50 shroud transition was printed on 20 lb. copy paper. I felt it was unusable. A 110 lb. cardstock print of the shroud was sent with the parachute.
To the right is the LONG dowel for a lug standoff, the laser cut launch lug and
the two, 1 3/4" 18mm casings.
The short BT-20 tube is the engine mount tube for the upper stage, probably the shortest engine mount tube I've seen in a kit.
Above it all is the 20 lb. copy paper shroud. More on that later.
To the far right are the very short 1/8" long engine blocks. One goes above the upper stage engine as normal.
The other goes below the booster engine in the first stage.
Ray Lapanse has just started posting photos. He currently only has photos of Troj's Insane Project flying and CATOing on a 'P' motor. The album will be worth visiting again over the next few weeks. (While you're at it, check out his other albums. The LDRS-29 photos are really great!) More good news. He allows re-posting with attribution. Consider this attributed. Here are just a few low res copies to show how big the rocket was, and how big the ensuing boom was.
I picked this kit up for $10.00 at the May TTRA Tampa launch. I'd seen a few on EBAY, but never closeup.
Stellar Dimensions is no longer in business, they had a half dozen kits in production in the late 1990s. Their claim to fame was their rocket bodies were square. Most all parts were laser cut from basswood and thin ply. The visible side of the body parts had faint laser cut lines in geometric patterns.
Here's all the parts laid out. If you count everything, there is 48 pieces to put together.
In the bag, the kit seems flat. There is no round body tube or nose cone to be seen. Some of the laser cut parts had broken free from the sheets. The loose pieces were taped together for the picture.
Along the bottom from left to right are the 4 engine mount sides, 4 fins, 6 engine block centering rings and 4 mid body pieces.
The four long tapered pieces above are the nose cone sides.
Here's some of the more interesting parts. One the left are the big shroud line tabs and plywood reinforcements. The tabs look like Breathe-Right nasal strips! The white circular piece is the Teflon motor lock ring. The black coil is the short shock cord. It's like a thin piece of licorice, too short for my liking. On the far right is the "centering rings / baffle" pieces. More on those later.
This may look like a standard build but we will be covering:
Making your own centering rings from card stock and cereal box cardboard
Making a "close" clone from a internet photograph
The Odd'l Rockets XLEH EXtended Length Engine Hooks
I know that most modelers would "clone" a favorite old rocket model that has been out of production (OOP) for many years.
The Cobalt is a new kit. It was first shown in last year's Quest catalog with a scheduled release date of July, 2010. It was released just a few months back. I have a few extras in this nose cones style (PNC-40) and plenty of the Quest 40mm body tube. Why not build a new Squatty for the A6-4 schoolyard launches?
Please note, this will be a close, not exact clone of the Cobalt.
Parts needed from Quest: PNC-40 Nose Cone T403000 40mm Body Tube 4" needed
I supplied other parts from my stash: 1/8" X 1 1/4" Launch Lug 3/32" Balsa 12" Kevlar 18" Round Elastic Shock Cord 2" Wide Crepe Paper Streamer
Specialized Engine Mount 3" Long ST-7 Engine Mount Tube (Semroc) TR-7 Thrust Ring (Semroc) One Odd'l Rockets XLEH Extended Length Engine Hook Two homemade Centering Rings (ST-7 / 40mm) The rings in the picture are not the ones used in this build.