LOC/Precision - Onyx {Kit} (PK-12)

Contributed by Nick Esselman

Construction Rating: starstarstarstarstar_border
Flight Rating: starstarstarstar_borderstar_border
Overall Rating: starstarstarstar_borderstar_border
Diameter: 3.10 inches
Length: 25.20 inches
Manufacturer: LOC/Precision
Style: Sport

The LOC Onyx is my second LOC kit and I purchased it as one of three "stubby" rockets that were around three inches in diameter. This diameter compliments my 2.6" and my 4" collection. I had also purchased a RocketVision Grymm and the Estes Big Daddy. See my 3" Stubby Rocket Comparison Page

The Onyx is the biggest of the three being 3.1" in diameter and 25.2" long, qualifying as a "stubby" rocket because it has less than 10:1 ratio (8.1 to be exact). It also uses the largest motor mount with a 29mm verses the 24mm mounts in the other two mentioned kits.

Rocket PicThe Onyx includes a 14" long standard LOC paper glassine coated airframe. It is pre-marked for the fins and launch lug with lines. The 11.2" plastic nose cone makes up the remaining length. There are three (3) 1/8" thick plywood fins that are pre-cut. There are also two (2) 1/8" thick plywood centering rings. The motor mount is 29mm and 6" in length. The recovery system consists of a round 16" nylon parachute and ~65" of 1/4" wide elastic along with the standard LOC nylon loop for mounting the recovery system to the side wall. There is an 1/4" launch lug to wrap up the components.

CONSTRUCTION:

The instructions for the Onyx were printed on the back of the 8½ x 11" card stock that displays the kit specifics through the plastic bag that held the kit. There are only two illustrations, a rear view and a side exposed view. These give some direction, however, the kit is designed for those that have built some before and don't need picture-step to picture-step guidance. The text instructions are clear and take the builder from start to finish and give some insight into flying preparation. Also the shock-cord mount has its own instructions separate.

I built this kit exactly as the instructions directed. There were no surprises and all of the parts fit very nicely.

I don't understand why LOC doesn't use through-the-wall fins that go to the motor mount (or even just some tabs) and had some frustration with that fact during flight.

I built my own 24mm adaptor for this rocket. Here's what you need:

  • 1/2" length of 29mm tubing
  • 4 to 6" length of 24mm tubing (I used 4")
  • masking tape

Take the masking tape and start wrapping at the top of the 24mm tube about 1/8" from the end. Wrap fairly tightly and evenly. Around and around and around until it looks to be about 29mm in diameter. Tear off and test fit into the 29mm motor tube. It should be snug but not overly tight. Once you have the right amount of masking tape at the top, repeat the process at the bottom but making the tape even with the bottom of the 24mm tube. Test fit until it is snug then take two passes of tape back off. Now take a hobby knife and cut some horizontal slits (while holding the adaptor as it would sit in the motor mount (up and down)) in the tape on the end. Make several on three sides. Wiggle the knife so it opens up the slit slightly. Next test fit the 1/2" length of 29mm tube and make sure it fits over the tape. It's now ready for epoxy.

Using 30-minute epoxy, seal and make a small fillet on the both sides of the masking tape around the top of the adaptor (opposite of where you made the slits). Be sure not to get epoxy on the face of the masking tape as that will prevent the nice fit into the 29mm tube. Next using some level of precision, fill the slits you cut with epoxy and then immediately coat the inside of the 1/2" length of 29mm tube. Give it plenty. Then slide with twisting motion the 1/2" length of 29mm tube over the masking tape until it is even with the end. Wipe off any excess that got onto the face of the exposed masking tape and the upper edge of the 29mm tube since this sits against your 29mm motor mount. Run your gloved finger around the end of the adaptor spreading the epoxy on the outer edges of the 24mm tube, masking tape and 1/2" length of 29mm tube. Wipe off any excess that got into the 24mm tube. Place this assembly on some wax paper with the 1/2" length of 29mm tubing down. Once dry, make a small fillet on the top of the lower masking tape the same way as you did on the top masking tape. That's it. You can modify this technique and add a motor hook to the 24mm adaptor, however, you would either need to glue the adaptor into the motor mount or still come up with a way to retain the adaptor in the motor mount.

The Onyx's recovery system is assembled from its own set of instructions. It consists of a length of braided nylon cord which is knotted at both ends, and knotted with a 1" loop in the center. The two knotted ends are taped to the inside of the body tube with the knots on the far side of the tape. Then it is coated with epoxy to completely cover the tape and the knots. The top of the nylon with the 1" loop sticks out of the top of the rocket and is used to tie the elastic shock-cord to.

I know I didn't spend any time talking about the actual construction and that is truly because it is straight-forward and quite easy.

For finishing, I didn't use anything to fill the spirals and just started in with several coats of Plasti-Kote Sandable Primer. I coated the plywood fins heavily with primer for the first coat . . . and I mean heavily. I sanded back most of this primer and did it again. The third coat allowed everything to look smooth. I then painted the entire rocket with Kylon Gloss Orange paint, per the recommendation and desire of my 3 year old son. LOC doesn't provide any decals and since I was in Arizona, where this entire rocket was built and finished, I grabbed an Arizona sticker to commemorate that.

Rocket Pic

Overall, for CONSTRUCTION I would rate this kit 4 points. Instructions are adequate if you have built other rockets. It has quality components that fit together without sanding. The main detractions are that the fins are not through-the-wall which for a 29mm powered rocket I would like to see. There is no provision for motor retention. Also this kit should have some decals to spice it up.

FLIGHT/RECOVERY:

Download RockSim file here! This file is set up with an added mass object that is used to set the weight equal to my finished rocket (16 ounces) and adjust the CG to 16" without motor.

RockSim PicAs I mentioned before I was in Arizona when I built this on a vacation. We planned this trip to Arizona and it just so happened that there was a launch on 12/23/00. So I packed this kit and 3 assembled rockets into a box and shipped them to Arizona.

I had to rely on the vendor at the launch for motors and I was able to buy a 2-pack of EconoJet F23-7 BlackMax motors. So, all set and ready to go.

I prepped the Onyx™ using a RocketMan RHFS12 Round Heatshield that I purchased from the same vendor. After setting up and positioning for a picture . . . which I was not successful in getting . . . I launched her.

It was an excellent flight, with nice black smoke and very straight. It was just before apogee when the ejection charge blew. The descent on the supplied 16" round parachute was quite fast and it landed within 50 feet of the pad. Upon landing one of the fins separated from the body tube. The fillet and paper tore away on one entire side and it was just hanging by the paper on the opposite side just past where that fillet ended.

Well, since I wanted to use both of my EconoJets I decided to try to repair this in the field. I had some SuperGlue and soaked the paper under the separation and held the fin back in place. After about 1/2 hour I checked it and to my surprise it felt really strong. I showed another rocketeer for a second opinion and then decided to go for it. The fact that I was flying on F23's helped my decision since it is a low thrust motor.

For the second flight I added a second parachute (18"). The second launch was also very straight and ejection was just before apogee. Descent, although better, was still somewhat fast. No damage this time though.

For FLIGHT/RECOVERY, I would rate this kit 3½ points. The descent rate is simply too high for this rocket. Even if it weighed in at the manufacturer's specified weight of 13 ounces, the minimum diameter parachute should be around 30" for high descent rate of 15 fps. My kit came in at 16 ounces so I would expect needing an even larger one. Secondly, the fin came off. This is probably due to the high descent rate, however, the surface mount fins didn't seem to help the situation.

Overall, the Onyx™ has great looks and assembles quickly. It uses quality parts. Its lack of decals, motor retention and the parachute size detract from it. Experienced fliers will adjust for all these things on their own which probably draws many builders to this kit, however, as a kit it appears to be lacking some. I give the kit an OVERALL rating of 3½ points.

Other Reviews
  • LOC/Precision - Onyx {Kit} (PK-12) By Chip Jenkins

    Single stage mid-power rocket. All of the parts were contained in a plastic bag and they were all intact and high quality. The airframe had a very small spiral groove, the fins were top quality plywood, and the nose cone was sturdy plastic. The centering rings were also quality plywood. The parachute provided was hot pink in color and 15" diameter. The instructions were contained on the ...

  • LOC/Precision - Onyx {Kit} (PK-12) By Alex Jordan

    The LOC Onyx is a stubby 3 inch mid power single stage rocket with 14 inch chute recovery. The fins are glued directly to the body tube with no tabs. It has a 29mm motor mount. This was my first 3 inch and LOC/Precision kit. I didn't know what the quality of the parts would be but they turned out to be great. The contents of the bag were: 2 3" x 29mm plywood centering rings (1/8" thick) ...

  • LOC/Precision - Onyx {Kit} (PK-12) By Bryan M. Chuck

    ( Contributed - by Bryan Chuck) Brief: The LOC/Precision Onyx is a popular entry level mid-power rocket capable of G motor flights. After tinkering around with RockSim, I decided to convert the rocket for a 38mm motor. Modifications: Although for me this project was born via spare LOC parts, I had sitting around, the listing below is what one would need if he or she bought the Onyx as ...

Flights

Comments:

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B.H. (January 1, 2000)
At the Danville 99 launch we launched 3 of the Onyx's on H128 reloads. They held up just fine.
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R.F. (June 1, 2000)
I bought this rocket because I like the stubby profile rockets. I am also trying to stay within the less than 1 lb, less than 1000' limitations. Personally, I am not a fan of surface mount fins, so I cut slots in the body tube and made identical fins, except tabbed to the motor mount. I, too, used epoxy everywhere (I won't trust glue on anything anymore). Instead of fussing with a smooth surface finish, I sprayed on a faux granite, which gave a marvelous rough green surface, and made its own fillets. It was pretty heavy stuff, and was used up pretty fast, so I painted the nose cone fire red. (I am not so sure that pursuing pure laminar flow is always the best idea, remember the dimpled golf ball). Anyhow, I stuck an EconoJet F20 in it, and it flew great. With the relatively small 'chute, it came down pretty close to the launch pad. Wrasp says it went to about 950' (not sure about that drag coefficient and the borderline weight). I expect many great flights out of this bird, because it is very sturdy, and very simple (what, me worry?). If it were my review, I'd give it about a 5. I liked the review. I found it very much like my experience with this rocket.
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B.B. (July 1, 2000)
I personally suggest this kit for anyone looking for a small fat rocket with little experience in high powerrocketry. This rocket will fly on just about any motor, it doesn't have to be selected from the list on the title page. I have flown it twice and both of the flights have been on an ECONOJET F20-7W. Both flights were beautiful. This rocket is easy to build, I built it in one day!!! Plus it is always neat to see a small fat rocket fly!!
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B.B. (July 1, 2000)
I personally suggest this kit for anyone looking for a small fat rocket with little experience in high powerrocketry. This rocket will fly on just about any motor, it doesn't have to be selected from the list on the title page. I have flown it twice and both of the flights have been on an ECONOJET F20-7W. Both flights were beautiful. This rocket is easy to build, I built it in one day!!! Plus it is always neat to see a small fat rocket fly!!
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T.E. (April 1, 2001)
My 13 yr old son bought this kit and ask me to help/built this kit for him. I agree it is a neat,relatively inexpensive kit. Most of the parts fit great. The only exception was the fins. They were all the exact same size but the root edges had 2 noticeable curves in them. It took a fair amount of sanding on a block of 100 grit paper to fit them flush against the tube. I also do not like the surface mount to start with. I solved this by using PML's and Vaughn Bros. technique for minimum diameter rockets. I cut "dado" slots approx half way thru the tube. Tacked the fins on with medium viscosity CA and then filleted with epoxy. This works great and is very easy with the LOC tubing as opposed to phenolic. I had suspected that the chute was too small and after reading these reviews , it looks like I was correct. I would also like to see some decals -- maybe some stripes and an Onyx decals as shown in their photos of the rocket.
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D.P. (December 5, 2001)
This is a great kit. It will fly on anything from small E's to big G's without any problems. The stock parachute needs to be upgraded, and a 22" or 24" will work fine. Load her up with a G80FW to give her a ride!
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S.P. (August 29, 2002)
I loved this rocket an easy build and great flyer. The people i fly with always enjoyed seeing this one go up. Unfortunately it was destroyed when the g-38 I was flying it on exploded on the pad. I was sorry to see it go, I'm planing on building another one this time i might modify it to fly with 38 mm motors.
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M.M. (August 2, 2004)
Want to have some fun? Try a cluster version of this kit. I bought a kit, and ordered a 3x24mm set of centering rings and a coupler tube. Cut three short 24mm motor tubes and epoxy into the front centering ring. Cut the fin slots through the body tube. Then epoxy the front centering ring (with long Kevlar® shock cord installed) into the body tube. Epoxy the coupler tube in the body tube. Epoxy in the aft centering ring. Now install the fins using plenty of epoxy in the slots, which attach the fins to the coupler tube. Cut off the bottom of the nosecone and add lead to the nose tip, using epoxy. Also add an eyebolt so you have an attachment point for the shock cord. My verion needed 4oz. of lead shot to ensure stability. I first flew this rocket on 3 D12-5 motors to about 500 feet. The I installed 3 E30-7 motors and it blew me away, hissing skyward to about 1800 feet. I plan to fly it on 3 F21-8 motors for a high power flight (165Ns).
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A.M.D. (July 11, 2005)
I flew my ONYX on an F-21 Econojet motor and she tracked straight and true. However, when deployment occurred the shock cord split and the parachute disappeared. The nosecone separated from the body and the two fell separately to earth. Upon impact only minor scuffing was observed. I wanted to share that the fins remained firmly attached to the body, probably because of my using epoxy rivets during construction. I love this tough little rocket.

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