Public Missiles - Bull Puppy {Kit}

Public Missiles Bull Puppy

Public Missiles - Bull Puppy {Kit}

Contributed by Casey Smith

Construction Rating:
Flight Rating:
Overall Rating:

Length:	27.75 inches
Manufacturer:	Public Missiles
Style:	Scale

Photo courtesty of PML Rocket Pic

Brief:
Scale-like rocket of the big brother PML Bulldog. Excellent military styling, good experience here with boat-tails.

Construction:
The new Bull Puppy comes with the nice Quantum Tubing (pre slotted for TTW fin attachment), a PML nosecone, G-10 fiberglass main and canard fins, and piston ejection system. It comes with 2 centering rings, one that goes in the main 3" tube and one at the aft end of the motor mount in the boat-tail. The piston strap is about 30" long, the nylon shock cord is about 3 feet long, the parachute is 36". The chute is a nice purple and yellow, easily visible with 8 shroud lines.

This was my first PML kit and was extremely easy to build. I had just completed upscaling an Estes Strikefighter (3x) and I was looking for a solid rocket to level 1 on and still be able to use for 38mm motors. This kit was perfect. As with most PML kits, if you are an experienced builder, the instructions are very straight forward and easy to follow. They tell you the yes and no's of what to do, plus have nice drawings to illustrate the point.

The only real problem that I had with the kit was putting the fillets on the wings on the boat-tail, and putting a positive retention system on the motor mount. I ended up putting a small hole next to the pre-cut spots for the wings, to make little "epoxy rivets". I had to sand the area around the wings extensively to get a good seal with the epoxy. I used both Pacer Corporation epoxy and Devcon epoxy (30 minute) to see if it was an epoxy problem, but it was not. It is just difficult to glue things to what essentially is a cut off nose cone.

I solved the motor retention after a suggestion from a friend, I ran 2 pieces of coat hanger wire from the aft centering ring along the motor mount to the end and bent them down a little. I bent the other end of them up and epoxied them to the forward portion of the aft centering ring. I had to use a small dowel with a piece of 220 grit sandpaper to sand a tract on the inside of the boat-tail, so there is room when you slide it on for assembly. I also sundered them together. The result is a upgraded Estes clip system.

I cut up a ironing board cover and made that into the protective cover for the piston strap. I also glued a piece of fiberglass cloth from WalMart to the inside of the piston, thus further protecting and strengthening the unit. I also glassed the motor mount to strengthen it. Check PML's website FAQ'S for strengthening if you want to build an extremely strong rocket, or one that will be taking large engines. DO it strong the first time right? Practice glassing on the inside, so if you mess up no one sees it. You can also put minimally expanding foam in the boat-tail before you glue it to the main tube for increased strengthening. MAKE SURE YOU LET THE FOAM CURE PER INSTRUCTIONS ON THE CAN OR IT COULD DESTROY YOUR ROCKET!!! After curing, epoxy to the main tube.

Finishing:
I use a 220 grit to sand the whole model, and then prime it with Duplicolor primer. You can get this at most WalMart's or auto store. They have it in a few different colors, be sure and get the filler/sealer, not just sealing primer, it has more solid in it. Do not be afraid to sand/prime, sand/prime. You should have a nice glass like finish on the model. I like to use Krylon White for the kit, but your favorite white will do. Let a few light coats dry first before you go for the gusto. This way you will see what needs more sanding or where the problem areas are. The rest of the directions are very clear, and you can be like me, take it to an auto body shop, buy the paint, and have them paint, clear coat it. It will shine!!!! Good Luck!!

Construction Rating: 4 out of 5

Flight:
Aerotech's G40-4 goes great in this kit for a first flight with an 29mm adapter, or in small fields. I will be flying it on 29mm H220's mostly, but plan on using I357's and I300's in it at our high power launches. I used a standard LOC 29-38 motor mount adapter, but added a longer 29mm tube and also another set of rings and this is very strong. I have flown mine twice now out of my yard on a G40 and G80. It went just as the motor predictor on PML's site said it would.

Recovery:
This is a strong kit, it deploys with a nice POP and landing on the road in 10+ MPH winds caused some paint damage, but none to the integrity of the kit. Beautiful straight boosts!

Flight Rating: 5 out of 5

Summary:
Main PRO- excellent kit to level 1 on (I used my Cosmodrome Nike Apache instead) and to explore the range of 38mm motors on, strong enough to take them all. It is a classic example of PML quality. Main CON- figuring out positive motor retention, making sure you sand the piston enough so it slides freely!

Overall Rating: 4 out of 5

Other Reviews

Public Missiles Bull Puppy By Lucas Kalathas (November 15, 2007)
Presented with written permission from RocketyPlanet: Product Review by Lucas Kalathas Thursday, November 15, 2007 Contents of the PML Bull Puppy kit. There are some companies that blend in with their competition, to stock their items on the shelf in hopes of selling to undemanding customers. Others try to provide the cheapest ...

Flights

Comments:

T.M. (March 1, 2001)

I built a Bull Puppy for my level 1 rocket, and it went together real eazy. I had an old version of the BP that I had lying around for two years un-built (phenolic tube) so I put it together in a few days before the February Michigan Team 1 HP launch. I made two modifications to the kit. I used a slightly longer 38mm MMT tube and left it extending out from the boat tail 3/8" for attaching an AeroPac motor retention system. I also got a piece of tubular Nomex heat shield and put it around the shock cord under the piston. I Had some trouble getting paint to stick to the NC and Boat Tail, and when I removed masking tape from the NC, a section of paint and primer about 3/8" x 2" came along with it. The Launch day was very cold (sub zero wind chill) and kind of windy. I had selected an H73J medium for my L1 flight, but it was so windy that we cut a few seconds of the delay. The Table on the PML page puts the Bull Puppy up to 1800 ft. on an H73 in perfect conditions. My puppy crawled off the pad, leaned over into the wind, and flew about 400 yards down range. (it attained an altitude of maybe 700ft.) The chute deployed and it drifted toward the ground. Success! I felt kind of lucky that I had the old Phenolic airframe, as two times that day deployment failures were blamed on QT shrinkage binding the piston.

H.D.C. (June 8, 2006)

Great kit. Not too difficult to build and has several mods that are good for learning how to build strength into a rocket. Built it for my level one. Changes included leaving about 2/3 inch of motor mount extended from the boat tail so I could mount a slimline motor retainer, also uses a slimline adapter. Drilled 3/16ths holes along the slots in the boat tail to aid with epoxy holding power. Put good fillets inside and out w/ 30 min epoxy. Filled can w/ foam as well after drilling 1/4 inch holes in fin roots for more holding power. Installed a Nomex® sleeve on the shock cord. Has 1 1/2 oz of lead in nose and nose cone is foamed w/ a threaded rod in the center. The rocket is over built, but very solid and should last for many flights. Flies straight as an arrow and no problem w/ cert.

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