Public Missiles Pterodactyl, Jr.

Public Missiles - Pterodactyl, Jr.

Contributed by John Meckley

Manufacturer: Public Missiles
(by John Meckley) 

[Rocket Pic]This is a fairly simple kit to put together -- basic through-the-wall fin mounting and single body tube/nose cone construction. This kit has a "piston"-type ejection system and since the body tube is relatively short in relation to the forward end of the tapered fins, there's really no opportunity to use the "zipperless design" that I favor. However, the piston system works very well. Since the fins are G10 fiberglass, sanding the edges is quite labor-intensive. Also, when mounting the motor tube/centering ring, you need to be VERY aware that you position the piston strap (which is epoxied to the motor tube) BETWEEN the fin slots, otherwise you'll have to sand and sand and sand the root of the fin that's going into that slot!!!! You'll have to add no less than 3 oz. of nose weight to bring the CG forward since the CP is 30" from the nose and the CG is less than 1 caliber (the length of the tube diameter... 4" in this case) away. When I flew it, I added Greg's beeper/locator which weighs about 3 oz. and it could have used about 1 or 2 oz. more... just a suggestion. Otherwise, this kit is big, fun and impressive in the air. Have fun with it, I highly recommend it! :)

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Flights

Comments:

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B.O'B. (January 1, 2001)
I can personally attest to the ruggedness of this rocket. On one launch with an I-161, my parachute didn't unfold (my fault). Boy, was it coming down fast! I closed my eyes while my son was carrying it back to the jeep. Damage report: 1 small crack in the epoxy near the trailing edge of one fin (not worth fixing). Another time with the same motor, 3 of the 6 'chute lines pulled from the canopy (not my fault). Damage report: ballast came loose inside nose cone. This rocket is really cool to see fly. Now that I have filled the nose cone with foam and replaced the parachute I have plans of flying on a J-280 at the next launch.
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G.B. (February 1, 2001)
Indeed a fine kit, sturdy too: I wanted a little extra oomph and built it with a 54mm MMT. It successfully flew on a J180 and suffered premature separation with a J460 (my fault). The only damage done was a 4" zipper at roughly 600mph! A K1100 might be a little dangerous due to fin flutter - we will see!

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