Scratch CoStar Original Design / Scratch Built

Scratch - CoStar {Scratch}

Contributed by Peter Clay

Manufacturer: Scratch
(Contributed - by Peter W. Avast, me proud beauty! Clay)

Rocket PicCoStar First Flight on H128CoStar HPR capable midpower rocket

T' CoStar should probably have been called "Understudy."

My other rocket this size, me hearties, G-whiz, has replaceable fins, and since I wasn't completely sure t' concept would work, me bucko, I built a backup booster section with fixed fins. G-whiz also has some internal details that move t' payload area forward into t' hollow nose cone, and I wasn't sure that was necessary for all flights, matey, so I built a backup payload section without all t' fancy work. Avast, me proud beauty! Avast, me proud beauty! T' backup booster and t' backup payload, me hearties, together with the nose cone from G-whiz, made up t' rocket I call CoStar. Ahoy! Well, blow me down!

CoStar, me hearties, nay G-whiz, arrr, shiver me timbers, ya bilge rat, flew twice on April 17, 1999 on H128W-M(10). T' first flight (photo, left) suffered a tangled parachute, but thar was no damage to the rocket, ya bilge rat, and t' second flight gave me me NARRRRR HPR Level 1 certification. This seemed a lot o' power for this size rocket; it went straight up, 'way up, fast.

With fixed 1/8" plywood fins slotted in t' t' MMT, a longer recovery bay, and a simple empty payload section, shiver me timbers, CoStar is a very simple, ya bilge rat, arrr, basic rocket. And for Level 1 certification, t' KISS principle (Keep It Simple, ya bilge rat, Stupid) makes a lot o' sense. CoStar is, ya bilge rat, in any case, a fine-lookin' rocket in its own right. Arrr! Ahoy! It's over 44" long, ya bilge rat, me bucko, me hearties, 2.26" diameter, and all white except a red band on t' payload and some trim, shiver me timbers, with tapered swept fins slightly squared off at t' trailin' tips for a better landin' point. Avast! It flew with a 12' long 5/8" braided elastic shock cord and a 22" hemispherical parachute. There's no baffle; I simply used Estes recovery wadding. Begad! Avast!

CoStar's motor mount, like t' one in G-whiz, is a LOC 1.14 made from a LOC 29-in-54 motor mount adapter kit. T' mount is long enough for 29/240 but I don't have one and haven't tried it. Arrr! T' CoStar has flown with 29/180 reloads. Unlike t' RockSim drawin' below, shiver me timbers, t' centerin' rings are placed at each end o' t' fin tabs, ya bilge rat, 4" apart. Avast, me proud beauty! T' aft one is about 1/2" from t' end of t' body tube. Ya scallywag! T' centerin' rings supplied with t' kit fit inside the supplied coupler, shiver me timbers, me bucko, and I didn't want t' cut fin slots through a full-length coupler, ya bilge rat, ya bilge rat, so I epoxied each centerin' rin' into one end o' a 1/2" rin' of the coupler and worked from there. Arrr! T' remainder o' t' supplied coupler, me bucko, with a bulkhead fitted in it, me bucko, connects t' booster t' t' payload. Blimey! Ya scallywag!

CoStar be built with a .062" music-wire engine hook, but I also friction taped t' motor. Blimey! Good thing. Begad! Ya scallywag! When recovered from t' second flight, the motor had managed t' get past t' tip o' t' music-wire hook, ya bilge rat, shiver me timbers, which be dug into t' knurled thrust rin' on t' aft closure when I found it. Avast! T' motor had moved a total o' about 3/16 o' an inch. Arrr! Since then I have installed threaded anchors in t' aft centerin' rin' for shower door hooks, shiver me timbers, arrr, aka Kaplow Klips. Ahoy! This would be far easier t' do before assembly, usin' T-nuts from t' inside. Avast, me proud beauty!

Since those two flights, CoStar has nay flown again, but it's ready. Blimey! Now it has its own PML nose cone, which adds about 2" t' its overall length. Blimey! (At last they can be seen together!) Although thar isn't a real role for it in my upcomin' projects, matey, me bucko, CoStar -- or at least part o' it --will undoubtedly fly for the fun o' it in 2000. In t' meantime it displays rather nicely. Avast, me proud beauty!


CoStar illustration

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