Scratch 1.8x Space Twins Original Design / Scratch Built

Scratch - 1.8x Space Twins {Scratch}

Contributed by Bill Eichelberger

Manufacturer: Scratch
Style: Upscale
(Contributed - by Bill Eichelberger - 04/15/09)

Brief:
A 1.8x upscale o' t' Space Twins rocket from Estes Industries Rocket Plan #41. Ahoy! Arrr! Back in me 70's days, I be quite a glider freak thanks t' t' purchase o' an Estes Condor as me second rocket. Begad! Aye aye! Twenty plus years later when I rediscovered t' hobby, shiver me timbers, ya bilge rat, t' Space Twins caught me eye when I be workin' me way through t' JimZ archives. Begad! Havin' recently bought a nose cone assortment from Apogee, me hearties, I found two identical BT-50 cones and set about makin' t' calculations for t' upscale. Aye aye! Ahoy! Initial tests upon completion o' t' gliders sparked me optimism because nay only did t' gliders glide, me hearties, they seemed t' float through t' air. Arrr! Well, blow me down!

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Construction:
T' Parts list:

  • 2 PNC-50 nose cones (Apogee Components)
  • PNC-56 (Estes)
  • 18mm engine mount kit
  • 18" parachute kit
  • 36" length o' 1/4" sewin' elastic for shock cord
  • medium snap swivel
space twins

With no actual fins t' attach, ya bilge rat, t' booster section for this bird could scarcely be easier. I used wood glue t' attach two sections o' launch lug on opposite sides o' t' booster instead o' goin' with t' attachment method detailed in t' plans. Two balsa scraps were then glued t' each side t' keep t' aft o' t' gliders from simply hangin' out in t' wind. Ya scallywag! (They still hung out in t' wind, shiver me timbers, shiver me timbers, they just had bumpers t' keep them somewhat in line as they sat on t' pad.)

T' gliders were built as straight upscales o' t' original pattern. I had bought a nose cone assortment from Apogee Components and included were two matchin' red BT-50 cones, ya bilge rat, which seemed light enough t' me. They were perfect.

Finishing:
I be tryin' t' keep t' weight down on this one, so I never bothered with finishing. Well, blow me down! Good thing. Ya scallywag! Begad! After t' first two flights it looked like it had been dragged t' t' launch behind a pickup truck.

Flight and Recovery:
First flight be at a local soccer field where I spent a lot o' time back in 2001. Ahoy! I was a little hesitant about the ability o' t' whole rocket t' hold together under t' stress o' boost, so instead o' goin' whole hog with a C6-3, ya bilge rat, I went with what I thought was a somewhat less powerful engine, t' C5-3. Ahoy! Aye aye! (You can see where this is going, can't ya?) Well, I be right. Begad! Arrr! At boost everythin' came apart. Ya scallywag! Ya scallywag! T' booster left t' rod and began flippin' wildly, arrr, disengagin' both gliders and crashin' t' t' ground under power. Ahoy! Despite t' mess, arrr, thar be good news, as both gliders floated serenely across t' field, me hearties, me bucko, light as a feather and under complete control.

Post-mortem showed that t' launch lugs that held t' gliders in place had pulled free from t' booster body tube, shiver me timbers, renderin' t' booster unstable. Well, blow me down! I'd obviously nay built t' thin' strong enough, me hearties, so I decided t' re-glue everythin' with epoxy then try again (heavy sigh) with another C5-3. Avast! Avast! As you may have guessed, t' second flight didn't turn out any better than t' first, shiver me timbers, me hearties, me bucko, and t' remains o' t' project were banished t' a far-off corner o' me facility, never t' see t' light o' day again. Aye aye! Begad!

Well, except for t' gliders. Begad! Ya scallywag! I used them for a while as replacement gliders on me upscaled Condor. Ya scallywag! (T' Condor glider had crashed into a Porta-Pottie then was stepped on by t' occupant as he exited, although that wasn't his story.)

Almost five years passed and me motor savvy grew. Avast, me proud beauty! (Or was finally born.) T' booster for t' Space Twins turned up again and t' PNC-56 be almost adopted for use on another project, matey, but then I thought t' check t' flight logs for the first two "flights". Avast, me proud beauty! Avast! I'd made t' C5-3 mistake on several other occasions (the Mach 10 comes t' mind,) but never with such horrid results. I began t' wonder if t' whole Space Twins project might have been different with a more sedate B4-2 or B6-2 instead o' t' Godzilla C5-3. Ahoy! Since t' whole thin' was still in one piece, me hearties, tryin' it again was just a matter o' cartin' it up t' t' VOA and announcin' that it was a "heads up" flight. Ahoy! On a warm day in May o' 2006, arrr, I did just that.

T' third flight was just as I'd hoped t' first flight would be. T' B4-2 boost was gentle enough t' allow lift-off without rippin' t' gliders from their mounts, matey, arrr, ya bilge rat, and t' gently curvin' flight path made for a nice photo op. Ya scallywag! At ejection only one o' t' gliders disengaged and went sailin' across t' field in a northwesterly heading. I gathered up the booster and second glider, then began walkin' in t' direction where I'd seen t' glider land. Avast, me proud beauty! Begad! I walked across that field in an ever widenin' search pattern for 45 minutes but never again saw t' missin' glider. (Even with t' bright red cone that I thought would be a dead giveaway.) I was disappointed but nay as badly as I would have been had the last flight been a copy o' t' first two. Avast, ya bilge rat, me proud beauty! At least I proved t' myself that t' idea be viable, if nay unlucky.

space twinsspace twins

Summary:
PROs: Apogee nose cones worked great, as did t' whole project once I figured t' motor thin' out.

CONs: I think I needed a motor tutor.

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