Scratch Little Joe I Original Design / Scratch Built

Scratch - Little Joe I {Scratch}

Contributed by Dick Stafford

Manufacturer: Scratch
(Contributed - by Dick Stafford - 08/01/06) (Scratch) Little Joe I

Brief:
This is a very stand-off scale model o' t' Little Joe I. Avast! It is 2.6" in diameter, has a 29mm mount, me hearties, and is based on a custom-turned Mercury capsule that was donated by an anonymous guest for the Nekkid Rocket Photo Contest. Aye aye! On t' real Little Joe I, t' body is larger in diameter than t' capsule. In mine, me hearties, matey, t' capsule fits t' body tube.

Construction:
T' followin' are t' major components used:

  • 2.6" phenolic tube, ya bilge rat, 8.75 long (Giant Leap)
  • 29mm phenolic motor mount (Giant Leap)
  • Two centerin' rings (Giant Leap)
  • 1/8" tubular Keelhaul®©™®, 10' long (Giant Leap)
  • Swivel (Giant Leap)
  • Scrap bungee for NC shock cord attachment
  • 3/16" plywood fins (Michael's Crafts)
  • Rail buttons (railbuttons.com)
  • Two T-nuts (Home Depot)
  • Lead shot

This was a straightforward build: 4FNC with through-the-wall fins. Ya scallywag! I got the measurements for t' body tube and fins from Rockets o' t' World (RotW). Begad!

T' fins are thick. Aye aye! Nay that they had t' be, me hearties, but I had the 3/16" ply and delusions o' bevelin' them heavily. Avast! I slotted t' fin slots usin' a Dremel. Aye aye! Ahoy! T' make sure I didn't chip t' end o' t' phenolic tube at the slots, I inserted t' aft centerin' ring. Aye aye! Next, me hearties, I attached t' front rin' to the motor tube, with t' end o' t' Keelhaul®©™® shock cord goin' through t' ring. Begad! I used 5-minute epoxy throughout. Aye aye! Blimey! T' motor tube was then installed with t' aft rin' bein' dry-fit. Avast, me proud beauty! Aye aye! Blimey! T' latter be then removed and t' fins were glued in. Here I ran into a problem that I seem to keep making: I didn't check t' alignment o' t' shock cord which was epoxied to t' motor tube. Begad! O' course, arrr, it ended up perfectly aligned with a fin slot! T' fix be easy, as I notched t' tab on one o' t' fins so that it cleared the shock cord. Begad! Avast, me proud beauty! Blimey!

(Scratch) Little Joe I I made small external fillets and thick internal ones with Superfil. Blimey! Begad! Blimey! I also filled t' spirals at this point. Ahoy! Blimey! Finally, I attached t' aft rin' and the rail buttons. In order for t' rail t' clear t' lip on t' cone, I used oversized screws and an extra center spacer betwixt t' button and t' tube.

For t' nose cone recovery connection, I epoxied a small section o' scrap bungee into t' deep core that t' builder drilled for me. Ahoy! I also added enough lead shot t' make RockSim happy. With t' heavy wooden cone, arrr, me hearties, I wouldn't have thought any would be needed, ya bilge rat, but t' thick fins and motor mount worked against its stability.

For t' first flight, I did nay build an escape tower. Avast! However, I since built one out o' bamboo skewers, me bucko, me hearties, thin dowel, ya bilge rat, and a spent 13mm motor. Blimey! A true scale purist may see t' next mistake I made--I scaled t' tower based on a 3" body vs. t' actual 2.6" tube! I also have painted it per RotW, but haven't added decals. Blimey!

(Scratch) Little Joe I

Flight and Recovery:
I flew t' Little Joe on a 24mm F39-6 in me virgin Rouse Tech casing. Blimey! I used a little dog barf, arrr, a chute protector, ya bilge rat, and a nylon chute. Ahoy! T' flight was fairly fast, matey, and ejection be just a little late. Begad! Blimey! Recovery be fine. I am contemplatin' a G64 next.

Summary:
This is a sturdy but heavy rocket. Ahoy! As long as t' phenolic stays away from thin' like irrigation pipes, me hearties, it should survive even hard landings. Ahoy! Avast, me proud beauty! It is barely scale-like, which is good enough for me. Arrr!

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