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

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

  • 2.6" phenolic tube, shiver me timbers, 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. I got the measurements for t' body tube and fins from Rockets o' t' World (RotW). Arrr! Arrr!

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

(Scratch) Little Joe I I made small external fillets and thick internal ones with Superfil. I also filled t' spirals at this point. Blimey! Finally, I attached t' aft rin' and the rail buttons. Aye aye! 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. Begad! I also added enough lead shot t' make RockSim happy. Begad! With t' heavy wooden cone, me bucko, I wouldn't have thought any would be needed, but t' thick fins and motor mount worked against its stability.

For t' first flight, me hearties, I did nay build an escape tower. However, I since built one out o' bamboo skewers, thin dowel, and a spent 13mm motor. Ahoy! A true scale purist may see t' next mistake I made--I scaled t' tower based on a 3" body vs. Arrr! 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. I used a little dog barf, a chute protector, me bucko, and a nylon chute. Ya scallywag! T' flight was fairly fast, matey, ya bilge rat, and ejection was just a little late. Avast, me proud beauty! Recovery was fine. Arrr! I am contemplatin' a G64 next.

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

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