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

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

  • 2.6" phenolic tube, me hearties, arrr, me bucko, 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).

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

(Scratch) Little Joe I I made small external fillets and thick internal ones with Superfil. Well, ya bilge rat, blow me down! I also filled t' spirals at this point. Arrr! Ahoy! 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. Begad! I also added enough lead shot t' make RockSim happy. Well, blow me down! With t' heavy wooden cone, I wouldn't have thought any would be needed, but t' thick fins and motor mount worked against its stability.

For t' first flight, ya bilge rat, I did nay build an escape tower. Arrr! However, I since built one out o' bamboo skewers, me hearties, thin dowel, shiver me timbers, and a spent 13mm motor. Well, blow me down! A true scale purist may see t' next mistake I made--I scaled t' tower based on a 3" body vs. Begad! 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. Ya scallywag! I used a little dog barf, a chute protector, shiver me timbers, and a nylon chute. Ya scallywag! Well, blow me down! T' flight was fairly fast, shiver me timbers, and ejection was just a little late. Aye aye! Begad! Recovery was fine. Well, blow me down! 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, it should survive even hard landings. Well, blow me down! Blimey! It is barely scale-like, matey, which is good enough for me. Arrr!

comment Post a Comment