Scratch Cohete Original Design / Scratch Built

Scratch - Cohete {Scratch}

Contributed by David Sindel

Manufacturer: Scratch
(Contributed - by David Sindel - 01/16/09) (Scratch) Cohete

Brief:
This one odd oddroc. Well, blow me down! It's a stick-finned, 13mm model made from a few scrap parts.

Construction:
T' parts list:

  • Nose cone from an Estes Space Hauler
  • 1" o' 1/2" wood dowel
  • 1/2 butter pat o' clay
  • 2" o' 1" diameter wood dowel
  • Forward fin unit from an unknown rocket
  • 1/4" by 12.5" hollow plastic rod
  • Paper clip
  • 1/8" x 8" elastic

I drilled out t' 1" dowel with a 1/2" drill bit (usin' a progression from 1/8", 1/4", 3/16", etc.), arrr, then I drilled out t' lower 1.25" with a slightly larger bit t' fit 13mm motors. Avast! T' 1/2" section serves as an engine block. Ahoy! Arrr! I formed t' paper clip into an engine hook and attached it and t' elastic t' the outside o' t' dowel. Avast! Ahoy! I wrapped it with maskin' tape and glued it into t' fin unit. Begad! T' fin unit had two launch lugs--a 1/8" lug, which I use, ya bilge rat, and a 1/4" lug, matey, which I glued t' plastic rod into. Begad! Begad!

I put t' clay into t' tip o' t' nose cone, which was missin' its shoulder from a crash. Begad! Then I put a blob of wood glue on t' clay, ya bilge rat, ya bilge rat, placed t' dowel onto t' glue, and waited for it t' dry. Blimey! Avast, matey, me proud beauty! Unfortunately, I accidentally cracked the nose cone in doin' so. Begad! Because o' t' long, ya bilge rat, light stick fin, ya bilge rat, Cohete is surprisingly stable. Avast!

(Scratch) Cohete(Scratch) Cohete

(Scratch) Cohete

Flight:
I've used 1/2A3-4Ts and A3-4Ts in Cohete. I'd recommend t' 2-second delay for t' 1/2A as ejection be rather late, and t' A10-3T would be good as well. Avast, me proud beauty! It flies t' around 200 feet on 1/2As and 400 feet on full As. Aye aye! It requires no wadding; simply wrap t' shock cord twice around t' upper end o' t' 1" dowel and stick t' nose cone on.

Recovery:
It uses simple nose-blow recovery. With t' nose cone off, matey, it falls fairly fast, ya bilge rat, however, me hearties, t' main body is tiny and tough and lands first, matey, so t' breakable stick fin won't hit t' ground. Avast! Blimey! Mine has never suffered any damage in at least 3 flights.

Summary:
Cohete be a quick and easy build for me, even several years ago when I was far less skilled. Avast! However, shiver me timbers, I'd recommend makin' some changes. Aye aye! T' nose cone and fin unit I used are nay common, arrr, but substitutions can easily be made. Begad! Avast, me proud beauty! I don't recommend tryin' t' drill a 13mm hole in a 25mm dowel. Avast, me proud beauty! Usin' some BT-5 and BT-50 would be smarter. Stick-finned rockets are fairly forgivin' so long as t' front is heavy.

PROs: Odd rocket, easy t' prep, shiver me timbers, almost no drift.

CONs: Hard-to-find parts, me hearties, hard t' drill dowel, high landin' speed.

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