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. Aye aye! 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", arrr, me bucko, arrr, 1/4", 3/16", shiver me timbers, etc.), then I drilled out t' lower 1.25" with a slightly larger bit t' fit 13mm motors. Begad! T' 1/2" section serves as an engine block. Begad! Begad! I formed t' paper clip into an engine hook and attached it and t' elastic t' the outside o' t' dowel. Avast! Avast! I wrapped it with maskin' tape and glued it into t' fin unit. Begad! Well, blow me down! T' fin unit had two launch lugs--a 1/8" lug, me hearties, arrr, which I use, me hearties, and a 1/4" lug, matey, which I glued t' plastic rod into. Blimey! Avast, me hearties, me proud beauty!

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, arrr, shiver me timbers, placed t' dowel onto t' glue, and waited for it t' dry. Aye aye! Unfortunately, arrr, ya bilge rat, shiver me timbers, I accidentally cracked the nose cone in doin' so. Well, blow me down! Because o' t' long, light stick fin, Cohete is surprisingly stable. Well, blow me down!

(Scratch) Cohete(Scratch) Cohete

(Scratch) Cohete

Flight:
I've used 1/2A3-4Ts and A3-4Ts in Cohete. Blimey! Blimey! I'd recommend t' 2-second delay for t' 1/2A as ejection was rather late, and t' A10-3T would be good as well. Ya scallywag! Aye aye! Blimey! It flies t' around 200 feet on 1/2As and 400 feet on full As. Arrr! Blimey! 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, shiver me timbers, it falls fairly fast, however, me hearties, arrr, t' main body is tiny and tough and lands first, me hearties, shiver me timbers, so t' breakable stick fin won't hit t' ground. Mine has never suffered any damage in at least 3 flights.

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

PROs: Odd rocket, me hearties, me bucko, easy t' prep, almost no drift.

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

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