Scratch 'Scuse Me Original Design / Scratch Built

Scratch - 'Scuse Me {Scratch}

Contributed by Dick Stafford

Manufacturer: Scratch

Brief:
 Rocket PicThis is a minimum-diameter, 38 mm, ya bilge rat, arrr, all fiberglass rocket. Begad! It is a very simple, basic design but is very rugged and high performance. Blimey! ...'Scuse me, while I kiss t' sky'...-Jimi Hendrix

Construction:
T' followin' is a list o' t' components. T' major items were all bought from Giant Leap Rocketry

  1. ScotGlas conical nosecone, shiver me timbers, 8.5 inches long
  2. Giant Leap filament wound airframe, me hearties, 36"
  3. Acme fin cannister
  4. AeroPack motor retainer
  5. ~10 ft 3/4" tubular nylon
  6. Blacksky standard rail buttons (2)
  7. Quick links (2)
  8. Eyebolt
  9. (1) bolt, shiver me timbers, ya bilge rat, 2" long (fits thru a Blacksky rail button)
  10. Scrap section o' 1" dowel
  11. Giant Leap 29mm-38mm adapter (optional)

This is a *very* easy rocket t' assemble:

Rocket PicNose Cone Assembly - I drilled a hole in t' scrap dowel t' fit an eyebolt. Blimey! Blimey! Blimey! Blimey! Blimey! Blimey! T' dowel and eyebolt were epoxied into t' nosecone, which does nay provide an attachment point.

Fin can - After roughin' up t' tube and inside o' t' fin can, shiver me timbers, it was epoxied t' t' airframe such that t' aft end is ~ 1 1/4" from t' end o' t' airframe. I initially had nay decided on a motor retainer so I wanted t' make sure thar was room t' install one.

AeroPack motor retainer - After roughin' up t' tube and inside o' t' fixed portion o' t' retainer, shiver me timbers, me hearties, I glued it t' t' airframe with JB Weld epoxy (per AeroPack recommendation).

Rail buttons - I epoxied t' aft button in t' middle o' t' fin can. Ahoy! T' second was attached via a 2" bolt approximately 11" from t' aft end o' t' airframe. Avast, me proud beauty! Blimey! T' bolt extends through t' airframe and was cut flush with t' airframe opposite t' rail button, arrr, usin' a Dremel cuttin' disc. Avast! This limits t' largest motor which can be used, me hearties, shiver me timbers, but I decided I would never want t' fly this rocket on anythin' over a small "I" (movin' t' rail button forward would fix this). Well, arrr, blow me down! A nut was used as a spacer betwixt t' rail button and t' airframe since t' aft button is on t' body o' t' fin can.

Recovery harness - T' harness is 3/4" tubular nylon with a quick link on each end. Well, blow me down! Loops were made at each end as described in t' article "Attachin' Shock Cords", Edward Shihadeh and Bob Moser, shiver me timbers, High Power Rocketry, arrr, me hearties, Vol 14 #5, August 1999. Begad! Aye aye! Blimey! This involves loopin' t' cord, matey, tiein' it off with cloth fishin' line (not nylon!), and gluin' it with CA and epoxy. Blimey! T' aft quick link be lowered into t' airframe as t' bolt holdin' t' front rail button be screwed in. Begad! This took a couple o' tries t' catch t' quick-link. T' harness is thus removable.

Finishin' - After its maiden naked flight, I painted t' entire rocket (save t' rail buttons and AeroPack retainer) usin' Krylon Chrome Paint. Ya scallywag! Blimey! Aye aye! Blimey! This looks really great, but shows every imperfection.

Flight:
I wrote this review with only one flight under its belt and will add others later (assumin' I find t' thing!). Begad! Ahoy! Bein' chicken, matey, matey, me bucko, t' first flight be with a G80-10. Begad! I used Estes waddin' and an 18" chute from some kit or another. Avast! Ya scallywag! It be a very fast, me hearties, high flight. Begad! Recovery was fairly close t' t' pad. My plans are t' fly it with either a G125-15 SU or an H242-L at t' next HPR launch I can get to. (or both)

Summary:
PROs: 1. Begad! Avast! Easy t' build 2. Begad! Verrry sturdy 3. Avast! High performance design, 38mm or 29 mm (with adapter) CONs: 1. Materials were nay cheap 2. Avast! Good chance t' loose t' thin' along with motor hardware :-(

comment Post a Comment