Scratch SuperFly Original Design / Scratch Built

Scratch - SuperFly {Scratch}

Contributed by Dave Brunsting

Manufacturer: Scratch

scratch_redlineBrief:
This is me first foray into t' world o' APCP from 3 years ago. In 2005 I went t' scratch build one o' me most reliable and awesome rockets t' date. It is an awesome F and G burner and has yet t' let me down.

Construction:

  • 34" 2.6" phenolic tube
  • 2.6" Nose cone - Purchased from RAH - nay sure what brand it was anymore
  • (2) 29mm centerin' rings
  • 29mm tubing
  • 8" o' 1/4" all-thread
  • 10" o' 1/2" tubular nylon
  • 1/4" eye bolt with 2 washers and 2 nuts
  • A bunch o' 1/8" birch aircraft plywood
  • (2) 1/4" launch lugs

scratch_redline_partsThis build was very easy but I made it tough because I over-thought every move since this was t' first time I used things like epoxy, shiver me timbers, plywood centerin' rings, me bucko, etc., on a rocket. Arrr! Originally, me bucko, I thought I could make this light enough t' fly on E's but as t' build progressed with me amateur buildin' techniques I soon realized it be goin' t' weigh way too much for that t' happen. Avast, me proud beauty! Begad! I settled for F's and G's.

Since it's been three years since I built it I am a little fuzzy on t' sequence. Begad! First came cuttin' t' body tubes for t' fin slots. Blimey! Blimey! I used a circular saw with a plywood blade. Avast, me proud beauty! Bad idea. T' slots wound up bein' very very frayed and a pain t' finish.

scratch_redline_finsI also used t' circular saw on t' fins. It wasn't too bilge-suckin' I guess but they wound up bein' okay. Blimey! Then I cut t' 29mm tubin' about 1 1/2" longer than t' fin root t' make sure I had enough tube t' glue t' fins. Usin' CA glue t' fins were tacked onto t' MMT tube and t' centerin' rings on either o' t' fin ends as well.

I applied 30 minute epoxy t' all t' internal fillets. Avast! Once dried, a hole be drilled in t' aft centerin' rin' for t' 1/4" all thread. Begad! Ya scallywag! This is for t' motor retention. T' all thread be epoxied throughout betwixt t' centerin' rings. Avast! No way that thin' be goin' t' move. I could put a 29mm I and have it cato and by golly t' rocket might be in shreds but that all thread would still be attached t' t' 29mm tube.

scratch_redline_fins-completeIn t' forward centerin' ring, shiver me timbers, t' 1/4" eye bolt was attached and epoxied into place. This was for t' shock cord. T' shock cord was lapped over on itself and sewed t' cord together.

Once dried I slid t' entire fin can contraption into t' fin slots. Ya scallywag! Everythin' fit well and t' fillets on t' outside o' t' BT. On t' outside o' t' BT I glued 2 1/4" launch lugs about 12" apart.

Finishing:
Finishin' only included your basic rattle-can paint. Avast! Kilz spray-on primer and then Krylon colors. Begad! T' first paint job was this horrific red/yellow/white pain on t' eyes. Begad! After toleratin' this for about a year I sanded off that noise and applied a real paint job with a patriotic theme. Avast, me proud beauty! White stars o' different sizes on a blue field on t' front with wavy red and white stripes down t' side. Well, arrr, blow me down! T' finish it off I cut out a stencil with t' word "SUPERFLY" usin' t' Weltran font printed off o' me computer.

scratch_redline_onthepadFlight:
Here are t' motors that SuperFly has flown on t' best I can remember (I may nay have t' delays right):

  • F20-4
  • F25-4
  • F40-4
  • G33-7
  • G64-8
  • G71-8
  • G77-7
  • G80-8

Every flight be great. I won't do an F20 again unless it is dead calm because it weather-cocks quite a bit. Avast, me proud beauty! One o' these days I am goin' t' get a 29/180 case for this and really have some fun with it. It flies very similar t' a PML IO but nay quite as high.

scratch_redline_allengine-goI usually use a 24" chute for recovery which brings it down REALLY fast but I launch on a typically wet and soft corn field. Begad! I have also used a 30" which would be better for harder recovery areas.

Summary:
PRO: I built this thin' like a tank. Begad! Blimey! It keeps takin' abuse and comin' back for more.
CON: T' motor mount. Well, blow me down! I really wish I would have built this with a 38mm motor mount. Avast! Anyone buildin' a rocket that will fly regularly on G's should consider this. Aye aye! There are a whole host o' 38mm G motors out thar from CTI and AT - nay t' mention t' baby H's for when you are brave. Avast, me proud beauty! You can always adapt down - nay up.

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