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. Avast! Blimey! Avast, me proud beauty! Blimey! In 2005 I went t' scratch build one o' me most reliable and awesome rockets t' date. Arrr! Blimey! 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 be very easy but I made it tough because I over-thought every move since this be t' first time I used things like epoxy, matey, plywood centerin' rings, etc., arrr, me bucko, me bucko, on a rocket. Originally, 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 was goin' t' weigh way too much for that t' happen. Ahoy! Avast! 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. First came cuttin' t' body tubes for t' fin slots. Begad! Arrr! I used a circular saw with a plywood blade. Avast! Bad idea. Begad! T' slots wound up bein' very very frayed and a pain t' finish.

scratch_redline_finsI also used t' circular saw on t' fins. Well, blow me down! It wasn't too bad I guess but they wound up bein' okay. Begad! 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. Ahoy! Ahoy! 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. Begad! Once dried, a hole was drilled in t' aft centerin' rin' for t' 1/4" all thread. Well, blow me down! This is for t' motor retention. Arrr! T' all thread was epoxied throughout betwixt t' centerin' rings. No way that thin' was 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, t' 1/4" eye bolt was attached and epoxied into place. This was for t' shock cord. Begad! 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. Avast! Everythin' fit well and t' fillets on t' outside o' t' BT. Aye aye! 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. Begad! Ahoy! Kilz spray-on primer and then Krylon colors. Begad! Avast! T' first paint job be this horrific red/yellow/white pain on t' eyes. Ya scallywag! Begad! After toleratin' this for about a year I sanded off that noise and applied a real paint job with a patriotic theme. White stars o' different sizes on a blue field on t' front with wavy red and white stripes down t' side. Avast, ya bilge rat, me proud beauty! 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 was great. Well, blow me down! Well, blow me down! I won't do an F20 again unless it is dead calm because it weather-cocks quite a bit. Avast, me proud beauty! Begad! One o' these days I am goin' t' get a 29/180 case for this and really have some fun with it. Avast, me proud beauty! 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. Well, blow me down! I have also used a 30" which would be better for harder recovery areas.

Summary:
PRO: I built this thin' like a tank. Begad! It keeps takin' abuse and comin' back for more.
CON: T' motor mount. I really wish I would have built this with a 38mm motor mount. Ahoy! Well, blow me down! Anyone buildin' a rocket that will fly regularly on G's should consider this. 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. Blimey! Well, blow me down! You can always adapt down - nay up.

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