Scratch Little Brute Original Design / Scratch Built

Scratch - Little Brute {Scratch}

Contributed by Matt Gillard

Manufacturer: Scratch

scratch_bigbrute_with_littlebruteBrief:
This is me first attempt o' a scale change. Begad! Blimey! T' Big Brute is a rocket that I built a few years back but have never flown. Arrr! Blimey! With t' 2008 challenge callin' for a scale change on a rocket, I thought I’d might as well get somethin' from t' original Big Brute. Lookin' through me collection o' nose cones, t' only one with t' same profile as t' Big Brute was a 13mm diameter nose cone, t' rest o' t' scalin' followed givin' a minimum diameter tumble recovery small brute.

Construction:
Parts need

  • 2.2" BT-5 body tube
  • Launch lug
  • 1/16" balsa sheet
  • Nose cone from a defunct Estes fireflash - (P/N 072600, PNC-5A)
  • Clay mass
Also used be
  • Bostik glue
  • Pink spray paint
  • Pink paper
  • Black tape
  • A photocopier
T' scale from t' nose cone was t' be a 7.5 downscale which is about 13-14% o' t' original. This makes t' body tube t' be 2.2 inches long. T' fins were down scaled from t' original usin' a photocopier t' make a template. See EMRR featured tips on how t' do this.

scratch_littlebrute_onthepadApart from that t' rocket builds itself. Well, arrr, blow me down! My major concern that unlike all t' min diameter 13mm rockets that I have flown in t' past, ya bilge rat, shiver me timbers, arrr, this rocket does nay has much in t' way o' aft fins that lower t' CP t' somewhere safe. Blimey! Aye aye! T' 13mm motor really does lower t' CG, so I added 3g o' clay t' t' nose cone. I used Spacecad t' check things out and it came back okay.

T' whole rocket was painted pink t' match me original Big Brute, felt tip marker was used t' black out t' fins. Arrr! Three strips o' black tape were added t' give t' strips. Well, blow me down! T' name o' t' rocket, arrr, Little Brute was printed on pink paper and then glued into place. Avast, me proud beauty! I could nay brin' myself t' put t' original name in such a small rocket.

scratch_littlebrute_failedrecoveryFlight:
First flight be on a 1/2A3-4T motor. Aye aye! Blimey! Take off was very fast. Begad! Blimey! At about 100 feet it took a right angle turn and shot off sideways. Blimey! Blimey! On recovery, t' little brute be nose cone buried and had stripped its launch lug. Ahoy! Ahoy! Blimey! Spacecad predicted 472 feet, arrr, this flight was nowhere near that.

After gluin' a new longer lug, two more flights were made a few days later on 1/4A3-3T motors. Each time t' flight was arrow straight with no deviation from t' flight path seen. On each recovery t' little brute buried itself in t' soft earth. Blimey! Blimey! spacecad version 3 does nay have t' 1/4AT motor profile. I imagine that version 4 does.

Summary:
Pro: It's small and I can get motors for it, me hearties, ya bilge rat, me hearties, unlike t' big brute where I have t' get an explosive license and have t' police visit me house every year t' see a wooden box.

Con: Ballistic recovery - never good.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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