Scratch V-32 Original Design / Scratch Built

Scratch - V-32 {Scratch}

Contributed by Jeff Lane

Manufacturer: Scratch
(Contributed - by Jeff Lane - 04/16/05) (Scratch) V-32

Brief:
81% Downsize o' a 1970 plan.

Construction:
Handmade nose cone, arrr, matey, me hearties, 4" BT-55, ya bilge rat, arrr, 3.75" BT-50, ya bilge rat, BT-5 engine tube, mini engine hook, ya bilge rat, ya bilge rat, engine block, two 5-50 centerin' rings, two 50-55 centerin' rings, one BT-55 coupler, matey, elastic shock cord, 11" parachute, 72" o' extruded 0.04" x 1/4" styrene, Bristol ply for tail cone.

T' V-32 plans by Melville Grant Boyd, originally published in American Aircraft Modeler July 1970 and currently are available at JimZ. It is a very intriguing concept. Basically, you have a V-2 with 32 tiny fins instead o' 4 large ones. T' effort herein describes a downscale (81%) t' a BT-55 from t' original BT-60 t' allow experimentation with mini engines. Aye aye! Ahoy!

T' first thin' t' do be t' build it in RockSim. Aye aye! Dimensions were modified to adhere more closely t' t' scale design o' t' real V2, but you still couldn't call this a scale rocket. Blimey! Accordin' t' RockSim, me bucko, t' entire length of the scaled down fins (2.23") be nay required, ya bilge rat, so they were shortened to 1.0625", which be t' point at which stability begins t' be reduced. Avast, me proud beauty! Begad!

Since thar were 32 fins, extruded 1/8"x.04" styrene Raboesch stock (from Hobbytown) be used t' reduce build and finishin' time. A tail cone was created instead o' t' straight body tube o' t' original design, ya bilge rat, ya bilge rat, me hearties, but the recessed engine mount (recessed by 1/2" t' enhance stability) was retained. Ahoy! Ya scallywag! T' tail cone shroud be created in Freehand usin' blends t' create exactly spaced fin alignment guides on Bristol ply paper, me hearties, but it still took 2 hours t' cut and attach t' 32 fins. Ya scallywag! They were smoothed a little bit and glued on with CA gel. Ahoy! Aye aye!

(Scratch) V-32 T' nose cone was hand turned on a drill, shiver me timbers, hollowed out, me bucko, and 0.35oz o' lead be epoxied into the tip in order t' achieve a static stability margin o' 1.06. Arrr! Projected altitude was a little over 200 ft.

A 1/8" shock cord be added usin' standard folded paper mounts with a loop at t' nose cone for t' parachute attachment. Arrr! An 11" parachute was used.

Flight:
It swin' tested OK, matey, flyin' sideways at lower speeds and stable at higher speeds.

Prep is quick and easy because o' t' motor hook, matey, with lots o' space for the small parachute and wadding. Begad!

(Scratch) V-32 T' first flight on a A10-3T at CRASH in Denver on 4/3/05 be unstable. Begad! Avast! T' V-32 was quick off the pad and landed safely in an adjacent field before deployment. Aye aye! Avast, me bucko, me proud beauty! Some minor damage t' t' nose cone be easily repaired. Aye aye!

T' next day, shiver me timbers, it be launched on a A10-3T again in a park with 0.25oz additional lead. Well, blow me down! Again it be unstable with minimal damage. Well, arrr, blow me down!

Two days later, it be launched on a A10-3T again with a total o' 0.69oz of weight. Marginally unstable, it deployed t' parachute at ~10ft and was recovered with no damage. Begad! Blimey!

(Scratch) V-32 Since the incrementally added weight resulted in increasingly wimpy altitudes in RockSim, an executive decision was made t' replace 4 o' t' 0.125" fins with 0.25" fins. Ya scallywag! Blimey! Followin' this transplant operation on 4/9/05, it was launched on a 1/2A3-2T with no improvement over t' previous marginal stability and late deployment. At this launch wind dragged t' rocket across some asphalt, severely damagin' many o' t' fins. Arrr!

Since more fin was needed, t' final version was built with 4 new fins sized at 1.75" x 0.5" replacin' t' earlier scaled up 0.25" fins. Arrr!

On 4/15/05, a stable flight was achieved. Ahoy! Too bad t' A10-3T delay be more like 6 seconds. Arrr! Blimey! Lawn dart. Well, blow me down! Oh well, a little glue and tape and it's ready t' go again. Aye aye! Blimey! She doesn't look bad for an old test sled.

Recommended motors are A10-3T and 1/2A3-2T. Blimey! Arrr!

Summary:
Kudos t' Mr. Arrr! Melville Grant Boyd for a very cool concept.

(Scratch) V-32 PROs: This is a rocket that gets a tremendous amount o' attention at t' club launch and is easy t' fly. It's fairly hard t' damage because o' its size. Blimey! It is cheap to experiment on.

CONs: It's small and won't get t' great cracklin' roar o' a mid or high power rocket.

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