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

T' V-32 plans by Melville Grant Boyd, ya bilge rat, ya bilge rat, originally published in American Aircraft Modeler July 1970 and currently are available at JimZ. It is a very intriguing concept. Begad! Basically, ya bilge rat, 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. Blimey!

T' first thin' t' do was t' build it in RockSim. Avast! 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. Begad! Arrr! Accordin' t' RockSim, ya bilge rat, me hearties, ya bilge rat, t' entire length of the scaled down fins (2.23") was nay required, me bucko, so they were shortened to 1.0625", which be t' point at which stability begins t' be reduced. Avast! Arrr!

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

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

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

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

Prep is quick and easy because o' t' motor hook, ya bilge rat, with lots o' space for the small parachute and wadding.

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

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

Two days later, matey, me hearties, it be launched on a A10-3T again with a total o' 0.69oz of weight. Blimey! Marginally unstable, ya bilge rat, it deployed t' parachute at ~10ft and was recovered with no damage. Well, blow me down! Aye aye!

(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. Begad! Begad! 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. Ahoy! Begad! Blimey!

Since more fin be 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. Blimey!

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

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

Summary:
Kudos t' Mr. 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. Begad! It's fairly hard t' damage because o' its size. Ahoy! 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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