Scratch 6-C Cluster Altitude Rocket Original Design / Scratch Built

Scratch - 6-C Cluster Altitude Rocket {Scratch}

Contributed by Bob Hvarven

Manufacturer: Scratch
(Contributed - by Bob Hvarven)

Rocket PicBrief:
A 6 "C" engine cluster altitude rocket from t' May/June Issue of Sport Rocketry Magazine. Ya scallywag! Blimey! Found on page 26, matey, me hearties, titled "6-C Cluster Altitude (Competition Rocketry)" By Dan Wolf.

Construction:
This is a very easy rocket t' build from scratch. Begad! Blimey! T' alignment o' t' side tubes is best accomplished usin' a line drawn on body tube for a guide. The fins just need t' be centered on t' five side tubes and straight as any rocket fin should be. Ya scallywag! Blimey! T' body tube, because o' it's small diameter and length is prone t' bendin' durin' a hard landing. Well, me hearties, blow me down! Blimey! No special tools needed. I Used scrap 1/8 balsa for fins, and some Estes BT 20 tube I already had layin' around. Aye aye! Blimey! Avast, me proud beauty! Blimey! I had t' purchase some PNC 20 nose cones (short ones) as five are required for the side tubes; I already had a regular PNC 20 for t' nose.

Flight:
T' recommended motors are 6 o' t' C6-7's. Avast! Avast! I used this combination on me first flight. Avast, me proud beauty! Aye aye! Normal preparations are used, i.e. Avast! waddin' in body tube, careful foldin' o' parachute, etc. T' motor tubes have no retention other than a tight fit. Tape around motors as needed t' insure a tight fit. Ya scallywag!

T' flight was straight as an arrow, shiver me timbers, shiver me timbers, shiver me timbers, with no spinnin' or wobble. Avast! Aye aye! T' large smoke trail be beautiful as was t' flames from t' 6 engines.

Rocket PicA "Clip Whip" or a special set of soldered igniters is needed t' ignite all engines at once. Ahoy! I made a special set of igniters soldered together. Blimey! (worked perfectly)

I used a 1/8" elastic shock cord approx. Ya scallywag! 3 times t' body length for the recovery. Ahoy! T' 7 sec. delay is nay long enough t' get t' most out o' this rocket. It is still goin' up when t' ejection occurs. T' article discusses this, and an alternate method is t' use a composite C10-10 for t' center (body tube) engine for a longer delay before ejection. Arrr! This also has draw-backs mentioned in t' article.

Summary:
This is a specialty rocket for sure. Ahoy! Begad! It is a blast t' launch and is very impressive. Well, blow me down! Ahoy! It is an attention-getter by looks and flight performance. Avast, ya bilge rat, me proud beauty! T' 6 "C" motors give you approx. Begad! Arrr! a F36 power range launch. Well, blow me down! This is a bunch for such a light rocket and t' performance shows it. Well, blow me down! It is a bit o' a chore to prep, me bucko, and really doesn't lend itself t' multiple launches durin' t' day, unless a good reliable "Clip Whip" is employed. Well, shiver me timbers, blow me down! T' body tube is prone t' damage if recovery isn't exactly smooth.

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