Scratch Red Fin Original Design / Scratch Built

Scratch - Red Fin {Scratch}

Contributed by David Urbanek

Manufacturer: Scratch
(Contributed - by David Urbanek)

View/Print a Plan here!

Rocket PicBrief:
A dual 18mm cluster rocket. Simple to build and fly.

Construction:
Body tubes are BT-60. The front one is 9" long and the back on is 9.875". Originally it was a egglofter, but when the egg capsule separated and broke, I made a front payload section. The nose cone is from the Estes BT-60 nose cone set. The fins are 1/8" balsa clad with 1/2 oz fiberglass. The motor mount does not have motor clips and the motor must be friction fit. The centering rings were cut from an Estes centering ring set, but you could get the pattern from the RockSim file too. Recovery is fine with a 12" nylon parachute. I recommend a Nomex® shield as you will have two ejection charges firing on this one. 3/16" or 1/4" launch lug. I used 1/4" on mine. My colors were Krylon white and Krylon red. I used black pinstripe available from any auto parts store.

Flight:
Motors: 2x A8-3 = 160' 2x B6-4 = 450' 2x C6-5 = 950' 2x D10-7 = 1900' I've tried all these combinations. The Dual D10's is the trickiest as you have to cluster using copperhead ignitors.

Summary:
Really cool flier, unusual looks. Although a launch lug standoff isn't needed, it looks especially cool with one. It's a good first cluster model as a two motor cluster is easy to wire and fire.

Other:
Make the shock cord extra long.

comment Post a Comment