Scratch USA Gymnastics Original Design / Scratch Built

Scratch - USA Gymnastics {Scratch}

Contributed by Alex Rothchild

Manufacturer: Scratch
(Contributed - by Alex Jordan - 01/06/05) (Scratch) USA Gymnastics rocket

Brief:
This is a single stage, scratch built rocket with six fins, 24mm motor mount, and 3/16 launch lug. It can hold up to a F21-8. It is painted yellow, orange, and black along with a big USA Gymnastics sticker on it since I built it for my sister, who is a gymnast.

Construction:
I used all Estes components. The parts list:

  • 1 14" long BT-80 body tube
  • 1 3" long BT-80 body tube
  • 1 BT-80 tube coupler
  • 1 NC-80
  • 1 24mm motor mount for BT-80
  • 1 18" chute
  • 1 1/4" x 48" inch shock cord
  • 2 3" x 12" x 3/16" balsa sheets
  • 1 plastic straw (used as a launch lug)

This was a simple rocket to build. It consisted of building a traditional 24mm motor mount (centering rings, MM tube, engine hook, engine block, and paper ring). Once those were on, I used the Estes body tube marking guide (a MUST have) to make six lines on the BT. I then cut out two different fin patterns and positioned the fins around the body tube. I glued them on and applied the usual fillets. The fins were surface mounted. I then glued the tube coupler into the 3" BT-80 tube and the nose cone on the other end. The shock cord was connected to the upper centering ring and to the nose cone. The chute was connected to the shock cord. I then used regular straws for launch lugs.

Finishing:
I primed it with Rustoleum and painted it yellow, orange, and black. I put a USA Gymnastics sticker on it.

Flight:
This rocket has flown once on a D12-3. It was a great flight to about 1000 feet. The delay could be a bit longer though. It got scratched up a lot on landing and popped a fin.

Recovery:
Ejection was right at apogee. The 18" chute inflated and the rocket drifted about 100ft down field.

Summary:
I think this is a great rocket. It came out well and flies great on 24mm engines. The next flight is planned for a D12-3.

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