Descon 11 Project X Original Design / Scratch Built

Scratch - Project X {Scratch}

Contributed by Tater Schuld

Manufacturer: Scratch

 

Rocket Pic At one time I was building a model plane and decided to take a few extra parts and fiddle with them. I went and attempted to make some centering rings using a saber saw on some balsa and came out with the tissue and balsa framework for Project X. I then let it sit for about 3 months while trying to figure out how to finish it. While Descon X raged on, I saw the design for rear deployment would be ideal, but decided i could not compete with the "Purple People Eater of Death" (Descon 10, Robert Galejs) so I finished all but the fins and launch lugs. RocSim said that it would not be stable without a large fin area, so i let it sit while my subconscious worked on it.

Finally DesCon 11 came out and I realized that I had this rocket waiting to be shown. I whipped up some fins for it, rocsimmed it, added nose weight, rocsimmed it again, checked the wind forecast, rocsimmed it again, and still did not like what I saw. the rocket was too draggy for the 18mm Estes engines I had, and I did not have time to modify it to a 24mm mount.
 

Rocket Pic
Rocket Pic
Rocket Pic

But it looked right. I decided to fly it anyway. at least it would be an interesting flight.
 

Rocket Pic
the winds seemed worse than what i thought they would be, and i was prepared for a wild flight. I prepped the rocket on a Estes C6-3 and put her on the pad, with a 3/16" 5 foot rod. amazingly the rocket flew straight and arced over DOWNWIND! not upwind as it should have. 
I must have had a bonus delay as ejection happened about halfway down and the chute did not unfold (it deployed, but would *not* unfold) the rocket hit the ground and the nosecone shattered into many pieces as the photos show
Rocket Pic


 

Overall, Project X allowed us to test quite a few things. model rockets do not need cardboard tubes for airframes. Tissue over balsa construction can work for small model rockets. a close coupled rear ejection design will work, even if a parachute doesn't.

Project XI will be designed with a smaller diameter, dual chutes, even less rocket specific items, and will hopefully survive to fly a second launch.

Parts list

  • 2 sheets balsa 4"x36"x1/8"
  • one to be sliced into 1/8"x1/8" lengths, the other for cutting the rings and to support motor mount
  • 3" BT-20 , engine hook, and thrust ring for motor mount
  • 2 3" BT-60 tubes, one for looks, one opposite for rear ejection chute
  • soda box cardboard for forming the ejection duct from the BT-20 to the BT-60
  • 1 more sheet of above balsa for cutting 4 fins (3"x4")

Rocket Pic

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