Last weekend, 27-29 July, I flew a mostly 3D Printed Rocket at URRF. I was hopeful that the nosecone and fins could hold up to the stresses of launch.
The nosecone was developed first. An OpenSCAD file, including adjustable parameters is available. The nosecone may be a little loose in the body tube. A little tape on the inside edge will make a tighter fit.
Next a fincan was developed. The SCAD source for this is also available. A five fin pattern was chosen as someshing a little different. The rocket name was chosen because this looks like a star pattern. A two part launch lug is part of the design. Two parts makes it easier to drill out and ensure it fits on a 1/8″ launch rod. The fincan inside diameter is chosen to fit a BT-50 body tube.
Before gluing the fincan to the body tube, add a motor mount. I like to tie kevlar cord to the motor mount with a length long enough to reach through the body tube then add a length of elastic to connect to the nosecone. I sanded the nosecone a bit and wiped with a paper towel dipped in acetone, which smoothed it a bit. I didn’t do much with the fins, only wiping with acetone. It should have been sanded too.
A draft openrocket model can be used to model the flight. Include extra mass in the model, if needed.
The rocket was flown with an A8-3 and a C6-5 motor. The A8-3 only went up about 50 ft, a bit low, but worked. The C6-5 worked well, with an estimated altitude of 500 ft. B6-4 should work well too.
© David B. Snyder, 2014