Odd Roc - Aspect Ratio

[kramer714]

I have been playing a bit lately with tapered rockets, they certainly are a challenge from a design standpoint. Built 2 that taper from big to small and one that is from small to big. The largest one to date is 12 foot long, tapering from 4 inch at the top to 2.4 inch at the bottom.

Aspect Ratio
I have a tapered fiberglass tube from a work project (day job left over), the tube is 175 inches long, tapering from 1.5 to 2.1 inch. I made 48 inch long 54mm I.D. fiberglass booster section with fiberglass surface mount fins. Empty (without parachute) the weight looks like it will be around 3400g and be 230 inches long for an aspect ration of 100/1

Chutes, The design uses a piston in the booster section that ejects a drogue, the drogue pulls the main out of the tapered tube. I'm still working on the 'chute puller' I'm going to use a paper sabot to help get the main in the body tube.

Launching, I need to figure this one out, the thought of a 19 foot long rocket on a 8 foot rail just doesn't seem like a great idea, the weight isn't bad at all, I just worry about the getting hung up on the rod. Right now the plan is to use regular buttons one at the top and one at the bottom of the booster section.

Motor, the original plan was to use a Skyripper K and have a small inter stage for the altimeter. Since I only have 2 or 3 K reloads and sky ripper isn't around I decided to go with a 54mm solid, and use motor ejection. Biggest fear with this is if the rocket arcs over it may be going at a pretty good clip when the chute comes out, plus with single deploy this is definitely a 'no wind' rocket.

Pictures to follow..

 

[jeffgeraci]

Well, Bryce launched a 26-foot upscaled Mean Machine, 6" dia on an 8 or 10 foot rail, and it flew great.
If you mount the rail buttons securely into the centering rings, then an 8 foot rail should be fine. also, be sure your motor will provide you enough speed off the rail. Just be prepared for a TON of bowing during thrust.