Dude rocket in duration events

OK, with NARAM fast approaching, who had figured out the ultimate duration airframe? Forget high altitude and sleek designs...

Would a Dude rocket, filled with a mix of He and air be allowed? Say in streamer duration? Say a mix of He that would almost counteract the weight of the Mylar, expended engine and rigging. Kick the motor out the rear, with a streamer tied around the casing or just between the airframe and casing.

Check-in weight? 6 grams? Or less.

If you built it so the sink rate is only slightly negative, it shouldn't be that hard to get durations measured in minutes, from a couple hundred feet.

Or, check-in weight? -1 gram? With a slight pin hole. Hey, maybe even an altitude version. Use a MicroMax to burn the tie down string, launching the balloon, err, I mean rocket and let the He leak out very slowly. At some point, it would come back down.

Is there a rule that would prohibit that? Interesting idea? Not quite really practical, given the variables to deal with, but interesting...

Heyen

Reply to
n.heyen
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join groups.yahoo.com contest rocketry

search the archive, this was discussed in length late last fall.

Reply to
almax

This was discussed here shortly after the Dude came out.

In short, the volume of the gas bag isn't enough to substantially overcome the weight of the rest of the hardware. Helium (and hydrogen) don't have enough lifting power to make a stock Dude get into the extremely low mass arena.

Reply to
Anonymous

I ran the numbers and posted them here right after the Dude first appeared. Reduction in total weight was very little switching from air to He. Do a Google search.

-Fred "BT-5 Blowout" Shecter NAR 20117

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Reply to
Fred Shecter

The big weight reduction would come from eliminating the top "mass ring", but that's necessary for stability.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

helium is irrelevant

even the mylar bag ALL BY ITSELF with nothing else is too heavy to life on helium (I know I tried)

Reply to
Chris Taylor Jr

*Nothing* short of removing material will reduce the mass of any rocket....

- Rick "Weight a minute" Dickinson

Reply to
Rick Dickinson

The net buoyancy that can be produced by replacing a contained volume of air with a light gas such as helium is just over

1 oz./cu.ft. - i.e., the difference in density between air and the other gas.

-dave w

Reply to
David Weinshenker

OK, so the Dude is a Dud, too heavy. If people can make vellum body tubes, how about quarter mil gas bags? Obviously this isn't going to handle much 'push' from a motor, but maybe meet the rules for a rocket powered balloon. Hey, at least is should make for a decent R&D project.

Old idea proven dumb, my apologies. Back to occasional lurking.

Norman

Reply to
n.heyen

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