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Screwing up

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The model rocket body is a thin, solid plastic, gradually tapering helix about a foot and a half long with a hollow egg shaped nose cone at its widest end.

The missile’s launcher is a hollow tube with a relatively heavy flywheel near its top that can be depressed, (or joyful if the occasion warrants), about eight to ten inches down into the tube on strong spring loaded sliders.
The corkscrew is loaded into the top of the tube and twisted slightly until small splines on its side align with slots in the flywheel but do not slide all the way through the flywheel's center. The flywheel is depressed causing bumps on its inner surface to raise, these keep the corkscrew from disengaging from the flywheel.
A spring-return pull cord on the launch tube's side is pulled repeatedly until the flywheel is rotating as fast as you can make it go. (deluxe models may have gear boxes for greater speed).
When the launch button is pressed the fly wheel is jerked violently towards the end of the tube on its sliders while releasing the extrusions which hold the corkscrew to it. It stops its upward movement just as suddenly.
The unfettered rocket then screws itself into the sky until the resistance of its forward momentum is no longer enough to hold the egg shaped nose cone from releasing the parachute that lets you do the whole thing over again, without having to buy a new rocket engine.

Helical propulsion. http://www.pnas.org...nt/full/94/21/11307
[2 fries shy of a happy meal, Oct 05 2004, last modified Oct 21 2004]

(?) nomel's link http://schutz.ucsc....k/notes/node56.html
[jutta, Oct 05 2004, last modified Oct 21 2004]

Oops, not as original as I thought. http://www.davincis...com/MR_ASReview.pdf
[2 fries shy of a happy meal, Oct 05 2004, last modified Oct 21 2004]


       If you had a rock, and threw it into the air...you could find the height it will reach by the speed that it left your hand by the speed and the acceleration of gravity.   

       this would be, as shown here [see link --admin.]   

       max height = 1/2(v^2/g)
nomel, Jul 02 2004

       Okay I agree that "rocket" might not quite apply, (name change), but in all fairness [Tabs] since it has no wings and goes straight up I don't know what else to call it.
Both you and [nomel] seem to think that this will only fly as high as the sliders can throw it. Now I don't have the math to back this up but if the corkscrew is spinning at the same speed as the flywheel when it is released, then that spin is going to be forcing a lot of air downwards and will propel the "rocket" up in the same way that a helicopter produces lift from spinning the rotor. So to say that this is just flung projectile or to use the same formulas used to determine how far a thrown rock would travel is just wrong.

       I've seen the little flywheel propellor-with-a-rim toys that work basically this way, except no push; just spin, release, and they fly away. I can't figure how a tapered corkscrew-shaped tube is going to move much air, though; seems you just have a very wobbly unstable dart.
lurch, Jul 02 2004

       The body is not a tube but a long flat plastic strip which has been twisted into a helical shape, it’s the launcher that is a tube. Because it is spinning so fast it would wobble very little, much like the spiral on a thrown football or the spin given to a bullet by a gun barrel's rifling.
A spinning helix is supposed to be one of natures most efficient forms of propulsion, something to do with laminar flow. Lemme just see if I can rustle up a link.

       This is very much more like a flywheel powered helicopter with a helical set of blades than a rocket, right?
GutPunchLullabies, Jul 08 2004

       In its operation I would say yes, but its flight characteristics (straight up fast; release parachute; float down slow) are more similar to what we expect from a rocket.
spacemoggy, Jul 08 2004

       Love it!   

       Can you make me one.   

       A picture might help the non-believers.
DesertFox, Jul 08 2004


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