h a l f b a k e r yFewer ducks than estimates indicate.
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One can generate a large amount of lift by rotating a cylinder in an airstream.
Imagine two cylinders linked together on both sides by fixed structural members: Like this:
(==), where the == represent two rotating cylinders in front and back. There could easily be 3, 4 etc. It moves upward in this
diagram. The motors to turn the cylinders are in the sides.
With a 20 foot long, 2 foot diameter cylinder at 300 rpm one could generate about 1300 lbs of lift. At higher rpm even more...compare to the rpm of a typical car tire.
Each of the parenthesis (sides) would need to have a propeller (or something) on the front. because the aircraft would need forward momentum while the cylinders are rotating (with backspin).
I wonder how the lift of the cylinder compares to a standard fixed airfoil. The only reason I can think of to make an aircraft like this would be if the lift was more than a standard airfoil (supposedly it's about 10X more efficient??). I.e. rotating cylinders instead of wings. It may also be really high lift but just not go forward very fast, in which case it may be interesting for moving heavy objects around.
There is a neat Java Applet here: SEE LINK
Lift Applet
http://www.grc.nasa...2/airplane/cyl.html
[ShawnBob, Apr 08 2010]
Magnus effect
http://en.wikipedia.../wiki/Magnus_effect
Interesting. [8th of 7, Apr 08 2010]
Rotor ship
http://en.wikipedia.org/wiki/Rotor_ship
An early practical application [8th of 7, Apr 08 2010]
Flettner airplane
http://en.wikipedia...i/Flettner_airplane
A first attempt [8th of 7, Apr 08 2010]
This is "close" to what I described above in principle, but not the same physical form exactly.
http://www.pilotfri..._albums/potty/2.htm
[ShawnBob, Apr 08 2010]
Flying cylinder
http://www.10papera...es/07-the-ring.html
Incredibly simple. [8th of 7, Mar 29 2016]
Toroidal possible preheat
http://amasci.com/f...rg/ideas.html#blimp
"Mechanical Smoke Ring" by [wbeaty] [notexactly, Mar 30 2016]
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The Magnus effect ? Have to be a very lightweight structure ... |
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Yes, I didn't know it was called that. |
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I would think that if it provides enough lift (vertically) to propell a ship throught he water than that is encouraging for the concept. It seems like you can get an extraordinary amount of lift this way at relatively low speeds even. |
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I find the link to the rotorship intriguing, but I'm not sure immediately why the "lift" when turned sideways as a rotating tower makes the ship move forward instead of toward the flatside of the ship...it must have a really hellacious keel underneath to keep it from side-slipping. |
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I once saw two guys who had cut the top and bottom off a coke can and were playing catch with it. They somehow spun it as they threw it and the thing glided through the air about the speed of a frisbee. |
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I was unable to replicate this myself later; there must have been some trick to making it or throwing it or both. I cannot find any demonstration of this on youtube. |
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I am positive I did not dream it. |
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You did not dream it, nor is the memory the consequence of your frequent indulgence in psychoactive fungi (lay off those things, they aren't doing you any good). |
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The "spinning cylinder" paper aeroplane is counter-intuitive and awesome to watch. |
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Not sure I understand this idea correctly, but maybe it's
preheated by [wbeaty]: [link] |
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// The "spinning cylinder" paper aeroplane is counter-
intuitive and awesome to watch. // |
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That's just a spin-stabilized wing. No need for the Magnus
effect AFAIK. |
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