I was talking to a 'copter pilot recently and he was telling me about going through a valley in Hawaii with updrafts so strong that he shut off the engines and still maintained flight.
This led to a discussion of auto-gyros.
My question is:
Could you use the principal of the auto-gyro to make a hang-copter? The downward motion (of gravity) would cause the blades to spin causing lift. Yes?
The German Kriegsmarine had a motorless gyrocopter that they towed behind a couple of submarines to give them “eyes” at a far greater distance than their low conning towers. They did not have many and I do not know whether they were experimental or whether they were just too much aggravation to haul around and launch, but they did build and fly a few.
An article on the Fa330 Bachstelze.
The Smithsonian’s article on the Focke-Achgelis Fa 330A-1.
Gyrogliders do exist - I knew a guy who owned one up in Wisconsin. Used to tow it behind a pickup truck on long, straight rural roads with few police patrols. But it never struck me as being as practical a means to fly without an engine as a fixed-wing glider.
Thanks for the link tomndebb.
The Focke-Achgelis Fa 330A-1 is cool. Practical or not I want one!
I menyioned this to a nonpilot friend and he served up paper gyrogliders vs. regular paper airplanes. I made a few and sure enough the gyros stayed in the air much longer (in my trials). Now I know that was not very scientific but why would the paper kind behave differetly than real ones?
YES
For a little while till you ran out of altitude. :rolleyes:
What was the wing configuration on the paper airplanes? Even ignoring the traditional delta shape of the classroom paper plane (which is intended to provide stability, not lift), few paper planes have the extreme wingspread of an actual sailplane. The dynamics of those long, slender wings to provide a large amount of lift cannot be easily reproduced on a rotating wing (where the “downwind” wing has to change its angle of attack to keep the device from rolling). A paper gyrocopter is basically an extreme parachute. A helicopter on autorotation can also stay up (slightly) longer and land (somewhat more softly) than a fixed wing airplane when the engines are turned off, but one cannot use a helicopter to glide for any length.
I thought that it was the forward motion of an autogyro (they have a little propellor like an airplane) that provides lift (by causing the rotor to spin). If you were to cut power while the rotor is spinning you’d be OK, since it takes some time for the rotor to stop spinning.
If you were to just drop an autogyro straight down from a standing start I can see the rotor spinning a bit but I have a feeling that it wouldn’t generate much lift - instead of a really really bad crash it’d just be a really bad crash.
Gyro-gliders exist in nature too: there are many seeds designed for wind dispersal, and the spinning rotor design is pretty common.
[ nitpick ]
The engine and propellor never provide lift. Lift is always delivered by the wings. The motion of the wings, of course, is provided by the reaction of the wing surfaces to the air moving over them due to the forward motion of the device, provided by the engine and propellor.
[ /nitpick ]
This is, in essence, also true for the unpowered autogyro about which the OP asked, since the examples we have seen have all had “external” power sources (submarines or pickup trucks) that dragged them through the air, causing the wings to spin.
As long as the plane is moving (forward or down) there will be enough relative wind to cause the wings to rotate, but there may not be enough to cause them to rotate fast enough to provide very much lift.
[nitpick]
Sailplane wings are long and slender not to provide a large amount of lift, but rather to provide a normal amount of lift with low induced drag.
[/nitpick]