What's up, folks!? Its been a while.
There doesn't seem to be a pigeon hole for this topic (at least I didn't find one) so I post it here. I just watched a video from 1931 on autogyros. There was one item of information that was new to me and it may be the reason that homebuilt RC autogyros have a rough time. The rotors on the autogyro in the video (looks like a Pitcairn to me - but all autogyros with radial engines from the '30s look like Pitcairns) are hinged to allow them to sort of furl. This compensates for the difference in lift caused by advancing vs retreating rotors. The advancing rotor, which generates greater lift than the retreating rotor, is pulled upward at an angle, resulting in a smaller lift force than a rotor in the plane of rotational motion.
Now, I don't know what goes into the design of the rotors such that the centripetal force holding the hinged rotor extended is large enough to prevent the rotors from folding upward and clapping hands. The centripetal force part is easy, but designing the airfoil such that lift doesn't overcome the centripetal force is beyond my experience. Anyway, I found it interesting. Here's the video.
Later!
There doesn't seem to be a pigeon hole for this topic (at least I didn't find one) so I post it here. I just watched a video from 1931 on autogyros. There was one item of information that was new to me and it may be the reason that homebuilt RC autogyros have a rough time. The rotors on the autogyro in the video (looks like a Pitcairn to me - but all autogyros with radial engines from the '30s look like Pitcairns) are hinged to allow them to sort of furl. This compensates for the difference in lift caused by advancing vs retreating rotors. The advancing rotor, which generates greater lift than the retreating rotor, is pulled upward at an angle, resulting in a smaller lift force than a rotor in the plane of rotational motion.
Now, I don't know what goes into the design of the rotors such that the centripetal force holding the hinged rotor extended is large enough to prevent the rotors from folding upward and clapping hands. The centripetal force part is easy, but designing the airfoil such that lift doesn't overcome the centripetal force is beyond my experience. Anyway, I found it interesting. Here's the video.
Later!