Thread: Discussion Japanes Ball Drone.
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Old Jun 18, 2011, 08:26 AM
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with a fixed pitch prop it does not really matter where the CoG is in relation to the prop as far as stability in the hover is concerned. the thrust vector tilts with the airframe, so there's no way to obtain a self-righting setup. what matters is the distance between the control surfaces and the CoG, or, if you want to see it this way, between the vector of thrust and the CoG. Any tilting moments in a hover, for a single rotor platform, are a function of the moment arm between the global thrust vector and the CoG.

P.S.: Rockets are perfectly stable with their thrust applied at the tail. As long as the CoG is ahead of the center of pressure, the design is stable. Hover will be always unstable, you can only mitigate it with stabilization devices like gyros or flybars. they won't prevent the plane from tipping over, but they will slow it down enough that the pilot will manage to keep it upright
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Last edited by Brandano; Jun 18, 2011 at 08:33 AM.
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