Re:Feasibility of a Dune Ornithopter
by adrian_b on Saturday October 23, 2021 @03:45AM
(#28966509)
The problem with the supersonic tips is identical for normal aircraft propellers.
For aircraft with fixed wings for generating lift, the propellers can be small, so supersonic speed is reached only at a higher rpm, but for a helicopter there is no difference from this point of view compared with an ornithopter.
The blades of a helicopter propeller must also be able to rotate along their longitudinal axis, like those of an ornithopter, but nonetheless they are more efficient than flapping wings, because there is no dead time and no energy lost for the reversing motions, and the fatigue resistance need not be as extreme as it would be required for flapping wings.
For aircraft with fixed wings for generating lift, the propellers can be small, so supersonic speed is reached only at a higher rpm, but for a helicopter there is no difference from this point of view compared with an ornithopter.
The blades of a helicopter propeller must also be able to rotate along their longitudinal axis, like those of an ornithopter, but nonetheless they are more efficient than flapping wings, because there is no dead time and no energy lost for the reversing motions, and the fatigue resistance need not be as extreme as it would be required for flapping wings.