5 ms·
My guess is complexity. The double rotors require coaxial drives and the helicopter itself ends up being taller. The top rotor maintenance is going to be more
by gvb 16y ago
My guess is complexity. The double rotors require coaxial drives and the helicopter itself ends up being taller. The top rotor maintenance is going to be more difficult.
The Kamov company's helicopters were all(?) double-rotor.
http://en.wikipedia.org/wiki/Kamov http://en.wikipedia.org/wiki/Kamov
Kamen Aerospace has double rotor helicopters without the coaxial drive (interleaved rotors)
http://en.wikipedia.org/wiki/Kaman_Aircraft http://en.wikipedia.org/wiki/Kaman_Aircraft
- stan_rogers 16y agoComplexity, yes, but for a different reason -- gyroscopic precession. Cyclic inputs for differential lift require that the actual (mechanical) blade adjustment be at an angle to the change in the lift produced. With a single rotor you can accomplish that with a simple mechanical linkage (and a bit of body english -- the angle of input precession is rarely at the "proper" 90 degrees). Counter-rotating blades mean two sets of blade pitch controls (swash plates, rods, followers and linkages, etc.) and, if you want to avoid unplanned pitch adjustments, a servo system that can moderate cyclic control input based on direction (input will be much more sensitive to fore-aft adjustment than to left-right without a compensation circuit).
- jacquesm 16y ago> if you want to avoid unplanned pitch adjustments I read that as 'detours to the nearest hospital'.