A three mass helicopter could evade fire from all directions with out turning, maybe with a simpler linkage.
The first obvious constraints to the problem:
1. the center of lift needs to be above the center of mass at all
times. This means each section will need it's own rotor. To avoid a
lot of transmission shafts and U joints each rotor will need its own
2. the linkage mechanism must be long enough to give missiles a wide
berth. It must also be light weight so bending moments should be as
low as possible. This probably means the center of lift from each
rotor must be over the center of mass of each respective section.
3. the torque balance must be more or less controllable if they don't
want to get dizzy from spinning. On the 3 body this means one large
rotor and two smaller counter rotating rotors.
A 2 body craft might always be vulnerable in one direction. Even if
it could spin 90 degrees fast enough it may have problems when
receiving fire from several directions.
Unless there is some elegant solution to the 2 body linkage, the 3
body craft may be the way to go.
- posted 10 years ago