Helicopter with tandem rotors - has rotors angled so that front does not reduce lift of rear

摘要

The helicopter with rotors in tandem, has the front rotor turning in the opposite direction to the rear. The dia. of the front rotor is smaller than that of the rear. The downwards deflection of the front rotor does not interfere with the tips of the blades of the rear rotor. The axes of the two rotors slope at an acute angle from the vertical, and in opposite directions from each other. The front rotor has fewer blades than the rear and is in the ratio of their dias. The front rotor may have three blades, and the rear rotor has four. They may rotate at different speeds and in inverse ratio to the number of blades.