Question

For low rotor solidity, profile drag increases.

(a) True

(b) False

I got this question in an international level competition.

This intriguing question comes from Blade Element Theory topic in section Helicopter Dynamics of Aerodynamics

Answer 1

Correct choice is (a) True

Easiest explanation: When the rotor solidity is too low, high angle of attack is required to achieve the lift. This leads to an increase in profile drag. Therefore the rotor should always have solidity which is as low as possible.