Question: At 1.5-m radius, the thrust and torque gradings on each blade of a threebladed airscrew revolve at 1200 rpm at a flight speed of 90 m s-1 TAS at an altitude where σ = 0.725 are 300 N m-1 and 1800 N m m-1, respectively. If the blade angle is 28 degrees, find the blade section absolute incidence. Ignore compressibility.