Question: 1. At 1.25-m radius on a three-bladed airscrew, the airfoil section has the following characteristics:
Solidity = 0.1; Θ = 29°7'; α = 4°7'; CL = 0.49; L/D = 50
Allowing for both axial and rotational interference, find the local efficiency of the element
2. The thrust and torque gradings at 1.22-m radius on each blade of a two-bladed airscrew are 2120 N m-1 and 778 N m m-1, respectively. Find the speed of rotation (in rad s-1) of the airstream immediately behind the disc at 1.22-m radius.