Question

If the geometric angle of attack is higher at the tip than the root, it is called as ______

(a) Washout

(b) Geometric twist

(c) Aerodynamic twist

(d) Washin

I had been asked this question in examination.

This interesting question is from The Vortex Filament, the Biot-Savart Law, Helmholtz Theorem topic in chapter Flow over Airfoils over Finite Wing of Aerodynamics

Answer 1

Right answer is (d) Washin

Easiest explanation: For a finite wing, the geometric angle of attack can be different at different locations along the span. If the geometric angle of attack is higher at the tip than the root it is called washin. Washout is the condition when angle of attack at the tip is lower than at the root is called washout.