Question

An airfoil is operated with flow velocity such that the pressure on upper and lower surface are 30 Pa and 15 Pa respectively. If chord is 1m then, what will be the lift produced by this airfoil?

(a) 15N

(b) 15KN

(c) 25N

(d) 30 Pa

I got this question during an interview.

I would like to ask this question from Airfoil Selection-3 topic in chapter Airfoil and Geometry Selection of Aircraft Design

Answer 1

Right answer is (a) 15N

For explanation I would say: Given, Pressure on upper surface P1 = 30Pa,

Pressure on lower surface P2 = 15Pa, chord = 1m.

Now lift = (P1- P2)*Chord = (30-15)*1 = 15N.