DGCA Technical General question paper, January 2025

Question 1

Which description defines the aerodynamic centre of an aerofoil?

Accepted Answer

The point about which the pitching moment coefficient stays the same as angle of attack changes

Answer

The point where the lateral axis passes through the CG

Answer

The point through which the total lift always acts at every angle of attack

Answer

The point about which the lift coefficient stays the same as angle of attack changes

Question 2

A modern aeroplane has a lift to drag ratio somewhere between 10:1 and 20:1. What does this tell you?

Accepted Answer

The lift produced is 10 to 20 times the drag

Answer

The drag produced is 10 to 20 times the lift

Answer

The lift and the drag are both between 10 and 20 kN

Answer

The lift is 20 units while the drag is 10 units

Question 3

Air flows through a normal shock wave. What happens to the local speed of sound behind the shock?

Accepted Answer

It rises

Answer

It falls

Answer

It stays the same

Answer

It falls at first and then rises above a certain Mach number

Question 4

Wingtip vortices form because of the pressure difference between the two wing surfaces. In which direction does air spill around the tip?

Accepted Answer

From the lower surface up round the tip to the upper surface

Answer

From root to tip along the lower surface only

Answer

From the upper surface down round the tip to the lower surface

Answer

From tip to root along the lower surface only

Question 5

Apart from reducing induced drag, what effect do winglets have on the stability of an aeroplane?

Accepted Answer

They improve lateral and directional stability

Answer

They mainly increase the rate of roll

Answer

They have no noticeable effect on stability

Answer

They reduce lateral and directional stability

47 more questions in this paper, free with an account.