Why does the trailing edge of a supercritical airfoil have a cusp-like shape?

Reduce drag

Increase fuel carrying capacity in the wing

Counter highly positive camber at the front end

Counter highly negative camber at the front end

Correct Answer : Counter highly negative camber at the front end

Explanation : Due to the presence of flatter top surface in supercritical airfoil, the 60% of the front end of airfoil is highly cambered resulting in less lift. To counter the reduced lift, positive camber is provided at the bottom aft section of the airfoil by giving it a cusp-like shape. This increases the lift.

Recently Updated in Aerodynamics Questions

What happens to the coefficient of pressure in a supersonic flow for an increase in Mach number?

Increases

Decreases

Remains unaffected

First increases then decreases

Correct Answer : Option (B) : Decreases

Explanation : For linearized supersonic flow, the coefficient of pressure is inversely proportional to

Thus, when the Mach number increases, the coefficient of pressure decreases. This in contrast to the trend followed by the subsonic flow where an increasing Mach number results in decreasing coefficient of pressure.

What is the source of wave drag exerted on the supersonic airfoil?

Skin friction

Trailing vortex

Shock waves

Viscous boundary layer

Correct Answer : Option (C) : Shock waves

Explanation : Wave drag is a result of pressure distribution which is exerted over the airfoil. This is a consequence of formation of shock waves and expansion wave pattern due to the presence of supersonic flow.

What is the lift coefficient over a flat plate at an angle of attack of 3 degrees in a supersonic flow at Mach 4?

0.0512

0.0541

0.0628

0.0714

Correct Answer : Option (B) : 0.0541

Explanation :