Principles of Flight - Drag (2)

Another type of induced drag is called Parasite Drag. It includes (1) Form Drag, (2) Interference Drag and (3) Skin Friction Drag.


Form Drag arises because of the form of the object. Object with a larger cross section tends to face more resistance when travelling through the air which thus has more drag. Streamlined designs can reduce form drag e.g wheel fairing.

Interference Drag forms at the intersection of different aircraft bodies. It can never be completely eliminated but can be reduced by filleting.

                  

Skin Friction Drag arises when air is passing through a rough surface which therefore creates turbulence. It can be reduced by using flush rivet (鉚釘), painting, cleaning, waxing, polishing or applying surface coatings.