Introduction to Glider Flying > Aerodynamics of Flight > Forces of Flight > Parasite drag

Parasite drag is caused by any aircraft surface, which deflects or interferes with the smooth airflow around the glider. Parasite drag is divided into three types— form drag, interference drag, and skin friction drag. [Figure 3-8]

Figure 3-8. Parasite drag increases fourfold when air-speed is doubled.