Practice question 1
As speed increases, induced drag will
- A remain constant.
- B decrease.
- C increase.
Show the answer
Answer: B. decrease.
FAA source: FAA-H-8083-25C ch. 5, Drag Curves / Induced Drag
FAA-H-8083-25C, ch. 5
What is parasite drag?
Parasite drag is the drag that does nothing to help an aircraft fly. Here are its three types, the exam traps and practice questions, with the FAA source under each answer.
What is parasite drag and what are its three types?
Parasite drag is all the drag not associated with the production of lift. It includes the displacement of air by the aircraft, turbulence in the airstream, and air hindered as it moves over the surface. The three types are form drag, interference drag and skin friction. Parasite drag increases as the square of the airspeed.
Sources: FAA-H-8083-25C ch. 5, Parasite Drag · FAA-H-8083-25C ch. 5, Induced Drag
What the FAA handbook says
FAA-H-8083-25C ch. 5, Parasite Drag
Parasite drag is comprised of all the forces that work to slow an aircraft’s movement. As the term parasite implies, it is the drag that is not associated with the production of lift.
FAA-H-8083-25C ch. 5, Parasite Drag
There are three types of parasite drag: form drag, interference drag, and skin friction.
FAA-H-8083-25C ch. 5, Induced Drag
Conversely, parasite drag increases as the square of the airspeed.
Sources: FAA-H-8083-25C ch. 5, Parasite Drag · FAA-H-8083-25C ch. 5, Parasite Drag · FAA-H-8083-25C ch. 5, Induced Drag
Exam traps
- The two basic types of drag are parasite drag and induced drag; induced drag is the result of an airfoil developing lift.
- Form drag is the portion of parasite drag caused by the aircraft's shape and airflow around it, and it is the easiest to reduce by streamlining.
- Interference drag comes from the intersection of airstreams, such as at the wing root, and is most observed when two surfaces meet at perpendicular angles.
- As an aircraft nears its never-exceed speed (VNE), total drag rises rapidly because of the sharp increase of parasite drag.
Try it: practice questions
Similar to the FAA test, not the actual test questions.
Practice question 2
As the angle of attack increases, induced drag will
- A remain the same.
- B increase.
- C decrease.
Show the answer
Answer: B. increase.
FAA source: FAA-H-8083-25C ch. 5, Induced Drag
What is skin friction drag?
Skin friction drag is the aerodynamic resistance due to the contact of moving air with the surface of an aircraft. Every surface, however smooth it looks, is rough when viewed under a microscope.
Source: FAA-H-8083-25C ch. 5, Skin Friction Drag