Aero Chapter 01, General Aerodynamics Review
T-45 Aerodynamics Student Workbook
AERO CHAPTER 01, GENERAL AERODYNAMICS REVIEW
This lesson reviews the basic forces acting on an aircraft in flight, the aerodynamic principles involved in
producing lift, aircraft stability, and the envelope. It does not contain T-45 aircraft specific material, as do
the remaining aerodynamic lessons.
Four basic forces act upon an aircraft in flight.
They are lift, drag, weight, and thrust (Figure 1).
Lift acts through the aerodynamic center (AC) of
the aircraft. Thrust and drag are sometimes said
to act through the center of gravity (CG), but this is
a vast simplification of the physics involved.
Weight always acts through the center of gravity.
In steady flight, it is true that the sum of thrust and
drag through the CG is zero. Since Naval
Aviators do not require all the underlying physics
to fly an aircraft, this course will consider that
Figure 1: AERODYNAMIC FORCES
weight, thrust, and drag act through the center of
Lift, the primary support force of an aircraft, is usually thought of as the force acting in an upward direction.
However, lift acts 90 degrees to the relative wind. The aircraft attitude may be such that the lift is acting in
varying directions to the other forces that act through the center of gravity.
Lift is the result of air flowing faster over the upper surface of the wing in comparison to the lower surface.
According to Bernoullis principle, this difference in
airflow velocity creates an area of low pressure on the
upper surface of the wing compared to the lower surface.
The pressure differential produces lift.
The basic lift equation is L = CL 1/2 r V2 S
COEFFICIENT OF LIFT
AIRCRAFT TRUE AIRSPEED
WING SURFACE AREA
COEFFICIENT OF LIFT
The coefficient of lift (CL) is determined by the shape of
the wing, the wing airfoil section/planform, and the angle
of attack (AOA). Angle of attack is the angle measured
between the chord line of the wing and the relative wind.
Shape of the wing includes wing thickness, chord,
camber, leading edge radius, and wing sweep. The
shape of a wing is dictated by the intended use of the
aircraft, whether glider or fighter (Figure 2).
Figure 2: CL CURVE OF HIGH VS LOW