Linear Flight

When the aircraft velocity V is in a fixed straight line the flight is termed linear. When V is in the plane of symmetry the flight is termed symmetric. There are three types of linear symmetrical flight; gliding,

Theoretical Aerodynamics, First Edition. Ethirajan Rathakrishnan.

© 2013 John Wiley & Sons Singapore Pte. Ltd. Published 2013by John Wiley & Sons Singapore Pte. Ltd.

Gliding Horizontal Climbing

Figure 10.2 Illustration of gliding, horizontal and climbing flight.

horizontal, and climbing, as illustrated in Figure 10.2. Among these, gliding is the only flight possible without use of the engine.

The flights can be steady (constant V) or accelerated. In the case of steady flight the resultant force on the aircraft must be zero. The forces are: (i) engine thrust (under control of the pilot), (ii) weight (not under control of the pilot), and (iii) aerodynamic force (in some measure under control of the pilot by use of ailerons, rudder, and elevators).