Barnaby Wainfan

Pitch is not the only axis involved in making an airplane fly well. Yaw and roll are also important, and this month Barnaby Wainfan turns his attention to lateral/directional stability and its effect on flying qualities.

When is an airplane in trim? At least to the pilot, the airplane is trimmed when no stick force is required to maintain equilibrium. So how do we achieve this? Barnaby Wainfan explains any number of ways to go about it, including the use of trimtabs, spring systems, sparrow strainers and variable incidence tails.

This month Barnaby Wainfan turns his attention to the control system and how various aspects such as linkages, the elevator planform and tail aspect ratio, and trailing-edge treatments affect pitch control.

The diagnosis of pitch sensitivity problems boils down to one of two things: too little static margin or control system problems. This month we discuss how to modify the airplane to fix them;

This month we use the accumulated flight-test data to determine what exactly is causing the unacceptable flying qualities of the airplane so that the best way to fix the problem can be identified;

The perils of PIO;

Its an age-old duality: stability versus maneuverability. Many factors go into developing and building any aircraft, and the designers choices will affect a pilots workload, for good or ill. Among the topics discussed are trim, pitch stability and yaw stability;

The author discusses the theory and effect of constant-speed propellers on piston-engine airplane performance, and compares fixed-pitch versus constant-speed props, effect on thrust HP and propulsion, the comprises involved in choosing a prop, how props perform in various conditions and phases of flight, how variable-pitch props work, and why a constant-speed prop is the best choice for high-performance aircraft.