6 - Lateral static stability and control

Abstract

This chapter discusses the lateral static stability and control and their importance in flying an aircraft. Wright brothers were successful in designing and constructing the first man-carrying aircraft because they realized that it was necessary to provide control about all three axes. It is all too evident from cinefilm of many of the early attempts to fly that control in roll was desperately needed, not least to react the propeller torque. The Wrights used wing warping and used coupled contrarotating propellers. Shortly after their first flight, ailerons were invented and are almost universally used today. The chapter considers control and stability about the roll and yaw axes. It considers some of the simple background aerodynamics, assuming that the aircraft has conventional flap type controls and a conventional layout. Discussing the trimmwed lateral maneuvers, it considers the aileron and rudder angles required to perform two simple maneuvers, the correctly banked turn and the straight sideslip. Finally, the discussion concludes that the airworthiness requirements ask that an aircraft is laterally stable as discussed here. And moreover, it is required that the trim curves and the rudder pedal force curve do not have any reversal of slope up to the maximum angles available.