Preliminary flight assessment of the low-speed handling of the BAC 221 ogee-wing research aircraft

Abstract

The handling of the BAC 221 slender-ogee-wing research aircraft, at speeds down to 114 knots ias and incidences up to 22°, is described. Pilots considered the aircraft handling as pleasant, in general. The mayor problems were of lateral/directional control at high angles of incidence when difficulty was experienced in preventing large sideslip angles from building up. At all angles of incidence in the low-speed range, the response to aileron was oscillatory. Reducing the effective adverse aileron yaw of the aircraft by an interconnect, enabling the ailerons to drive the rudder, lessened the difficulties in sideslip control and the oscillatory response to aileron inputs was reduced. Longitudinal control was good, but at a = 22° a mild pitch-up occurred. Aerodynamic buffet increased at this incidence and vortex bursting is thought to have reached forward to the rear parts of the wing. Although approaches were made well below the minimum drag speed, speed control presented no difficulty, provided that it could be given full attention. Cross-wind take-offs and landings presented no problems except during the ground run. Side-step manoeuvres on the approach were made with no difficulty.