Research on the Control of Aeroplanes¹

Abstract

AN essential factor in the control of anything, whether it be a motor-car, a ship, or an aeroplane, is some means of applying the necessary force in the desired direction. The car requires its steering wheel, the ship its rudder. But this is not the only factor which decides the character of the control, whether quick or slow, difficult or easy. Other factors inherent in the craft to be controlled have to be considered. One such factor is inertia. A motor-car has very little inertia compared with the forces which can be exerted through the road wheels; consequently, it responds at once to a movement of the steering wheel, and the turning stops immediately the wheel is centralised. A ship has great inertia compared with the force exerted by the rudder; consequently the rudder must be applied some time before an appreciable turn is started, and reversed against the movement long before the ship has swung to its new course. The character of the control of a ship is thus entirely different from that of a car, on account of this factor of inertia, which has nothing to do with the controls themselves.