Lateral control with high lift devices

Abstract

The increasing attention which high-lift devices are receiving makes it desirable that a summary of the present information on lateral control with high-lift devices should be available. The devices considered are classified as - (A) those devices that can be used with full span flaps ; these include (i) spoilers, (ii) auxiliary aerofoils, (iii) ailerons behind Zap type flaps, (iv) ailerons behind slotted flaps, and (B) those devices which can be used only with nearly full-span flaps and which include (i) short span, wide chord ailerons (straight and skew hinge), (ii) floating tip ailerons, (iii) ailerons formed from part of rear flap of large double-slotted flap. A brief summary of the main characteristics of the various devices considered is found in Table 1. No satisfactory method of lateral control has yet been developed that permits full use of the high-lift devices covering the complete wing span, although there is a reasonable hope that a satisfactory spoiler control will yet be developed. For the present, methods of lateral control must be accepted which restrict to some extent the span or type of flap ; a number of such methods which are fairly satisfactory are available. The loss of possible lift increment incurred in their use need not be greater than about 15 per cent. of the increment due to full-span flaps.