Study for Air Vehicles at High Speeds, Identifying the Potential Benefits to Transport Aircraft of a Continuously Variable Geometry Trailing- Edge Structure that can be Utilized for Aircraft Control, Trim, Load- Alleviation, and High Lift.

摘要

One of the technologies emerging in recent years concerns variable aerofoil shaping (or morphing), using 'clever' internal mechanisms. Previous studies have noted potential aerodynamic efficiency gains, gust loads alleviation, stagnation point control for laminar flow onset or Shock position / strength control. Previous work along some of these lines has also been in TACT & MAW programs. Although such mechanisms may provide a lower sectional Clmax, compared with a point design high-lift system, the main advantage is that these mechanisms could be utilized across the entire flight envelope for different functions. It is also known that to obtain optimum L/D performance at high-lift, TE deflections may need to be accompanied by LE deflections or devices. Many, varied aspects of VTE technology have been assessed. At high and low speed, a VTE capable wing provides higher L/D. This advantage can be assimilated in a variety of ways, increased range efficiency gives typically 5% to 15% increase in range, Take-Off field lengths are reduced by 10% to 15% depending upon Clmax capability. A wing with VTE capability can control 'off- design' gust loads thereby reducing structural strength requirements leading to a lighter wing. Using simplified but modest assumptions, the wing weight saving can be immediately absorbed as increased payload within given MTOW. On current, reasonably fuel efficient, long-range civil transports this leads to 45% increased efficiency. On small, comparatively inefficient long-range executive transports the wing weight reduction virtually doubles the design payload leading to 70% to 80% increase in efficiency.