1163. Application of the Thrust Augmentation Wing Principle for Potential Military Use

Paper

Abstract

The development of heavier-than-air powered flight encompassed over 70 years and literally thousands of different fling designs. The evolutionary process underlying this development, while considerable, has retained a general state of separation between achievement of aerodynamic lift and propulsive force required for forward flight. The preoccupation of the Wright Brothers and their contemporaries was the addition of motive thrust to what were otherwise ‘gliders’. The modern airliner and high performance fighter are no different from the earliest aircraft in this regard, the consequence of which has been the need for long take-off and Landing runs. (Figure 1). The notable exception is the helicopter which achieves efficient vertical flight but accepts as position on the scale of tradeoffs towards the low speed end of the flight regime.
This general situation has always been well known. With the advent of turbine engines whose power-to-weight ratios were improved over those of reciprocating engines, aircraft designers perceived the possibility that high performance aircraft could achieve vertical flight through power lift. The history of the last 25 years shows that this was easier said than done as attested by reaching operational service is the Hawker Siddley the multitude of configurations built and tested ‘Harrier,’ although thjs required a considerable (Figure 2). The only aircraft of this vast family development time period.
Tremendous resources have gone into these programs to achieve vertical flight and also into the minimizing of take-off and landing speeds of conventional aircraft through high lift technology. The desire to merge these two objectives has led to the concept of the ‘Thrust Augmented Wing.’
The TAW is an approach to integrating lift, propulsion, and control so that an otherwise normal airfoil can be ‘flying’ not only at high aerodynamic speeds, but also at zero speed, and any speed in between with smooth conversions in acceleration and deceleration.
The general arrangement of TAW with the main elements is shown in Figure 3.
Current configurations have three movable flaps, one upper ‘center ejector’ and two lower ‘diffusers.’ Engine exhaust air can either be directed aft in a normal manner or completely diverted into these flaps and ejected through long slot nozzles, directly for the center ejector and over coanda surfaces for the diffusers. All subsequent control of the TAW’S thrust vector is performed by proper movement of these three surfaces.