Vertical/short take-off and landing - Bleed air for STOL

Bleed air for STOL

Fig. 18-14 Flap blowing engine.

22. Fig. 18-14 shows one method how STOL can be achieved with a form of 'flap blowing'. The turbo- fan engine has a geared variable pitch fan and an oversized low pressure (L. P.) compressor from the exit of which air is bled and ducted to the flap system in the wing trailing edge.  The variable pitch fan enables high L.P. compressor speed and thus high bleed pressure to be maintained over a wide range of thrusts.  This  gives  excellent  control  at  greatly different aircraft flight conditions.