Thrust reversal

An early problem with turbo-jet propulsion was that the high speed aircraft that it produced tended to have a high landing speed. As there was no propeller drag to help slow them down, they needed very long runways. One solution to this problem is to fit thrust reversers in the form of a movable device to deflect the exhaust jet forwards. Thrust reversers take many forms, and may either use cold air from the compressor, or the hot exhaust gases. Two typical hot-jet

deflector designs are shown in Fig. 6.31. The louvred cascade for the hot-jet deflector used on Concorde may be seen in Fig. 6.32.

Despite the added cost and weight penalty, thrust reversers are now popular even on small executive jets. Apart from reducing the landing run, the feature enables the aircraft to manoeuvre more easily on the ground under its own power.

A more detailed description of jet engine components is given in the well – illustrated Rolls-Royce publication The Jet Engine (1986).