Vertical/short take-off and landing - Swivelling engines

Swivelling engines

Fig. 18-13 Jet lift with swivelling nozzles.

20. This  method  consists  of  having  propulsion engines which can be mechanically swiveled closed through  at  least  90  degrees  to  provide  thrust vectoring (fig. 18-13). In addition to these propulsion engines, one or more lift engines may be installed to provide supplementary lift during the take-off and landing phase of flight.

21. The swivelling engine system can only be used with two or more engines. This then introduces the problem of safety in the event of an engine failure. So, although there is only a small weight penalty and no increase in fuel consumption, safety considera- tions tend to offset these advantages compared to some of the other powered lift systems. The normal method of providing aircraft control at low speeds is by differential throttling and vectoring of the engines which simplifies the basic engine design but makes the control system more complex.