In selecting the power plant for the Belfast it was considered imperative that the engine and propeller should each have an appreciable background of experience behind them at the in‐service date and should have extensive development lives ahead of them. Shorts did not relish participating in the teething troubles of new engines and were prepared to make small performance concessions to avoid this possibility. Thus a Stage 2 development of the Rolls‐Royce Tyne engine was chosen in preference to Stage 3 which also met the time scale requirements, and the 4/7000/6 de Havilland propeller of 16 ft. diameter was adopted. Though many civil power plants embody the fruits of military experience with broadly similar engines, the Tyne range springs directly from civil stock. In particular, the service experience which Shorts sought for the Belfast engine has been gained on the T.C.A. Vanguard and the Canadair CL‐44.