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Three lift/propulsion concepts for a V/STOL supersonic combat aircraft have been compared. The intention was to show the effect of the propulsion system on aircraft weight and size, performance, and life cycle costs for: 1 Vectored thrust with Plenum Chamber Burning (bypass air augmentation) 2 Lift engines and a lift/cruise reheated turbofan 3 A reheated lift/cruise turbofan with a remote augmented lift system (RALS) For a postulated deck-launched intercept mission, the vectored thrust propulsion system with Plenum Chamber Burning gives the smallest and cheapest aircraft having the required performance. In addition, for a given take-off ground run the vectored thrust powered aircraft has the longest fighter escort mission radius.

By testing a large bypass ratio fan engine in an altitude test facility the performance under simulated flight conditions can be measured. Good accuracy of the results demands careful selection and use of pressure transducers and load measuring equipment. Such a test measures thrust under quiescent air conditions. Model tests need to be used to determine the changes in engine flow and thrust coefficients brought about by the influence of the free stream flow.

Optimising the engine size to the multi-engine helicopter's needs is a difficult process which has traditionally been carried out through the mechanism of the engine rating structure. However, the rating structure has many limitations and does not allow the best potential use of the engine to be realised in service. The introduction of the micro-processor based Engine Monitoring System permits a re-evaluation of the rating structure and also the presentation of limitations to the pilots. By using EMS it should be possible to achieve a better relationship between the demonstrated capability of the engine as shown in the Qualification Programme and the authorised release for in-service use. This may be regarded as a first step to be followed later by a change of the qualification test to a more representative form with the EMS giving a more tangible link between bench test and customer operation.

The Rolls-Royce/S.N.E.C.M.A. Olympus 593 employs a variable area primary nozzle and has a reheat system - both novelties to civil aviation. The main purpose of this paper is to show that these innovations are accommodated without generating crew work load problems. Consequently the paper is aimed primarily at the airline user rather than the control system specialist. A brief description is given of the basic engine electrical control and its interface with the intake system. The flight deck mounted thrust management controls and indicators are identified and their use described during the course of a typical flight. The subject of engine mechanical condition monitoring is also examined.

Front nozzle thrust augmentation, on lift/cruise engines like the Pegasus, could greatly improve the range and load carrying capacity of Harrier/AV-8B type VTOL aircraft and is essential for supersonic derivations. However its introduction requires several new technologies to be developed for the augmentor itself, for the augmentor and engine control system and to cater for various potentially adverse ground effects and related matters. These are the subject of a number of current research and development programmes which will lead to an engine demonstration of an advanced augmentor.

The progress with the use of deflected thrust in European V/STOL airplanes is reviewed. The difficulties which arise in adopting this concept are examined and commented upon in the light of the practical experience which has been accumulated. Several configurations are discussed: the single sided deflector, a more complex rotating cascade version, the tilting pod-engine configuration, and the vectoring nozzle.

INDIRECT or liquid-cooled aircraft engines fit into the picture of future aircraft types better than do the direct or air-cooled engines, the authors contend. As reasons for their belief they draw attention to the small frontal area of this type; the heat capacity of the liquid in equalizing temperatures; and greater freedom in cylinder design because large heat-transfer surfaces are unnecessary. Rolls-Royce has been producing liquid-cooled aero engines for 23 yr, they announce, and has concentrated a large staff on installation problems. One of the results of this work, they report, has been the development of the interchangeable powerplant in which the engine-mounting auxiliaries and bulkhead form a complete detachable unit. These units, the authors explain, are interchangeable within 48 hr, and provide interchangeability between air-cooled and liquid-cooled engines.