The Evolution and Development Status of the ALF 502 Turbofan Engine

The factors influencing the design of the ALF 502 engine are reviewed in context with explanations and some retrospective comments.

Early experiments are outlined, followed by a more detailed account of the intense short-term development which culminated in the Pre-Flight Rating Test.

The conclusion reached is that, in the 6000 to 8000 lb. thrust class, the economy and rapid availability achieved by combining a carefully tailored fan module with a simple, well proven core engine of modest pressure ratio can outweigh the advantages of higher cycle efficiency obtainable with a more complex machine.