The lecture discusses the extent to which the problems met in the fuel systems of subsonic aircraft are aggravated by flight at supersonic speeds and mentions some new problems of considerable severity. These arise from the relatively large fuel quantity required, its high rate of consumption and its heating by kinetic effects or by its use as a heat sink for the aircraft systems. The paper includes a discussion on fuel management and gauging and of the means used to transfer fuel to the engines—showing the relative merits of some of the available pumping techniques. A few comments only are made on the engine control system.

The problem of thermal degradation of the fuel in the tanks and in components leading to the engine is discussed, with particular attention being paid to the difficulty of establishing a valid test method for differing aircraft configurations.

Spontaneous ignition of flammable mixtures in contact with heated surfaces is a hazard that is likely to arise in a particularly acute form at a Mach number of about 3. The progress of research into this phenomenon is briefly outlined, and some of the measures which may be adopted to ensure safety are indicated. Associated with this is the necessity to develop instruments to detect hazardous conditions in various parts of an aircraft, on which some recommendations are made.