ADEQUATE fuel feeding at altitude, these authors point out, is a matter of vapor elimination, either by preventing its formation or by removing it from the system in the event that its formation cannot be prevented. The effect of vapor is invariably to cause failure of the fuel flow if it forms in sufficient quantity in any part of the fuel system that lies between the fuel tank and the carburetor.
This paper gives the results of a study of the conditions that bring about this type of fuel failure, and describes means of exploring the phenomena experimentally so that it can be ascertained in advance of manufacture if remedial steps are necessary.
The greatly accelerated rate at which designs of military aircraft with increased performance have been developed, they explain, has added materially to the difficulty of feeding vapor-free fuel to the carburetors at the higher altitudes.
The influence of the following variables that affect aviation fuel during flight to high altitude is discussed: dissolved air, vapor pressure, fuel temperature, turbulence, velocity of fuel flow, rate of climb, altitude, vent-line effects, and heat transfer.
In the first part of the paper the simulation equipment is described and illustrated; simulation test procedure is specified; and experimental observations are discussed. The second section, on the centrifugal booster pump, gives the results of three series of tests: one on an isolated tank of fuel, and two on the booster fuel system.