1930-01-01

Aircraft-Engine Installation 300037

THE PAPER urges united cooperation instead of the present division of responsibility between the engine designer and the airplane designer in the installation of aircraft engines. The tubular rings upon which engines are commonly mounted are usually supported by structural members that are welded to the ring and attached to the fuselage at the four longitudinals. Inaccuracy is common in these structures, and many of them lack sufficient stiffness.
Gravity gasoline-feed is recommended for its simplicity, provided the pressure head required by the carbureter can be secured, but the author reports having seen an installation in which the engine would operate so long as the airplane had its tail on the ground, yet the engine would die as soon as the tail was raised during a take-off. The use of gasoline-resisting rubber-hose with metal liners and the avoidance of sharp bends are recommended for the gasoline connections. A strainer of ample capacity with an accessible drain should be located near the carbureter.
The overflow from the pressure-relief valve is reported to be the cause of vapor lock sometimes, when it is merely a return to the pump inlet. The location of oil tanks often is such as to prevent effective cooling, and oil thermometers frequently are located at the engine oil-inlet instead of at the outlet. For new installations, thermometers are recommended to indicate both the inlet and outlet temperatures of the oil.
Too little attention is given to carbureter heating, the author says. The carbureter must be jacketed if warm air is not supplied in sufficient quantity to prevent the formation of ice around the jets and throttle. Other installation details that require more attention are the electric wiring, the engine controls and the cowling.
In the discussion* it is stated that there has been a constant battle between the Air Corps and the manufacturers to secure uniform and adequate installations. More direct cooperation between the Department of Commerce and the Army and Navy Services is recommended because the latter have learned much that would be of great help to commercial operators. Further discussion has to do with carbureter heating and oil cooling.

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