AN outline of some current problems in aircraft engines with particular reference to the types used for main-line scheduled-transport operations is presented, it being limited so far as possible to a consideration of the conventional four-stroke gasoline-engine.
Types of airline service are considered and, as regards engine sizes, it is remarked that airline service demands engines in a range of sizes from the maximum available to about 250 hp. as a minimum.
Statistics of the present performance of airline engines are given, and it is stated that the horsepower output required to meet the contemplated schedule with the most adverse wind normally expected on the route is a nearly correct measure of the true effective size of the airline engine; further, that its durability and performance should, in general, be judged on that basis.
The importance of fuel consumption is stressed. As to preliminary tests of the hypothetical engine discussed, a dynamometer calibration of the sea-level performance-characteristics-which should be extended to cover altitude operation also if the necessary equipment is available-should be made.
Data on cylinder cooling are presented, and lubrication and other problems-such as compression ratios, fuels, supercharging and mixture-strength control at altitude-are treated.
