IF the gains in production of light aircraft made in recent years are continued at the same rate, the light plane and engine industry can be expected to at least double 1939 volume, Mr. Bachle points out graphically.
Present trends are toward two types of light airplanes, he announces: those in the 50-hp class intended for student training and three-place or higher-performance types for private owner usage, requiring up to 90 hp. He tells how the output of one engine originally developed for a 50-hp unit had been increased to 80 hp, to put it into the latter type. Developments and refinements made to boost the output are described, covering cylinder-head design, exhaust valves and seats, pistons and rings, valve mechanisms, and fuel injection.
The introduction of fuel injection (replacing carburetion) in light aircraft engines has been a major development of the year, Mr. Bachle asserts, and gives a detailed description of the injection equipment adopted. He believes that the outstanding advantage of this equipment is the positive prevention of ice in the induction system without the use of an air heater or manifold jacket. Also, he adds, power at altitudes is higher, and there is greater assurance of uniform mixture distribution under all operating conditions.