hollow crankshaft

The hollow crankshaft was of nickel steel and mounted in ball bearings.

A hand-controlled butterfly valve was located in the hollow crankshaft to regulate throttle.

It was also limited by its inherent restriction on breathing capacity due to the need for the fuel/air mixture to be aspirated through the hollow crankshaft and crankcase, which directly affected its volumetric efficiency.

E engines are lighter compared to earlier Toyota engines, due the hollow crankshaft, thinned casting of the cylinder block, and several other reductions in auxiliaries as well as in the engine itself.

The Griffon was the first Rolls-Royce production aero engine to use a hollow crankshaft as the means of lubricating the main and big end bearings, providing a more even distribution of oil to each bearing.

Another factor in the demise of the rotary was the fundamentally inefficient total-loss oiling system, caused by the need to aspirate the fuel/air mixture through the hollow crankshaft and crankcase along with the lubricating medium, as in a two-stroke engine.

The charge was an overly rich mixture of air, which was acquired through the hollow crankshaft, and fuel that was continuously injected by a fuel nozzle on the end of a fuel line, entering the crankcase through the hollow crankshaft.

By the end of the war the rotary engine had reached the limits of the design, particularly in regard to the amount of fuel and air that could be drawn into the cylinders through the hollow crankshaft, while advances in both metallurgy and cylinder cooling finally allowed stationary radial engines to supersede rotary engines.