Mr . Henry Ford II 1972 statement regarding the production of a Ford Wankel engine was :'The Rotary probably won't replace the piston in my lifetime " . ( Harris Edward Dark,'the Wankel rotary engine, introduction and guide '.
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The Moller Skycar M400 is a prototype personal VTOL ( vertical take-off and landing ) aircraft which is powered by four pairs of in-tandem Wankel rotary engines, and is approaching the problems of satellite-navigation, incorporated in the proposed Small Aircraft Transportation System.
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The Renesis engine also 13B-MSP ( Multi-Side Port ) which first appeared in production in the 2003 Mazda RX-8, is an evolution of the previous 13B . It was designed to reduce exhaust emission and improve fuel economy, which were two of the most recurrent drawbacks of Wankel rotary engines.
34.
Wankel rotary engine and piston engine displacement and corresponding power output can more accurately be compared by displacement per revolution of the eccentric shaft . A calculation of this form dictates that a two-rotor Wankel displacing 654 cc per face will have a displacement of 1.3 liters per every rotation of the eccentric shaft ( only two total faces, one face per rotor going through a full power stroke ) and 2.6 liters after two revolutions ( four total faces, two faces per rotor going through a full power stroke ).
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The results are directly comparable to a 2.6-liter piston engine with an even number of cylinders in a conventional firing order, which will likewise displace 1.3 liters through its power stroke after one revolution of the crankshaft, and 2.6 liters through its power strokes after two revolutions of the crankshaft . A Wankel rotary engine is still a four-stroke engine and pumping losses from non-power strokes still apply, but the absence of throttling valves and a 50 % longer stroke duration result in a significantly lower pumping loss compared to a four-stroke reciprocating piston engine.
