Editing Sarich orbital engine (section)

== Overview ==
The engine promised to be about one third the size and weight of conventional piston engines due to the compact arrangement of the combustion chambers. Another advantage is that there is no high-speed contact area with the engine walls, unlike in the Wankel engine in which edge wear is a problem. However, the combustion chambers are divided by vanes which do have contact with both the walls and the orbiting piston and are more difficult to seal due to the eight corners of the combustion chamber.<ref>{{cite book
|title=Philippine Technology Journal
|url=https://books.google.com/books?id=L9JtAAAAIAAJ
|volume=22-23
|year=1997
|publisher=Science and Technology Information Institute
|page=17
|quote=While the Wankel engine rotor has line contact with the internal surface of the housing, the concentric rotary vane internal combustion engine rotor has plane contact with the cylinder. Wankel engine is basically an orbital engine because its ...}}</ref>

In the patent, the engine is described as two stroke internal combustion engine,<ref name="US3787150">{{Cite web|title=Rotary motor|url=https://www.google.co.in/patents/US3787150}}</ref> but the patent claims that with a different valve mechanism it could be used as a four stroke engine.<ref name="US3787150" /> However most of the development work was done on four stroke versions with both poppet and disk valve arrangements. A supercharger is required if operated in two stroke mode since crankcase pumping can't be used to charge the combustion chamber.

Interestingly, in his seminal book <ref>{{Cite book|last=Wankel|first=Felix|title=Rotary Piston Machines|publisher=Iliffe Books Ltd|year=1965|isbn=0592006166|location=London|language=English}}</ref> researching and documenting all the possible ways to create a rotary piston displacer, Felix Wankel shows the orbiting piston and reciprocating vane mechanism used in the orbital engine.