This category holds websites with information on internal combustion engines working via rotary geometries and principles, rather than the more common reciprocating geometries, which are found in this subcategory's parent category. Rotary engines can have reciprocating components, within a rotary component (context), but the main impulses (driving forces) are applied in the direction of rotation of the main power component(s), which usually rotate/turn in the direction of the power output/shaft. Rotary engines include, but are not limited to, Wankel engines and their many variants.