It was called a "rotary engine" because the entire engine rotated apart from the end casings.

An engine rotates the paddle wheel in the water to produce thrust, forward or backward as required.

The rotary engines used in early aircraft rotated along with the propeller at the same speed.

Because the entire engine rotated, it had to be precisely balanced, requiring precision machining of all parts.

As the lower end of this member moved forward, the engine rotated into the horizontal position, its fairing closing the fuselage opening.

The engine does not run or rotate in reverse; instead, thrust reversers are used to block the blast and redirect it forward.

Virtually the whole engine rotates about a fixed crankshaft.

This design has asymmetric bearing surfaces and so supports the forces better when the engine rotating in one direction than the other.

When the engine is rotating at high speeds, the high-speed mechanisms keep the valves open longer.

An engine within the plow's carbody rotates the large circular assembly at the front of the plow.