Rotary engines only have three moving parts, an eccentric shaft, and two rotors. The engine works very similarly in principle to a piston-cylinder engine, with intake, compression, combustion, and exhaust occurring within the combustion chamber which is somewhat oval shaped. As the rotor spins around, it rotates the eccentric shaft sending power to the transmission. There are many advantages to this design. First off, there are only three moving parts, making it a very simple design. There are no reciprocating parts, and this leads to an ability to rev high as the engine does not need to be concerned with valve float. Also as a result of only having rotational parts, the engine has very little vibration. Power delivery is also very smooth, and rotary engines pack a lot of power into a very compact design.