Abstract: Methods of sealing a planetary rotor engine, and the resulting seals, are described which improve the engine's efficiency and solves each of three main problem areas. A first method and resulting dynamic seal for sealing the rotor face surfaces as they translate across one another to constantly reform the contact between each other includes the key step of moving the shaft centerlines of each of the rotors, thereby radially positioning the rotors along diametric axes at positions which compensate for varying thermodynamic conditions (e.g. thermal expansion or contraction of rotor materials). A second method and resulting dynamic seal for effectively minimizing leakage between the end space formed between the rotor end and the case includes the key step of introducing a surface depression of any shape on one, or both, of the rotor end and opposing casing, thereby eliminating the need for a frictional seal and, in essence, forming a pressure wave plug.