Abstract: An engine (400) is disclosed and comprises: a compressor (428) which periodically defines a chamber and carries out a pressurization process wherein the chamber volume is decreased to produce pressurized air; a combuster (426) which combusts fuel with the pressurized air to produce primary exhaust; an air motor (408) which is driven by the primary exhaust to produce power and secondary exhaust; an expander (410) which expands the secondary exhaust to produce tertiary exhaust and power; and a shaft (314) which directs power produced by the motor (408) and the expander (410) to the compressor (428) and any load. The combuster (426) is adapted to receive varying amounts of fuel, thereby to vary the power to the load. The compressor (428), during pressurization. releases air from the chamber such that the chamber pressure during pressurization and the primary exhaust pressure is substantially constant at steady state conditions, said constant being a function of the load being driven by the power.

Abstract: The invention comprises a quick-release locking device for attachment of an accessory having a threaded shaft at one end thereof to an archer's bow. This locking device includes a body having a bore extending therein, which bore is sized so that the shaft of the accessory may be inserted therein. The device also includes a shaft engagement mechanism within the body which is adapted to engage the threads of the shaft of the accessory within the bore, and a manually operable release mechanism within the body which may be actuated to release the engagement mechanism from the shaft. The locking device may be incorporated into the handle or riser of a bow, or it may be provided in the form of an attachment that can be threaded into the existing accessory hole of a conventional bow.