"General: It is intended that this SAE Aerospace Recommended Practice (ARP) will set down guidelines for the development and test of gas motors to provide a practical and reliable hot gas rotary actuation mechanism. Specific operational and test requirements shall be specified in a detail specification. Specific: The areas to be discussed are: Requirements (performance@ environment@ life@ and reliability)@ design and fabrication@ and test considerations. Life: This ARP will define in a general way the life requirements of ""gas motors"" for three broad categories of flight vehicles. Long-Range Air Breathing Vehicles: The motors for vehicles@ which will have a long operational life in proportion to their ground checkout life. Manned Reentry Vehicles: The motors for vehicles@ which will have a moderately long operational life and will be significantly less than their ground checkout life. Single Use Vehicles: The motors for vehicles@ which have a long ground checkout life in proportion to their operational life and that range from seconds to an hour or more. Environment and Performance: This ARP will be confined to discussing the environments and gas temperatures most likely to be encountered@ listing some of the performance parameters without numerically defining them@ and to specifying tests to show compliance with the performance and reliability requirements under the expected environmental conditions. This ARP will not define a specific ""gas motor."""