Abstract: The invention is an airframe which includes a vehicle (12) having a solid propellant rocket engine (14) and a ramjet or scramjet engine (16); a thrust plug (18) extending from an end (20) of the vehicle which directs combustion gases (23 and 64) produced by the solid propellant rocket engine or ramjet/scramjet engine to produce forward thrust; a longitudinal passage (38) extending from the end of the vehicle to an opening (30) forward of the end which receives external air directed by forward movement of the vehicle and in which solid propellant (32) of the solid propellant rocket engine is located, and wherein during rocket operation solid propellant is combusted to produce the combustion gases in the longitudinal passage which are conveyed by the longitudinal passage into contact with the thrust plug and during ramjet/scramjet operation the longitudinal passage is open to flow of external air after operation of the solid propellant rocket engine is completed and which supports mixing and combustion of the a

Abstract: A pair of serially connected electrically operated computer controlled gas valves combine with a pressure sensor to output pressure regulated low pressure gas dispensed from a high pressure gas source and define a pressure regulation system of relatively simple construction, great versatility and of heretofore unknown flexibility, well suited to remote control. The computer controlled valve controller selectively operates the valves in any and all of three operational modes, including the familiar Bang-Bang mode in which both valves operate simultaneously, a Bang-Wait mode in which both valves operate simultaneously for a precise time interval and thereafter close while the outlet gas pressure is checked, and a newly defined Burp mode. In the novel Burp mode, the valve closest to the high pressure gas source is first opened and closed to admit and capture a small volume of gas within inter-valve piping. Thereafter only the outlet valve is opened and closed to release that small volume of captured gas.