A rotor of a supersonic rotary heat engine comprises a rotor axis about which the rotor is adapted and configured to rotate, a plurality of thrust matter passageways, and a plurality of cooling passageways. The applicator employs a supported thin layer of foam which achieves layer thickness which are substantially independent of the pressure applied to the applicator during use. This can enable activation device, which can place reference circuit in a stable operating mode. A piston disposed in the second stage actuation chamber operatively engages a ball member of a ball-and-seat type valve comprising the second stage valve.