German researcher Otto Lutz introduced the swing-piston concept about 1923. Intended primarily as a high pressure compressor or gas generator for relatively high power gas turbine engines for long-range transport aircraft, principal advantages were improved fuel economy, use of Diesel fuel, and a compact design.

To reduce the space occupied by conventional reciprocating engines, cylinders were located inside a liquid-cooled annulus, and were the spaces between members of two sets of piston. Pistons were free floating and, instead of driving connect rods and a crankshaft as in conventional engines, generated compressed and heated gases by recoiling between cushions of charged air, with combustion at the time of maximum compression of each charge. Combustion products either passed directly through a discharge nozzle, furnishing jet propulsion, or through a turbine, to generate power for a propeller or ducted fan.

Two experimental units were briefly tested, but no substantiating data generated. An Allied bombing raid on the plant ended development.