Rocket Engine, BMW 109-558

This rocket engine was most commonly used as the sustainer motor for the Henschel Hs 117 antiaircraft missile. Designed by the BMW rocket-engine group at Berlin-Spandau, under the direction of Helmut von Zborowski, the 109-558 used concentrated nitric acid as an oxidizer and a composite hydrocarbon mixture codenamed "Tonka" as fuel. Initial thrust was 375 kg (825 lb), falling to 60 kg (130 lb) in the last 24 seconds of burning as a result of falling pressures in the gas-pressurized tanks of the missile. In order for the Hs 117 not to exceed the velocity at which it was stable, the engine's thrust could be regulated. Gears on the head of the nozzle were mechanically linked to two flat sliding valves in the nozzle heads. The gears, missing on this artifact, were actuated by an electromotor.

The U.S. Air Force transferred this artifact to the Smithsonian in 1949.