The 109-509A-1 was the power plant for the World War II German Me 163 B-1 Komet rocket fighter. It was the first variable-thrust rocket engine to be installed in a service aircraft and employed hydrogen peroxide with a hydrazine hydrate/methanol mixture as propellants. Some peroxide was diverted to a catalytic chamber containing potassium permanganate, producing steam to drive turbopumps to move the propellants The engine produced from 200-1800 kg (660-3740 lbs) thrust for 8-10 minutes. Developed by the firm of Helmut Walter in Kiel, it went into series production in August 1944. The Me 163 B-1, the world's first and only operational rocket fighter, was used in attacks against U.S. bombers in the fall of 1944, but did not prove very successful.
The Smithsonian received this engine as a gift from Purdue University in 1967, which presumably had received it from the U.S. Air Force after World War II.