Of all the experimental German antiaircraft missiles of World War II, the Schmetterling (Butterfly) came closest to deployment. It originated in 1941, when Henschel's talented missile designer, Herbert Wagner, proposed several antiaircraft projects. However, the Air Ministry did not authorize the missile's development until 1943. Mass production was ordered in December 1944, with deployment to begin in March 1945--an unrealistic timetable typical of Germany's desperation programs late in the war.
Two solid-fuel Schmidding rocket units, missing from this Hs 117, served as boosters. An operator using a telescopic sight and joystick guided the missile by radio control. The U.S. Army Ordnance Museum transferred this Schmetterling to the Smithsonian in 1988.
Transferred from the U.S. Army Ordnance Museum
Of all the experimental German anti-aircraft missiles of World War II, the Hs 117 Schmetterling (Butterfly) came closest to deployment. The Schmetterling had its origin in 1941, when Herbert Wagner, Henschel's talented missile designer, proposed a number of anti-aircraft projects, but the Air Ministry did not authorize its development until 1943. Mass production was ordered in December 1944, with deployment to begin in March 1945, but the plans were quite unrealistic, as was typical of the desperation programs of the last year of the Third Reich.
The Hs 117 was fueled by a combination of nitric acid and Tonka, a mixed hydrocarbon fuel, and was boosted by two solid-fuel Schmidding rocket units that are missing from this artifact. Guidance was by radio-control from an operator with a telescopic sight and joy-stick. The Museum's artifact was acquired from the U.S. Army Ordnance Museum at Aberdeen, Maryland, in 1988.
The missile is aircraft-shaped with sweptback wings and cruciform tail, and has an asymmetrical nose with warhead extension on one side and a shorter extension on the other with a wind-driven generator propeller. The missile does not have regular control surfaces, but instead uses spoilers known as "Wagner bars" on the trailing edges of the wings and tailplane.
Originally designated the Henschel Hs 297, the Schmetterling was first proposed in 1941 but not approved by the German Air Ministry until 1943. Beginning in May 1944, 59 experimental launchings were made at Karlshagen, near Peenemuende. The Hs 117 normally used the BMW 109-558 rocket motor of 375 kg (825 lbs.) thrust for 33 seconds which fell to 60 kg (132 lbs.) over the last 24 seconds. The propellants were R-Stoff or Tonka, a mixed hydrocarbon fuel, and nitric acid. The propellants were fed into the combustion chamber by gaseous pressure and were hypergolic, or self-igniting. The two Schmidding 109-553 solid-fuel boosters weighed 170 kg (374 lb.) total, and produced 1,750 kg (3,850 lbs.) thrust each for four seconds.
There were several variants, including the the Hs 117H, the only known air-launched version. Designed for use from the Do 217, Ju 188, and Ju 388 aircraft, the Hs 117H had a truncated top tailfin and no boosters. Twenty-one flight tests were conducted from a Do 217, with only 15 being satisfactory. Development of the Hs 117-H ended in February, 1945. A standard Revi reflector sight was to be used for sighting the missile, while guidance was accomplished with conventional radio-link and line-of-sight by the pilot of the carrier plane. There were plans to install a homing device and proximity fuse in the missile, but this never materialized and detonations were normally activated by a radio signal. The Hs 117-H was designed to attack an enemy aircraft up to 5,000 m (16,400 ft) above the carrier aircraft.
The Museum's artifact is missing the boosters and the promixity fuse cone (the latter has been simulated with a wood replica made in December 2000). It appears to be an Hs 117 C, or the Hs 117 A-1, the production version, based on the exterior configuration and dimensions. Nothing is known about where or when in 1945 the U.S. Army captured this particular missile.
Originally written by Frank Winter; revised and edited by Michael Neufeld
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Smith, J.R., and Antony L. Kay, German Aircraft of the Second World War (London: Putnam, 1972), 688-691.