Henschel Hs 117

Henschel Hs 117 Schmetterling (German for Butterfly) was a radio-guided German surface-to-air missile project developed during World War II. There was also an air-to-air version, the Hs 117H.

In 1941, Professor Herbert A. Wagner invented the Schmetterling missile but the idea was rejected by the Reich Air Ministry as it was felt that there was no need for more anti-aircraft weaponry. When the air situation had changed for the worse by 1943, the project was revived and   Henschel was given a contract to develop and manufacture the Schmetterling. The team was led by Professor Wagner, and it produced a weapon somewhat resembling a bottlenose dolphin with swept wings and cruciform tail. 

The Hs 117 was an odd looking piece of equipment with an asymmetrical nose, a pointed cone on the right and a propeller on the left that was used to power a small generator. Two booster rockets were carried for take-off, mounted above and below the fuselage. A third rocket was built into the missile. 

Launch power was provided by two Schmidding 109-553 solid fuel rockets, each of which provided 3,850lb of thrust for four seconds, bring the rocket up to 680mph. The internal rocket was normally a BMW 109-558, which used R-Stoff (which self ignited) as its main fuel and SV-Stoff to oxidize the R-Stoff. It was also possible to use the Walter 109-729 rocket, which used low-octane petrol (Br-Stoff), SV-Stoff and an alcohol igniter.

Like the Enzian, the operators used a telescopic sight and a joystick to guide the missile using solenoid-controlled Wagner bars on the trailing edge of the wings and the tail plane by radio control. The missile used the Kehl/ Strassburg system for steering- using four radio frequencies, two for the vertical controls and two for the horizontal. A fifth frequency was used to detonate the warhead, which was detonated by acoustic and photoelectric proximity fuses, at 10–20 m from the target. 

Characteristics

Power Plant: 

Booster rockets: 2 Schmidding 109-553 solid-fuel boosters, 

Main rocket: liquid fuel BMW 109-558 rocket motor

Propellants:                  SV-Stoff (nitric acid), Tonka

Length:                        4.2 m (13 ft 9 in)

Diameter:                     350 mm

Wing Span:                  2 m

Launch Weight:           420 kg 

Warhead:                     25 kg explosive 

Range:             32 km 

Altitude:                      10.7 km

Guidance system:         MCLOS; visual guidance, radio controls

The first test launch of the Hs 117 was made in May 1944, and by September twenty two launches had been made, including some with the Hs 117H . Over half the trials failed, yet mass production was ordered in December 1944, but the first deliveries were not expected until March 1945, and full production was not expected until November.

In January 1945, a prototype for mass production was completed with the operational missiles to be launched from a 37mm gun carriage and it was hoped that the first operational unit would enter service in March. A production of 3,000 missiles a month was anticipated but on 6 February 1945, the project was cancelled.

It also had an air-launched variant, the Hs 117H, designed to be launched from a Dornier Do 217, Junkers Ju 188, or Junkers Ju 388.This version was designed to attack enemy aircraft up to 5 km above the launching aircraft.