[2] The operators used a telescopic sight and a joystick to guide the missile by radio control, which was detonated by acoustic and photoelectric proximity fuses, at 10–20 m (33–66 ft).

[3] In 1941, Professor Herbert A. Wagner (who was previously responsible for the Henschel Hs 293 anti-ship missile) invented the Schmetterling missile and submitted it to the Reich Air Ministry (RLM), who rejected the design because there was no need for more anti-aircraft weaponry.

However, by 1943 the large-scale bombing of Germany caused the RLM to change its mind, and Henschel was given a contract to develop and manufacture it.

The team was led by Professor Wagner, and it produced a weapon somewhat resembling a bottlenose dolphin with swept wings and cruciform tail.

[1] In May 1944, 59 Hs 117 missiles were tested, some from beneath a Heinkel He 111; over half the trials failed.