Luftwaffe experiments with "bouncing bombs" dropped from a Focke-Wulf Fw 190

After the Royal Air Force Operation Chastise, the attack on German dams carried out on the night of 16/17 May 1943 by 617 Squadron using "Upkeep" bouncing bombs, an intact bomb was captured in the wreckage of a Lancaster bomber commanded by Flt Lt Barlow which had struck high tension cables at Haldern, near Rees in Germany and crashed.

The bomb had not been released and the aircraft had crashed on land, so none of the detonation devices had been set off. Heinz Schweizer, a renowned bomb disposal officer in the Luftwaffe's Sprengkommando unit, was tasked with safely recovering and examining the ordnance. Subsequently, a 385-kilogram (849 lb) version of Upkeep, code-named "Kurt" or "Emil", was built at the Luftwaffe's Erprobungsstelle, or "test site", on Germany's Baltic coast at Travemünde, one in a network of four such establishments in Nazi Germany. The importance of back-spin was not understood and trials by a Focke-Wulf Fw 190 proved to be dangerous to the aircraft, because the bomb matched the speed at which it was dropped. Attempts to rectify that with booster rockets failed and the project was cancelled in 1944.