I HAD to do this one b/c Rheingold was Third Reich tech! It was part of the Elsass control unit for the Wasserfall (Waterfall) SAM being developed for use in 1945 against Allied bomber streams. The unit, developed by Telefunken, was a radio guidance (RG) type linked to a Wurzburg (WB) radar tracking set. It also worked with the Ruse transponder to measure the roll attitude of the missile in flight. An operator used it from the ground via joystick, telescope, and oscillascope linked to the radar set. Very complicated, the Wasserfall went through several guidance systems and a separate night version using IR seekers to kill RAF Lancs. Test-firings in the field were made but there is a lack of result record. The Wasserfall was a scaled-down A-4 (V-2) that could hit high altitudes at supersonic speed- ideal as SAM interceptor. When all German SAMs were cancelled in Feb 1945, it had been planned to move Wasserfall underground with a force of 14,000 workers in a facility with 60,000 sq meters of floorspace!!! Each Wasserfall cost a mere 500 manhours to build vs 4000 for the V-2!!!