Is there any credibility in German claims that a Me-163 broke the sound barrier during World War Two?
From Wikipedia (I know, but it was the only reference to this flight I could quickly find):
"On 6 July 1944, the Me 163B V18 (VA+SP), like the B V6 basically a standard production Me 163B airframe outfitted with the new-twin chamber "cruiser" rocket motor with the aforementioned modifications beneath the original rocket motor orifice to accept the extra combustion chamber, set a new unofficial world speed record of 1,130 km/h (702 mph), piloted by Heini Dittmar, and landed with almost all of the vertical rudder surface broken away from flutter.[27][5][28] This record was not broken in terms of absolute speed until 6 November 1947 by Chuck Yeager in a flight that was part of the Bell X-1 test program, with a 1,434 km/h (891 mph), or Mach 1.35 supersonic speed, recorded at an altitude of nearly 14,820 m (48,620 ft).[N 1] The X-1 never exceeded Dittmar's speed from a normal runway liftoff. Heini Dittmar had reached the 1,130 km/h (702 mph) performance, after a normal "sharp start" ground takeoff, without an air drop from a mother ship. Neville Duke exceeded Heini Dittmar's record mark in 31 August 1953, with the Hawker Hunter F Mk3 at a speed of 1,171 km/h (728 mph), after a normal ground start.[29][N 2]"