Vultee XA-41
Originally designed as a dive-bomber, the role of the Vultee XA-41 was changed to a low level attack aircraft when the USAAF decided that dive bombers were too vulnerable. Changing priorities and the coming end of the Second World War saw the order for two prototypes changed to just one.
The only prototype first flew on 11 February 1944. It was used predominantly as an engine test bed for the R-4360, although the US Navy evaluated it against other attack aircraft (Douglas AD-1 Skyraider and Martin AM-1 Mauler). Engine tests continued until 1950 when the XA-41 was scrapped.