Original sentence: Also Air Force officials were not comfortable with an aircraft that required an autopilot or yaw damper for accurate bombing.Consequently the Air Force did not spend any money upgrading the YB-49 to test operational items, for example by moving a bomb bay bulkhead to allow carriage of the first generations of American atomic weapons (Mk III, IV and VI).It exhibited low radar cross section and high altitude performance which would have eliminated fighter interceptions, but the Air Force preferred the slightly faster B-47 since Air Force officials could not comprehend the tactical advantages of minimal radar detection and out maneuvering fighters at high altitude, instead believing speed was the key to survival.Of course today all new Air Force cannot fly without artificial stability, but in 1948 it was untrusted new technology.Speculation at the time was that the aircraft was lost due to loads imposed when a stall recovery resulted in a high speed dive.The Northrop flying wings due to their low drag resulted in a high speed stall recovery technique.The YB-49 was technologically ahead of Air Force doctrine at the time
Edited sentence: Bombing tests showed that the tendency of flying wings to "hunt" in yaw when in "disturbed" air tended to degrade bombing accuracy unless an autopilot or yaw damper was used.It retained the B-35's very thick airfoil section designed for cruising at 240 mph (386 km/h).Speculation at the time was that the aircraft was lost due to loads imposed when a spin recovery resulted in a high speed dive.The Northrop flying wings required an unconventional spin recovery technique which involved the use of no rudder input and aileron input against the spin.The YB-49 had several severe design limitations which doomed it.Thick as the wing was, its bomb cells were incapable of holding the first generations of American atomic weapons (Mk III, IV and VI).This wing gave the aircraft a low Mach limit