<p>The cancellation of the B-35 piston-engined flying wing bomber had been predicted by Northrop, which had sought approval from the USAAF to convert two of the YB-35 pre-production aircraft to jet power. Initially designated YB-35B, these two aircraft (42-102367/42-102368) were completed as YB-49s with eight Allison J35A-5 turbojets buried in the wings in two groups of four outboard of the main undercarriage. Each group of engines was bounded by small vertical fins which projected above and below the wing trailing edge. The aircraft first flew on 21 October 1947, and initial reports were complimentary. However, on 5 June 1948 the aircraft crashed, killing its crew, including Captain Glenn W. Edwards, for whom Muroc Dry Lake test center was subsequently named.
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<p>In spite of this tragedy, the US Air Force placed an order for 30 RB-49As, a reconnaissance-dedicated version. Of these, Northrop was to build one and Convair the remainder. Coincidentally, the remaining YB-35s were to be converted to jet power, but in the end only one was completed and flown. Known as the YRB-49A, this aircraft featured four Allison J35-A-21 turbojets mounted in the wings, each of 5,600 lb thrust, with another pair of engines mounted in pods beneath the wings.
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<p>Although the RB-49A contract was cancelled in April 1949, and the entire Northrop all-wing bomber program was officially scrapped in October 1949, the YRB-49A did make it into the air on 4 May 1950, proving as satisfactory in handling as its predecessors. The aircraft succumbed to the cutter's torch in 1953.
