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XB-39 factory
XB-39
XB-39
XB-39
XB-39
XB-39 41-36954 side view
XB-39 2
XB-39 cockpit side cockpit
XB-39 41-36954 2
XB-39 cockpit 2
XB-39 Spirit of Lincoln in flight
XB-39 was a single example of the B-29 converted to fly with alternative powerplants.
The aircraft was a modification of the first YB-29. Similar to the XB-38, the original Wright R-3350-21 piston radial engines were replaced with liquid-cooled Allison V-3420-11 V-engines. Only one plane was built, which was tested in 1944 by the USAAF. Bomber showed good performance, but the problems experienced in producing the B-29s were solved, and the B-39s were not put into production.