Photographed at Logan International Airport, Boston, Massachussetts, USA, August 1950, from Leo Kohn via Dan Shumaker, source unknown
01/31/2009. Originally produced as a B-29B-55-BA by Bell at Marietta, Georgia, this example was converted to a flying engine test laboratory. The test engines where fitted to a rig in the bomb bay
(in this case an Allison J35) that could be lowered in flight
. Note the feathered propellers, indicating the aircraft flew on jet propulsion only. Also tested were the General Electric J47 and J73.