I'm not sure the B-54 would count since it never was built. OTOH, the
Tu-4 was stretched even further than a B-29; the Tu-80 & even bigger
Tu-85, & to an extent, even the Tu-95. Tupolev had a number of other
stretches proposed, but not built. The B-36 was stretched to the XC-99
& even the YB-60. I suppose the F-82 could be considered a stretch of
the P-51. The Heinkel He-177 was developed into the He-274 or
something. I think that was a stretch anyway. Sorry for any
duplications from previous posts if I made any.


"Kyle Boatright" wrote in message ...
One aircraft which was stretched considerably was the B-29. It eventually
morphed into the B-50, the B-54, the C-97, the KC-97, the TU-4, the Guppy,
the Super Guppy, and probably a few more variants I've left off.