North American NA-98X Super Strafer

The North American NA-98X was a ground attack version of the North American B-25H medium bomber. The initial design replaced the B-25 tail with a conventional single tail, and used Pratt & Whitney R-2800 air-cooled radial engines housed inside low-drag cowlings and driving a pair of cuffed, four-blade propellers with spinners. A squared off wing added area to the ailerons. This design was considered too ambitious, so a standard B-25H was modified.

The increase in engine power and added aileron area without strengthening the wings resulted in the possibility of of exceeding the aircrafts design limits. As a precaution, speed and G-force limits were imposed during test flights. Unfortunately, on the aircrafts 29th flight, the pilot exceeded these limits, causing the wings to detach, causing the aircraft to crash, killing the pilot and observer on board. Further development was cancelled.