The prototype aircraft was built full-span automatic slots and slotted flaps, given the Army designation YO-49 for evaluation, with the first flight by test pilot Al Schramm on July 15,1940.
The prototype aircraft was built full-span leading-edge automatic slots manufactured by Handley Page, and slotted flaps. The Model V-74 was given the Army designation YO-49 for evaluation, with the first flight by test pilot Al Schramm on July 15,1940.