BT-13

It was back in 1938 that Vultee Aircraft’s chief designer, Richard Palmer, began the design of a fighter. At this time the USAAC issued a requirement and design contest for an advanced trainer for which substantial orders had been promised to the victor. Palmer began to adapt his design concept from a fighter to that of an advanced trainer and the result of this was the V-51 prototype. The aircraft made its maiden flight sometime during March of 1939 as a cantilever low-wing monoplane of all-metal construction. Despite the use of metal throughout the design the control surfaces remained fabric covered. The USAAC instead chose the North American BC-2, but purchased the BC-51 prototype anyway. Despite the disappointment, Palmer was not finished yet. He continued to refine the design of the VF-51 into the VF-54 in an attempt to meet the expectation of an export market for just such a trainer. The next variant was actually designated BT-15 due to the fact that Pratt & Whitney found it impossible to keep up production of the R-985 engine. Instead a Wright R-975-11 radial was substituted into the 1,263 aircraft produced. The US Navy began to show an interest in the aircraft as well and ordered 1,150 BT-13A models as the SNV-1. In addition, the Navy ordered some 650 aircraft designated as SNV-2 roughly equivalent to the BT-13B. Once in service, the aircraft quickly got its nickname of “Vibrator” due to the fact that it had a tendency to shake quite violently as it approached its stall speed. The BT-13 served its intended purpose well. It and its successors were unforgiving aircraft to fly, but were also extremely agile. Thus the BT-13 made a good aircraft to help transition many hundreds of pilots toward their advance trainers and fighters yet to be mastered.