Definition of brace
Although the turbocharged AP-4 demonstrator had been lost, the Air Corps liked it enough to order thirteen more in May 1939, to be designated "YP-43". However, the USAAC kept shifting requirements and the YP-43 ended up looking much different from the AP-4. The YP-43 was powered by a P&W R-1830-35 14-cylinder Twin Wasp radial engine with a turbocharger, providing 895 kW (1,200 HP) and driving a three-blade propeller. Armament consisted of two -millimeter Brownings in the nose, plus a single -millimeter Browning in each wing. The cockpit scheme was revised, leading to a distinctive "razorback" configuration.