What was the XB-38?

Short answer

The XB-38 was the conversion of a single production B-17E to test whether the Allison V-1710 V engine could replace the usual Wright R-1820 radial. It carried four V-1710-97s of 1,425 hp (1,063 kW) each. An engine caught fire on its ninth flight, on June 16, 1943, and the aircraft was destroyed.

Published: November 4, 2026 · Updated: November 4, 2026 · Edited by Above Ten Thousand · Editorial policy

Sunset silhouette of flying fortress, Langley Field, Va

A B-17E with V-engines

The XB-38 Flying Fortress was the conversion of a single standard B-17E, made to test whether the Allison V-1710 V-engine could replace the Wright R-1820 radial that was standard in the early years of the Second World War. Only one was built, modified from an ordinary production aircraft. The powerplant consisted of four turbosupercharged, liquid-cooled V12 Allison V-1710-97 engines of 1,425 hp (1,063 kW) each.

The fire on the ninth flight

Once a fault had been resolved, testing resumed until the ninth flight, on 16 June 1943, when the right inboard engine caught fire and the crew bailed out. The XB-38 was destroyed and the project was cancelled, partly because the V-1710 engines were in heavy demand for the Lockheed P-38 Lightning, Curtiss P-40 Warhawk and North American P-51A Mustang fighters.

Other Flying Fortress conversions

The B-17E with serial number 41-2593 was converted to VIP transport standard for General Douglas MacArthur. A B-17F, 42-6036, also intended for MacArthur, received the same role. In the first of those conversions, that of B-17E 41-2593, designated XC-108, a retractable door with steps was fitted in the rear fuselage to ease entry and exit.