Pictured here is one of the Liberty Belle's Pratt & Whitney engines. Originally sold on June 25, 1947 as scrap to Esperado Mining Co. of Altus, OK, it sold again later that year to Pratt & Whitney for $2,700. Pratt & Whitney operated the B-17 from November 19, 1947 to 1967 as a heavily modified test bed for their P&W T-34 and T-64 turboprop engines. It became a “5-engine aircraft”, having the powerful prototype engine mounted on the nose! The aircraft was flown “single-engine”, with all four radial engines feathered during test flights.