The X-1 program was first envisioned in 1944 when a former NACA engineer working for Bell Aircraft approached the Army for funding of a supersonic test aircraft. Neither the Army nor Bell had any experience in this area, so the majority of research came from the NACA Compressibility Research Division, which had been operating for more than a year by the time Bell began conceptual designs. The Compressibility Research Division also had years of additional research and data to pull from, as its head engineer was previously head of the high speed wind tunnel division, which itself had nearly a decade of high speed test data by that time. Due to the importance of NACA involvement, Stack was personally awarded the Collier Trophy along with the owner of Bell Aircraft and test pilot Chuck Yeager.