The second generation X-1s used the same wing, horizontal tail, and XLR-11 rocket engine as the first generation aircraft, with a new cylindrical fuselage just over 4 1/2 feet longer than the original design. This was the maximum length that could be carried by a B-29 or B-50 launch aircraft. The cockpit design was also changed to a “stepped” canopy, allowing the pilot to enter from the top, instead of the side hatch on the original X-1. A more significant change was the fuel system. The new aircraft used a low-pressure turbopump, which eliminated the heavy spherical liquid oxygen (LOX) and alcohol tanks. The new, larger tanks now conformed to the fuselage shape. As a result, the airplane’s calculated maximum performance had increased to Mach 2.47 at 70,000 feet.
Four of the second generation X-1s were originally to be built by Bell Aircraft: the X-1A for dynamic stability tests; the X-1B for air load research; the X-1C for armaments tests using a .50 cal. machine gun in the nose and a gun sight for the pilot; and the X-1D for heat transfer research. The X-1C was canceled while in the mockup stage…Learn more
The X-1B made its last flight in January of 1958 and was transferred to the National Museum of the United States Air Force in Dayton, Ohio in 1959.
