12 May 1953: A Boeing B-50A-5-BO Superfortress, 46-011, modified to carry a Bell X-2 supersonic research rocketplane, was engaged in a captive test flight at 30,000 feet (9,144 meters) over Lake Ontario, between Canada and the United States. The number two X-2, 46-675, was in the bomb bay.
The bomber was equipped with a system to keep the X-2’s liquid oxygen tank filled as the cryogenic oxidizer boiled off. With Bell’s Chief of Flight Research, test pilot Jean Leroy (“Skip”) Ziegler, in the bomb bay above the X-2, the system operation was being tested.
There was an explosion. The X-2 fell from the bomber and dropped into Lake Ontario, between Trenton, Ontario, Canada, and Rochester, New York, U.S.A. Skip Ziegler and an engineer aboard the bomber, Frank Wolko, were both lost. A technician, Robert F. Walters, who was in the aft section of the B-50 with Wolko, was badly burned and suffered an injured eye.
The B-50’s pilots, William J. Leyshon and David Howe, made an emergency landing at the Bell Aircraft Corporation factory airport at Wheatfield, New York (now, the Niagara Falls International Airport, IAG). The bomber was so heavily damaged that it never flew again.
Heavy fog over the lake hampered search efforts. Neither the bodies of Ziegler and Wolko or the wreckage of the X-2 were found.
After a series of explosions of early rocketplanes, the X-1A, X-1-3, X-1D and the X-2, investigators discovered that leather gaskets which were used in the fuel system had been treated with tricresyl phosphate (TCP). When this was exposed to liquid oxygen an explosion could result. The leather gaskets were removed from the other rocketplanes and the explosions stopped.
The X-2 was a joint project of the U.S. Air Force and NACA (the National Advisory Committee on Aeronautics, the predecessor of NASA). The rocketplane was designed and built by Bell Aircraft Corporation of Buffalo, New York, to explore supersonic flight at speeds beyond the capabilities of the earlier Bell X-1 and Douglas D-558-II Skyrocket. Two X-2s were built.
In addition to the aerodynamic effects of speeds in the Mach 2.0–Mach 3.0 range, engineers knew that the high temperatures created by aerodynamic friction would be a problem, so the aircraft was built from stainless steel and K-Monel, a copper-nickel alloy.
The Bell Aircraft Corporation X-2 was 37 feet, 10 inches (11.532 meters) long with a wingspan of 32 feet, 3 inches (9.830 meters) and height of 11 feet, 10 inches (3.607 meters). Its empty weight was 12,375 pounds (5,613 kilograms) and loaded weight was 24,910 pounds (11,299 kilograms).
The X-2 was powered by a throttleable two-chamber Curtiss-Wright XLR25-CW-1 rocket engine that produced 2,500–15,000 pounds of thrust (11.12–66.72 kilonewtons)
Rather than use its limited fuel capacity to take off and climb to altitude, the X-2 was dropped from a modified heavy bomber as had been the earlier rocketplanes.
The launch altitude was 30,000 feet (9,144 meters). After the fuel was exhausted, the X-2 glided to a touchdown on Rogers Dry Lake at Edwards Air Force Base.
The X-2 reached a maximum speed of Mach 3.196 (2,094 miles per hour/3,370 kilometers per hour) and maximum altitude of 126,200 feet (38,466 meters).
© 2017, Bryan R. Swopesby