X-2 46-675

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X-2 Bell Aircraft Corporation Ziegler and aircraft #2 (46-675) were subsequently lost on 12 May 1953, in an inflight explosion during a captive flight intended to check the aircraft’s liquid oxygen system. A B-50 crew member, Frank Wolko, was also killed during the incident. The wreckage of the aircraft fell into Lake Ontario and was not recovered. First Flight: 27 June 1952 Sponsors: USAF Last Flight: 27 September 1956 Fastest Flight: Mach 3.196 (2,094 mph) Total Flights: 20 Highest Flight: 125,907 feet

General characteristics #

Crew: one, pilot Length: 37 ft 10 in (11.5 m) Wingspan: 32 ft 3 in (9.8 m) Height: 11 ft 10 in (3.6 m) Wing area: 260 ft² (24.2 m²) Airfoil: 2S-50 bicon Empty weight: 12,375 lb (5,600 kg) Loaded weight: 24,910 lb (11,300 kg) Max. takeoff weight: 24,910 lb (11,300 kg) Powerplant: 1 × Curtiss-Wright XLR25 rocket engine, 15,000 lbf (67 kN)at sea level Performance Maximum speed: Mach 3.196 (2,094 mph, 3,370 km/h) Service ceiling: 126,200 ft (38,466 m)

The X-2 was designed to explore flight at speeds and altitudes far beyond those attainable by the X-1s. The X-2 was originally ordered under the designation XS-2. (NASA photo E-5749) Two X-2s were built by Bell Aircraft at their Niagara Falls, New York, facility. The airframes were composed primarily of stainless steel and “K-Monel,” an advanced lightweight heat-resistant steel alloy. Like the X-1, the X-2 was air-launched, this time from a Boeing B-50 bomber. Although plagued with a variety of problems, the X-2 program did produce a number of technological advances that helped pave the way for future high-speed, high-altitude aircraft. Among the most important was the use of high-strength steel alloys in aircraft construction—which gave rise to several innovative construction techniques and the development of specialized tooling. Additionally, the X-2 contributed to the continued understanding of high-Mach aerodynamics. The first X-2 was dropped into Lake Ontario on 12 May 1953 following an explosion and fire that also caused extensive damage to the EB-50A launch aircraft.

E-5749 This 1952 photograph shows the X-2 #2 aircraft mounted on a special transportation dolly at Edwards Air Force Base, California. The dolly was steerable and was used for transporting the X-2 around and for towing it off the lakebed at Edwards Air Force Base after a landing. This was the number 2 airplane (46-675), which was lost on May 12, 1953, on a captive flight over Lake Ontario when the airplane exploded during a liquid-oxygen top off test, killing the pilot, Jean Ziegler, and EB-50A crewman Frank Wolko. Almost no debris was recovered from Lake Ontario, so no cause for the explosion could be determined. Later, however, investigations of similar explosions in the X-1 #3, X-1A and X-1D traced the problem to Ulmer leather gaskets, which exuded tricresyl phosphate. This substance caused detonations in the supercold atmosphere of the airplanes’ liquid oxygen tanks. As X-2 #2 also had these gaskets, they were probably the cause of the explosion in that aircraft as well. 1952 NASA Photo / NASA photo X-2 Project Description

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.