Tag Archives: David Clark Co.

6 November 1958

Bell X-1E 46-063 on Rogers Dry Lake. (NASA)
Bell X-1E 46-063 on Rogers Dry Lake, 1955. (NASA)

6 November 1958: NASA Research Test Pilot John B. (Jack) McKay made the final flight of the X-1 rocketplane program, which had begun twelve years earlier.

Bell X-1E 46-063 made its 26th and final flight after being dropped from a Boeing B-29 Superfortress over Edwards Air Force Base on a flight to test a new rocket fuel.

John B. McKay, NACA/NASA Research Test Pilot. (NASA)
John B. McKay, NACA/NASA Research Test Pilot. (NASA)

When the aircraft was inspected after the flight, a crack was found in a structural bulkhead. A decision was made to retire the X-1E and the flight test program was ended.

The X-1E had been modified from the third XS-1, 46-063. It used a thinner wing and had an improved fuel system. The most obvious visible difference is the cockpit, which was changed to provide for an ejection seat. Hundreds of sensors were built into the aircraft’s surfaces to measure air pressure and temperature.

The Bell X-1E was 31 feet (9.449 meters) long, with a wingspan of 22 feet, 10 inches (6.960 meters). The rocketplane’s empty weight was 6,850 pounds (3,107 kilograms) and fully loaded, it weighed 14,750 pounds (6,690 kilograms). The rocketplane was powered by a Reaction Motors XLR11-RM-5 rocket engine which produced 6,000 pounds of thrust (26.689 kilonewtons). The engine burned ethyl alcohol and liquid oxygen. The X-1E carried enough propellants for 4 minutes, 45 seconds burn.

The Bell X-1E rocketplane being loaded into a Boeing B-29 Superfortress mothership for another test flight. (NASA)
The Bell X-1E rocketplane being loaded into NACA 800, a Boeing B-29-96-BW Superfortress mothership, 45-21800, for another test flight. (NASA)

The early aircraft, the XS-1 (later redesignated X-1), which U.S. Air Force test pilot Charles E. (“Chuck”) Yeager flew faster than sound on 14 October 1947, were intended to explore flight in the high subsonic and low supersonic range. There were three X-1 rocketplanes. Yeager’s Glamorous Glennis was 46-062. The X-1D (which was destroyed in an accidental explosion after a single glide flight) and the X-1E were built to investigate the effects of frictional aerodynamic heating in the higher supersonic ranges from Mach 1 to Mach 2.

Bell X-1E loaded aboard Boeing B-29 Superfortress, circa 1955. (NASA)
Bell X-1E 46-063 loaded aboard NACA 800, a Boeing B-29-96-BW Superfortress, 45-21800, circa 1955. (NASA)

The X-1E reached its fastest speed with NASA test pilot Joseph Albert Walker, at Mach 2.24 (1,450 miles per hour/2,334 kilometers per hour), 8 October 1957. Walker also flew it to its peak altitude, 70,046 feet (21,350 meters) on 14 May 1958.

NACA test pilot Joseph Albert Walker made 21 of the X-1E's 26 flights. In this photograph, Joe Walker is wearing a David Clark Co. T-1 capstan-type partial-pressure suit with a K-1 helmet for protection at high altitudes. (NASA)
NACA test pilot Joseph Albert Walker made 21 of the X-1E’s 26 flights. In this photograph, Joe Walker is wearing a David Clark Co. T-1 capstan-type partial-pressure suit with a K-1 helmet for protection at high altitudes. (NASA)

There were a total of 236 flights made by the X-1, X-1A, X-1B, X-1D and X-1E. The X-1 program was sponsored by the National Advisory Committee on Aeronautics, NACA, which became the National Aeronautics and Space Administration, NASA, on 29 June 1958.

The X-1E is on display in front of the NASA administration building at the Dryden Flight Research Center, Edwards Air Force Base, California.Bell X-1E 46-063 on display at Dryden Flight Research Center© 2016, Bryan R. Swopes

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14 October 2012

Felix Baumgartner prepares to step off the gondola, 127,852 feet (38,969 meters) over New Mexico. The Mescalero Dunes are directly below. (Red Bull Stratos)

14 October 2012: At 12:08 p.m. MDT (1808 UTC) Felix Baumgartner jumped from the gondola of a helium-filled balloon at 127,852.4 feet (38,969.4 meters) over eastern New Mexico.

At 12:08 p.m. MDT (1808 UTC), Felix Baumgartner steps off the gondola. (Red Bull Stratos)

The free fall distance was 119,431.1 feet (36,402.6 meters). He fell for 4 minutes, 19 seconds before deploying his parachute and touched down after nine minutes, 3 seconds. During the free fall, he reached 843.6 miles per hour (1,357.6 kilometers per hour), Mach 1.25.

Felix Baumgartner in full-pressure suit, prepares to jump during an earlier intermediate test. (Red Bull Stratos)
Felix Baumgartner in full-pressure suit, prepares to jump during an earlier intermediate test. The geological feature running diagonally across the center of the image is the Mescalero Escarpment, western boundary of the Llano Estacado. The light-colored features are sand dunes. (Red Bull Stratos)

The Fédération Aéronautique Internationale (FAI) recognizes three Sub-Class G-2 World Records set by Baumgartner with this jump:

16669: Vertical Speed Without Drogue: 1,357.6 kilometers per hour (843.6 miles per hour miles per hour)

16670: Exit Altitude: 38,969.4 meters (127,852.4 feet)

16671: Freefall Distance: 36,402.6 meters (119,431.1 feet)

Felix Baumgartner wore a custom-made full-pressure suit designed and manufactured by the David Clark Co., Worcester, Massachusetts, based on their S1034 Improved Common Suit.

The helium balloon, with a volume 29,470,000 cubic feet, was manufactured by Raven Aerostar, Sioux Falls, South Dakota. Baumgartner’s pressure capsule was designed and built by Sage Cheshire Aerospace, Lancaster, California.

© 2016, Bryan R. Swopes

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8 October 1958

The Project MANHIGH III balloon and gondola, shortly after launch at Holloman AFB, 1151 UTC, 8 October 1958. (Al Fenn/LIFE Magazine)
The Project MANHIGH III balloon and gondola, shortly after launch at Holloman AFB, 6:51 a.m., 8 October 1958. (Al Fenn/LIFE Magazine)

8 October 1958: At Holloman Air Force Base, southeast of Alamogordo, New Mexico, the Project MANHIGH III balloon was launched at 6:51 a.m., Mountain Standard Time (13:51  UTC). The helium balloon lifted a 1,648 pound (748 kilogram) pressurized gondola. Inside was Lieutenant Clifton Moody McClure III, U.S. Air Force.

Over the next three hours, the balloon ascended to an altitude of 99,700 feet (30,389 meters)¹ over the Tularosa Basin.

From this altitude, “Demi” McClure radioed to Dr. David G. Simon, who had flown a previous MANHIGH mission, “I see the most fantastic thing, the sky that you described. It’s blacker than black, but it’s saturated with blue like you said. . . I’m looking at it, but it seems more like I’m feeling it. . . I have the feeling that I should be able to see stars in this darkness, but I can’t find them, either—I have the feeling that this black is so black it has put the stars out.”

The purpose of the MANHIGH flights was to conduct scientific research through the direct observations of the pilot while in contact with ground-based scientists and engineers, and to gather physiological data about the stresses imposed on a human body during extreme high altitude flight.

Lieutenant Clifton M. McClure, U.S. Air Force (1932–2001)
1st Lieutenant Clifton Moody McClure III, United States Air Force

Lieutenant McClure was born at Anderson, South Carolina, 8 November 1932, the son of Clfton M. McClure, Jr., a bookkeeper (who would serve as a U.S. Marine Corps officer during World War II) and Frances Melaney Allen McClure. He attended the Anderson High School, graduating in 1950. He earned a bachelor’s degree in materials engineering and a master’s degree in ceramic engineering from Clemson University. He had been an instructor pilot, flying the Lockheed T-33A Shooting Star jet trainer, at air bases in Texas, but was then assigned to the Solar Furnace Project at Holloman AFB.

Prior high-altitude balloon flights had shown the need for extreme physiological fitness, and McClure was selected through a series of medical and physical evaluations similar to those that would later be used to select astronaut candidates for Project Mercury. He was considered to be physiologically and psychologically the best candidate for MANHIGH flights.

The MANHIGH III balloon was manufactured by Winzen Research, Inc., Minneapolis, Minnesota. It had a capacity of approximately 3,000,000 cubic feet (84,950 cubic meters) and was filled with helium.

The gondola was built of three cast aluminum cylindrical sections with hemispherical caps at each end. It was 9 feet (2.743 meters) high with a diameter of 3 feet (0.914 meters). Inside were cooling and pressurization equipment ,and equipment for various scientific experiments.

Lieutenant McClure wore a modified David Clark Company MC-3A capstan-type partial-pressure suit with an International Latex Corporation MA-2 helmet for protection. He breathed a mixture of 60% oxygen, 20% nitrogen and 20% helium.

During the flight, Lieutenant McClure became dehydrated. Later, temperatures inside the gondola rose to 118 °F. (47.8 °C.). The cooling system was unable to dissipate heat from McClure’s body, and his body core temperature rose to 108.6 °F. (42.6 °C.). After twelve hours, it was decidede to end the flight. MANHIGH III touched down a few miles from its departure point at 2342 UTC, 9 October 1958.

After his participation in Project MANHIGH, Clifton McClure applied to become an astronaut in Project Mercury. He was turned down because his height—6 feet, 1 inch (1.854 meters)— exceeded the limits imposed by the small Mercury space capsule. He was awarded the Distinguished Flying Cross for the MANHIGH III flight. He later flew Lockheed F-104 Starfighters with the South Carolina Air National Guard.

Clifton Moody McClure III died at Huntsville, Alabama, 14 January 2000, at the age of 67 years.

Lieutenant Clifton M. McClure, USAF, seated inside the MANHIGH III gondola. (U.S. Air Force)

¹ Sources vary. A NASA publication, Dressing For Altitude, cites McClure’s maximum altitude as 98,097 feet (29,900 meters) (Chapter 4, Page 162). The Albuquerque Tribune reported McClure’s altitude as 99,600 feet (30,358 meters), (Vol. 36, No. 163, Saturday, 11 October 1958, Page 7 at Column 6. The National Museum of the United States Air Force states 99,700 feet (30,389 meters). 99,700 feet is also cited in Office of Naval Research Report ACR-64, “Animals and Man in Space,” 1962.

© 2016, Bryan R. Swopes

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