Martin Marietta X-24

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X-24
X-24b-flying.jpg
The X-24B in flight
General information
Type Lifting body
National originUnited States
Manufacturer Martin Marietta
Primary users United States Air Force
Number built1 (X-24A, rebuilt as X-24B)
History
First flight
  • 17 April 1969 (X-24A)
  • 1 August 1973 (X-24B)
Retired26 November 1975
Developed from X-23 PRIME

The Martin Marietta X-24 is an American experimental aircraft developed from a joint United States Air Force-NASA program named PILOT (1963–1975). It was designed and built to test lifting body concepts, experimenting with the concept of unpowered reentry and landing, later used by the Space Shuttle. [1] Originally built as the X-24A, the aircraft was later rebuilt as the X-24B.

Contents

The X-24 was drop launched from a modified B-52 Stratofortress at high altitudes before igniting its rocket engine; after expending its rocket fuel, the pilot would glide the X-24 to an unpowered landing. [2] [3]

Design and development

Martin X-24A X24.jpg
Martin X-24A

The X-24 was one of a group of lifting bodies flown by the NASA Flight Research Center (now Armstrong Flight Research Center) in a joint program with the U.S. Air Force at Edwards Air Force Base in California from 1963 to 1975. The lifting bodies were used to demonstrate the ability of pilots to maneuver and safely land wingless vehicles designed to fly back to Earth from space and be landed like an airplane at a predetermined site.

Lifting bodies’ aerodynamic lift, essential to flight in the atmosphere, was obtained from their shape. The addition of fins and control surfaces allowed the pilots to stabilize and control the vehicles and regulate their flight paths.

The X-24 (Model SV-5P) was built by Martin Marietta and flown from Edwards AFB, California. The X-24A was the fourth lifting body design to fly; it followed the NASA M2-F1 in 1964, the Northrop HL-10 in (1966), the Northrop M2-F2 in 1966 and preceded the Northrop M2-F3 (1970).

The X-24A was a fat, short teardrop shape with vertical fins for control. It made its first, unpowered, glide flight on April 17, 1969 with Air Force Maj. Jerauld R. Gentry at the controls. Gentry also piloted its first powered flight on March 19, 1970. The craft was taken to around 45,000 feet (13.7 km) by a modified B-52 and then drop launched, then either glided down or used its rocket engine to ascend to higher altitudes before gliding down. The X-24A was flown 28 times at speeds up to 1,036 mph (1,667 km/h) and altitudes up to 71,400 feet (21.8 km).

X-24B

The X-24B's design evolved from a family of potential reentry shapes, each with higher lift-to-drag ratios, proposed by the Air Force Flight Dynamics Laboratory. To reduce the costs of constructing a research vehicle, the Air Force returned the X-24A to the Martin Marietta Corporation (as Martin Aircraft Company became after a merger) for modifications that converted its bulbous shape into one resembling a "flying flatiron"—rounded top, flat bottom, and a double delta planform that ended in a pointed nose.

John Manke was the first to fly the X-24B, a glide flight on 1 August 1973. He was also the pilot on the first powered mission 15 November 1973.

X-24C

There were a variety of "X-24C" proposals floated between 1972 and 1978. Perhaps the most notable was a Lockheed Skunk Works design, the L-301, which was to use scramjets to reach a top speed of Mach 8. [4]

SV-5J

SV-5J displayed as the X-24A at the National Museum of the United States Air Force Martin Marietta SV-5J (5-22-2022).jpg
SV-5J displayed as the X-24A at the National Museum of the United States Air Force

After learning about a remark by Chuck Yeager that he would like to have some jet-powered lifting bodies for training purposes, Martin designed and built, on their own initiative, two examples of the SV-5J. [1]

The SV-5J was a jet-powered version of the rocket-powered X-24A. The SV-5J had identical dimensions to the X-24A, but was powered by a single Pratt & Whitney J60-PW-1 jet engine of 1360 kgf, in place of the X-24A's Reaction Motors XLR-11-RM-13 rocket engine. Martin also manufactured a full-scale, unflyable, mock-up of the SV-5J. (Confusion over number built may be due to the mock-up being included in the production list.)[ citation needed ]

Martin were unable to convince Milt Thompson to fly the SV-5J, even after offering a $20,000 bonus. Both examples remained unflown.

As the original X-24A was converted to X-24B, one of the SV-5Js eventually was converted to represent the X-24A, for display at the National Museum of the United States Air Force, Wright-Patterson AFB, Ohio, beside the original X-24B.

Operational history

The X-24A was flown 28 times in the program that, like the HL-10, validated the concept that a Space Shuttle vehicle could be landed unpowered. The fastest speed achieved by the X-24A was 1,036 miles per hour (1667 km/h or Mach 1.6). Its maximum altitude was 71,400 feet (21.8 km). It was powered by an XLR-11 rocket engine with a maximum theoretical vacuum thrust of 8,480 pounds force (37.7 kN).

The X-24A was modified into the more stable X-24B with an entirely different shape in 1972. The bulbous shape of the X-24A was converted into a "flying flatiron" shape with a rounded top, flat bottom, and double delta planform that ended in a pointed nose. It was the basis for the Martin SV-5J. The X-24A shape was later borrowed for the X-38 Crew Return Vehicle (CRV) technology demonstrator for the International Space Station.

X-24A pilots

X-24B

X-24B at the USAF Museum Martin Marietta X-24B (28179310796).jpg
X-24B at the USAF Museum

The X-24B demonstrated that accurate unpowered reentry vehicle landings were operationally feasible. Top speed achieved by the X-24B was 1,164 mph (1873 km/h) and the highest altitude it reached was 74,130 feet (22.59 km). The pilot on the last powered flight of the X-24B was Bill Dana, who also flew the last X-15 flight about seven years earlier.

Among the final flights with the X-24B were two precise landings on the main concrete runway at Edwards. These missions were flown by Manke and Air Force Maj. Mike Love, and represented the final milestone in a program that helped write the flight plan for the Space Shuttle program.

The X-24B was the last aircraft to fly in Dryden's Lifting Body program. The X-24B was flown 36 times.

The X-24B is on public display at the National Museum of the United States Air Force, Wright-Patterson AFB, Ohio.

X-24B pilots

Serial number

Specifications (X-24B)

Diagram of X-24A X-24A 3-view.svg
Diagram of X-24A
Diagram of X-24B X-24B 3-view.svg
Diagram of X-24B

Data from Jane's All the World's Aircraft 65th ed. (1974–75) [5]

General characteristics

Performance

See also

Related development

Aircraft of comparable role, configuration, and era

Related lists

Related Research Articles

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<span class="mw-page-title-main">Fixed-wing aircraft</span> Heavier-than-air aircraft with fixed wings generating aerodynamic lift

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<span class="mw-page-title-main">Lifting body</span> Aircraft configuration in which the fuselage produces significant lift

A lifting body is a fixed-wing aircraft or spacecraft configuration in which the body itself produces lift. In contrast to a flying wing, which is a wing with minimal or no conventional fuselage, a lifting body can be thought of as a fuselage with little or no conventional wing. Whereas a flying wing seeks to maximize cruise efficiency at subsonic speeds by eliminating non-lifting surfaces, lifting bodies generally minimize the drag and structure of a wing for subsonic, supersonic and hypersonic flight, or spacecraft re-entry. All of these flight regimes pose challenges for proper flight safety.

<span class="mw-page-title-main">North American X-15</span> Rocket-powered aircraft and spaceplane operated by the US Air Force and NASA

The North American X-15 is a hypersonic rocket-powered aircraft operated by the United States Air Force and the National Aeronautics and Space Administration (NASA) as part of the X-plane series of experimental aircraft. The X-15 set speed and altitude records in the 1960s, crossing the edge of outer space and returning with valuable data used in aircraft and spacecraft design. The X-15's highest speed, 4,520 miles per hour, was achieved on 3 October 1967, when William J. Knight flew at Mach 6.7 at an altitude of 102,100 feet (31,120 m), or 19.34 miles. This set the official world record for the highest speed ever recorded by a crewed, powered aircraft, which remains unbroken.

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<span class="mw-page-title-main">Northrop X-4 Bantam</span> American experimental jet aircraft

The Northrop X-4 Bantam is a prototype small twinjet aircraft manufactured by Northrop Corporation in 1948. It had no horizontal tail surfaces, depending instead on combined elevator and aileron control surfaces for control in pitch and roll attitudes, almost exactly in the manner of the similar-format, rocket-powered Messerschmitt Me 163 of Nazi Germany's Luftwaffe. Some aerodynamicists had proposed that eliminating the horizontal tail would also do away with stability problems at fast speeds resulting from the interaction of supersonic shock waves from the wings and the horizontal stabilizers. The idea had merit, but the flight control systems of that time prevented the X-4 from achieving any success.

<span class="mw-page-title-main">NASA X-38</span> Experimental space lifeboat vehicle

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<span class="mw-page-title-main">William H. Dana</span> NASA research pilot and astronaut (1930–2014)

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<span class="mw-page-title-main">Milton Orville Thompson</span> American aviator (1926–1993)

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<span class="mw-page-title-main">Rocket-powered aircraft</span> Aircraft which uses a rocket engine for propulsion

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<span class="mw-page-title-main">Northrop HL-10</span>

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<span class="mw-page-title-main">NASA M2-F1</span> Lifting body prototype

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<span class="mw-page-title-main">Northrop M2-F2</span> Lifting body prototype

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<span class="mw-page-title-main">Jerauld R. Gentry</span> United States Air Force pilot (1935–2003)

Jerauld Richard "Jerry" Gentry was a United States Air Force (USAF) test pilot and Vietnam combat veteran. As chief USAF pilot of the Lifting Body Research Program, he helped validate the concept of flying a wingless vehicle back to Earth from space and landing it like an aircraft—an approach used by the Space Shuttle and to a greater degree by vehicles such as the Lockheed Martin X-33 and NASA X-38. Gentry completed thirty lifting body flights including the first flight of the Martin-Marietta X-24A and the second flight of the Northrop HL-10.

<span class="mw-page-title-main">Drop test</span> Method of testing aircraft/spacecraft

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<span class="mw-page-title-main">SSC Demo-1</span> Planned 2025 American test spaceflight to the ISS

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References

Notes

  1. 1 2 Reed, R. Dale; Darlene Lister (2002). Wingless Flight: The Lifting Body Story. University Press of Kentucky. ISBN   0-8131-9026-6. also available as a PDF file .
  2. "MARTIN X-24B". National Museum of the US Air Force. August 26, 2009. Archived from the original on December 16, 2013. Retrieved July 15, 2017.
  3. "X-24B launch – air drop from mothership". Dryden Flight Research Center. Archived from the original on October 6, 1999. Retrieved March 25, 2013.
  4. Jenkins, Dennis R. (2001). Space Shuttle: The History of the National Space Transportation System (3rd ed.). Voyageur Press. ISBN   0-9633974-5-1.
  5. Taylor, John W. R., ed. (1974). Jane's All the World's Aircraft 1974–75 (65th annual ed.). New York: Franklin Watts Inc. p. 382. ISBN   978-0354005029.

Bibliography

  • Miller, Jay. The X-Planes: X-1 to X-45. Hinckley, UK: Midland, 2001.
  • Reed, R. Dale with Darlene Lister. Wingless Flight: The Lifting Body Story. Lexington, KY: University Press of Kentucky, 2002. ISBN   0-8131-9026-6.
  • Rose, Bill, 2008. Secret Projects: Military Space Technology. Hinckley, England: Midland Publishing.
  • Winchester, Jim. "Martin-Marietta X-24." X-Planes and Prototypes.' London: Amber Books Ltd., 2005. ISBN   1-904687-40-7.