Martin-Marietta X-24

The X-24 was an experimental US aircraft developed from a joint USAF-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.

X-24A Development

The X-24 was one of a group of lifting bodies flown by the NASA Flight Research Center (now Dryden Flight Research Center), Edwards, California, in a joint program with the U.S. Air Force at Edwards Air Force Base 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 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 1968 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 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-24A 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 a 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 platform 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
  • Jerauld R. Gentry - 13 flights
  • John A. Manke - 12 flights
  • Cecil W. Powell - 3 flights

X-24B Development

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.

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

X-24B Operational History

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 vehicle is on display at the Air Force Museum, Wright-Patterson Air Force Base, Ohio. 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 which showed that accurate unpowered reentry vehicle landings were operationally feasible. 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 today's 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 Air Force Museum, Wright-Patterson AFB, Ohio.

• X-24B pilots
  • John A. Manke - 16 flights
  • Michael V. Love - 12 flights
  • William H. Dana - 2 flights
  • Einar K. Enevoldson - 2 flights
  • Thomas C. McMurtry - 2 flights
  • Francis Scobee - 2 flights

• Much of the above text taken from the NASA Dryen webserver webpages. (http://www.dfrc.nasa.gov/gallery/photo/X-24/HTML/EC75-4914.html)

Specifications (Martin-Marietta X-24A)

General Characteristics

• Crew: one pilot
• Length: 24 ft 6 in (7.47 m)
• Wingspan: 11 ft 6 in (3.51 m)
• Height: 9 ft 7 in (2.92 m)
• Wing area: 195 ft² (18.1 m²)
• Empty: 6,360 lb (2,885 kg)
• Loaded: 10,700 lb (4,853 kg)
• Maximum takeoff: 11,447 lb (5,192 kg)
• Powerplant: 1 x Reaction Motors Upgraded XLR-11 four-chamber rocket engine. 8,480 lbf (37.7 kN) thrust.

Performance

• Maximum speed: 1,036 mph (1,667 Km/h)
• Range: 45 miles (72 Km)
• Service ceiling: 71,407 ft (21,763 m)
• Rate of climb: ft/min (m/min)
• Wing loading: 59 lb/ft² (288 Kg/m²)
• Thrust-to-Weight: 1:0.70 lbf/lb, 14.0 N/Kg

Specifications (Martin-Marietta X-24B)

General Characteristics

• Crew: one pilot
• Length: 37 ft 6 in (11.43 m)
• Wingspan: 19 ft 0 in (5.79 m)
• Height: 9 ft 7 in (2.92 m)
• Wing area: 330 ft² (30.7 m²)
• Empty: 8,500 lb (3,855 Kg)
• Loaded: 11,800 lb (5,350 Kg)
• Maximum takeoff: 13,800 lb (6,260 Kg)
• Powerplant: 1 x Reaction Motors Upgraded XLR-11 four-chamber rocket engine. 8,480 lbf (37.7 KN) thrust.

Performance

• Maximum speed: 1,164 mph (1,873 Km/h)
• Range: 45 miles (72 Km)
• Service ceiling: 74,130 ft (22.59 Km)
• Climbing rate: ft/min (m/min)
• Wing loading: 42 lb/ft² (205 Kg/m²)
• Thrust-to-Weight: 1:0.58 lbf/lb (16.9 N/Kg)

Serial number

• 66-13551
  • X-24A, 28 free flights; 10 unpowered, 18 powered
  • X-24B, 36 free flights; 12 unpowered, 24 powered

X-24A flights

Vehicle Flight #	Date	Pilot	Mach	Velocity km/h	Altitude m	Duration	Comments
X-24A #1	April 17, 1969	Gentry	0.718	763	13,716	00:03:37	First X-24A Flight Unpowered glide
X-24A #2	May 8, 1969	Gentry	0.693	735	13,716	00:04:13	Unpowered glide
X-24A #3	August 21, 1969	Gentry	0.718	782	12,192	00:04:30	Unpowered glide
X-24A #4	September 9, 1969	Gentry	0.594	647	12,192	00:03:52	Unpowered glide
X-24A #5	September 24, 1969	Gentry	0.596	637	12,192	00:04:17	Unpowered glide
X-24A #6	October 22, 1969	Manke	0.587	623	12,192	00:03:58	Unpowered glide
X-24A #7	November 13, 1969	Gentry	0.646	687	13,716	00:04:30	Unpowered glide
X-24A #8	November 25, 1969	Gentry	0.685	731	13,716	00:04:26	Unpowered glide
X-24A #9	February 24, 1970	Gentry	0.771	819	14,326	00:04:18	Unpowered glide
X-24A #10	March 19, 1970	Gentry	0.865	919	13,533	00:07:04	1st powered flight
X-24A #11	April 2, 1970	Manke	0.866	919	17,892	00:07:15	-
X-24A #12	April 22, 1970	Gentry	0.925	982	17,587	00:06:48	-
X-24A #13	May 14, 1970	Manke	0.748	795	13,594	00:08:33	Only 2 chambers lit
X-24A #14	June 17, 1970	Manke	0.990	1,051	18,593	00:07:12	-
X-24A #15	July 28, 1970	Gentry	0.938	996	17,709	00:06:28	-
X-24A #16	August 11, 1970	Manke	0.986	1,048	19,477	00:06:53	-
X-24A #17	August 26, 1970	Gentry	0.694	737	12,649	00:07:59	Only 2 chambers lit
X-24A #18	October 14, 1970	Manke	1.186	1,262	20,696	00:06:51	1st supersonic flight
X-24A #19	October 27, 1970	Manke	1.357	1,447	21,763	00:06:57	Highest flight
X-24A #20	November 20, 1970	Gentry	1.370	1,456	20,604	00:07:12	-
X-24A #21	January 21, 1971	Manke	1.033	1,093	17,648	00:07:42	-
X-24A #22	February 4, 1971	Powell	0.659	700	13,716	00:03:55	Unpowered glide
X-24A #23	February 18, 1971	Manke	1.511	1,606	20,544	00:07:27	-
X-24A #24	March 8, 1971	Powell	1.002	1,064	17,343	00:07:17	-
X-24A #25	March 29, 1971	Manke	1.600	1,667	21,488	00:07:26	Fastest flight
X-24A #26	May 12, 1971	Powell	1.389	1,477	21,610	00:07:03	Delayed engine start
X-24A #27	May 25, 1971	Manke	1.191	1,265	19,903	00:09:08	Only 3 chambers lit
X-24A #28	June 4, 1971	Manke	0.817	867	16,581	00:08:37	Only 2 chambers lit Last flight

X-24B flights

Vehicle Flight #	Date	Pilot	Mach	Velocity km/h	Altitude m	Duration	Comments
X-24B #1	August 1, 1973	Manke	0.640	740	12,192	00:04:12	First X-24B Flight Unpowered glide
X-24B #2	August 17, 1973	Manke	0.650	723	13,716	00:04:27	Unpowered glide
X-24B #3	August 31, 1973	Manke	0.716	797	13,716	00:04:37	Unpowered glide
X-24B #4	September 18, 1973	Manke	0.687	724	13,716	00:04:31	Unpowered glide
X-24B #5	October 4, 1973	Love	0.704	742	13,716	00:04:39	Unpowered glide
X-24B #6	November 15, 1973	Manke	0.930	962	16,082	00:06:44	1st powered flight
X-24B #7	December 12, 1973	Manke	0.646	1,038	19,227	00:07:14	-
X-24B #8	February 15, 1974	Love	0.696	734	13,716	00:05:07	Unpowered glide
X-24B #9	March 5, 1974	Manke	1.086	1,139	18,390	00:07:17	1st supersonic flight
X-24B #10	April 30, 1974	Love	0.876	930	15,862	00:06:59	-
X-24B #11	May 24, 1974	Manke	1.140	1,212	17,062	00:07:28	-
X-24B #12	June 14, 1974	Love	1.228	1,304	19,968	00:06:45	-
X-24B #13	June 28, 1974	Manke	1.391	1,481	20,772	00:07:07	-
X-24B #14	August 8, 1974	Love	1.541	1,645	22,366	00:06:35	-
X-24B #15	August 29, 1974	Manke	1.098	1,170	22,080	00:07:47	-
X-24B #16	October 25, 1974	Love	1.752	1,873	21,991	00:06:57	Fastest flight
X-24B #17	November 15, 1974	Love	1.615	1,722	21,964	00:08:01	-
X-24B #18	December 17, 1974	Love	1.585	1,667	20,964	00:07:00	-
X-24B #19	January 14, 1975	Manke	1.748	1,862	22,185	00:07:57	-
X-24B #20	March 20, 1975	Love	1.443	1,537	21,450	00:06:49	-
X-24B #21	April 18, 1975	Manke	1.204	1,279	17,648	00:07:30	-
X-24B #22	May 6, 1975	Love	1.444	1,542	22,372	00:07:28	-
X-24B #23	May 22, 1975	Manke	1.633	1,745	22,586	00:07:41	Highest flight
X-24B #24	June 6, 1975	Love	1.002	1,786	21,976	00:07:54	-
X-24B #25	June 25, 1975	Manke	1.343	1,427	17,678	00:07:06	-
X-24B #26	July 15, 1975	Love	1.585	1,685	21,178	00:06:55	-
X-24B #27	August 5, 1975	Manke	1.190	1,244	18,288	00:07:00	1st runway landing
X-24B #28	August 20, 1975	Love	1.548	1,625	21,946	00:07:00	2nd runway landing
X-24B #29	September 9, 1975	Dana	1.481	1,593	21,641	00:07:15	-
X-24B #30	September 23, 1975	Dana	1.157	1,255	17,678	00:07:18	Last powered flight
X-24B #31	October 9, 1975	Enevoldson	0.705	724	13,716	00:04:11	Unpowered glide
X-24B #32	October 21, 1975	Scobee	0.686	744	13,716	00:04:15	Unpowered glide
X-24B #33	November 3, 1975	McMurtry	0.702	734	13,716	00:04:08	Unpowered glide
X-24B #34	November 12, 1975	Enevoldson	0.702	734	13,716	00:04:01	Unpowered glide
X-24B #35	November 19, 1975	Scobee	0.700	740	13,716	00:04:09	Unpowered glide
X-24B #36	November 26, 1975	McMurtry	0.713	740	13,716	00:04:05	Unpowered glide Last flight

Related content

Related development:

Comparable aircraft: M2-F1 - M2-F2 - M2-F3 - HL-10

See also:

• X-plane - A list of all the X planes
• List of experimental aircraft

External link

• NASA Dryden X-24 Photo Collection (http://www.dfrc.nasa.gov/gallery/photo/X-24/)
• Wingless Flight: The Lifting Body Story. NASA History Series SP-4220 1997 PDF (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19980169231_1998082126.pdf)

Related content
Related Development
Similar Aircraft	Northrop HL-10
Designation Series	X-21 - X-22 - X-23 - X-24 - X-25 - X-26 - X-27
Related Lists	List of experimental aircraft

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