Modern-Aviation

Design and Development
The X-24 was one of a group of lifting bodies flown by the NASA Flight Research Center (now Dryden 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 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 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.
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-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.

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.

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 weight: 6,360 lb (2,885 kg)
Loaded weight: 10,700 lb (4,853 kg)
Max. takeoff weight: 11,447 lb (5,192 kg)
Powerplant: 1 × Reaction Motors XLR-11rs four-chamber rocket engine, 8,480 lbf (37.7 kN)
Max Speed: 1,036 mph
Maximum speed: Mach 1.35 (1,667 km/h or 1,036 mph)
Range: 45 miles (72 km)
Service ceiling: 71,407 ft (21,763 m)
Wing loading: 59 lb/ft² (288 kg/m²)
Thrust/weight: 0.70

Role: Lifting body
National origin: United States
Manufacturer: Martin Marietta
First flight: 17 April 1969 (X-24A)
1 August 1973 (X-24B)
Retired: 26 November 1975
Status: Out of service
Primary users: United States Air Force
NASA
Number built: 1 (X-24A, rebuilt as X-24B)
Developed from: X-23 PRIME
Nation: United States
Interesting Fact: The rocket-powered aircraft was dropped from 45,000 feet.
These wingless planes were characterized by their aerodynamic lift which enabled it to fly in the atmosphere. The X-24 was built by Martin Marietta and based at Edwards Air Force Base, and the X-24A was the really fascinating specimen. It included vertical fins for enhanced control and could cruise at altitudes of 71,400 feet.

General Characteristics - X24B
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 weight: 8,500 lb (3,855 kg)
Loaded weight: 11,800 lb (5,350 kg)
Max. takeoff weight: 13,800 lb (6,260 kg)

Performance
Powerplant: 1 × XLR-11-RM-13 four-chamber rocket engine, 8,480 lbf (37.7 kN)
Maximum speed: Mach 1.52 (1,873 km/h)
Range: 45 miles (72 km)
Service ceiling: 74,130 ft (22.59 km)
Wing loading: 205 kg/m² ()
Thrust/weight: 0.71