The Lockheed X-7

First Flight: April 26, 1951
Mission: Test bed for high speed air-breathing engines (ramjets).
Major Accomplishments: Successfully served as a test bed for ramjet engines, primarily for the Boeing Bomarc anti-aircraft missile. There were 3 major configurations of the X-7 series: the X-7A-1, the X-7A-3 and the X-7B.

Additional Information: Holds the ultimate speed record for air-breathing aircraft, at over 2,000 mph. This X-7 series was flown in many different configuration and had many missions during its 10 year service life. In addition to serving as a ram-jet test bed, it carried communication equipment for acceleration testing, and was used to test aerodynamics, booster propellants, thermodynamics and high speed parachutes. Flight testing was conducted by the United States Air Force, United States Army and the United States Navy. Several X-7 examples can be found around the United States including at the White Sands missile test range.

Photos courtesy of Richard Dukes, who provides the following information:
This X-7 was saved by my self and staff many years ago and it was finally restored and placed on display in Aug. 2001 in Alamogordo @ the New Mexico Museum of Space History. Photo here shows the 7 nearly completed next to a XQ-4B Supersonic high altitude target drone (supercruise ability) at the museums restoration facility, the Museum Support Center. Today this project is almost complete and we plan to have it on display by summer. Note that our seven is a very early model (rudder and engine) I cannot confirm that this one was flown due to Holloman AFB personnel that had sandblasted any markings away. However from internal markings and fittings it is very possible that it could have been one of the three boosted flights to iron out initial problems with the booster. The 20" ramjet is not an actual engine but had proper inlet and outlet fashioned from wood also contained wiring harness more than likely for instrumentation. Also the paint scheme was selected from a video of an early seven being pushed from a hanger at near by HAFB.

The X-7

The Lockheed X-7 (dubbed the "Flying Stove Pipe") was an unmanned test bed for ramjet engines and missile guidance technology. It was carried aloft by a B-29 or B-50 Superfortress carrier aircraft. The booster ignited after launch and propelled the vehicle to a speed of 1,000 mph (1,625 km/h). The booster was then jettisoned, and the underslung ramjet took over from that point. The X-7 eventually returned to Earth, its descent slowed by parachute. A maximum speed of 2,881 mph (4640 km/h / Mach 4.31) was attained, setting a record for fastest air-breathing aircraft. A total of 130 X-7 flights were conducted from April 1951 to July 1960.

Specifications (X-7A-1)

General characteristics

Crew: None
Length: 32 ft 9 in (9.98 m)
Wingspan: 12 ft (3.66 m)
Height: 7 ft (2.1 m)
Loaded weight: 8,000 lb (3,600 kg)
Powerplant:
- 1× Alleghany Ballistics Laboratories X202-C3 solid-fuel rocket, 105,000 lbf (467 kN)
- 1× various ramjets under test , ()

Performance

Maximum speed: Mach 4.31 (2,881 mph, 4,640 km/h)
Service ceiling: 106,000 ft (32,317 m)

The Kingfisher was a target version of the U.S. Air Force's X-7 test vehicle. As such, its development began in December 1946, when the USAF requested an unmanned ramjet test vehicle for speeds up to Mach 3. Under project MX-883, Lockheed designed the Model L-151, initially designated PTV-A-1, but redesignated as X-7 in 1951. The first launch of an X-7 in April 1951 was unsuccessful, but in the following years, the X-7 successfully tested many different types of ramjet.

The X-7 was air-launched from B-29 or B-50 carrier aircraft, and was boosted to ramjet ignition speed by a single large expendable solid-fueled rocket booster attached to the vehicle's tail. An unusual feature of the X-7 was the method of recovery. A multistage parachute system slowed the drone to a descent in a vertical nose-down attitude. The nose consisted of a long spike which penetrated the ground upon impact. Therefore the vehicle literally rammed itself nose first into the desert floor, preventing damage to the rest of the airframe.

In 1954, a significantly modified version, designated X-7A-3 (the original X-7 having been redesignated as X-7A-1), was introduced. It had a redesigned wing and a new booster installation, consisting of two smaller boosters located at the fuselages sides under the wings. The new configuration allowed a semi-recessed carriage under the fuselage of the B-50 carrier, much simpler than the underwing arrangement necessary with the X-7A-1's large booster. The X-7A-3's instrumentation and control equipment was improved as well. The X-7 test program continued with the new vehicle until the final flight in July 1960. The X-7B, based on the X-7A-3, was intended to test guidance and control systems, but the program was cancelled very early in the flight test phase.

To satisfy the need for a very high performance target drone to test the SAM-A-7/MIM-3 Nike Ajax, SAM-A-25/MIM-14 Nike Hercules, and IM-99/CIM-10 Bomarc surface-to-air missiles, a relatively unmodified target version of the X-7A-3 was ordered by the USAF. The target, named Kingfisher, was designated by the Air Force as XQ-5, but the Kingfisher program was soon transferred to the U.S. Army, which did not use the Q-5 designator. Eventually, in June 1963, the XQ-5 was redesignated as AQM-60A.

However, the performance of the Kingfisher proved to be a bit too high for the interceptor missiles, and relatively few hits were scored. This was somewhat embarrassing to the military and the manufacturers of the SAMs, and therefore political pressure played a role when the Kingfisher flight program was cancelled in the mid-1960s. Production of the X-7/XQ-5 series had ended in 1959, after 61 X-7/XQ-5 missiles of all variants had been built.

Specifications

Length

X-7A-1: 9.98 m (32 ft 9 in)
X-7A-3: 11.3 m (37 ft)
XQ-5: 11.6 m (38 ft)

Wingspan

X-7A-1: 3.7 m (12 ft)
X-7A-3, XQ-5: 3.0 m (10 ft)

Height

2.1 m (7 ft)

Diameter

61 cm (20 in)

Weight

3600 kg (8000 lb)

Speed

Mach 4.3; 4500 km/h (2800 mph)

Ceiling

30000 m (100000 ft)

Range

210 km (130 miles)

Propulsion

Booster:	X-7A-1: Alleghany Ballistics Lab. X202-C3 (4DW105000) solid-fuel rocket; 467 kN (105000 lb) for 4 s X-7A-3/XQ-5: 2x Thiokol XM45 (5KS50000) solid-fuel rocket; 222 kN (50000 lb) each for 5 s
Sustainer:	X-7A-1/X-7A-3: Ramjet (various types) XQ-5: Marquardt XRJ43-MA ramjet