Directory of U.S. Military Rockets and Missiles
Copyright © 2002-2003 Andreas Parsch

Northrop (Radioplane) Q-4/AQM-35

In 1953, Northrop's Radioplane division started the development of the Model RP-61 supersonic target drone, and in June 1954 the USAF awarded a contract for the Q-4 vehicle under project MX-2144. The first air launch of an XQ-4 aircraft occurred in January 1956, and although the XQ-4 had a ground-launch capability, this was never used.

The XQ-4 was powered by an XJ81-WE-3 turbojet engine, and could reach a speed of Mach 1.55. It was air-launched by B-50D or GC-130A aircraft, and was controlled by a radio-command guidance system. The drone was tracked by radar, and a telemetry system was used to transmit flight parameters in real time. The XQ-4 could be recovered by a three-stage parachute system and was equipped with four inflatable bags which softened the landing to prevent damage to the airframe. The Q-4 was planned to be used to test various types of air-to-air and surface-to-air missiles designed for use against supersonic enemy aircraft. Optionally, it could also be fitted with photographic or TV reconnaissance equipment.

Photo: USAF

The XQ-4A was specifically designed to meet the radar-appearance requirements for testing the IM-99/CIM-10 Bomarc missile. It was to use the Fairchild J83 engine, but was cancelled when the latter didn't become available in time. In February 1959, the USAF awarded Radioplane a contract for the much improved Q-4B model, and the first flight of an XQ-4B occurred in March 1961. Some sources state that the XQ-4B vehicles were actually built by Bendix. The XQ-4B had improved performance using the significantly more powerful J85-GE-5 engine and a slightly redesigned airframe.

Photo: Northrop
XQ-4B (AQM-35B)

In June 1963, the Q-4 and Q-4B were redesignated as AQM-35A and AQM-35B, respectively. However, the Q-4/AQM-35 never became fully operational with the USAF, and only 25 XQ-4/Q-4B missiles were built. Quoted reasons for the cancellation include problems during development and flight-test, and the fact that the AQM-35's performance was too high for the surface-to-air missiles of the early 1960s anyway. The AQM-35 had apparently been removed from the inventory by the mid-1960s.

Note: There are a few sources which call the AQM-35 the "Bendix Talos" and/or refer to RIM-35A or RTM-35A designations. I don't know the origin of these reports, but they are certainly erroneous. There is no way a variant of the AQM-35 could have been built as a ship-launched interceptor missile, and I strongly suspect some major confusion between the Bendix-built AQM-35B and that company's RIM-8 Talos ship-based air-defense missile.


Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for XQ-4, Q-4B (AQM-35B):

 XQ-4Q-4B (AQM-35B)
Length10.06 m (33 ft)10.77 m (35 ft 4 in)
Wingspan3.38 m (11 ft 1 in)3.86 m (12 ft 8 in)
Diameter51 cm (20 in)
Height1.69 m (5 ft 6.7 in)1.88 m (6 ft 2 in)
Weight900 kg (1985 kg)1540 kg (3400 lb)
SpeedMach 1.55Mach 2
Ceiling18300 m (60000 ft)21300 m (70000 ft)
Propulsion Westinghouse XJ81-WE-3 turbojet; 8.0 kN (1810 lb)General Electric J85-GE-5 turbojet; 17.1 kN (3850 lb)

Main Sources

[1] Richard A. Botzum: "50 Years of Target Drone Aircraft", Northrop, 1985
[2] Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960
[3] Norman J. Bowman: "The Handbook of Rockets and Guided Missiles", Perastadion Press, 1963

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Last Updated: 19 January 2003