Directory of U.S. Military Rockets and Missiles|
Appendix 1: Early Missiles and Drones
|Copyright © 2003-2005 Andreas Parsch|
Between 1943 and 1953, the U.S. Navy's Bureau of Aeronautics (BuAer) developed a whole family of guided missiles under the Gorgon name. The Gorgon project resulted in numerous different vehicles with a bewildering list of designations (some Gorgon variants were (re-)designated four times within about two years). To write a useful historical summary of the whole Gorgon program, and to put the various variants in context with each other, all Gorgon missiles are discussed in this article.
As early as 1937, U.S. Navy Cdr D.S. Fahrney proposed to develop an unmanned "drone" aircraft for a variety of tasks, including ground attack and the interception of bomber formations. In mid-1940, the BuAer began to tentatively design what was then called an "aerial torpedo", but then available piston engine technolgy resulted in an aircraft with far too low performance to be useful. The project re-emerged in May 1943 when the new rocket and turbojet propulsion began to show promise for missile applications, and in July 1943, the Gorgon developmant program was formally begun. The Gorgon missiles were designed and built by the NAMU (Naval Aircraft Modification Unit), which became the NADS (Naval Air Development Station) in 1947 and finally the NADC (Naval Air Development Center) in 1949.
Gorgon was to be a light (300 kg (660 lb)) air-launched missile using a small (9.5 in) Westinghouse turbojet for a speed of up to 820 km/h (510 mph). The primary mission was to be the interception of large aircraft (i.e. bombers or transports), with a secondary ground-attack capability. The proposed guidance options included TV/command guidance (where the missile was controlled by an operator using the picture of a TV camera in the missile nose), radar homing, or a simple heat (infrared) seeker. For the air-to-air mission, the missile would be equipped with both a proximity and a contact fuze. However, it seems that the problems of air-to-air missile guidance were a bit underestimated at that time, because initial Gorgon development focused on airframe and propulsion. Accordingly, in late 1943 alternative airframe configurations were proposed, the Gorgon II with canards, and the Gorgon III with conventional layout. Both configurations were to be tested with rocket, turbojet and pulsejet propulsion, indicated by suffix letters "A", "B" and "C", respectively (e.g. Gorgon IIC would be the pulsejet-powered canard airframe). In late 1943, 25 missiles each of Gorgon II and Gorgon III type were ordered to be used as test and evaluation vehicles. This order was later amended and changed, and by April 1945 had arrived at 21 Gorgon IIA, 4 Gorgon IIB, 34 Gorgon IIIA, 16 Gorgon IIIB and 20 Gorgon IIIC.
No turbojet variants (Gorgon IIB and Gorgon IIIB) were actually built, because no suitable flight-rated engine was available at that time. The other Gorgon II/III variants were actually built, although the Gorgon IIIC ended up with a rocket instead of a pulsejet propulsion system. Initially, all variants were indeed developed (and designated) as tactical missiles with either anti-aircraft or ground-attack missions. However, a March 1945 live test of a TV/command-guided air-to-air Gorgon IIA failed miserably, because there was effectively no way an operator could manually steer the rather sluggish missile to an interception point when closing speeds reach 1300 km/h (800 mph). Because the other proposed guidance methods were also immature and/or unsuitable, the whole Gorgon program was reoriented in mid-1946 to a research and development effort, and all Gorgon variants then in existance were redesignated as test vehicles. For an overview of the numerous designations, which the Gorgon II/III missiles received between 1945 and 1948, refer to the table at the end of this article. Some of the Gorgons used as research vehicles were modified with a parachute recovery system.
The Gorgon IIA, of which 21 were built, was powered by a Reaction Motors CML2N liquid-propellant rocket engine. Unpowered flight tests began in early 1945, followed by the first powered launches in March that year. While launching and flying characteristics were generally satisfactory, the same could not be said about the guidance system. The missile used the radio command guidance system with a TV camera in the nose, but as said in the previous paragraph, this was unsuitable for air-to-air applications. Intially designated as KA2N-1 anti-aircraft missile in October 1945, Gorgon IIA was redesignated as KU2N-1 control test vehicle in 1946. In September 1947 and early 1948, the KU2N-1 was redesignated as CTV-4 and CTV-N-4, respectively.
|Photo: Smithsonian Institution|
The Gorgon IIC was of similar canard layout as the Gorgon IIA, but was powered by a single 14 in. pulsejet instead. It was originally planned as a ship-to-shore bombardment missile, and accordingly designated KGN-1 in October 1945. At one time, in April 1945, the production of several hundred Gorgon IICs for the expected invasion of Japan had been planned, but these plans were cancelled after the end of the war. The missile could be ground-launched from a sled or catapult with the assistance of a solid-propellant rocket booster with 4.0 kN (900 lb) thrust. The Gorgon IIC had a significantly longer range than the Gorgon IIA at a maximum speed of about 725 km/h (450 mph). However, like the rest of the early Gorgon vehicles, it became a pure test vehicle in late 1946, and was then known as KUN-1. It was used to test homing devices, control systems and a variety of other equipment related to guided missile development. The Gorgon IIC was finally redesignated as CTV-2 in September 1947, and as CTV-N-2 in early 1948. In 1950, a CTV-N-2 tested an active radar seeker against ship targets.
|Photo: Mikael Olrog|
|CTV-N-2 (wings detached)|
There was also a Gorgon target drone version very similar to the Gorgon IIC. Eight examples of this drone were built, and designated as TD3N-1 and (after March 1946) KD2N-1. The RTV-N-15 Pollux is also described as a test vehicle of Gorgon IIC configuration, and it's possible that it used auxiliary rocket propulsion in addition to its pulsejet. The RTV-N-15 was probably used as a general research vehicle for a short time around 1950/51.
|Photo: Joel Carpenter|
|Gorgon IIC (CTV-N-2 or KD2N-1)|
The liquid-fueled rocket-powered KA3N-1 Gorgon IIIA (the engine was the same Reaction Motors CML2N type as in the Gorgon IIA) was of conventional layout, and was intended as an air-to-air missile for long range patrol aircraft. It was equipped with TV/radio-command guidance, a homing device (of unspecified type), a radio proximity fuze, and a 116 kg (257 lb) fragmentation warhead. Introduced in 1945, it was downgraded to control test vehicle status in mid-1946 (designated KU3N-1), and was used to test various guided missile components. A total of 34 Gorgon IIIAs were built, and the final two designations of this missile were CTV-6 and CTV-N-6.
|Photo: Smithsonian Institution|
Although originally planned to be pulsejet-powered, the Gorgon IIIC emerged as very similar to the Gorgon IIIA. The primary difference was the use of two CML2N liquid-fueled rocket engines instead of only one as in the IIIA. The missile was successively designated KA3N-2, KU3N-2, RTV-4 and RTV-N-4. 12 Gorgon IIICs were built, and were used by NACA for high-speed (high subsonic regime) research and by the U.S. Navy for performance and stability tests.
|Photo: via Ordway/Wakeford|
Although the Gorgon IIIB tactical missile was cancelled very early during the Gorgon program, a derivative was tested as the TD2N-1 (later KDN-1) air-launched target drone. It was a vehicle very similar in layout to the Gorgon IIIA/IIIC, but powered by a Westinghouse 9.5 in. turbojet. Drop tests began in June 1945, and the first successful powered flight occurred in August 1945. Because of difficulties with the engine, the TD2N/KDN program was cancelled in March 1946 after only nine drones had been delivered.
In May 1945, the U.S. Navy began the Gorgon IV program. This missile, contracted to Martin, was originally planned to be a ramjet-powered air-to-surface missile with an active radar seeker. It was relegated to propulsion test vehicle status in 1946, and successively designated KUM-1, PTV-2 and PTV-N-2. It had slightly swept wings and an underslung Marquardt XRJ30-MA (model C-20-85C) ramjet. Free flight tests of KUM-1/PTV-2 vehicles began in July 1947, and the first successful high-speed flight occurred in November that year. The Gorgon IV's ramjet was designed for a maximum speed of Mach 0.85. The PTV-N-2 flight test program was terminated in December 1949, and the few remaining Gorgon IV vehicles were used up as KDM-1 Plover target drones. A total of 19 PTV-N-2/KDM-1 missiles were built.
|Photo: Smithsonian Institution|
The last of the Gorgon series was the Martin ASM-N-5 Gorgon V, begun around 1950 as an unpowered air-to-ground chemical warfare derivative of the PTV-N-2 Gorgon IV. The latter's ramjet was to be replaced by an Edo X14A aerosol generator, and the missile was to be equipped with an autopilot and a radio altimeter. The Gorgon V was to be dropped from about 10700 m (35000 ft), diving at a shallow angle at a speed of Mach 0.95 to an altitude of 30-150 m (100-500 ft), where a spray run of 9-20 km (5-11 nm) range would begin, covering a 9 km (5 nm) wide area. However, the ASM-N-5 was cancelled in 1953, and it is not clear whether any XASM-N-5 vehicles were actually built and flown.
The following table summarizes the various designations of the Gorgon family vehicles:
|1945||October 1945||March 1946||ca. May 1946||September 1947||ca. February 1948 and later|
|Gorgon||Similar to Gorgon IIIB||TD2N-1||KDN-1|
|Gorgon||Derivative of Gorgon IIC||TD3N-1||KD2N-1|
|Gorgon IIA||Canard layout; single rocket||(none)||KA2N-1||KU2N-1||CTV-4||CTV-N-4|
|Gorgon IIC||Canard layout; single pulsejet||KGN-1||KUN-1||CTV-2||CTV-N-2|
|Gorgon IIIA||Conventional layout; single rocket||KA3N-1||KU3N-1||CTV-6||CTV-N-6|
|Gorgon IIIC||Conventional layout; twin rockets||KA3N-2||KU3N-2||RTV-4||RTV-N-4|
|Gorgon IV||Single ramjet||(none)||KUM-1||PTV-2||PTV-N-2|
|Gorgon V||Derivative of Gorgon IV||(n/a)||ASM-N-5|
|Plover||Drone variant of Gorgon IV||(n/a)||KDM-1|
|Pollux||Similar to Gorgon IIC||(n/a)||RTV-N-15|
Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!
Data for CTV-N-2, CTV-N-4, CTV-N-6, PTV-N-2, ASM-N-5:
|Length||5.98 m (19 ft 7 in)||4.42 m (14 ft 6 in)||4.93 m (16 ft 2 in)||6.60 m (21 ft 8 in)||8.79 m (28 ft 10 in)|
|Wingspan||3.50 m (11 ft 6 in)||3.35 m (11 ft)||3.05 m (10 ft)|
|Weight||880 kg (1950 lb)||440 kg (970 lb)||580 kg (1280 lb)||725 kg (1600 lb)||1180 kg (2600 lb)|
|Speed||725 km/h (450 mph)||800 km/h (500 mph)||845 km/h (525 mph)||Mach 0.7||Mach 0.95|
|Ceiling||?||10700 m (35000 ft)|
|Range||150 km (80 nm)||40 km (25 miles)||19 km (12 miles)||110 km (70 miles)||55 km (30 nm)|
|Propulsion||14" pulsejet; 1.5 kN (330 lb)||Reaction Motors CML2N liquid-fueled rocket;
1.55 kN (350 lb) for 130 s
|Marquardt XRJ30-MA ramjet||none|
 Norman Friedman: "US Naval Weapons", Conway Maritime Press, 1983
 Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960
 Bill Gunston: "The Illustrated Encyclopedia of Rockets and Missiles", Salamander Books Ltd, 1979
 US Navy: "Model Designations of Naval Aircraft", 1947 and 1950
 National Air and Space Museum Website
 "Navy Flies First Ram-Jet Pilotless Aircraft", article in Naval Aviation News, January 1948
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