SSM-N-9 Regulus II

SSM-N-9 Regulus II
USS Grayback (SSG-574) preparing to launch a Regulus II missile
Type	Cruise missile
Production history
Manufacturer	Chance Vought
Produced	1956
Specifications
Weight	23,000 pounds (10,000 kg)[1]
Length	57 feet 6 inches (17.53 m)[1]
Diameter	50 inches (1.3 m)[1]
Warhead	W27 warhead[1]
Detonation mechanism	air burst or surface burst (air burst – fireball does not reach the ground, usually at least 10,000 ft, surface burst – fireball touches the ground, less than 10,000 feet altitude)
Engine	1x General Electric J79-GE-3 turbojet 1x Rocketdyne solid-fuelled rocket[1] 15,600 lbf (69 kN) + 135,000 lbf (600 kN)[1]
Wingspan	20 feet 1 inch (6.12 m)[1]
Operational range	1,000 nautical miles (1,852 km)[1]
Flight ceiling	59,000 feet (18,000 m)[1]
Speed	M 2.0[1]
Guidance system	Inertial[1]
Launch platform	SSG and SSGN class submarines, cruisers

The SSM-N-9 Regulus II cruise missile was designed as a supersonic cruise missile armed with a nuclear warhead, for launch from surface ships and submarines of the United States Navy (USN).^[2]

History

The limitations of the Regulus I were well known by the time it entered service in 1955, so the USN issued a specification for a surface-launched supersonic ship-borne cruise missile, armed with a nuclear warhead, possessing greater range, accuracy and resistance to counter-measures.

Development of the Regulus II was well under way when the programme was cancelled in favour of the UGM-27 Polaris SLBM (Submarine-Launched Ballistic Missile) system, which gave unprecedented accuaracy as well as allowing the launch submarine to stay submerged and covert. Prototype and initial production missiles were later converted to Vought KD2U-1 supersonic target drones for the U.S. Navy and the U.S. Air Force, which used the KD2U-1 during tests of the Boeing IM-99/CIM-10 Bomarc SAM (Surface to Air Missile).^[2]

Interestingly the SSM-N-9a Regulus II was re-designated as the RGM-15A in June 1963, nearly five years after the missile programme had been terminated. At the same time the KD2U-1 target drones were re-designated as the Vought MQM-15A. Some landing-gear equipped targets were re-designated as Vought GQM-15As.^[1]

Design and development

The major drawback of the original Regulus was the use of radio-command guidance, which required a constant radio link with the launch ship / boat that was relatively easy to interfere with. The earlier missile also suffered from restricted range which required the launch ship to launch the missile close to the target and remain exposed until the missile hit the target. To alleviate these drawbacks the Regulus II was designed with an inertial navigation system, which required no further input from the launch ship / boat after launch, and a greater range through improved aerodynamics, larger fuel capacity and a lower specific fuel consumption from the powerplant.^[2]

Prototype missiles were built, designated XRSSM-N-9 Regulus II, with retractable landing gear, to allow multiple launches and Wright J65-W-6 engines and Aerojet General booster, which restricted them to sub-sonic flight, first flight of the XRSSM-N-9 took place in May 1956. from 1958 testing was carried out with the XRSSM-N-9a, equipped with the definitive General Electric J79-GE-3 and Rocketdyne booster allowing the full flight envelope to be explored. Evaluation and training missiles with retractable undercarriage were produced as the YTSSM-N-9a and TSSM-N-9a respectively.^[1]

After land-based testing, trials including missile firings were carried out on board USS King County (LST-857), which had been modified with a replica submarine missile hangar and launch system, after which it was re-designated as USS King County (AG-157)^[2]

The SSM-N-9 Regulus II missile was intended to be launched from the deck of SSG (Guided Missile Submarine), and would most likely have been operationally deployed on USS Grayback (SSG-574) and USS Halibut (SSGN-587), as well as four cruisers and 23 other submarines. Carrying up to five Regulus II missiles in a hangar integral with the hull, Regulus II equipped boats and ships would have been fitted out with the Ships Inertial Navigation System (SINS), allowing the missiles to be aligned accurately before take-off.^[2]

The launcher for the supersonic Regulus II cruise missile being installed aboard USS King County (AG-157), a World War II–era LST converted to an experimental guided-missile test ship, 5 April 1957. Secretary of the Navy Gates cancelled the project. At the time of cancellation Vought had completed twenty missiles with 27 more on the production line.^[2]

Description

The airframe followed contemporary aircraft construction techniques, with weight savings from the use of advanced materials and the short airborne life of the missile. The fuselage was essentially tubular, tapering to a point at the nose, housing the guidance equipment, warhead and systems equipment. And engine, which was fed with air through a distinctive wedge shaped intake under the centre fuselage. The swept wings attached to the fuselage at the mid position roughly halfway along the length and a large swept fin attached to the top of the fuselage at the rear which was sometimes augmented by a large ventral fin at the extreme rear of the fuselage.

Primary control of the Regulus II was through the use of elevons fitted to thje outer half of the wing trailing-edges, as the missile was not fitted with a tailplane, and a rudder fitted to the trailing edge of the fin. Flaps were fitted to the inner half of the trailing edge for use during take-off. Additional stability and contol in pitch was provided by small trapezoidal canard foreplanes near the nose of the fuselage.

To launch the missile, the carrier vessel had to surface and deploy the missile and launch apparatus, which consisted of a zero length launcher. Once deployed, the missile had to be linked to the submarine or ships navigation system to align the inertial navigation system and input target co-ordinates. With the navigation system ready and launch authorisation given, the missile engine would be run-up to full power with afterburner and the large solid-fuelled rocket booster ignited, immediately the missile would leave the zero length launcher and continue to the target autonomously.

Regulus Target Drones

Suitable missiles from the development programme and production line were converted to supersonic target drones as the KD2U-1, later re-designated as the MQM-15A and GQM-15A. These targets were used for training of IM-99 Bomarc missile crews firing from Santa Rosa Island and controlled by the Montgomery Air Defense Sector, at Gunter Air Force Base, in Alabama. The KD2U-1 targets were launched from the Eglin Gulf Test Range base near Venice, Florida. Drone flights at Eglin commenced on 3 September 1959 making 46 flights with 13 missiles. After the Bomarc tests the remaining missiles were moved to Roosevelt Roads Naval Station, in Puerto Rico by 30 September 1961, where flights commenced testing Tartar, Terrier and Talos missiles. On completion of the Puerto Rico testing in 1963 the Regulus IIs were moved to Point Mugu, California where they remained in use until December 1965.^[2]

Surviving Regulus II missiles

Frontiers of Flight Museum, Dallas Love Field, Texas

A Regulus II missile

Point Mugu Missile Park, Naval Air Station Point Mugu, California

The museum's collection includes both a Regulus and a Regulus II missile

Veterans Memorial Museum, Huntsville, Alabama

A Regulus II missile

Variants

SSM-N-9 Regulus II

The basic designation of the missile, pre 1964.

SSM-N-9a Regulus II

The designation of production missiles, pre 1964.

XRSSM-N-9 Regulus II

Prototype missiles fitted with retractable landing gear for land based development flights, powered by Wright J65 turbojet engines and Aerojet General booster rockets.

XRSSM-N-9a

Prototype missiles fitted with retractable landing gear for land based development flights, powered by General Electric J79 turbojet engines and Rocketdyne booster rockets.

YTSSM-N-9a

Development Training missiles with retractable landing gear.

TSSM-N-9a

Production training missiles with retractable landing gear.

RQM-15A

Regulus II missiles re-designated in April 1963.

MQM-15A

KD2U-1 Target drones used for research and as targets for the IM-99 Bomarc SAM.

GQM-15A

Gear equipped KD2U-1 target drones re-designated.

Operators

• United States Navy
• United States Air Force

See also

• List of missiles
• SSBN Deterrent Patrol insignia

References

1. ^ ^{a b c d e f g h i j k l m} http://www.designation-systems.net/dusrm/m-15.html
2. ^ ^{a b c d e f g h} http://www.angelfire.com/realm3/roynagl/regulus.htm

External links

• Carolinas Aviation Museum
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