Raytheon AIM-7 Sparrow

From Scramble - The Aviation Magazine

The AIM-7 Sparrow has been the major medium range air-to-air missile of U.S. fighters until the introduction of the AIM-120 AMRAAM (Advanced Medium Range Air-to-Air Missile), and the RIM-7 Sea Sparrow is still a very important short-range air-defense weapon on U.S. and NATO warships.

History

The history of the Sparrow missile dates back to 1947, when a U.S. Navy contract was awarded to the Sperry company to develop a beam-riding guidance (radar guidance) system for a standard 12.7 cm (5 in) HVAR (High Velocity Aerial Rocket) as Project Hotshot. The original designation for this missile project was KAS-1, but this was changed to AAM-2 in September 1947 and to AAM-N-2 in early 1948. The 5" diameter soon proved to be too small, so the Douglas company developed a new airframe of 20.3 cm (8 in) diameter. Development proved to be difficult and the first successful air-to-air interception was only done in December 1952. The AAM-N-2 Sparrow I entered service in . Because of the inherent disadvantages of beam-riding guidance, like poor low-level performance, only 2,000 Sparrow I missiles were produced, and it was withdrawn from service after only a few years. Another drawback of the AAM-N-2 was that the guidance beam was slaved to an optical sight in the aircraft, which necessitated visual identification of the target, making the Sparrow I a short-range VFR missile only.

Because of the above noted principal problems of the AAM-N-2, new guidance methods were searched almost from the beginning. As early as 1950, Douglas studied the possibility of equipping the Sparrow with a radar-homing seeker. The designation XAAM-N-2a was assigned to the project, together with the name Sparrow II (at the same time, the original beam-riding Sparrow became Sparrow I). At some time in 1951/52, this designation was changed to AAM-N-3. Operational evaluation models, designated YAAM-N-3, were flown, but in 1956 the U.S. Navy withdrew from the development of the AAM-N-3 Sparrow II missile. The Sparrow II was also planned as a weapon for the forthcoming Canadian CF-105 Arrow interceptor, but in September 1958, the missile was finally cancelled.

Development of the modern Sparrow began in 1955 by Raytheon, the new missile being designated XAAM-N-6. The AAM-N-6 Sparrow III and all subsequent versions of Sparrow used semi-active radar homing.

In 1963, all Sparrow missiles were redesigated in the AIM-7 series, as follows:

Old designation	New designation
AAM-N-2	AIM-7A
AAM-N-3	AIM-7B
AAM-N-6	AIM-7C
AAM-N-6a AIM-101	AIM-7D
AAM-N-6b	AIM-7E
XAAM-N-9	nuclear Sparrow, cancelled

The first combat kill was scored on 7 June 1965, when USN F-4B Phantoms shot down 2 MiG-17s. Despite all problems with guidance and maneuverability, more than 50 aircraft were shot down by Sparrow missiles during the Vietnam air war.

Variants

Air-launched variants

AIM-7A

Initially designated AAM-N-2 Sparrow I, entered service in 1956 with F3H-2M Demon and F7U-3M Cutlass fighters. Because of the inherent disadvantages of beam-riding guidance, like poor low-level performance, only 2,000 Sparrow I missiles were produced, and it was withdrawn from service after only a few years. Another drawback of the AAM-N-2 was that the guidance beam was slaved to an optical sight in the aircraft, which necessitated visual identification of the target, making the Sparrow I a short-range VFR missile only.

AIM-7B

Initially designated XAAM-N-3, intended as armament for the Douglas F5D Skylancer interceptor. Operational evaluation models, designated YAAM-N-3, were flown, but in 1956 the US Navy withdrew from the development of the AAM-N-3 missile. The Sparrow II was also planned as a weapon for the forthcoming Canadian Canadair CF-105 Arrow interceptor, but in September 1958, the missile was finally cancelled.

AIM-7C

Development of the modern Sparrow began in 1955 by Raytheon, the new missile being designated XAAM-N-6 Sparrow III. The AAM-N-6 and all subsequent versions of Sparrow used semi-active radar homing. Entered service in August 1958.

AIM-7D

Initially designated AAM-N-6a, produced from 1959. It had a new Thiokol Mk.6 MOD 3 (LR44-RM-2) storable liquid-propellant rocket motor, which increased effective range and ceiling. It also had an improved guidance system for higher closing-rates and anti-jammer capability.This version had a new storable liquid-propellant rocket motor, which increased effective range and ceiling. It also had an improved guidance system for higher closing-rates and anti-jammer capability. Entered service with the F-4B and F-4C Phantom II.

AIM-7E

In 1963, production switched to the AIM-7E version. It used a new propulsion system, a solid-fueled rocket, which significantly increased range and performance of the missile.

AIM-7E-2

The improved AIM-7E-2 was introduced in 1969 as a "dogfight missile". It had a shorter minimum range, clipped wings for higher manoeuvrability, and improved autopilot and fuzing.

AIM7-E-3

The AIM-7E-3 had further improved fuzing and higher reliability.

AIM-7E-4

The AIM-7E-4 was specially adapted for use with high-power fighter radars (like the F-14's AN/AWG-9).

AIM-7F

Developed from January 1972. New dual-thrust (boost/sustain) rocket motor, which greatly increased the missile's range. The AIM-7F also had a completely new solid-state electronic guidance and control system (GCS), which was also compatible with modern pulse-doppler radars. Continued improvement of the GCS resulted in versions from AN/DSQ-35A through -35H (used in the AIM-7F-11). With the AIM-7F, the official name of the missile was changed from Sparrow III to plain Sparrow.

AIM-7G

The AIM-7G was a version with a new seeker, developed for the USAF around 1970 for use by the F-111D aircraft. A few YAIM-7G prototype missiles were built, but this version did not enter production.

AIM-7M

This version had the new inverse monopulse seeker for look-down/shoot-down capability in a new WGU-6/B (later WGU-23/B) guidance section. The monopulse seeker improves missile performance in low-altitude and ECM environments. Other new features of the AIM-7M are a digital computer (with software in EEPROM modules reprogrammable on the ground), an autopilot, and an active fuze. The autopilot enables the AIM-7M to fly optimized trajectories, with target illumination necessary only for mid-course and terminal guidance. The AIM-7M entered production in 1982. The latest software version of the AIM-7M are the AIM-7M-F1 Build and the AIM-7M-H Build, which has been produced since 1987 and incorporates additional improvements in guidance.

AIM-7N

The designation AIM-7N was allocated to an upgraded version of the AIM-7F for use with the USAF's F-15 MSIP (Multistage Improvement Program). This version was not produced in quantity.

AIM-7P

The AIM-7P is an improved AIM-7M, and AIM-7P missiles are built since 1987 by new production as well as conversion of existing AIM-7Ms. The AIM-7P features improved guidance electronics and on-board computer, has a new radar fuze, and has an uplink to the autopilot for mid-course guidance updates. The AIM-7P improves Sparrow performance especially against small and/or low-flying targets. There are two subvariants of the AIM-7P, known as AIM-7P Block I and AIM-7P Block II. The AIM-7P Block I has a WGU-6D/B guidance section, and the Block II uses a WGU-23D/B guidance section and also features a new rear receiver.

AIM-7Q

Unconfirmed designation for dual mode (IR/active radar) terminal homing, in addition to a wide-band passive radar seeker which allowed it to home on any emission from the target. Apparently not built.

AIM-7R

The AIM-7R was projected in the early 1990s as an improved AIM-7P Block II. A new dual mode (Radar/IR) seeker was developed to improve the terminal phase performance. An equivalent ship-launched version was projected as RIM-7R. Although it was initially planned to upgrade many AIM/RIM-7M/P rounds to AIM/RIM-7R standard, the -7R program was cancelled because of high costs in December 1996 after the evaluation phase was completed.

Surface-launched variants

RIM-7 Sea Sparrow

RIM-7E Sea Sparrow

Sea Sparrow. A short-range missile defense system for ships. Essentially an unchanged AIM-7E system, it entered service in 1967.

RIM-7F=

The RIM-7F Sea Sparrow was the ship-launched equivalent of the AIM-7F. Therefore it was actually more advanced than the RIM-7H described below. The RIM-7F was relatively short-lived because further development was cancelled in favor of a ship-launched derivative of the AIM-7M, the RIM-7M.

RIM-7H

The RIM-7H was an improved RIM-7E missile better adapted for shipboard use. Above all, it had folding fins to fit into more compact MK 29 launchers. Otherwise it was essentially similar to the AIM/RIM-7E and therefore less advanced than the RIM-7F despite its "later" designation suffix. The RIM-7H is the missile used in the NATO Sea Sparrow Missile System (NSSMS) Block I, and production began in 1973.

RIM-7M Sea Sparrow launched from HNLMS Philips van Almonde

RIM-7M

The RIM-7M Sea Sparrow is the ship-launched equivalent of the AIM-7M, latest variants are the RIM-7M F1 Build and RIM-7M H Build.

RIM-7P

Ship-launched version of the AIM-7, delivered as RIM-7P Block I, and RIM-7P Block II.

RIM-7R

See above.

RIM-7T

Designation for the ESSM (Evolved Sea Sparrow Missile), intended as RIM-7M/P replacement. Unofficially referred to as RIM-7PTC (RIM-7P with Tail Control). Redesignated RIM-162.

RIM-162

The Raytheon RIM-162 Evolved Sea Sparrow Missile (ESSM) is a development of the RIM-7 Sea Sparrow missile used to protect ships from attacking missiles, aircraft and surface threats. ESSM is designed to counter supersonic manoeuvring anti-ship missiles. Compared to the Sea Sparrow, ESSM has a larger, more powerful rocket motor with TVC for increased range and agility, as well as upgraded aerodynamics using strakes and skid-to-turn. In addition, ESSM takes advantage of the latest missile guidance technology, with different versions for Aegis/SPY-1, APAR, and traditional target illumination all-the-way. ESSM also has the ability to be "quad-packed" in the Mk41 VLS system, allowing up to four ESSMs to be carried in a single cell. Many countries are using or plan to use the ESSM. The first countries to achieve operational status for ESSM were the United States and Australia. Canada, Germany, Turkey, Greece, Japan, Denmark, the Netherlands, Norway, New Zealand, Spain, and the United Arab Emirates have also integrated or are in the process of integrating the ESSM.

RIM-162A

Mk41 VLS-launched, with enhanced electronics for use with AN/SPY-1 Aegis radars

RIM-162B

Same as RIM-162A but for ships without Aegis (S-band electronics deleted).

RIM-162C

Mk48 VLS-launched.

RIM-162D

Same as RIM-162C but for 2x4 box-type (Mk29) launchers, such as fitted to US Navy CVN-69 Nimitz class carriers.

License built versions, related designs

There have been a few licenses granted to build the AIM-7 Sparrow abroad.

Selenia Aspide, built by Italian company Alenia Difesa, based on the AIM-7E.
Skyflash, built by British Aerospace (BAe), based on the AIM-7E-2. Skyflash used a Marconi XJ521 monopulse Semi-Active seeker together with improvements to the electronics. It was powered by the Aerojet Mk52 mod 2 rocket engine (later by the Rocketdyne Mk38 mod 4). Skyflash entered service with the Royal Air Force on their Phantom FG.1/FGR.2 in 1976, and later on the Tornado F3. The Skyflash was also exported to Sweden for use on their Saab AB J37 Viggen fighters.
PL-11, Chinese built version, licensed from the Aspide Mk1. The missile resembles the AIM-7 closely, but is based on indigenous technology. It basically is a Chinese missile with copied seeker and radar technology. It was built in limited numbers, mainly for test purposes.
AGM-45, Shrike series weapon system is a passive air-to-ground missile whose mission is to home on and destroy or suppress radiating radar transmitters, directing both ground antiaircraft fire and surface-to-air missiles.

Future development

Raytheon is still producing AIM/RIM-7Ps by upgrading existing Sparrow missiles to -7P standard. Although the AIM-7 is being replaced by the AIM-120 AMRAAM, the Sparrow missile system will probably remain in service for some time, because it is significantly cheaper than the AMRAAM.

Production

Until 2001 more than 62,000 AIM-7 Sparrow and 9,000 RIM-7 Sea Sparrow missiles of all versions have been built.

Aircraft platforms

Sources