|Directory of U.S. Military Rockets and Missiles|
|Copyright © 2002-2007 Andreas Parsch|
The AIM-7 Sparrow has been the major medium range air-to-air missile of U.S. fighters until the advent 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.
The history of the Sparrow missile dates back to 1947, when the U.S. Navy contracted Sperry to develop a beam-riding guidance system for a standard 12.7 cm (5 in) HVAR (High Velocity Aerial Rocket). 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 Douglas developed a new airframe of 20.3 cm (8 in) diameter. The first unpowered flight tests of XAAM-N-2 prototypes occurred in 1948. Development was difficult, however, and the first successful air-to-air interception was only done in December 1952. The 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of beam-riding guidance, like poor low-level performance, only 2000 Sparrow I missiles were produced, and it was withdrawn from service after only a few years.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.
The RAAM-N-2a and RAAM-N-2b were research and development missiles with an SPR guidance system of conventional (-2a) and modular (-2b) construction, respectively. The designation XAAM-N-2b was reserved for prototypes of a proposed operational version of the RAAM-N-2b, but this variant was not developed.
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 XAAM-N-3. By 1955, Douglas had reached the point of proposing active radar homing for the Sparrow II, using an AN/APQ-64 radar. The operational AAM-N-3 was originally intended as armament for the Douglas F5D Skylancer interceptor. 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 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. The designation XAAM-N-3a had been reserved for a proposed supersonic-launch model of the Sparrow II, but this was not built.
|Photo: © Bill Spidle|
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. After production of the AAM-N-2 Sparrow I had been completed in 1956, Raytheon took over the missile production facilities, and has since been prime contractor for the whole Sparrow program. After tests with YAAM-N-6 R&D missiles, production of the tactical AAM-N-6 began in January 1958, and it entered service in August 1958. The missile had an Aerojet solid-fueled rocket motor, and a 30 kg (65 lb) MK 38 continuous-rod warhead. About 2000 AAM-N-6 missiles were built. The TAAM-N-6, developed via XTAAM-N-6 prototypes, was an inert training version of the AAM-N-6.
The next version was the AAM-N-6a, developed via XAAM-N-6a and YAAM-N-6a prototype and test models, and 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. There were also XTAAM-N-6a and TAAM-N-6a inert training versions of the AAM-N-6a.
The USAF adopted the AAM-N-6a for its new F-110A Spectre (F-4C Phantom II after 1962) interceptor, and assigned the designation AIM-101.
The AAM-N-6b was a further improved version, which entered service in 1963. It is described below under its post-1963 designation of AIM-7E.
The designation XAAM-N-9 Sparrow X was allocated to a proposed nuclear-armed Sparrow derivative in 1958 with a low-yield W-42 fission warhead. However, this proposal was short-lived and the Sparrow X was cancelled early in the design stage.
In 1963, all Sparrow missiles were redesigated in the AIM-7 series, as follows:
|Old Designation||New Designation|
AIM-7B was a "paper designation" only, because the Sparrow II had long been cancelled in 1963. Inert training versions of the AIM-7D were later designated ATM-7D.
In 1963, production switched to the AIM-7E version. It used a new propulsion system, a solid-fueled rocket by Rocketdyne (either a MK 38 or later a MK 52). The new motor again significantly increased range and performance of the missile. Effective range of course depended greatly on firing parameters like launch speed and relative velocity of the target. In head-on attacks under optimal conditions, it could be as high as 35 km (20 nm), while in stern attacks, maximum effective range was more around 5.5 km (3 nm).
Inert training versions of the AIM-7E include the ATM-7E for firing practice, the captive (non-launching) CATM-7E, and the non-flying DATM-7E for handling and loading practice. There is also a captive-carry version designated CAEM-7E, which is equipped with special telemetry electronics.
About 7500 AIM-7D and 25000 AIM-7E missiles were built, and the Sparrow was used heavily in Vietnam by the USAF and the U.S. Navy. The first combat kill was scored on 7 June 1965, when USN F-4B Phantoms shot down 2 MiG-17s. However, the initial combat results were very disappointing. The potentially long range of the AIM-7 could not be used, because unreliable IFF capabilities of the time effectively required visual identification of all targets. Coupled with the high minimum range of the missile of 1500 m (5000 ft) and poor performance against manoeuvering and/or low-flying targets, this led to a kill probability of less than 10%. Therefore, the improved AIM-7E-2 was introduced in 1969 as a "dogfight missile". It had a shorter minimum range, clipped wings for higher manoeuverability, and improved autopilot and fuzing. The AIM-7E-3 had further improved fuzing and higher reliability, and the AIM-7E-4 was specially adapted for use with high-power fighter radars (like the F-14's AN/AWG-9). Despite all problems, more than 50 aircraft were shot down by Sparrow missiles during the Vietnam air war.
In the early 1960s, the U.S. Navy planned to provide a short-range missile defense system (called BPDMS - Basic Point Defense Missile System) for ships much smaller than then current missile defense ships. Initially the RIM-46 Sea Mauler missile was to be used for the BPDMS, but when this was cancelled in 1964, attention turned towards a derivative of the AIM-7E Sparrow. This missile was known as RIM-7E Sea Sparrow. The missile was essentially an unchanged AIM-7E, and was fired from modified ASROC launchers designated MK 25. The RIM-7E entered service in 1967.
In January 1972, Raytheon began development of the vastly improved AIM-7F. It featured a new dual-thrust (boost/sustain) rocket motor (usually a Hercules MK 58, but sometimes an Aerojet MK 65), which greatly increased the missile's range. The AIM-7F also had a completely new solid-state electronic guidance and control system (GCS), designated AN/DSQ-35, 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). The smaller GCS permitted the use of a larger 39 kg (86 lb) MK 71 warhead in the new WAU-10/B warhead section. Production began in 1975, and continued through 1981. With the AIM-7F, the official name of the missile was changed from Sparrow III to plain Sparrow.
The various training versions of the AIM-7F are designated ATM-7F, CATM-7F, DATM-7F, and CAEM-7F for the same purposes as the equivalent -7E versions. The CATM/DATM-7F missiles are also suitable for training for the later AIM-7M/P versions.
|Photo: Phil Callihan|
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. It is possible that the RIM-101A missile proposed in 1974 was also an advanced RIM-7E/H Sea Sparrow derivative, which was cancelled in favor of further RIM-7 development. 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 (q.v.).
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.
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 (these folding fins were also used on the subsequent RIM-7F/M/P/R versions). 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.
The next version of the AIM-7 was the AIM-7M, whose main new feature was the new inverse monopulse seeker for look-down/shoot-down capability in a new WGU-6/B (later WGU-23/B) guidance section. There is no evidence of any Sparrow variants officially designated -7J/K/L (although the designation AIM-7J is sometimes associated with the AIM-7E license-built in Japan). Source  says that the suffix "M" was deliberately chosen to mean "monopulse", suggesting that suffixes J/K/L were indeed skipped. 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 also has a new WDU-27/B blast-fragmentation warhead in a WAU-17/B warhead section. The first firing of a YAIM-7M occured in 1980, and the AIM-7M entered production in 1982.
|Photo: U.S. Navy|
|AIM-7M/P (exact model unknown)|
The various training versions of the AIM-7M are designated ATM-7M, CATM-7M, DATM-7M, and CAEM-7M for the same purposes as the equivalent -7E versions. The CATM/DATM-7M missiles are also used for training for the later AIM-7P.
The RIM-7M Sea Sparrow is the ship-launched equivalent of the AIM-7M, and its training version is designated RTM-7M. In addition to the 8-cell MK 29 box launcher, the RIM-7M (and the later RIM-7P) missiles can also be fired from MK 41 (AEGIS) and MK 48 VLS (Vertical Launch System) launchers.
|Photo: U.S. Navy|
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.
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 Block I and 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. The combat record of recent Sparrow missiles (AIM-7M/P) is much better than that of the AIM-7D/E of the Vietnam era. In Operation Desert Storm, 26 Iraqi aircraft were shot down with AIM-7 missiles, with 71 AIM-7s fired (a hit rate of 37%).
There is also a ATM-7P training version for the AIM-7P, but there are apparently no specialized CATM/DATM/CAEM-7P versions. For non-firing training (CATM/DATM), the equivalent -7F/M versions are used. The RIM-7P Sea Sparrow is the ship-launched equivalent of the AIM-7P, and its training version is designated RTM-7P.
The AIM-7Q was reportedly a significantly advanced Sparrow proposal. However, no official data on it is available and the following should therefore regarded as unconfirmed. The AIM-7Q was to have 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. The latter feature allowed it to search "silently" for the target after it had been fired by the launching aircraft into the general direction and range of the target. If no emissions were detected, the AIM-7Q would briefly switch on its own radar seeker and search for a target. If one was found, another short active radar sweep would be done a few seconds later to get speed and heading information. The missile would then fly into the computed "kill zone" where it would home for the target using the IR and active radar guidance. Unfortunately, no further information on the time line and final status (e.g. if any prototypes were actually built and test-flown) of the AIM-7Q development effort is available.
The final Sparrow variant was the 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 under the MHIP (Missile Homing Improvement Program) to improve the terminal phase performance. It also had a considerably improved on-board computer for the higher processing requirements of active terminal homing. 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. The MHIP seeker was also used in the RIM-66M-5 SM-2 Block III B missile.
Raytheon is still producing AIM/RIM-7Ps by upgrading existing Sparrow missiles to -7P standard. Although the AIM-7 has been replaced in U.S. service by the AIM-120 AMRAAM, Sparrow will probably remain in service with other nations for some time, because it is significantly cheaper than AMRAAM. The replacement for the RIM-7M/P Sea Sparrow is the ESSM (Evolved Sea Sparrow Missile). This was unofficially referred to as RIM-7PTC (RIM-7P with Tail Control) or RIM-7T, but is now known as RIM-162. Until 2001 more than 62000 AIM-7 Sparrow and 9000 RIM-7 Sea Sparrow missiles of all versions have been built.
Notes: Data given by several sources show slight variations. Figures given below may therefore be inaccurate! The AIM-7's range depends heavily on firing parameters and aircraft radar, and the numbers given below are only rough estimates for maximum effective range in head-on engagements.
Data for AIM-7A/B/C/E/F/M/P and RIM-7M/P:
|AAM-N-2 (AIM-7A)||AAM-N-3 (AIM-7B)||AIM-7C||AIM-7E||AIM-7F||AIM-7M/P||RIM-7M/P|
|Length||3.74 m (147.3 in)||3.85 m (151.7 in)||3.66 m (144 in)|
|Wingspan||0.94 m (37 in)||1.02 m (40 in)|
|Finspan||0.88 m (34.8 in)||?||0.81 m (32 in)||0.62 m (24.3 in)|
|Diameter||0.203 m (8 in)|
|Weight||143 kg (315 lb)||176 kg (389 lb)||172 kg (380 lb)||197 kg (435 lb)||231 kg (510 lb)|
|Speed||Mach 2.5||Mach 4|
|Range||10 km (5.4 nm)||7 km (4 nm)||11 km (6 nm)||30 km (16 nm)||70 km (38 nm)||26 km (14 nm)|
|Propulsion||Aerojet 1.8KS7800 solid rocket||Rocketdyne MK 38/MK 52
|Hercules MK 58 dual-thrust solid rocket|
|Warhead||20 kg (45 lb)||30 kg (65 lb) MK 38 continuous rod||39 kg (86 lb) MK 71
|40 kg (88 lb) WDU-27/B|
 Norman Friedman: "US Naval Weapons", Conway Maritime Press, 1983
 Norman Friedman: "World Naval Weapons Systems, 1997/98", Naval Institute Press, 1997
 Bill Gunston: "The Illustrated Encyclopedia of Rockets and Missiles", Salamander Books Ltd, 1979
 Hajime Ozu: "Missile 2000 - Reference Guide to World Missile Systems", Shinkigensha, 2000
 Christopher Chant: "World Encyclopaedia of Modern Air Weapons", Patrick Stephens Ltd., 1988
 BuAer Instruction 05030.4A: "Model Designation of Naval Aircraft, KD Targets, and BuAer Guided Missiles", Dept. of the Navy, 1958
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