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47-443: The early Sparrow was intended primarily for use against larger targets, especially bombers, and had numerous operational limitations in other uses. Against smaller targets, the need to receive a strong reflected radar signal made it difficult to achieve lock-on at the missile's effective range. As the launching aircraft's own radar needed to be pointed at the target throughout the engagement, this meant that in fighter-vs-fighter combat

94-456: A 51-aircraft production order to follow. Production aircraft were to be powered by the more powerful J57-P-14 engine, while there was a rejected proposal to use the even more powerful General Electric J79 and variable-geometry inlets in a Mach 2 version. The first flight was made by F5D-1 (Bu. No. 139208) on 21 April 1956 and was supersonic; the aircraft proved easy to handle and performed well. After four aircraft had been constructed, however,

141-412: A dedicated illuminator radar for this purpose. In older radar systems, through the 1980s, lock-on was normally assisted by a change in the radar signal characteristics , often by increasing the pulse repetition frequency . This led to the introduction of radar warning receivers that would notice this change and provide a warning to the operator. Modern radar systems do not have a lock-on system in

188-563: A late-1940s United States Navy program to develop a guided rocket weapon for air-to-air use. In 1947 the Navy contracted Sperry to build a beam-riding version of a standard 5-inch (127 mm) HVAR , the standard unguided aerial rocket, under Project Hotshot . The weapon was initially dubbed KAS-1 , then AAM-2 , and — from 1948 on — AAM-N-2 . The airframe was developed by the Douglas Aircraft Company . The diameter of

235-668: A new and more powerful engine and new control surfaces. These control surfaces were each independent of the others, giving the missile greatly improved maneuverability over the AIM-7E and the English Skyflash that still used dependent control surfaces. The PL-11 and HQ-6 are a family of Chinese missiles developed by the Shanghai Academy of Science and Technology, largely based on the Italian Aspide version of

282-482: A new rear receiver allowing the missile to receive mid-course correction from the launching aircraft. Plans initially called for all M versions to be upgraded, but currently P's are being issued as required to replace M's lost or removed from the inventory. The final version of the missile was to have been the AIM-7R , which added an infrared homing seeker to an otherwise unchanged AIM-7P Block II. A general wind-down of

329-542: A number of navies for air defense. Fired at low altitude and flying directly at its target, though, the range of the missile in this role is greatly reduced because of the higher air density of the lower atmosphere. With the retirement of the Sparrow in the air-to-air role, a new version of the Sea Sparrow was produced to address this concern, producing the larger and more capable RIM-162 ESSM . The Sparrow emerged from

376-604: A second source for US missiles, Canadair was selected to build the missiles in Quebec . The small size of the missile forebody and the K-band AN/APQ-64-radar limited performance, and it was never able to work in testing. After considerable development and test firings in the U.S. and Canada, Douglas abandoned development in 1956. Canadair continued development until the Arrow was cancelled in 1959. A subvariant of

423-522: A variation of it, and the aircraft was assigned a new designation as the F5D Skylancer. Almost every part of the airframe was modified, though the basic form remained the same as did the wing shape, though it became much thinner. The wing skinning was reinforced, correcting a problem found in the F4D. The fuselage was 8 ft (2.4 m) longer and area ruled to reduce transonic drag, being thinner in

470-764: Is a development of the F4D Skyray jet fighter for the United States Navy . Starting out as the F4D-2N , an all-weather version of the Skyray, the design was soon modified to take full advantage of the extra thrust of the Pratt & Whitney J57 eventually fitted to the Skyray instead of the Westinghouse J40 originally planned. Soon the design became too different from the Skyray to be considered just

517-562: Is a feature of many radar systems that allow it to automatically follow a selected target. Lock-on was first designed for the AI Mk. IX radar in the UK, where it was known as lock-follow or auto-follow . Its first operational use was in the US ground-based SCR-584 radar , which demonstrated the ability to easily track almost any airborne target, from aircraft to artillery shells. In the post-WWII era,

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564-421: Is achieved and the weapon is ready to be launched. The subject of a radar lock-on may become aware of the fact that it is being actively targeted by virtue of the electro-magnetic emissions of the tracking system, notably the illuminator. This condition will present a heightened threat to the target, as it indicates that a missile may be about to be fired at it. F5D Skylancer The Douglas F5D Skylancer

611-425: Is then powered up while the launch platform's illuminator radar "lights up" the target for it. The illuminator is a radar transmitter with a narrow, focused beam that may be separate from the search radar and that can be directed at a target using information from the search radar. When the passive radar of the missile's guidance system is able to "see"/detect the radio waves reflected from the target, missile lock-on

658-544: The AAM-N-6b started production in 1963. The new motor significantly increased the maximum range to 35 kilometres (22 mi) for head-on attacks. This new missile also improved tail-on performance, with the AAM-N-6a being capable of firing on only targets with 300 ft/sec closing velocity, and AAM-N-6b being capable of firing on targets with a 300 knot opening velocity (-300 knot closing velocity or higher). During this year

705-481: The McDonnell F3H-2M Demon and Vought F7U Cutlass fighter aircraft . Compared to the modern versions, the Sparrow I was more streamlined and featured a bullet-shaped airframe with a long pointed nose. Sparrow I was a limited and rather primitive weapon. The limitations of beam-riding guidance (which was slaved to an optical sight on single-seater fighters and to radar on night fighters) restricted

752-512: The 612 AIM-7D/E/E-2 missiles fired, 97 (or 15.8%) hit their targets, resulting in 56 (or 9.2%) kills. Two kills were obtained beyond visual range. In 1969, an improved version, the E-2, was introduced with clipped wings and various changes to the fuzing. Considered a "dogfight Sparrow", the AIM-7E-2 was intended to be used at shorter ranges where the missile was still travelling at high speeds, and in

799-891: The AIM-7E2 technology in the 1970s, producing the Skyflash missile. Skyflash used a Marconi XJ521 monopulse 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 (RAF) on their Phantom FG.1/FGR.2 in 1978, and later on the Tornado F3 . Skyflash was also exported to Sweden for use on their Viggen fighters. An upgraded version with active radar seeker, called Active Sky Flash ,

846-689: The Air Force and Navy agreed on standardized naming conventions for their missiles. The Sparrows became the AIM-7 series. The original Sparrow I and aborted Sparrow II became the AIM-7A and AIM-7B , despite both being out of service. The -6, -6a, and -6b became the AIM-7C , AIM-7D , and AIM-7E respectively. 25,000 AIM-7Es were produced and saw extensive use during the Vietnam War , where its performance

893-591: The Arrow. The Italian company Finmeccanica (now Leonardo S.p.A. ), Alenia Difesa licensed the AIM-7E Sparrow technology from the US, and produced its own version. Later in the 1980s, Alenia started to produce an improved version of the AIM-7 called the Aspide. Compared to the AIM-7E, it received an improved new monopulse guidance system that allowed for a better hit ratio and easier targeting of enemies at low altitude with ground-clutter confusion. It also received

940-520: The HVAR proved to be inadequate for the electronics, leading Douglas to expand the missile's airframe to 8-inch (203 mm) diameter. The prototype weapon began unpowered flight tests in 1947, and made its first aerial interception in 1952. After a protracted development cycle the initial AAM-N-2 Sparrow entered limited operational service in 1954 with specially modified Douglas F3D Skyknight all-weather carrier night fighters. In 1956, they were joined by

987-625: The Italian firm Alenia to develop advanced versions of Sparrow with better performance and improved electronics as the BAe Skyflash and Alenia Aspide , respectively. The most common version of the Sparrow today, the AIM-7M , entered service in 1982 and featured a new inverse monopulse seeker (matching the capabilities of Skyflash), active radar proximity fuse , digital controls, improved ECM resistance, and better low-altitude performance. It

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1034-555: The M model (for monopulse) and some of these were later updated as the P model, the last to be produced in the US. Aspides sold to China resulted in the locally produced PL-11 . The Japan Self-Defense Forces also employ the Sparrow missile, though it is being phased out and replaced by the Mitsubishi AAM-4 . The Sparrow was also used as the basis for a surface-to-air missile , the RIM-7 Sea Sparrow , used by

1081-493: The Navy cancelled its order. The stated reason was that the aircraft was too similar to the already-ordered Vought F8U Crusader , but it is believed by some historians that politics played as big a part; Douglas was already building a very large proportion of the Navy's planes, and giving them the F5D contract would have made it even closer to monopoly. The project test pilot was Lt. Cmdr Alan B. Shepard Jr. whose report stated that it

1128-547: The Sparrow I armed with the same nuclear warhead as the MB-1 Genie was proposed in 1958 but was cancelled shortly thereafter. Concurrently with the development of the Sparrow I, in 1951 Raytheon began work on a semi-active radar-homing version, the AAM-N-6 Sparrow III . The first of these weapons entered United States Navy service in 1958. The AAM-N-6a was similar to the -6, and included changes to

1175-460: The Sparrow II (AAM-N-3/AIM-7B). After Douglas dropped out of this program, Canadair continued on with it until the termination of the Arrow project. The AAM-N-3 Sparrow II was unique in that it had a fully active radar guidance system. This combined both a radar transmitter and receiver in the missile, making it unnecessary for the pilot to keep the aircraft aimed at the target after firing

1222-572: The Sparrow II a "fire and forget" weapon, allowing several to be fired at separate targets at the same time. By 1955, Douglas proposed going ahead with development, intending it to be the primary weapon for the F5D Skylancer interceptor . It was later selected, with some controversy, to be the primary weapon for the Canadian Avro Arrow supersonic interceptor, along with the new Astra fire-control system. For Canadian use and as

1269-631: The Sparrow missile. The Soviet Union acquired an AIM-7 in 1968 and a Vympel team started copying it as the K-25 . The missile did not enter production as the R-23 was thought to have better versatility, range, signal processing logic, and immunity to interference. K-25 work ended in 1971, but analysis of the Sparrow was later used to inform the design of the Vympel R-27 , particularly the servomechanisms and movable wings. British Aerospace (BAe) licensed

1316-485: The Sparrow use semi-active radar homing . To accommodate the active radar guidance system, the AAM-N-3 Sparrow II had a much greater volume than its predecessor. Its size would subsequently set the precedent for all future Sparrow variants. In 1959, Canadair had completed five missiles based on airframes from Douglas, and built two models from scratch, when the program was cancelled with the cancellation of

1363-479: The budget led to it being cancelled in 1997. The U.S. Navy planned to operate the missile through 2018. The Sparrow is now being phased out with the availability of the active-radar AIM-120 AMRAAM , but is likely to remain in service for several years. As part of the Avro Canada CF-105 Arrow program, Canadair (now Bombardier ) partnered with Douglas Aircraft Company in the development of

1410-587: The early 1960s, NASA 212 was used as a testbed for the American supersonic transport program, fitted with an ogival wing platform (the type eventually used on Concorde ; data from the program was shared with the European designers), as well as being used as a vision field test platform for the X-20 Dyna-Soar . This aircraft was retired in 1968. NASA 802 was used for simulation of abort procedures for

1457-589: The early 1970s, the RAF developed the Skyflash version with an inverse monopulse seeker and improved motor, while the Italian Air Force introduced the similar Aspide . Both could be fired at targets below the launching fighter (" look-down, shoot-down "), were more resistant to countermeasures, and were much more accurate in the terminal phase. This basic concept then became part of the US Sparrows in

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1504-415: The enemy fighter would often approach within the range of shorter-range infrared homing missiles while the launching aircraft had to continue flying towards its target. Additionally, early models were only effective against targets at roughly the same or higher altitudes, below which reflections from the ground became a problem. A number of upgraded Sparrow designs were developed to address these issues. In

1551-553: The fuzing, and the E-4 featured a modified seeker for use with the F-14 Tomcat . Improved versions of the AIM-7 were developed in the 1970s in an attempt to address the weapon's limitations. The AIM-7F , which entered service in 1976, had a dual-stage rocket motor for longer range, solid-state electronics for greatly improved reliability, and a larger warhead. Even this version had room for improvement, leading British Aerospace and

1598-576: The guidance electronics to make it effective at higher closing speeds. It was originally designed to take the Thiokol LR44-RM-2 liquid-fuel rocket motor, but the decision was made to retain the solid fuel rocket motor. The -6a was also selected to arm the Air Force's F-110A Spectre ( F-4 Phantom ) fighters in 1962, known to them as the AIM-101 . It entered production in 1959, with 7500 being built. With an improved Rocketdyne solid-fuel motor,

1645-462: The head-on aspect, making it much more useful in the visual limitations imposed on the engagements. Even so, its kill rate was only 13% in combat, leading to a practice of ripple-firing all four at once in hopes of increasing kill probability. Its worst tendency was to detonate prematurely about 1,000 feet ahead of the launching aircraft, but it also had many motor failures, erratic flights, and fuzing problems. An E-3 version included additional changes to

1692-419: The internal components of newer missiles represent major improvements, with vastly increased capabilities. The warhead is of the continuous-rod type. As with other semi-active radar guided missiles, the missile does not generate radar signals, but instead homes in on reflected continuous-wave signals from the launch platform's radar. The receiver also senses the guidance radar to enable comparisons that enhance

1739-433: The missile to attacks against targets flying a straight course and made it essentially useless against a maneuvering target. Only about 2,000 rounds were produced to this standard. As early as 1950, Douglas examined equipping the Sparrow with an active radar seeker, initially known as XAAM-N-2a Sparrow II , the original retroactively becoming Sparrow I . In 1952, it was given the new code AAM-N-3 . The active radar made

1786-427: The missile's resistance to passive jamming. The launching aircraft illuminates the target with its radar. In 1950s radars, these were single-target tracking devices using a nutating horn as part of the antenna, thereby sweeping the beam in a small cone. Signal processing is applied to determine the direction of maximum illumination, thereby developing a signal to steer the antenna toward the target. The missile detects

1833-507: The missile, unlike Semi-active radar homing (SARH) missiles which require continuous radar-assisted guidance throughout flight. This allowed the aircraft that fired the AAM-N-3 to turn away, prosecute other targets, and/or escape from potential retaliatory missiles fired by the enemy aircraft during the time it took for the Sparrow to reach its target. Despite the significant advantages of this design over SARH guidance, all subsequent models of

1880-485: The reflected signal from the target with a high-gain antenna in a similar fashion and steers the entire missile toward closure with the target. The missile guidance also samples a portion of the illuminating signal via rearward-pointing waveguides . The comparison of these two signals enabled logic circuits to determine the true target reflection signal, even if the target were to eject radar-reflecting chaff . Related development Radar lock-on Lock-on

1927-405: The region of the wing roots. Everything was shaped to reduce drag and increase stability at high speed. Although the four 20 mm (.79 in) cannon in the wing roots were retained, primary armament was to be missiles or rockets; four AIM-9 Sidewinders or two AIM-7 Sparrows , and/or a battery of spin-stabilized unguided 2 in (51 mm) rockets. Nine test airframes were ordered, with

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1974-406: The term became more widely used in connection to missile guidance concepts. Many modern anti-aircraft missiles use some form of semi-active radar homing , where the missile seeker listens for reflections of the launch platform's main radar. To provide a continuous signal, the radar is locked-onto the target, following it throughout the missile's flight. Ships and surface-to-air missiles often have

2021-431: The traditional sense; tracking is provided by storing radar signals in computer memory and comparing them from scan to scan using algorithms to determine which signals correspond to single targets. These systems do not change their signals while tracking targets, and thus do not reveal they are locked-on. With a semi-active radar homing system, the launch platform acquires the target with its search radar . The missile

2068-420: Was considered disappointing. The mixed results were a combination of reliability problems (exacerbated by the tropical climate), limited pilot training in fighter-to-fighter combat, and restrictive rules of engagement that generally prohibited BVR (beyond visual range) engagements. The P k (kill probability) of the AIM-7E was less than 10%; US fighter pilots shot down 59 aircraft out of the 612 Sparrows fired. Of

2115-431: Was not needed by the Navy. One F5D crashed during testing by the Navy. The four aircraft continued to fly in various military test programs. Two were grounded in 1961 (likely 139209 and 142349 which had been designated for spare parts in 1958 ), but the other two: F5D-1 (Bu. No. 139208) NASA 212, later becoming NASA 708 and F5D-1 (Bu. No. 142350) NASA 213, later becoming NASA 802 continued to fly. Transferred to NASA in

2162-550: Was proposed by BAe and Thomson-CSF , but did not receive funding because the RAF opted for other missiles. The Sparrow has four major sections: guidance section, warhead , control, and rocket motor (currently the Hercules MK-58 solid-propellant rocket motor). It has a cylindrical body with four wings at mid-body and four tail fins. Although the external dimensions of the Sparrow remained relatively unchanged from model to model,

2209-462: Was used to good advantage in the 1991 Gulf War , where it scored many USAF air-to-air kills. Of 44 missiles fired, 30 (68.2%) hit their intended targets resulting in 24/26 (54.5%/59.1%) kills. 19 kills were obtained beyond visual range. The AIM-7P is similar in most ways to the M versions, and was primarily an upgrade for existing M-series missiles. Changes were mainly to the software, improving low-level performance. A follow-on Block II upgrade added

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