Interceptor aircraft

[
MiG-25 'Foxbat' is a Russian interceptor that was the mainstay of the Soviet air defence.] An interceptor aircraft (or simply interceptor) is a type of fighter aircraft designed specifically to intercept and destroy enemy aircraft, particularly bombers, usually relying on great speed. A number of such aircraft were built in the period starting just prior to World War II and ending in the late 1960s, when they became less important due to the shifting of the strategic bombing role to ICBMs.

Design

There are two types of interceptors, emphasizing different aspects of performance. Point defense interceptors were the first type, designed to take off and climb as quickly as possible to the attacking aircraft's altitude. This was a necessity in the era of limited radar range, which meant defenders had very short warning times before having to engage the enemy. Area defense interceptors are larger designs intended to protect a much larger area from attack. These were important only during the Cold War, when the US and USSR needed to provide a defense over their respective large land areas.

Both types of aircraft sacrifice performance in the air superiority fighter role (ie fighting enemy fighter aircraft) by tuning their performance for either fast climbs or high speeds, respectively. The result is that interceptors often look very impressive on paper, typically outrunning, outclimbing and outgunning less specialized fighter designs. Yet they tend to fare poorly in combat against those same "less capable" designs due to limited maneuverability.

In the 1970s, the utility of interceptors waned as the role became blurred into the roles of the heavy air superiority fighters dominant in military thinking at the time. In addition, it is arguable that the change of the great threat of the era - nuclear weapons that were carried on bombers being moved to various missile systems - left the interceptor-style aircraft without its primary target. Today interceptor missions are generally relegated to "mainline" fighters; for instance, the US Air Force bases its defense on its F-15 and F-16 fighters. The exceptions are the USSR, who maintained a number of dedicated interceptors in order to provide coverage over its huge and little inhabited coastline, and, perhaps oddly, the UK, who introduced a fleet of modified Panavia Tornados in the 1980s and continued to use them while awaiting the introduction of the Eurofighter Typhoon in 2005. The Eurofighter Typhoon has now replaced the role of an interceptor and the Tornado is now used for air superiority and attack.

Point defense

Point defense interceptors, usually of European origin, are designed to defend specific targets. They are designed to take off and climb to altitude as quickly as possible, destroy the incoming bombers, and then land. A particularly extreme example of a point defense interceptor is the rocket-powered Bachem Ba 349.

At the start of the Second World War, most single engine fighters were "short-legged", with limited internal fuel capacity. These were not designed specifically as interceptors, but the long-range bomber escort role had not been envisaged. This proved to be a critical problem for German single-engined fighters (essentially, only one design at that time, the Bf 109), during the Battle of Britain, which could escort bombers across the channel, but only had sufficient fuel for a few minutes of combat if they were also to return to their airfields in France. At this stage, the similar limitation of British single-engined fighters was less of a problem for the defending Royal Air Force (RAF).

When RAF Bomber Command began its own bombing campaign over Germany, most of its missions were flown at night, unescorted, or escorted by larger, longer-ranged and twin-engined night fighters. As the war progressed, however, Bomber Command flew increasing numbers of daylight missions. The Spitfire, designed several years before the war, was adapted to other roles - older machines were re-assigned to fighter-bomber squadrons, based nearer the front, while newer marks developed into more highly-focused interceptors. These later, Griffon-engined Spitfires were primarily retained in Britain to defend against V-1s and bombing raids by single, high-speed or high-altitude, German bombers. Newer designs, like the Hawker Tempest, and P-51 Mustangs bought under Lend-Lease, would fill the conventional and long-range fighter gap.

The Germans, quickly losing their ability to project their airpower over enemy territory, no longer had much requirement for a long-range escort fighter. They were obliged to keep using the Bf 109 throughout the war, although it and newer designs were developed as fighter bombers, the "Luftwaffe"'s most critical requirement was for interceptors as the Commonwealth and American air forces pounded German targets day and night. As the bombing effort grew, notably in early 1944, the Luftwaffe attempted to introduce a number of high-performance designs like the Messerschmitt Me 163 "Komet" and even odder designs like the Bachem Ba 349 "Natter" in the very-short-range interceptor role. In general these designs proved difficult to operate, and had little effect on the bombing effort.

[
F-8 Crusader of USS "Oriskany" intercepts a Tu-95 'Bear-B'.] In the Cold War, bombers were expected to attack flying higher and faster (near supersonic). This led to fighter designs emphasizing acceleration and operational ceiling, such as the mixed power (jet/rocket) Saunders Roe SR.53, or Convair XF-92, or Soviet trials with catapult launched MiG-19s, although none of them found practical use. Improvements in jet engines made the rocket assistance redundant, and a new series of designs evolved that were purely jet powered, including the MiG-21, English Electric Lightning and F-104 Starfighter. This class of aircraft has since disappeared completely; ever increasing engine power has made even small aircraft suitable for practically any role, and aircraft that would have fallen into this class are generally multi-role and find most of their use in the attack role.

Examples of point defense interceptors:

* Messerschmitt Me 163
* English Electric Lightning
* Saab Draken
* Saab Viggen (JA 37 variant)
* MiG-21
* F-104 Starfighter

Area defense

Area defense interceptors usually of North American or Soviet origin, are designed to defend a large area of territory from attack. The design emphasis is on range, missile carrying capacity and radar quality rather than on acceleration and climb rate. They usually carry long-range or medium-range air-to-air missiles, and often had no bomb carrying capability.

In the Soviet Union during the Cold War, an entire military service, not just an arm of the pre-existing air force, was designated for their use. The planes of the PVO-Strany differed from those of the Red Air Force in that they were designed for airfield use only; they couldn't take off from grass, only concrete runways, they couldn't be towed for hundreds of kilometres from airfield to airfield by tractor across open fields; they couldn't be disassembled and shipped back to a maintenance center in a boxcar; and they were by no means small as necessary and rudely simple, but huge and refined with large, powerful radars. Similarly, they were not given the same training in combat maneuvers, but were directed to their targets by radio. Until the 1980s, they were fitted with medium-range or long-range missiles only, unsuitable for dogfight or destroying maneuvring targets. The basic interceptor was Sukhoi Su-9, then Sukhoi Su-15 and MiG-25. The newest and most advanced interceptor aircraft is MiG-31. Soviet Tupolev Tu-28 was the heaviest fighter aircraft ever to see service.

The USAF maintained a dedicated Air Defense Command (ADC) for some time, consisting primarily of dedicated interceptors. Many post-war designs were of limited performance, including designs like the F-86D and F-89 Scorpion. In the late 1940s ADC started a project to build a much more advanced interceptor under the 1954 interceptor effort, which eventually delivered the F-106 Delta Dart after a lengthy development process. Replacements were studied during the 1960s, but came to nothing as the USSR moved their strategic force to ICBMs. The F-106 ended up serving as the primary USAF interceptor into the 1980s, when the performance of general purpose aircraft like the F-15 Eagle rendered the need for a custom design moot.

Several other countries also introduced wide-area interceptor designs. Avro Canada produced the Avro CF-100, generally similar to the F-89, which went on to serve for a lengthy period of time in the Royal Canadian Air Force. Avro's replacement, the Avro Arrow, was controversially cancelled in the late 1950s. The Royal Air Force operated the Gloster Meteor and then Gloster Javelin in the night/all-weather role, but efforts to replace the Javelin with a supersonic design under Operational Requirement F.155 likewise never came to fruition. The Tornado ADV was eventually introduced into this role in the 1980s, and continue to serve in this role to this day.

Examples of area defense interceptors:

* Shenyang J-8
* F-101B Voodoo
* F-102 Delta Dagger
* F-106 Delta Dart
* F-14 Tomcat
* Avro CF-100
* CF-105 Arrow
* Tornado F3
* Mikoyan-Gurevich MiG-25 'Foxbat' and MiG-31 'Foxhound'
* Sukhoi Su-15 'Flagon'
* Tupolev Tu-28 'Fiddler'
* Yakovlev Yak-25 'Flashlight'
* Yakovlev Yak-28 'Firebar'
* Lockheed YF-12

ee also

* Air superiority fighter
* Bomber destroyer
* Day fighter
* Escort fighter
* Night fighter