Light fighter

Official roll-out of first USAF F-5E Tiger-II.

A YF-16 and a YF-17, flying side-by-side, part of the Lightweight Fighter program.

This article refers to a class of aircraft. Light infantry is sometimes referred to in this fashion in the US, see 7th Infantry Division.

A light fighter or lightweight fighter is a type of fighter aircraft with a diminutive airframe, deliberately designed to fill a performance niche based on a high thrust-to-weight ratio with high maneuverability. Light fighters development was based on results from real-world experience studies. In the U.S. this was based on short comings during the Vietnam War,^[1] while in Sweden the requirement was a Mach 2 versatile platform with good short-field performance for a defensive dispersed basing plan in the event of invasion.^[2] Although most light fighters are new designs, some of them were based on previous or current successful multi-role fighters like the F-16, F-5 and Mirage III and 2000. Typically, light fighters have been dismissed by military planners as being too limited in capability, but several light fighter designs have fairly good combat records. Some of the light fighters of today are now being developed or have variants as an unmanned fighter aircraft as well as new designs to add as force multiplier also to minimize human casualties.^[3]

History

WWII

The original light fighter class developed out of a concern over the gradually increasing size and cost of the frontline fighters in the 1920s, and the earliest such program was the 1926 French Armée de l'Air 'Jockey lightweight fighter program', for which several aircraft, including the Nieuport-Delage NiD 48 and Amiot 110 were trialled, without much success. These were possible because of a series of late 1920s aircraft engines that delivered a high power-to-weight ratio, albeit at a low power rating. In order to make use of these engines, the aircraft using them had to be as light as possible. However, this is not always easy; some components cannot be scaled down.

Despite the failure of the Jockey program, during the late 1930s, the French Armée de l'Air, in an attempt to modernize her fleet of aircraft, produced several more light fighter designs of wooden construction that could be built quickly. The most numerous, with about 90 eventually being built, was the Caudron C.714 which exemplified the fundamental flaws of the light fighter concept: underpowered, underarmed, and limited endurance. Delivery began in early 1940, but France fell before sufficient numbers could be produced to prove the concept in combat.

Similar British programs such as the Miles M.20 remained as prototypes and were cancelled before ever entering production.

The United States Army Air Corps also contracted for several light fighter designs based on the Ranger V-770 engine, an air-cooled inverted V12 engine, smaller than most of the Axis-designed engines of the same format, that delivered up to 700 hp. Fears of an imminent massive German attack was forthcoming led to plans to build fighters designs based on the Ranger, which could be rapidly put into production. Performance of the engine proved uninspiring, and aircraft designed around it failed to live up to expectations, including the Bell XP-77, and by the time development had progressed to testing the fear of a German attack had faded.

During the war, the Hawker Fury was developed initially as the "Tempest Light Fighter" a lightweight version of the Hawker Tempest although in practice the resulting naval Sea Fury was a full sized fighter, and not significantly different in weight.

Early jets

The first jet light fighter in service was the Luftwaffe's He 162A of 1945.

Yugoslav Gnat, dwarfed by Sabres

Light fighters again became popular in during the early era of jet engine development, for much the same reasons. Jet engines scale downward quite well, and a number of very small and lightweight engines had become available. Many attempts have been made to produce relatively high-performance designs using these inexpensive jets. The only realized attempt at producing a turbojet-powered "light fighter" during World War II was the 1945-introduced Heinkel He 162A Spatz (German for "sparrow"), the winner of the Third Reich's Volksjäger, or "people's fighter" design competition to produce an emergency fighter to defend the by-then crumbling Third Reich. The He 162A was powered by a single BMW 003 jet engine, as specified in the Volksjäger design competition's rules.^[4] Some 320 of the He 162A aircraft had been completed by V-E Day, with hundreds more incomplete airframes on production lines scattered around the defeated Third Reich's territory.

The Folland Gnat was a British private venture design for a light fighter.^[5] Although not adopted by the UK as a fighter (but as a trainer), it did serve successfully as a fighter for the Indian Air Force.

Luftwaffe G.91

The NATO Light Weight Strike Fighter competition of the early 1950s led to designs such as the French SNCASE Baroudeur, Breguet Taon^[6] and Dassault Étendard VI, the Italian Aeritalia G.91 and Aerfer Ariete (derived from the Aerfer Sagittario 2) and the US Northrop N-156. The competition also compared engines and selected the Bristol Siddeley Orpheus - which had been developed for the Gnat - as the winner.

In spite of losing the NATO competition, Northrop's design was offered to the USAF where is found little interest. However, the introduction of the Mutual Defense Assistance Act led to the N-156 being placed in competition with several other US designs, which it handily beat in terms of cost. Becoming the Northrop F-5 "Freedom Fighter", just under 1000 were sold worldwide, and another 1,400 of the updated Tiger II version. This makes the F-5 the most successful light fighter to date, by far.

New generation and future designs

Hal Tejas

F-20 Tigershark

Several attempts have been made to introduce newer designs in the same general performance range as the F-5, but none have been nearly as successful. One such aircraft is the Northrop F-20 Tigershark, an evolution of the famous Northrop F-5 series. It lost to the F-16 in a lightweight fighter competition, it also lost in sales until cancellation and never went into full production. Only 3 were built. In 1987 BAE developed a combat-oriented variant of the Hawk trainer designated Hawk 200. This has been developed into a light multi-role fighter aircraft for air-to-air, air-to-ground and maritime strike role.

The HAL Tejas may be the best example of a modern light fighter design, its use of composite materials makes the aircraft both lighter and stronger at the same time compared to an all-metal design. It was introduced in 2013 and several hundred aircraft are planned to enter service with both the Indian Airforce and Indian Navy.

The YF-16 along with the YF-17 was originally conceived under the Lightweight Fighter program, but grew into a highly capable multirole fighters. Now known as the F-16 Fighting Falcon and F/A-18 Hornet. Their Soviet counterpart Mikoyan MiG-29 though not really a light fighter was originally part of the Perspektivnyy Lyogkiy Frontovoy Istrebitel (LPFI, or "Advanced Lightweight Tactical Fighter") program.^[7] In the 1980s SAAB began a lightweight fighter design as a replacement for the SAAB 37 Viggen. The resulting prototype was the JAS-39 Gripen first came out in 1989.^[8] The French Dassault Mirage 2000 was designed as a lightweight fighter that evolved into a multirole aircraft with several variants developed, with sales to a number of nations.^[9]

KAI FA-50

South Korea's T-50 Golden Eagle designed by Lockheed Martin with Korea Aerospace Industries is based on its famous F-16 multirole-fighter.^[10][11] Its latest variant called the FA-50 Fighting Eagle is designated as a light fighter while retaining its trainer capabilities using the same air frame as the T-50 advance trainer introduced in August 2002.^[12] It is now deployed with South Korea's air force replacing its aging Northrop F-5E/F multirole light fighters and trainers.^[13][14]

JF-17 Thunder

In 2003, a lightweight fighter was introduced by Pakistan Aeronautical Complex prototype PT-01 now called the JF-17 Thunder, it was co-developed with Chengdu Aircraft Industry Group.^[15] it was officially inducted into the Pakistan Air Force on February 18, 2010.^[16]

Unmanned fighter aircraft

U.S. Navy UCAV X-47

By dispensing with the mass of the pilot and the cockpit equipment, and by eliminating the physical human g-force limitations, the concept of remotely controlled fighter aircraft may allow higher performance. The intention of unmanned lightweight fighters is to be a force multiplier rather than a full replacement of main fighters.^[17] The US Navy is currently studying using a drone to dogfight other planes. Some factors have to be resolved such as enemy jet detection, maneuvering to firing position and shooting it down automatically, which means still needing human help via another manned fighter jet helping the drone achieve its mission. Some ability to evade incoming missiles will be included into its capability.^[18]

References