Editing Heavy fighter (section)

==United States==
[[File:P38 Lightning.jpg|thumb|The [[Lockheed P-38 Lightning]]]]

The US military never officially designated an aircraft as a "heavy fighter," but from the 1930s through to the immediate post-WWII period there were a slew of American designs that were twin-engined, relatively heavy in weight, and designed in line with other nations’ heavy fighter philosophy.

During the late 1930s, [[Bell Aircraft]] of the United States designed the [[Bell YFM-1 Airacuda|YFM-1 Airacuda]] "bomber destroyer". The design was heavily armed, particularly for a pre-WWII design, mounting two {{convert|37|mm|in|2|abbr=on}} [[M4 cannon|M4 cannons]] as her primary armament along with two {{convert|.30|in|mm|2|abbr=on}} [[M1919 Browning machine gun|M1919 Browning machine guns]] and two {{convert|.50|in|mm|1|abbr=on}} [[M2 Browning machine gun|M2 Browning heavy machine guns]] for defense. A very large and unique airframe, the Airacuda was plagued with design flaws; only 13 prototypes were built, none of which participated in World War II.

The US would enter WWII with one of the most effective heavy fighters in history, the [[Lockheed P-38 Lightning]]. It was designed as a twin-engine bomber interceptor to climb quickly and carry heavy armament at high speed, with the lighter [[Bell P-39 Airacobra]] meeting the single-engine version of the same requirement. An advanced design crewed by a lone pilot, the P-38 performed best in the [[Pacific Ocean theater of World War II|Pacific theater]] where its long-range proved a pivotal advantage. This range allowed a team of sixteen early P-38 models to [[Operation Vengeance|intercept and kill Japanese Admiral Isoroku Yamamoto]] while he was traveling aboard a transport aircraft. The P-38 proved adaptable enough to undertake [[Multirole combat aircraft|multiple roles]] including escort fighter, [[Aerial reconnaissance|reconnaissance]] (as the F-4 and F-5 variants of which over 1,200 were built), night fighter (as the [[radar]]-equipped P-38M variant), and as a [[fighter-bomber]]. In the escort fighter role, the P-38 accompanied [[Boeing B-17 Flying Fortress]] raids deep into German-held Europe. The P-38 and the much lighter [[North American P-51 Mustang]] were the first two American fighters over Berlin in March 1944.<ref>{{cite book |last=Bodie |first=Warren M. |title=The Lockheed P-38 Lightning: The Definitive Story of Lockheed's P-38 Fighter |location=Hayesville, North Carolina |publisher=Widewing Publications |date=1991 |isbn=0-9629359-5-6 |page=223}}</ref>

The only other American heavy fighter to serve in great numbers during WWII was the [[Northrop P-61 Black Widow]], which was also the United States’ first dedicated night fighter, in addition to being the first aircraft designed to utilize [[radar]].<ref>Wilson 1998, p. 142.</ref><ref>Parker, Dana T. ''Building Victory: Aircraft Manufacturing in the Los Angeles Area in World War II,'' p. 93, Cypress, CA, 2013. {{ISBN|978-0-9897906-0-4}}.</ref> Armed with four forward-firing 20&nbsp;mm (.79&nbsp;in) [[Hispano-Suiza HS.404|AN/M2]] cannons mounted in the lower fuselage and four .50&nbsp;caliber (12.7&nbsp;mm) [[M2 Browning|Browning AN/M2]] machine guns mounted in a remote-controlled dorsal [[gun turret]] (capable of firing forwards as well as rearwards for defense), it was one of the most heavily armed aircraft in American service during the WWII-period. The P-61 was unofficially credited with the last [[Allies of World War II|Allied]] air victory before [[Victory over Japan Day|VJ Day]].{{sfnp|Pape|1991}} The P-61 was also modified to create the unarmed [[Northrop F-15 Reporter|F-15 Reporter]], a specialized [[photo-reconnaissance]] aircraft for the United States Army Air Forces and subsequently used by the [[United States Air Force]].<ref name="Johnson 1976, pp. 30–44">Johnson 1976, pp. 30–44.</ref> The F-15 Reporter was the last piston-powered photo-reconnaissance aircraft designed and produced for the United States Air Force.<ref name="Johnson 30–44">{{cite magazine |last=Johnson |first=Bob |title=Seeing Eye Widow |magazine=Scale Modeler |volume=11 |issue=2 |date=February 1976 |pages=30–44}}</ref> The Reporter was also responsible for producing most of the aerial reconnaissance photographs of [[North Korea]] during the [[Korean War]].<ref name="Thompson WoF p84-85">Thompson 1999, pp. 84–85: Note: "Their photos of Korea were invaluable to the UN forces during the first few weeks of that war. It was not until the Marine photo version F7F-3P Tigercat made its sweeps over Inchon that any additional pictures were taken."</ref> The P-61 — redesignated as the F-61 in June 1948 — would also serve as a [[night fighter|night/all-weather]] interceptor with the USAF's [[Air Defense Command]] (ADC) until 1951.

In 1945, with the large-scale use of jet aircraft becoming commonplace, the United States Army Air Forces put forward technical specifications to the US aerospace industry, requesting both day and night [[interceptor aircraft|interceptors]]. While the night interceptor technical specification did not specifically require jet power, it did place a minimum speed requirement of 503&nbsp;mph (810&nbsp;km/h) on the project, effectively necessitating jet power. By 1946, two aircraft were chosen by the USAAF to compete for the contract ; the [[Curtiss-Wright XF-87 Blackhawk|Curtiss-Wright XP-87 Blackhawk]] and the [[Northrop F-89 Scorpion|Northrop XP-89 Scorpion]]. While the XP-89 would eventually emerge as the winner, due to multiple issues with both competing aircraft, the first Scorpions would not reach operational [[Aerospace Defense Command|Air Defense Command]] interceptor units until 1951. With no other night interceptors to call on from 1945 to 1951, the P-61 Black Widow was charged with protecting American airspace from the growing threat of Soviet [[strategic bombers]]. The P-61 would be re-designated as the F-61 in 1948.<ref>{{cite book|last1=Knaack|first1=Marcelle Size|url=https://media.defense.gov/2010/May/26/2001330287/-1/-1/0/AFD-100526-027.pdf|title=Encyclopedia of US Air Force Aircraft and Missile Systems: Volume 1|date=1978|publisher=Office of Air Force History|location=Washington, D.C.|page=1|access-date=10 December 2020}}</ref> With F-61s no longer in production post-war, they were usually replaced with the newer [[F-82 Twin Mustang]] once they became unserviceable.

The F-82 Twin Mustang was America's last heavy fighter design as well as being the last American piston-engined fighter ordered into production by the United States. The Twin Mustang, while appearing to be simply a ‘[[Twin-fuselage aircraft|twinned]]’ P-51 Mustang,  actually only shared less than 20% commonality of parts with the original Mustang. Initially intended as a long-range [[escort fighter]] for [[Boeing B-29 Superfortress]] [[strategic bombers]] attacking the [[Japanese archipelago|Japanese home islands]], it would become operational only after the [[VJ Day|Japanese surrender]]. Originally designed in 1943, it was officially accepted into USAAF service in August 1945. The design carried six .50&nbsp; in (12.7&nbsp;mm) [[heavy machine guns]] (HMGs) on the ‘center’ wing, between each fuselage, with three on each outboard wing as on the original Mustang design. The HMGs were also [[M2 Browning#Aircraft guns|AN/M3s]] instead of the original Mustang's AN/M2 HMGs. The AN/M3 increased the rate of fire to around 1,200-1,300 rounds per minute (firing the same round with minimal change in weight or size) compared to the AN/M2's 750-850 rounds per minute, a roughly 60% increase in rounds per minute.<ref name="Carel, M3" >
{{Cite thesis
 |title=The History of the Aerial Gatling Gun
 |year=1987
 |publisher=US Air Command and Staff College
 |id=87-0415
 |last=Carel |first=Dennis C.
 |url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a179871.pdf
 |page=3
 |access-date=2019-05-12
 |archive-url=https://web.archive.org/web/20190512222703/https://apps.dtic.mil/dtic/tr/fulltext/u2/a179871.pdf
 |archive-date=2019-05-12
 |url-status=live}}
</ref> The first XP-82 prototype was equipped with a removable centerline gun pod housing eight additional .50 caliber M3 Brownings, but this did not feature on production aircraft. A separate centerline gun pod containing a {{cvt|40|mm}} cannon was considered, but was never built.<ref name="Carey2014">Carey, 2014, p.20</ref>  The outer wings were reinforced to allow the addition of hard points for carrying additional fuel or {{cvt|1000|lb}} of ordnance. The F-82E was the first operational model and its initial operational assignment was to the [[Strategic Air Command]] [[27th Special Operations Wing|27th Fighter Wing]] (later re-designated the 27th Fighter-Escort Wing, or 27th FEW) at [[Kearney Air Force Base]], [[Nebraska]] in March 1948. With no long-range jet fighters to escort the strategic bomber force, the 27th FEW was to fly these missions in F-82Es.{{sfn|Pape|1991|pp=48–63}}

During the start of the [[Korean War]], the F-82 replaced the F-61 Black Widow as the USAF's night interceptor in the [[Pacific Air Forces|Far East Air Forces]]. The Twin Mustang was utilized in the night [[interceptor aircraft|fighter-interceptor]] and [[fighter-bomber]] role early in the war, and it scored the first US aerial victory, with Lt. William G. "Skeeter" Hudson, USAF, scoring a [[Yak-11]] kill.{{citation needed|date=February 2024}} The Twin Mustang was increasingly out-classed by jet aircraft, and was eventually replaced in Korea by [[Republic F-84 Thunderjet|Republic F-84 Thunderjets]] and [[North American F-86 Sabre|North American F-86 Sabres]].

[[File:449th FAWS North American F-82H Twin Mustang 46-415.jpg|thumb|upright=1.2|USAF operational F-82 Twin Mustang, F-82F on the ramp at [[Ladd AFB]], just before going to salvage at [[Elmendorf AFB]], May 1953.]]

The F-82 would end its life as the last operational American piston-engined interceptor. Primarily stationed in Alaska out of [[Adak Island]] (and later out of [[Ladd Air Force Base]]) as part of the 449th Fighter (All-Weather) Squadron (F(AW)S), a winterized variant, known as the F-82H was developed specifically for this task. The winterized Twin Mustang would perform long-range aerial patrols over the extremes of American airspace around Alaska, with the area being viewed as a possible ‘back door’ for Soviet strategic bombers. The F-82H was slowly supplemented by the [[Lockheed F-94 Starfire]] all-weather [[interceptor aircraft|interceptor]], and by 1953, it had completely replaced the Twin Mustang.

Apart from the P-38 and P-61, other mid-WWII projects included the proposed [[XP-71|Curtis XP-71]]. It was an exceptionally large heavy fighter, intended to serve as a long-range escort fighter and bomber destroyer. Its design was based around a 75&nbsp;mm cannon capable of destroying large [[heavy bombers]] with one hit, but interest in the project waned and the {{convert|83|ft|m|abbr=on}}-[[wingspan]] aircraft did not progress beyond a single mockup.<ref>Buttler, T and Griffith, A. ''American Secret Projects: Fighters Bombers and Attack Aircraft 1937 to 1945'' p 73-74</ref> Another bomber destroyer was the [[Beechcraft]] Model 28, also bearing a 75&nbsp;mm cannon, with twin turrets mounting .50&nbsp;in (12.7&nbsp;mm) Browning AN/M2 heavy machine guns for defence. The design was re-designated the [[Beechcraft XA-38 Grizzly|XA-38 Grizzly]] and was repurposed as a ground attack aircraft intended to be able to defeat enemy [[tanks]] and ground fortifications with its heavy cannon. However, for reasons including need of the chosen powerplant for B-29 bombers it did not enter service.<ref>Buttler and Griffith, p144</ref>

Post-war, the [[Grumman F7F Tigercat]] was the first twin-engine fighter aircraft to enter service with the United States Navy, using two [[Pratt & Whitney Double Wasp]] radial engines, achieving a top speed of 460&nbsp;mph (740&nbsp;km/h). It was among the fastest piston-engine aircraft ever built, and heavily armed with four 20mm [[Hispano-Suiza HS.404|M2 cannon]] and four [[.50 BMG|0.50&nbsp;in]] (12.7&nbsp;mm) Browning AN/M2 heavy machine guns, with hard points for bombs or a torpedo. Although Grumman designed and developed the aircraft during World War II, it entered service too late to see action before [[VJ Day]]. It served in the [[Korean War]] and retired in 1954.