Fighter aircraft

• 1. Introduction

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  Fighter aircraft fly for one purpose above all others: to win the airspace over a battlefield. The job is called air superiority, and once a side holds it, its bombers and attack aircraft can strike enemy targets while the other side cannot do the same. A fighter is judged on three things working together. Firepower matters, but so does high speed, and so does maneuverability against the target aircraft. Erwin Rommel, the German Field Marshal, put the stakes plainly. He said anyone who has to fight against an enemy in complete command of the air fights like a savage. From small fabric biplanes to stealth jets larger than World War II medium bombers, the fighter has been reinvented again and again. What forced each reinvention? Why did a gun outlast the missiles that were supposed to retire it? And how did a Swiss patent from 1913, an upward-firing cannon, and a theory about decision-making cycles each change the way these machines fight?

• 2. Naming The Hunter

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  Curtiss P-40 Warhawk, Republic P-47 Thunderbolt, Bell P-63 Kingcobra: that letter P stood for pursuit, the name the U.S. Army used for fighters until the late 1940s. The British Royal Flying Corps and Royal Air Force called them scouts until the early 1920s, then switched to fighters; the US Army made the change in the 1940s. The single letter encodes a nation's idea of the aircraft. In the English-speaking world, F now marks a fighter, as in the Lockheed Martin F-35 Lightning II or the Supermarine Spitfire F.22. The French used C for Chasseur, seen on the Dewoitine D.520 C.1, and the Americans borrowed it as a translation for pursuit. In Russia the letter was I, for Istrebitel, meaning exterminator, carried by the Polikarpov I-16. The categories matter as much as the letters. A short-range fighter built to defend against incoming aircraft is an interceptor, a class that trades maneuverability for climb rate to reach bombers fast. Recognized classes also include the air superiority fighter, the fighter-bomber, the heavy fighter, the light fighter, the all-weather and night fighter, the reconnaissance fighter, and the strategic fighter. Designation has never been an honest guide to capability. The F-111 and F-117 carried fighter designations despite having no fighter capability, given the labels for political or other reasons. The F-111B variant was meant for a fighter role with the U.S. Navy, then canceled outright.

• 3. Solving The Propeller

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  On the 5th of October 1914, a French Voisin III became the first aircraft to shoot down another. The Voisin pushers, beginning in 1910, were among the earliest armed aircraft, even though the word fighter first described a two-seater with a machine gun mounted on a pedestal and its own operator. Combat began with improvisation. On the 15th of August 1914, Miodrag Tomic met an enemy plane over Austria-Hungary; the other pilot fired a revolver, Tomic fired back, and within weeks every Serbian and Austro-Hungarian aircraft was armed. Pilots tried pistols, carbines, grenades, even light machine guns, all cumbersome when one hand had to fly the plane and make a difficult deflection shot. The real obstacle sat spinning at the front. The best direction to shoot was straight ahead, but the propeller was in the way. Builders tried pusher scouts like the Airco DH.2, with the propeller behind the pilot, though the high drag of the tail made them slow. Roland Garros bolted metal deflector plates to his propeller so his gun would not shoot the blades off, and a number of Morane-Saulnier Ns were modified this way; the deflected bullets stayed dangerous. The lasting answer was synchronization, timing each round to slip between the blades. Franz Schneider, a Swiss engineer, patented such a device in Germany in 1913, but it was not pursued. French designer Raymond Saulnier patented a working device in April 1914, foiled by ammunition that hung fire. Garros took Saulnier's gear into combat in March 1915 and scored three victories in three weeks before he was downed on the 18th of April, his gear and propeller captured by the Germans. The first system to enter service came from Anthony Fokker's firm, called the Stangensteuerung. On the 1st of July 1915, Leutnant Kurt Wintgens, flying one of five Fokker M.5K/MG prototypes armed with a synchronized Parabellum MG14, downed a Morane-Saulnier Type L. His victory opened the period the British called the Fokker scourge.

• 4. The Biplane Classic

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  The Albatros D.I and the Sopwith Pup, both of 1916, set the pattern fighters followed for about twenty years. Most were biplanes, only rarely monoplanes or triplanes, because the strong box structure of a biplane gave the rigid wing needed for accurate control in a dogfight. They carried one operator who flew and fought, armed with one or two Maxim or Vickers machine guns firing through the propeller arc. The breeches sat in front of the pilot, an obvious hazard, but jams could be cleared in flight and aiming was simple. Some engineers pushed past wood and fabric long before the rest of the world followed. A German biplane, the Albatross, used a plywood shell rather than fabric, which made it stronger and faster. Anthony Fokker built his fighter fuselages from chrome-molybdenum steel tubing, while Hugo Junkers developed all-metal single-seat monoplanes with cantilever wings, including the experimental Junkers J 2 and some forty examples of the corrugated-duralumin Junkers D.I. Dornier was the first to build a fighter from pre-stressed sheet aluminum with cantilevered wings, the Dornier-Zeppelin D.I, a form that would replace all others in the 1930s. The cost of flying these machines was brutal and personal. Allied and, before 1918, German pilots had no parachutes, so in-flight fires or structural failures were often fatal. In April 1917, during a stretch of German aerial supremacy, a British pilot's average life expectancy was about 93 flying hours, roughly three weeks of active service. More than 50,000 airmen from both sides died during the war. Manfred von Richthofen, the Red Baron, was wearing a parachute when he was killed; Allied command kept opposing their use on various grounds.

• 5. Between Two Wars

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  The Schneider Trophy races, not military budgets, drove the biggest leaps in fighter design right up to the late 1930s. Competition grew so fierce that only national governments could afford to enter, and the streamlining and powerful engines bred for racing flowed into the fighters of the coming war. Aircraft engines grew several-fold over the period, from a typical 180 horsepower in the 900-kilogram Fokker D.VII of 1918 to 900 horsepower in the 2500-kilogram Curtiss P-36 of 1936. Budgets shaped who pulled ahead and who fell behind. France, Italy and Russia kept large budgets and built monoplanes and all-metal structures, then overspent themselves by the end of the 1920s. The British, Americans, Spanish and Germans, who had not been spending heavily, overtook them in the 1930s. Conservative air forces kept biplanes in service long after they stopped being competitive; the Gloster Gladiator, Fiat CR.42 Falco and Polikarpov I-15 were common even in the late 1930s, with many still flying as late as 1942. The Spanish Civil War became a live laboratory. The German Luftwaffe, the Italian Regia Aeronautica and the Soviet Voenno-Vozdushnye Sily each sent aircraft to test. The Messerschmitt Bf 109 did well, as did the Polikarpov I-16, but the Bf 109 was earlier in its design cycle with more room to grow, and the I-16 stayed the most common Soviet front-line fighter into 1942 despite being outclassed. Spain also reshaped tactics. The German pilot Werner Molders developed the finger-four formation, in which a squadron, or Staffel, split into flights called Schwarme of four aircraft, each Schwarm into two Rotten, each Rotte a leader and a wingman. The flexible arrangement preserved situational awareness and let the pairs split off to attack alone. The finger-four would be widely adopted as the fundamental tactical formation of World War II, including by the British and later the Americans.

• 6. The Largest Air War

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  Mustangs over Berlin told Hermann Goring everything. The commander of the German Luftwaffe later said that when he saw them, he knew the jig was up. World War II featured fighter combat on a larger scale than any conflict before it, and design philosophy split sharply. The Japanese and Italians favored lightly armed and armored but highly maneuverable designs like the Nakajima Ki-27, the Nakajima Ki-43, the Mitsubishi A6M Zero, the Fiat G.50 Freccia and the Macchi MC.200. Britain, Germany, the Soviet Union and the United States bet instead on speed and firepower, believing the g-forces of faster aircraft would make First World War style dogfighting unbearable. The European theater turned on who controlled the sky. Luftwaffe Bf 109s held air superiority over Poland and France, but during the Battle of Britain the Hurricanes and Spitfires proved roughly equal, and Britain's radar-based Dowding system denied Germany the skies and possibly an invasion. On the Eastern Front, Operation Barbarossa caught Soviet forces flat, their leadership gutted by the Great Purge and their obsolescent I-15 biplanes and I-16s destroyed on the ground and in one-sided dogfights. By 1942 the Yakovlev Yak-9 and Lavochkin La-5 matched the Bf 109 and the Focke-Wulf Fw 190, and the Bell P-39 Airacobra arrived through Lend-Lease, proving effective in the low-altitude combat typical of the front. In the Pacific, the Zero and the Nakajima fighters first ran wild with better range, maneuverability, speed and climb, flown by veterans of Japan's China campaigns. The Allies answered with the rugged Curtiss P-40 Warhawk and Grumman F4F Wildcat and tactics like the Thach Weave, then with the Lockheed P-38 Lightning, the Grumman F6 Hellcat, the Vought F4 Corsair, the P-47 Thunderbolt and the North American P-51 Mustang. At the Battle of the Philippine Sea, American pilots shot down Japanese fliers so easily they likened it to a turkey shoot. The deepest Japanese failure was not metal but men: its training program could not replace lost pilots, and late in the war its fighter arm was largely reduced to Kamikaze attacks against B-29 Superfortress raids.

• 7. Speed Past The Propeller

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  By the end of World War II, propeller fighters were hitting a wall called compressibility, the trouble that builds as aircraft and their propellers approach the sound barrier. The Spitfire shows the climb and the ceiling at once. Powered by a 1030-horsepower Merlin II in 1939, its 1945 variants carried the 2035-horsepower Rolls-Royce Griffon 61, yet top speed gained only modestly. German jet and rocket fighters reached combat in 1944, too late to change the outcome, and the same year the Allies fielded their only operational jet, the Gloster Meteor. The turbojet rewrote the rulebook. Its weight was far below a piston engine, so carrying two engines was no longer a handicap. That shift demanded ejection seats so pilots could escape and G-suits to counter the greater forces of maneuvering. Wings were made thinner and swept back to cut transonic drag, and skins were milled from large slabs of alloy rather than riveted from sheet metal. Speeds quickly reached Mach 2, past which an aircraft cannot maneuver enough to avoid attack. The first jet-versus-jet dogfight came in the Korean War on the 8th of November 1950, when an F-80 shot down two North Korean MiG-15s. The swept-wing MiG-15, built around the transferred Rolls-Royce Nene engine, reached 1075 kilometers per hour and carried two 23-millimeter cannons and a single 37-millimeter cannon, a shock to F-80 pilots. The Americans rushed in the swept-wing North American F-86 Sabre to match it. Weapons changed too. Early infrared missiles like the AIM-9 Sidewinder and radar-guided ones like the AIM-7 Sparrow first appeared on naval fighters such as the Demon and Cutlass, and their descendants remain in use.

• 8. Generations Of The Jet

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  Richard P. Hallion, of the Secretary of the US Air Force's Action Group, once classified the F-16 as a sixth-generation jet fighter, which shows how loose the labels are. No official definitions of jet-fighter generations exist; they are stages in design thinking, and different authors sort the same aircraft differently. The second generation chased the missile. Strategists imagined guided missiles replacing guns entirely, so interceptors like the English Electric Lightning and the MiG-21F carried big missile payloads and powerful radars while sacrificing agility for speed, ceiling and climb. Beyond-visual-range combat became the dream, pursued through semi-active radar homing missiles that tracked a target painted by the launching aircraft. The Vietnam War broke the dream. Air-to-air missiles had largely replaced guns and rockets in the early 1960s, both thought unusable at high speeds, but Vietnam showed the gun still had a role, and most fighters since carry a cannon alongside missiles. Low kill probabilities for radar missiles, hurt by poor reliability and electronic countermeasures, and poor dogfight loss-exchange ratios led the U.S. Navy to found its TOPGUN fighter-weapons school. The McDonnell F-4 Phantom, built as an all-weather interceptor, became a versatile strike-bomber and claimed 280 aerial kills over Vietnam, more than any other U.S. fighter. The fourth generation was shaped by an idea. Colonel John Boyd and mathematician Thomas Christie built energy-maneuverability theory, and Boyd's OODA loop, Observation-Orientation-Decision-Action, prized fast transients over raw speed. His Fighter mafia produced the General Dynamics F-16 Fighting Falcon, made nimble by relaxed static stability and fly-by-wire controls, earning it the name the electric jet. The same era brought the high-low mix, pairing costly air-superiority fighters like the F-15 and Su-27 with cheaper multirole fighters like the F-16 and MiG-29. Then came stealth, the low-observable materials and shaping that hide an aircraft from radar, first seen on the Lockheed F-117 Nighthawk introduced in 1983 and the Northrop Grumman B-2 Spirit bomber that first flew in 1989. Stealth, pursued by the United States, Russia, India and China, still drives the competition: the global combat aircraft market, worth 45.75 billion dollars in 2017, is projected at 47.2 billion dollars in 2026, dominated by the Lockheed Martin F-35 with 3,000 deliveries planned over 20 years.