Fighter aircraft

The word "fighter" was first used to describe a two-seater aircraft with sufficient lift to carry a machine gun and its operator as well as the pilot. Some of the first such "fighters" belonged to the "gunbus" series of experimental gun carriers of the British Vickers company that culminated in the Vickers F.B.5 Gunbus of 1914. The main drawback of this type of aircraft was its lack of speed. Planners quickly realized that an aircraft intended to destroy its kind in the air had to be fast enough to catch its quarry. Another type of military aircraft was to form the basis for an effective "fighter" in the modern sense of the word. It was based on the small fast aircraft developed before the war for such air races as the Gordon Bennett Cup and Schneider Trophy. The military scout airplane was not expected to carry serious armament, but rather to rely on its speed to reach the scout or reconnoiter location and return quickly to report—essentially an aerial horse. British scout aircraft, in this sense, included the Sopwith Tabloid and Bristol Scout. French equivalents included the Morane-Saulnier N.

Soon after the commencement of the war, pilots armed themselves with pistols, carbines, grenades, and an assortment of improvised weapons. Many of these proved ineffective as the pilot had to fly his airplane while attempting to aim a handheld weapon and make a difficult deflection shot. The first step in finding a real solution was to mount the weapon on the aircraft, but the propeller remained a problem since the best direction to shoot is straight ahead. Numerous solutions were tried. A second crew member behind the pilot could aim and fire a swivel-mounted machine gun at enemy airplanes however, this limited the area of coverage chiefly to the rear hemisphere, and effective coordination of the pilot's maneuvering with the gunner's aiming was difficult. This option was chiefly employed as a defensive measure on two-seater reconnaissance aircraft from 1915 on. Both the SPAD A.2 and the Royal Aircraft Factory B.E.9added a second crewman ahead of the engine in a pod but this was both hazardous to the second crewman and limited performance. The Sopwith L.R.T.Tr. similarly added a pod on the top wing with no better luck.

Billy Bishop sitting in hisNieuport 23 with the machine gun (just visible at the top of the picture) mounted to fire over the propeller.

An alternative was to build a "pusher" scout such as the Airco DH.2, with the propeller mounted behind the pilot. The main drawback was that the high dragof a pusher type's tail structure made it slower than a similar "tractor" aircraft.

A better solution for a single seat scout was to mount the machine gun (rifles and pistols having been dispensed with) to fire forwards but outside the propeller arc. Wing guns were tried but the unreliable weapons available required frequent clearing of jammed rounds and misfires and remained impractical until after the war. Mounting the machine gun over the top wing worked well and was used long after the ideal solution was found. The Nieuport 11 of 1916 and Royal Aircraft Factory S.E.5 of 1918 both used this system with considerable success, however this placement made aiming difficult and the location made it difficult for a pilot to both maneuver and have access to the gun's breech. The British Foster mounting was specifically designed for this kind of application, fitted with the Lewis Machine gun, which due to its design was unsuitable for synchronizing.

The actual aircraft used by Wintgens in his pioneering aerial engagement, his Fokker M.5K/MG with IdFlieg military serial number "E.5/15", as it appeared at the time of the engagement.

The need to arm a tractor scout with a forward-firing gun whose bullets passed through the propeller arc was evident even before the outbreak of war and inventors in both France and Germany devisedmechanisms that could time the firing of the individual rounds to avoid hitting the propeller blades. Franz Schneider, a Swiss engineer, had patented such a device in Germany in 1913, but his original work was not followed up. French aircraft designer Raymond Saulnier patented a practical device in April 1914, but trials were unsuccessful because of the propensity of the machine gun employed to hang fire due to unreliable ammunition.

In December 1914, French aviator Roland Garros asked Saulnier to install his synchronization gear on Garros' Morane-Saulnier Type L. Unfortunately the gas-operated Hotchkiss machine gun he was provided had an erratic rate of fire and it was impossible to synchronize it with a spinning propeller. As an interim measure, the propeller blades were armored and fitted with metal wedges to protect the pilot from ricochets. Garros' modified monoplane was first flown in March 1915 and he began combat operations soon thereafter. Garros scored three victories in three weeks before he himself was downed on 18 April and his airplane, along with its synchronization gear and propeller was captured by the Germans.

Meanwhile, the synchronization gear (called the Stangensteuerung in German, for "pushrod control system") devised by the engineers of Anthony Fokker's firm was the first system to see production contracts, and would make the Fokker Eindeckermonoplane a feared name over the Western Front, despite its being an adaptation of an obsolete pre-war French Morane-Saulnier racing airplane, with a mediocre performance and poor flight characteristics. The first victory for the Eindecker came on 1 July 1915, when Leutnant Kurt Wintgens, flying with the Feldflieger Abteilung 6unit on the Western Front, forced down a Morane-Saulnier Type L two-seat "parasol" monoplane just east of Luneville. Wintgens' aircraft, one of the five Fokker M.5K/MGproduction prototype examples of the Eindecker, was armed with a synchronized, air-cooled aviation version of the Parabellum MG14 machine gun.

A Sopwith Camel at the RAF Museum

The success of the Eindecker kicked off a competitive cycle of improvement among the combatants, building ever more capable single-seat fighters. The Albatros D.I and Sopwith Pup of 1916 set the classic pattern followed by fighters for about twenty years. Most were biplanes and only rarely monoplanes or triplanes. The strong box structure of the biplane wing provided a rigid wing that allowed the accurate lateral control essential for dogfighting. They had a single operator, who flew the aircraft and also controlled its armament. They were armed with one or twoMaxim or Vickers machine guns, which were easier to synchronize than other types, firing through the propeller arc. Gun breeches were directly in front of the pilot with obvious implications in case of accidents, but jams could be cleared in flight, while aiming was simplified.

The use of metal aircraft structures was pioneered before World War I by Breguet but would find its biggest proponent with Anthony Fokker who used chrome-molybdenum steel tubing for the fuselage structure of all his fighter designs, while the innovative German engineer Hugo Junkers developed two all-metal, single-seat fighter monoplane designs with cantilever wings: the strictly experimental Junkers J 2 private-venture aircraft, made with steel, and some forty examples of the Junkers D.I, made with corrugated duralumin, all based on his experience in creating the pioneering Junkers J 1 all-metal airframe technology demonstration aircraft of late 1915. While Fokker would pursue steel tube fuselages with wooden wings until the late 1930s, and Junkers would focus on corrugated sheet metal, Dornier was the first to build a fighter (The Dornier-Zeppelin D.I) made with pre-stressed sheet aluminium and having cantelevered wings, a form that would replace all others in the 1930s.

As collective combat experience grew, the more successful pilots such as Oswald Boelcke, Max Immelmann, and Edward Mannock developed innovative tactical formations and maneuvers to enhance their air units' combat effectiveness.

German Fokker Triplanes ofJasta 26 in World War I

Allied and—before 1918—German pilots of World War I were not equipped with parachutes, so in-flight fires or structural failure were often fatal. Parachutes were well-developed by 1918 having previously been used by balloonists, and were adopted by the German flying services during the course of that year (the famous "Red Baron" was wearing one when he was killed), but the allied command continued to oppose their use on various grounds.[5]

In April 1917, during a brief period of German aerial supremacy, a grandstandingMember of Parliament (upset at the lack of orders for his own aircraft manufacturing firm) claimed that, on the Western Front, a British pilot's average life expectancy was 93 flying hours, or about three weeks of active service.[6][7] More than 50,000 airmen from both sides died during the war.[8]