World War I was the first major conflict involving the use of aircraft. Tethered observation balloons had already been employed in several wars and would be used extensively for artillery spotting. Germany employed Zeppelins for reconnaissance over the North Sea and Baltic Sea and also for strategic bombing raids over the Eastern Front and Britain.
Airplanes were just coming into military use at the outset of the war. Initially, they were used mostly for reconnaissance. Pilots and engineers learned from experience, leading to the development of many specialized types, including fighters, bombers, and trench strafers.
Ace fighter pilots were portrayed as modern knights, and many became celebrities back home. The war also saw the appointment of high-ranking officers to direct the belligerent nations' air war efforts.
While the impact of airplanes on the course of the war was mainly tactical rather than strategic, the most important role being direct cooperation with ground forces (especially ranging and correcting artillery fire), the first steps in the strategic roles of aircraft in future wars were also foreshadowed.
The early years of war
At the 1911 meeting of the Institute of International Law in Madrid, legislation was proposed to limit the use of aeroplanes to reconnaissance missions and banning them from being used as platforms for weapons. This legislation was rooted in a fear that aeroplanes would be used to attack undefended cities, violating Article 25 of the Den Hague Reglement (the set of international laws governing warfare).
At the start of the war, there was some debate over the usefulness of aircraft in warfare. Many senior officers, in particular, remained skeptical. However the initial campaigns of 1914 proved that cavalry could no longer provide the reconnaissance expected by their generals, in the face of the greatly increased firepower of twentieth century armies, and it was quickly realised that aircraft could at least locate the enemy, even if early air reconnaissance was hampered by the newness of the techniques involved. Early skepticism and low expectations quickly turned to unrealistic demands beyond the capabilities of the primitive aircraft available.Terraine, John. P.30
Even so, air reconnaissance played a critical role in the "war of movement" of 1914, especially in helping the Allies halt the German invasion of France. Aircraft were first used in Alexander von Kluck's German First Army during the Battle of Mons to target its guns on British II Corps positions. On 22 August 1914, British Captain L.E.O. Charlton and Lieutenant V.H.N. Wadham of the Royal Flying Corps (RFC) reported von Kluck's forces were preparing to surround the British Expeditionary Force, contradicting all other intelligence. The British High Command took note of the report and started to withdraw from Mons, saving the lives of 100,000 soldiers. Later, during the First Battle of the Marne, observation aircraft discovered weak points and exposed flanks in the German lines, allowing the allies to take advantage of them.
In Germany the great successes of the early Zeppelin airships had largely overshadowed the importance of heavier-than-air aircraft. Out of a paper strength of about 230 aircraft belonging to the army in August 1914 only 180 or so were of any use.Terraine, 1981, p.31. The French military aviation exercises of 1911, 1912, and 1913 had pioneered cooperation with the cavalry (reconnaissance) and artillery (spotting), but the momentum was, if anything, slacking.Terraine, 1981, p.30
The United Kingdom had "started late" and initially relied largely on the French aircraft industry, especially for aircraft engines. The initial British contribution to the total allied airwar effort in August 1914 (of about 184 aircraft) was three squadrons with about 30 serviceable machines. By the end of the war, the British Armed Forces had formed the world's first air force to be independent of either army or naval control, the Royal Air Force.Terraine, 1982, p.31 The United States Armed Forces air services were far behind; even in 1917, when the United States entered the war, they were to be almost totally dependent on the French and British aircraft industries for combat aircraft.Treadwell, Terry C. America's First Air War (London: Airlife Publishing, 2000)
The Germans' great air "coup" of 1914 was at the Battle of Tannenberg in East Prussia, where an unexpected Imperial Russian Army attack was reported by Leutnants Canter and Mertens, resulting in the Russians being forced to withdraw.Cheesman, E.F. (ed.) Reconnaissance & Bomber Aircraft of the 1914–1918 War (Letchworth, UK: Harleyford, 1962), p. 9.
Early Western Front reconnaissance duties
By the end of 1914 the line between the Imperial German Army and the Allied powers stretched from the North Sea to the Alps. The initial "war of movement" largely ceased, and the front became static. Three main functions of short range reconnaissance squadrons had emerged by March 1915.
The first was photographic reconnaissance. A building up of a complete mosaic map of the enemy trench system. The first air cameras used glass plates. (Photographic film had been invented by Kodak, but did not at this stage have sufficient resolution).An Illustrated History of World War I, at http://www.wwiaviation.com/earlywar.html
Artillery "spotting" enabled the ranging of artillery on targets invisible to the gunners. Radio telephony was not yet practical from an aircraft, so communication was a problem. By March 1915, a two-seater on "artillery observation" duties was typically equipped with a primitive radio transmitter transmitting using Morse code, but had no receiver. The artillery battery signalled to the aircraft by laying strips of white cloth on the ground in prearranged patterns. Observation duties were shared with the tethered balloons, which could communicate directly with their batteries by field telephone, but were far less flexible in locating targets and reporting the fall of shot.
"Contact patrol" work attempted to follow the course of a battle by communicating with advancing infantry while flying over the battlefield. The technology of the period did not permit radio contact, while methods of signalling were necessarily crude, including dropping messages from the aircraft. Soldiers were initially reluctant to reveal their positions to aircraft, as they (the soldiers) found distinguishing between friend and foe problematic.
Reconnaissance flying, like all kinds, was a hazardous business. In April 1917, the worst month for the entire war for the RFC, the average life expectancy of a British pilot on the Western Front was 93 flying hours. "8,000 men dying during their 15 hours of pilot training." There was an eagerness for many young men to join the Air Force but the main problem was the sheer lack of planes the countries had.
Early bombing efforts
Typical 1914 aircraft could carry only very small bomb loads – the bombs themselves, and their storage, were still very elementary, and effective bomb sights were still to be developed. Nonetheless the beginnings of strategic and tactical bombing date from the earliest days of the war. Notable are the raids by the RNAS on the German airship sheds at Düsseldorf, Cologne and Friedrichshafen in September, October and November 1914, as well as the formation of the Brieftauben Abteilung Ostende.
The dawn of air combat As Dickson had predicted, initially air combat was extremely rare, and definitely subordinate to reconnaissance. There are even stories of the crew of rival reconnaissance aircraft exchanging nothing more belligerent than smiles and waves. This soon progressed to throwing grenades, and other objects—even grappling hooks.Great Battles of World War I by Major-General Sir Jeremy Moore, p. 136 The first aircraft brought down by another was an Austrian reconnaissance aircraft rammed on 8 September 1914 by a Russian pilot Pyotr Nesterov in Galicia in the Eastern Front. Both planes crashed as the result of the attack, killing all occupants. Eventually, pilots began firing handheld firearms at enemy aircraft; however, pistols were too inaccurate and the single-shot rifles too unlikely to score a hit. On August 23, 1914, no 5 Squadron British observer Lt Leslie da Costa Penn Gaskell opened fire on a German aircraft with a machine gun for the first time and the era of air combat was underway as more and more aircraft were fitted with machine guns.
Evolution of fighter aircraft
The pusher solution As early as 1912, designers at the British firm Vickers were experimenting with machine gun carrying aircraft. The first concrete result was the Vickers Experimental Fighting Biplane 1, which featured at the 1913 Aero Show in London, a grand fest.Cheesman (1960), p. 76. and appeared in developed form as the FB.5 in February 1915. This pioneering fighter, like the Royal Aircraft Factory F.E.2b and the Airco DH.1, was a pusher type. These had the engine and propeller behind the pilot, facing backward, rather than at the front of the aircraft, as in a tractor configuration design. This provided an optimal machine gun position, from which the gun could be fired directly forward without an obstructing propeller, and reloaded and cleared in flight. An important drawback was that pusher designs tended to have an inferior performance to tractor types with the same engine power because of the extra drag created by the struts and rigging necessary to carry the tail unit. The F.E.2d, a more powerful version of the F.E.2b, remained a formidable opponent well into 1917, when pusher fighters were already obsolete. They were simply too slow to catch their quarry.
Machine gun synchronisation
The forward firing gun of a pusher "gun carrier" provided some offensive capability—the mounting of a machine gun firing to the rear from a two-seater tractor aircraft gave defensive capability. There was an obvious need for some means to fire a machine gun forward from a tractor aircraft, especially from one of the small, light, "scout" aircraft, adapted from pre-war racers, that were to perform most air combat duties for the rest of the war. It would seem most natural to place the gun between the pilot and the propeller, firing in the direct line of flight so that the gun could be aimed by "aiming the aircraft". It was also important that the breech of the weapon be readily accessible to the pilot so that he could clear the jams and stoppages to which early machine guns were prone. However, this presented an obvious problem: a percentage of bullets fired "free" through a revolving propeller will strike the blades, with predictably destructive results. Early experiments with synchronised machine guns had been carried out in several countries before the war. Franz Schneider, then working for Nieuport in France but later working for L.V.G. in Germany, patented a synchronisation gear on 15 July 1913. Early Russian gear was designed by a Lieutenant Poplavko: the Edwards brothers in England designed the first British example, and the Morane-Saulnier company were also working on the problem in 1914. All these early experiments failed to attract official attention, partly due to official inertia and partly due to the failures of early synchronising gears, which included dangerously ricocheting bullets and disintegrating propellers.Cheesman (1960), p 177 The Lewis gun used on many Allied aircraft was almost impossible to synchronise due to the erratic rate of fire resulting from its open bolt firing cycle.