Aviation in World War I

[1] 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).

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.

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.

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.

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.

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.

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.

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.

Some RNAS aircraft, including Bristol Scouts, had an unsynchronised fuselage-mounted Lewis gun positioned to fire directly through the propeller disk.

The Morane-Saulnier company designed a "safety backup" in the form of "deflector blades" (metal wedges), fitted to the rear surfaces of a propeller at the radial point where they could be struck by a bullet.

The psychological effect exceeded the material: The Allies had up to now been more or less unchallenged in the air, and the vulnerability of their older reconnaissance aircraft, especially the British B.E.2 and French Farman pushers, came as a very nasty shock.

:[17] this allowed the gun to slide backward for drum changing, and also to be fired at an upward angle, a very effective way of attacking an enemy from the "blind spot" under its tail.

The first purpose-designed fighter aircraft included the British Vickers F.B.5, and machine guns were also fitted to several French types, such as the Morane-Saulnier L and N. Initially the German Air Service lagged behind the Allies in this respect, but this was soon to change dramatically.

In July 1915 the Fokker E.I, the first aircraft to enter service with a "synchronisation gear" which enabled a machine gun to fire through the arc of the propeller without striking its blades, became operational.

Some 200 shots from the synchronised Parabellum MG14 machine gun on Wintgens' aircraft had hit the Gnome Lambda rotary engine of the Morane Parasol, forcing it to land safely in Allied territory.

[18] By late 1915 the Germans had achieved air superiority, rendering Allied acquisition of vital intelligence derived from continual aerial reconnaissance more dangerous.

Nonetheless, the impact on morale of the fact that the Germans were effectively fighting back in the air created a major scandal in the British parliament and press.

On the French front, the tiny Nieuport 11, a tractor biplane with a forward firing gun mounted on the top wing outside the arc of the propeller, also proved more than a match for the German fighter when it entered service in January 1916.

Almost all the fighters in service with both sides, with the exception of the Fokkers' steel-tube fuselaged airframes, continued to use wood as the basic structural material, with fabric-covered wings relying on external wire bracing.

Nonetheless, air superiority and an "offensive" strategy facilitated the greatly increased involvement of the RFC in the battle itself, in what was known at the time as "trench strafing" – in modern terms, close support.

[19] In a pioneering move in March 1916, German master aerial tactician Oswald Boelcke came up with the idea of having "forward observers" located close to the front lines to spot Allied aircraft approaching the front, to avoid wear and tear on the trio of Fokker Eindecker scout aircraft he had based with his own "KEK" unit based at Sivry-sur-Meuse,[20] just north of Verdun.

Its most famous and dramatic effect, however, involved the raising of specialist fighter squadrons or Jagdstaffeln – a full year after similar units had become part of the RFC and the French Aéronautique Militaire.

The RFC suffered particularly severe losses, although Trenchard's policy of "offensive patrol", which placed most combat flying on the German side of the lines, was maintained.

The surrender of the Russians and the Treaty of Brest-Litovsk in March 1918, and the resulting release of troops from the Eastern Front gave the Germans a "last chance" of winning the war before the Americans could become effectively involved.

By the end of April, the new Fokker, Pfalz and Roland fighters had finally begun to replace the obsolescent equipment of the Jagdstaffeln, but this did not proceed with as much dispatch as it might have, due to increasing shortages of supplies on the side of the Central Powers, and many of the Jastas still flew Albatros D types at the time of the armistice.

Recoilless rifles and autocannons were also attempted, but they pushed early fighters to unsafe limits while bringing negligible returns, with the German Becker 20mm autocannon being fitted to a few twin-engined Luftstreitkräfte G-series medium bombers for offensive needs, and at least one late-war Kaiserliche Marine zeppelin for defense – the uniquely armed SPAD S.XII single-seat fighter carried one Vickers machine gun and a special, hand-operated semi-automatic 37mm gun firing through a hollow propeller shaft.

Anti-aircraft artillery defenses were increasingly used around observation balloons, which became frequent targets of enemy fighters equipped with special incendiary bullets.

Even Manfred von Richthofen, the highest scoring ace of WWI, was once wounded and forced to crash land from the bullets of a two-seater, though he did survive the encounter and continued flying after he recovered.

[41] Calculations performed on the number of dead to the weight of bombs dropped had a profound effect on attitudes of the British government and population in the interwar years, who believed that "The bomber will always get through".

Manned observation balloons floating high above the trenches were used as stationary reconnaissance points on the front lines, reporting enemy troop positions and directing artillery fire.