Aviation in World War I

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Color Autochrome Lumière of a Nieuport Fighter in Aisne, France 1917

One of the many innovations of World War I, aircraft were first used for reconnaissance purposes and later as fighters and bombers. Consequently, this was the first war which involved a struggle for control of the air, which turned it into another battlefield, alongside the battlefields of land and sea.^[1].

[edit] History

[edit] Prewar development

About ten years after the Wright brothers made the first powered flight, there was still much to be improved upon. Because of limitations of the engine power of the time, aircraft could only lift a certain amount of weight. They were made mostly of hardwood (braced with steel wires) and canvas doped with flammable liquid^[2] to give them the stiffness required to form a wing surface. Aside from these primitive materials, the rudimentary aviation engineering of the time meant most aircraft were structurally fragile by later standards, and not infrequently broke up in flight especially when performing violent combat manuevers such as pulling up from steep dives.

As early as 1909, these evolving flying machines were recognized to be not just toys, but weapons:

The sky is about to become another battlefield no less important than the battlefields on land and sea....In order to conquer the air, it is necessary to deprive the enemy of all means of flying, by striking at him in the air, at his bases of operation, or at his production centers. We had better get accustomed to this idea, and prepare ourselves.

– Giulio Douhet (Italian staff officer), 1909^[2]

In 1911, Captain Bertram Dickson, the first British military officer to fly, also correctly prophesied the military use of aircraft. He predicted aircraft would first be used for reconnaissance, but this would develop into each side trying to "hinder or prevent the enemy from obtaining information", which would eventually turn into a battle for control of the skies. This is exactly the sequence of events that would occur several years later.^[2]

The first operational use of aircraft in war took place on 23 October 1911 in the Italo-Turkish War, when Captain Carlo Piazza made history’s first reconnaissance flight near Benghazi in a Blériot XI. ^[3]

[edit] The early years of war

Rumpler Taube

From the very start, there was some debate over the uses (or usefulness) of aircraft in warfare. Many senior officers, in particular, remained sceptical.

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. ^[4] The French military aviation exercises of 0f 1911, 1912, and 1913 had pioneered cooperation with the cavalry (reconnaissance) and artillery (spotting), but the momentum was if anything slacking. ^[5] Great Britain 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. ^[6] The US army and navy air services were hopelessly 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. ^[7]

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. It was quickly realised, on the other hand, that aircraft could at least locate the enemy – even if early air reconnaissance was hampered by the newness of the techniques involved. Early scepticism and low expectations quickly turned to unrealistic demands beyond the capabilities of the primitive aircraft available.^[8] 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. On August 22, 1914, British Captain L.E.O. Charlton and Lieutenant V.H.N. Wadham reported German General Alexander von Kluck’s army was starting to prepare to surround the BEF, contradicting all other intelligence. The British High Command listened to the pilots’ report and started a withdrawal toward Mons, saving the lives of 100,000 soldiers. Later, during the First Battle of Marne, observation planes discovered weak points and exposed flanks in the German lines, allowing the allies to take advantage of them. ^[9] The Germans' great air "coup" of 1914 was at the Battle of Tannenburg in East Prussia where an unexpected Russian attack was reported by Lts. Canter and Mertens, resulting in the Russians' being forced to withdraw. .^[10]

By 1915, and the stabilisation of the Western Front trench system the main responsibilities of reconnaissance aircraft became aerial photography ^[11] with the responsibility of mapping enemy positions below – and artillery spotting – duties shared with the observation balloon, which had to be tethered to the ground.

[edit] Aircraft

Aircraft of this early period included the Maurice Farman "Shorthorn" and "Longhorn", DFW B.I, Rumpler Taube, B.E. 2a, AEG B.II, Bleriot XI, and the Bristol Scout.

[edit] The dawn of air combat

As Dickson had predicted, initially air combat was extremely rare – and definitely subordinate to reconnaissance . There are even numerous stories of the crew of rival reconnaissance aircraft exchanging nothing more belligerent than smiles and waves.^[11] This soon progressed to throwing bricks, grenades, and other objects, even rope, which they hoped would tangle the enemy aircraft's propeller.^[12] Eventually pilots began firing handheld firearms at enemy aircraft.^[11] The era of air combat proper began as more and more aircraft were fitted with machine guns.

[edit] Problems mounting machine guns

[edit] The "pusher" solution

As early as 1912 the designers of the British firm of Vickers were experimenting with machine gun carrying aircraft – the first concrete result was the Vickers EFB.1, which was featured at the 1913 aero show, .^[13] and appeared in developed form as the FB.5 in February 1915. This pioneering fighter, like the Royal Aircraft Factory FE.2b and the Airco DH.1 were pusher types. The pusher design had the engine and propeller behind the pilot, facing backward, and "pushing" rather than "pulling" the aircraft through the air. This provided the opportunity to optimally mount a machine gun, which could be fired directly forward without an obstructing propeller, and of course reloaded and repaired in-flight. The drawback was pusher designs – because of the struts and rigging necessary to hold their tail units, and the extra drag this entailed – tended at best to have an inferior performance to a "tractor" type with the same engine. Although the FE.2d, a more powerful version of the FE.2b, remained a formidable opponent well into 1916 pusher fighters were already inherently obsolete – on the whole they failed in a most important criterion for a true fighter in that they were not fast enough to catch their quarry.

[edit] 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, to be able to aim it as well as service it during a gun jam. However, this presents an obvious problem – a percentage of the bullets will actually strike the propeller – quickly destroying it!

Early experiments with synchronised machine guns were carried out before the war in several countries. Franz Schneider – the former Nieuport designer now working for the L.V.G. concern in Germany patented a synchronisation gear on July 15, 1913. An early Russian gear was designed by a Lieutenant Poplavko, and the Edwards Brothers in England designed the first British example. Finally – the Morane-Saulnier company were working on the problem in 1914. All these early gears failed to attract official attention – partly due to official inertia – but partly also due to the terrifying results of failures of these early synchronising gears, which included dangerously ricocheting bullets as well as disintegrating propellers. ^[14]

The Lewis gun, used on many early Allied aircraft, proved next to impossible to successfully synchronize due to its open bolt firing cycle. In an open bolt firing cycle, it is impossible to predict the exact time any given round will fire, and for obvious reasons this is a unattractive characteristic in a weapon one is attempting to fire between the spinning blades of a propeller. Although some synchronized Lewis mountings were made, especially in the R.N.A.S) these were never entirely satisfactory.

Diagram of Fokker's "Zentralsteuerung" synchronization mechanism. Pulling the green handle lowers the red cam follower onto the cam wheel attached to the propeller shaft. When the cam raises the follower, the blue rod is depressed against the spring, enabling the yellow trigger plate to be reached when the purple firing button is pressed. This image shows a side view of one of the original Spandau LMG 08 guns, somewhat different in appearance from the LMG 08/15 later German fighters used.

The Maxim guns used by both the Allies (as the Vickers) and Germany (as the LMG 14 Parabellum and LMG 08 Spandau) had a closed bolt firing cycle that started with a bullet already in the breech and the breech closed, so the firing of the bullet was the next step in the cycle. This meant that the exact instant the round would be fired could be predicted with precision, making these weapons considerably easier to synchronize.

The standard French light machine gun, the Hotchkiss,was also most unamenable to synchronisation due to rounds "hanging fire" – and the Morane-Saulnier company designed a "safety backup" in the form of "deflector blades" (metal wedges) fitted to the propeller at the point where they would be struck by a bullet. Roland Garros trialled this system in a Morane-Saulnier L in April 1915. He managed to score several kills, but it was proved to be an inadequate and dangerous solution. Garros eventually was forced by engine failure (possibly caused by the repeated strain on his aircraft's crankshaft of the "deflected" bullets striking his propeller) to land behind enemy lines, and he, and his aircraft, were captured by the Germans. ^[15]

Famously – the German High Command passed Garros' Morane to the Fokker company, who already produced Morane type monoplanes for the German Air Service – with orders to copy the latest design. The deflector system was totally unsuitable for the steel jacketed German ammunition so that the Fokker engineers were forced to revisit the synchronisation idea (perhaps infringing Schneider's patent!) – resulting in the Eindecker fighter series. Crude as these little monoplanes were, they produced period of German air dominance, known as the "Fokker Scourge" by the Allies. 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.

[edit] Other methods

Another method used at this time to fire a machine gun forward from a tractor design was to mount the gun to fire above the propeller arc. This required the gun to be mounted on the top wing of biplanes and be propped up and secured by complicated, drag inducing mounting in monoplanes. Reaching the gun so that drums or belts could be changed, or jams cleared, presented problems – even when the gun could be mounted relatively close to the pilot. Eventually the excellent Foster mounting became more or less the standard way of mounting a Lewis gun in this position in the R.F.C. ^[16] - 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 his tail. This type of mounting was still only possible for a biplane with a top wing positioned near the apex of the propeller's arc - it put considerable strain on the fragile wing structures of the period, and it was much less rigid than a gun mounting on the fuselage - producing a greater "scatter" of bullets, especially at anything but very short range.

The earliest versions of the Bristol Scout to see aerial combat duty in 1915, the Scout C, had Lewis gun mounts in RNAS service that sometimes were elevated above the propeller arc, and sometimes (in an apparently reckless manner) firing directly through the propeller arc without synchronisation. Captain Lanoe Hawker of the Royal Flying Corps, however, had mounted his Lewis gun just forward of the cockpit to fire forwards and outwards, on the left side of his aircraft's fuselage at about a 30º angle, on his Scout C, with serial number 1611, and with this aircraft on July 25, 1915, managed to defeat three German two seat observation aircraft to earn the first Victoria Cross awarded to a British aviator.

[edit] 1915: The Fokker Scourge

Main article: Fokker Scourge

Max Immelmann of Feldflieger Abteilung 62 in the cockpit of his Fokker E.III.

In 1915, Anthony Fokker designed the interrupter gear, which turned the tide of the air war in Germany's favor. This ingenious device mechanically linked the gun to the propeller, stopping the fire when a propeller blade passed in front of the machine gun muzzle. This was first fitted in the spring of 1915 to the production prototypes of the Fokker Eindecker, known as the M.5K/MG, making it top-of-the-line in design, maneuverability (although the Eindecker used primitive wing warping for roll control), and most importantly, gun placement. Leutnant Kurt Wintgens, on July 1, 1915, scored the earliest known victory for a synchronized gun-equipped fighter with his M.5K/MG, with military serial number E.5/15, over a two-seat Morane Saulnier Parasol near Luneville, France. Soon Allied aircraft were forced to flee for home at the mere sight of German monoplanes. A solution was needed, and quickly.

The end of the E.III's supremacy came quickly for two reasons: first, the Allies had already produced new fighter aircraft with performance equal or superior to that of the E.III, and second, the appearance of the Eindecker spurred the production of allied synchronisation gears - the principles of which were already common knowledge.

The two aircraft most responsible for ending the Fokker Scourge were the Nieuport 11 Bébé (a highly maneuverable tractor sesquiplane), and the Airco D.H.2 (a pusher biplane). Both easily outperformed the Fokker, the DH.2 was a pusher, and the Nieport had a wing mounted gun.

The Fokker E-III, Airco DH-2, and Nieuport 11 would be the very first in a long line of single seat fighter aircraft used by both sides during the war. During the Fokker Scourge and immediately afterward, no one really knew what a fighter was, or how it should be used. Very quickly it became clear the primary role of fighters would be attacking enemy two-seaters, which were becoming increasingly important as sources of reconnaissance and artillery observation, while also escorting and defending friendly two-seaters from enemy fighters. Fighters were also used to attack enemy observation balloons, strafing enemy ground targets, and defending friendly airspace from enemy bombers.

[edit] Bloody April

Main article: Bloody April

In April 1917, the Allies launched a joint offensive, the British attacking near Arras in Artois, while the French Nivelle Offensive was launched on the Aisne. Air forces were called on to provide support, predominantly in reconnaissance and artillery spotting.

However, the Germans were prepared for the offensive, and were equipped with the new Albatros D-III, "the best fighting scout on the Western Front"^[17] at the time.

The month became known as Bloody April by the Allied air forces. The Royal Flying Corps suffered particularly severe losses. However, they managed to keep the German Air Force on the defensive, largely preventing them from using their aircraft on bombing or reconnaissance missions to assist their troops on the ground.

Shortly after "Bloody April", the Allies re-equipped their squadrons with new aircraft such as the Sopwith Pup, and S.E.5a which helped tip the balance back in their favor. The Germans responded with new types as well, such as the Fokker Dr.I, which were in turn countered by the British Sopwith Camel and French SPAD S.XIII. As a result, the Allies were able to maintain general air superiority toward the end of the year, which was in general maintained for the rest of the war.

[edit] Up to 1918: the final years of war

The final year of the war (1918) saw increasing shortages of supplies on the side of the Central Powers. Captured Allied aircraft were scrounged for every available material, even to the point of draining the lubricants from damaged engines just to keep one more German aircraft flyable.

Manfred von Richthofen, the famed Red Baron credited with around 80 victories, was killed in April, possibly by an Australian anti-aircraft machinegunner (although Royal Air Force pilot Captain Arthur Roy Brown was officially credited), and the leadership of Jagdgeschwader 1 eventually passed to Hermann Göring.

Germany introduced the Fokker D.VII, both loved and loathed to the point surrender of all surviving examples was specifically ordered by the victorious Allies.

This year also saw the United States increasingly involved. While American volunteers had been flying in Allied squadrons since the early years of the war, not until 1918 did all-American squadrons begin patrolling the skies above the trenches. At first, the Americans were largely supplied with second-rate weapons and obsolete aircraft, such as the Nieuport 28. As American numbers grew, equipment improved, including the SPAD S.XIII, one of the best French aircraft in the war.

[edit] Impact

By the war's end, the impact of air missions on the ground war was in retrospect mainly tactical - strategic bombing, in particular, was still very rudimentary indeed. This was partly due to its restricted funding and use, as it was, after all, a new technology. Some, such as then-Brigadier General William "Billy" Mitchell, commander of all American air combat units in France, claimed "the only damage that has come to [Germany] has been through the air".^[19] Mitchell was famously controversial in his view that the future of war was not on the ground or at sea, but in the air:

[edit] Anti-aircraft weaponry

Main article: Anti-aircraft warfare

Though aircraft still functioned as vehicles of observation, increasingly it was used as a weapon in itself. Dog fights erupted in the skies over the front lines - aircraft went down in flames and heroes were born. From this air-to-air combat, the need grew for better aircraft and gun armament. Aside from machineguns, air-to-air rockets were also used, such as the Le Prieur rocket against balloons and airships.

This need for improvement was not limited to air-to-air combat. On the ground, methods developed before the war were being used to deter enemy aircraft from observation and bombing. Anti-aircraft artillery rounds were fired into the air and exploded into clouds of smoke and fragmentation, called archie by the British.

Anti-aircraft artillery defenses were increasingly used around observation balloons, which became frequent targets of enemy fighters equipped with special incendiary bullets. Because balloons were so flammable, due to the hydrogen used to inflate them, observers were given parachutes, enabling them to jump to safety. Ironically, only a few aircrew had this option, due in part to a mistaken belief they inhibited aggressiveness, and in part to early aircraft being unable to lift their significant weight.

[edit] Bombing and reconnaissance

As the stalemate developed on the ground, with both sides unable to advance even a few hundred yards without a major battle and thousands of casualties, aircraft became greatly valued for their role gathering intelligence on enemy positions and bombing the enemy's supplies behind the trench lines. Large aircraft with a pilot and an observer were used to scout enemy positions and bomb their supply bases. Because they were large and slow, these aircraft made easy targets for enemy fighter aircraft. As a result, both sides used fighter aircraft to both attack the enemy's two-seat aircraft and protect their own while carrying out their missions.

While the two-seat bombers and reconnaissance aircraft were slow and vulnerable, they were not defenseless. Two-seaters had the advantage of both forward- and rearward- firing guns. Typically, the pilot controlled fixed guns behind the propeller, similar to guns in a fighter aircraft, while the observer controlled one with which he could cover the arc behind the aircraft. A tactic used by enemy fighter aircraft to avoid fire the from the rear gunner was to attack from slightly below the rear of two-seaters, as the tail gunner was unable to fire below the aircraft. However, Two-seaters could counter this tactic by going into a dive at high speeds, aided by their heavy weight. Pursuing a diving two-seater was hazardous for a fighter pilot, as it would place the fighter directly in the rear-gunner's line of fire; several high scoring aces of the war were shot down by "lowly" two-seaters, including Raoul Lufbery and Robert Little.

[edit] Strategic bombing

Plaque commemorating a September 8, 1915 Zeppelin raid on 61 Farringdon Road, London.

The first ever aerial bombardment of civilians was during World War I. On January 19, 1915, two German Zeppelins dropped 24 fifty-kilogram high-explosive bombs and ineffective three-kilogram incendiaries on Great Yarmouth, Sheringham, King's Lynn, and the surrounding villages. In all, four people were killed, sixteen injured, and monetary damage was estimated at £7,740, although the public and media reaction were out of proportion to the death toll.^[20]

There were a further nineteen raids in 1915, in which 37 tons of bombs were dropped, killing 181 people and injuring 455. Raids continued in 1916. London was accidentally bombed in May, and, in July, the Kaiser allowed directed raids against urban centres. There were 23 airship raids in 1916 in which 125 tons of ordnance were dropped, killing 293 people and injuring 691. Gradually British air defenses improved. In 1917 and 1918 there were only eleven Zeppelin raids against England, and the final raid occurred on August 5, 1918, which resulted in the death of KK Peter Strasser, commander of the German Naval Airship Department. By the end of the war, 51 raids had been undertaken, in which 5,806 bombs were dropped, killing 557 people and injuring 1,358.

The Zeppelin raids were complemented by the Gotha G bombers from 1917, which were the first heavier than air bombers to be used for strategic bombing. It has been argued that the raids were effective far beyond material damage in diverting and hampering wartime production, and diverting twelve squadrons and over 10,000 men to air defenses. The calculations which were performed on the number of dead to the weight of bombs dropped would have a profound effect on the attitudes of the British authorities and population in the interwar years.

[edit] Observation balloons

Main article: Observation balloon

A German observation balloon being bombed by an allied aircraft.

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. Balloons commonly had a crew of two equipped with parachutes: upon an enemy air attack on the flammable balloon, the crew would parachute to safety. Recognized for their value as observer platforms, observation balloons were important targets of enemy aircraft. To defend against air attack, they were heavily protected by large concentrations antiaircraft guns and patrolled by friendly aircraft. Blimps and balloons helped contribute to the stalemate of the trench warfare of World War I, and contributed to air to air combat for air superiority because of their significant reconnaissance value.

In order to encourage their pilots to attack enemy balloons whenever they were found, both sides counted downing an enemy balloon as an "air-to-air" kill, with the same value as shooting down an enemy aircraft. Some pilots, known as balloon busters, became particularly distinguished by their prowess at shooting down enemy balloons. Perhaps the best known of these was American ace Frank Luke: 14 of his 18 kills were enemy balloons.

[edit] Notable aces

Main article: List of World War I flying aces

[edit] Notable aircraft

• Aircraft of the Entente Powers
• Aircraft of the Central Powers

See also Category:World War I aircraft.

[edit] Notes

[edit] See also

[edit] Main articles

• World War I

[edit] Other articles

• Aviation history: 1914-1918
• Flying ace
• Dogfight

[edit] References

• The Great War, television documentary by the BBC.
• Pearson, George, Aces: A Story of the First Air War, historical advice by Brereton Greenhous and Philip Markham, NFB, 1993. Contains assertion aircraft created trench stalemate.
• Winter, Denis. First of the Few. London: Allen Lane/Penguin, 1982. Coverage of the British air war, with extensive bibliographical notes.
• Morrow, John. German Air Power in World War I. Lincoln: University of Nebraska Press, 1982. Contains design and production figures, as well as economic influences.
• Editors of American Heritage. History of WW1. Simon & Schuster, 1964.

[edit] External links

World War I Portal

Wikimedia Commons has media related to:

World War I aviation

• Rosebud's WWI and Early Aviation Image Archive
• Bombing during World War I
• Flyboys - World War I aviation movie
• - Aerial Russia - the Romance of the Giant Airplane - aviation in Russian before and during WWI - online book

Italian aircraft:

• Aircraft of the AEF - Caproni Ca.3
• Aerei Italiani (Italian)