The Race for Military Aviation Technological Supremacy

The Evolution of Military Aircraft

Farman Biplane
Farman Biplane: 1913

Designed by French aviator Henri Farman, the Farman Biplanes were employed in the early stages of WWI by the French military.

Caudron G.III - 1914
Caudron G.III – 1914

The French Caudron G.III was a two seat, single-engined tractor biplane built in 1913 for reconnaissance missions.

RAF FE.6 - 1914
RAF FE.6 – 1914

Relatively little is known of the FE6, other than it was a two-bay, single- engine pusher biplane which was as built in the second half of 1914.

Airco D.H.2 - 1915
De Havilland D.H.2: 1915

The D.H.2 had good maneuverability with an excellent rate of climb. Mounting the engine to the rear of the fuselage permitted the use of a fixed, forward-firing machine gun before the advent of the synchronous machine gun.

Fokker E.I - 1915
Fokker E.I Eindecker: 1915

The Fokker E.I was the first aircraft armed with a synchronized, forward firing machine gun. Although underpowered and slow it could out-turn most of its opponents

Nieuport 11 "Bébé" (baby) - 1915
Nieuport 11: 1915

The Nieuport 11 "Bébé" (baby) was fast and extremely maneuverable. Used by the British and French to counter the Fokker E.III.

Albatros D.III - 1916
Albatros D.III – 1916

The German Albatros D.III was a sesquiplane semi-monocoque, plywood skinned fightercraft armed with twin 0.312 in (7.92 mm) LMG 08/15 "Spandau" machine guns.

SPAD S VII: 1916

The French Air Service replaced the Nieuport 17 with the SPAD S.VII, it was fast, durable and difficult to shoot down.

Sopwith Camel - 1917
Sopwith Camel: 1917

An agile, highly maneuverable biplane, the Sopwith Camel accounted for more aerial victories than any other Allied aircraft during World War I.

Pfalz D.III - 1917
Pfalz D.III

Although the D.III was generally considered inferior to Albatros and Fokker fighters, it served from the fall of 1917 through the summer of 1918.

Fokker Dr.I - 1917
Fokker Dr.I – 1917

The Fokker DR.I triplane was small, lightweight and highly maneuverable, it offered good upward, visibility making it an outstanding plane in a dogfight.

Fokker D.VII - 1918
Fokker D.VII – 1918

The Fokker D.VII is widely regarded as the best German fighter aircraft of the Great War.

Salmson 2a
Salmson 2: 1918

The Salmson 2 was a reconnaissance aircraft made by Salmson, it was the main reconnaissance aircraft in use with the French army in 1918.

 Junkers D.I - 1918
Junkers D.I: 1918

The Junkers monoplane was rugid, fast, and agile. The design was a decade ahead of its time appearing a year too late.

Table of Contents

WWI Aviation Development

The Great War marked the first period of development in military aviation, from its primative beginnings, to technological sophistication in a timespan that was less than a decade. The First World War spured rapid technological innovation. Military aircraft quickly evolved from their humble beginnings as unarmed slow moving, fragile, powered kites, into quick, agile, sturdy, deadly fighter craft and rugid bombers bristling with machine guns and a large load of bombs to bring the battle to those on the ground.

The designers from the warring nations sought to improve their aerial weapons to bring about victory. In the process they unknowingly laid the groundwork for a technological timebomb that would explode decades later culminating in the aircraft of World War Two.

Scout Planes

The first airplanes were not seen as offensive weapons, but as “scouts”. Even at the end of the war, the fighter types, such as the Sopwith Snipe and Fokker D8, were still classified as scouts.

Although horses were used to scout out the enemies’ position, they had serious limitations.The scout planes had a greater freedom of movement, a much wider range of operation and the unparalelled speed to accomplish these missions. Unharrassed by the enemy ground forces the reconnaissance aircraft could monitor the enemies’ movement and positions from a great altitude. Aerial photography was a vital operation for both sides of the war.

The Genesis of Fighter Aircraft

The first airplanes were not seen as offensive weapons, but as “scouts”. Even at the end of the war, the fighter types, such as the Sopwith Snipe and Fokker D8, were still classified as scouts.

It soon became apparent that aircraft needed offensive firepower, and the best way to use it in combat was firing into the forward arc of travel. The obvious problem was painfully simple to see: firing a machine gun through the arc of the propellor would result in a shattered prop causing you and your aircraft sustain a fatal crash.Since the use of a parachute was not employed ot condoned it was suicide and not combat. Several methods were tried, none of them were completely satisfactory.

  • The Wing-Mounted Gun Solution:

    Simply move the machine gun to the upper wing angled to fire above the path of the propeller: You could fire your machine gun into the forward arc with a modest degree of accuracy. You were still faced with two issues. Because most machine guns suitable for wing mounted operation were fitted with either drum or clip ammunition feed systems; also their operation was fairly unreliable and prone to jamming creating an additional problem. The difficult task of reloading amunition or clearing a round from a jammed gun while flying in combat distracted the pilot. Unless the pilot could disengage long enough to complete the task, he would be unarmed, defenseless, and extremely vulnerable to enemy attack.

Wing mounted Lewis gun
Wing mounted Lewis gun
  • The Pusher Plane Option:

    Place the aircraft’s powerplant behind the fuselage so the propeller pushes the plane instead of pulling it through the air. Now you can mount your gun in the nose. The bad news is pusher planes are not as fast or efficient as tractor planes. There is also the problem of crashing. Momentum would cause the engine to travel forward and act like a meat grinder when it catches up with the pilot.

Vickers FB-6 Pusher Plane
Vickers FB-6 Pusher Plane
  • The Steel Deflector Plate Fix:

    This risky fix requires fitting angled metal guards on the propeller in line with the path of the bullets: The guard is a "V" shaped piece of steel with mounting brackets welded on the two ends at the top of the "V", these are attached to the propeller When viewed from the front or side you can see a "U" shaped bullet "gutter" intended to direct the deflected path of the bullet striking it away fro the propeller. This did not always work well due to vibrations causing the gun to shake, sending a ricocheting bullet back into the pilot. Another problem was the impact of the bullet striking the plate could create fractures in the propeller causing it to fail.

Steel Deflector Plate
Deflector Plate

The Quest for Synchronised Machineguns

During the month before the outbreak of the war, Raymond Saulnier had been working on an interupter gear that would allow a machine gun to be fired through the propeller arc. He had grown impatient with hang-fire failures so he attached steel deflection plates on the propeller where the bullets passed through the arc. The military lost interest in his idea once the war started and made Saulnier return the machine gun he had borrowed. After a few months into the war, all the pilots were unanimous in their desire for fixed machine guns facing forward that they could shoot in the direction they were flying.

Lieutenant Roland Garros came to Saulnier and had steel deflector plates attached to his propeller blades and a fixed machine gun mounted in front of the cockpit. The interrupter gear was not installed, Garros relying on the steel plates to ward off the bullets that hit the airscrew. On April 19, he was brought down by enemy ground fire while strafing an infantry unit near Coutrai. His attempts to set fire to his plane were unsuccessful and his modified airscrew was quickly in the workshop of Anthony Fokker.

The problem of perfecting a machine gun that would synchronize its firing with the rotation of the propellers was given to the Dutch engineer Anthony Fokker. According to stories, in a period of two days he improved on Garros’ innovation considerably. Shortly after German implementation of the interrupter gear, the Allies developed a synchronized machine gun designed by Georges Constantinesco.

Anatomy of the Interrupter Gear

Anatomy of the Interrupter Gear

The operation of an interrupter gear is the same principle used by the valves of a gasoline engine. They are timed to open and close at a given point in the revolution of the engine. A similar method is employed to time the firing of a machine gun.

An additional cam is placed on the end of the cam shaft of the motor. Next to this is a rod connected with the breech block of the gun. When the gun is not being fired the rod is held away from the cam by a spring. Pressing the trigger brings the two in contact, and each time the cam revolves it strikes the rod which in turn trips the hammer of the gun and causes it to fire. The cam is regulated so that it comes in contact with the rod just as each blade has passed the muzzle of the gun which can therefore fire at this time only.

The engine revolves at least 1,000 turns per minute and as there are two chances for the gun to fire for each revolution, this would allow the gun to fire 2,000 shots per minute. The rate of fire of a machine gun varies from about 400 to 1,000 shots per minute according to the type of gun and the way in which it is configured. The gun has many more oppurtunities to fire between the blades of the propeller than its rate of fire. Consequently, the gun can work at full speed regardless of ordinary variations in the number of revolutions of the engine.