Damaged propeller from a Sopwith Baby aircraft circa 1916/17 with evidence of bulletholes from a machine gun fired behind the propeller without an Interruptor. The propeller required immediate replacement after the aircraft landed.

Interrupter gear is a term that covers two related technologies. Image File history File linksMetadata Size of this preview: 450 × 600 pixelsFull resolution (1152 × 1536 pixel, file size: 308 KB, MIME type: image/jpeg) (All user names refer to en. ... Image File history File linksMetadata Size of this preview: 450 × 600 pixelsFull resolution (1152 × 1536 pixel, file size: 308 KB, MIME type: image/jpeg) (All user names refer to en. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...

The first is Synchronization gear, which is often incorrectly referred to as "interrupter gear"; this is a triggering device attached to the machine gun armament of a tractor-type fighter aircraft so that it would fire only at certain times. This allows the gun to fire through the arc of a spinning propeller without the bullets striking the blades. Introduced during the First World War, the gun synchronizer was a significant development in the history of air combat and remained in operational use until the Korean War when the widespread adoption of Jet aircraft rendered them obsolete. A machine gun is a fully-automatic firearm that is capable of firing bullets in rapid succession. ... This article or section does not adequately cite its references or sources. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Ypres, 1917, in the vicinity of the Battle of Passchendaele. ... Aerial warfare is the use of military aircraft and other flying machines in warfare, including military airlift of cargo to further the national interests as was demonstrated in the Berlin Airlift. ... Combatants United Nations:  Republic of Korea,  Australia,  Belgium,  Luxembourg,  Canada,  Colombia,  Ethiopia,  France,  Greece,  Luxembourg,  Netherlands,  New Zealand,  Philippines,  South Africa,  Thailand,  Turkey,  United Kingdom,  United States Medical staff:  Denmark,  Australia,  Italy,  Norway,  Sweden Communist states:  Democratic People’s Republic of Korea,  Peoples Republic of China,  Soviet Union Commanders... Jet aircraft are aircrafts with jet engines. ...

A true interrupter gear stops the firing of the machine gun when some part of the aircraft was in the way. For much of the early history of the fighter aircraft this was limited to the propeller. This would change with the introduction of the turret mounted armament firstly to the bomber aircraft and briefly to the fighter. Turret (highlighted) attached to a tower on a baronial building in Scotland In architecture, a turret is a small tower that projects from the wall of a building, such as a medieval castle or baronial house. ...

Though their effects were the same, there was a subtle difference between the concept of the interrupter and the synchronizer. A machine gun fitted with interrupter gear had the trigger normally enabled and the interrupter mechanism would disable the trigger when a propeller blade was in the way. A machine gun fitted with synchronization gear had the trigger normally disabled and the synchronizer mechanism would enable the trigger when the propeller was clear. In reality, the technical difficulties associated with reliably halting the firing of a Maxim-type machine gun meant that no working interrupter system was ever developed — all successful implementations used the concept of synchronization. This article does not cite its references or sources. ... An early Maxim gun in operation with the Royal Navy 1895 . ...

Origins

Experimentation with gun synchronization had been underway in France and Germany before the First World War but the engineers involved received little support or encouragement from the military who disregarded the need for armed aircraft, believing them solely useful for reconnaissance. Swiss engineer Franz Schneider, working for LVG, designed and patented a synchronizer in 1913. French aircraft designer Raymond Saulnier built and patented a practical gun synchronizer in April 1914, having borrowed a machine gun from the army for testing. No design was developed to the point of being operational in the field, one significant problem being the inconsistency of ammunition propellant resulting in hang fire rounds. Mixed reconnaissance patrol of the Polish Home Army and the Soviet Red Army during Operation Tempest, 1944 Reconnaissance is the military term for the active gathering of information about an enemy, or other conditions, by physical observation. ... A patent is a set of exclusive rights granted by a state to a patentee (the inventor or assignee) for a fixed period of time in exchange for the regulated, public disclosure of certain details of a device, method, process or composition of matter (substance) (known as an invention) which... Year 1913 (MCMXIII) was a common year starting on Wednesday (link will display the full calendar). ... 1914 (MCMXIV) was a common year starting on Thursday (see link for calendar). ... A propellant is a material that is used to move an object by applying a motive force. ... The term hang fire refers to a state in which an unexpected delay is encountered between a firearm being triggered and the initiation of the propellant. ...

Saulnier pursued a simpler method using armoured propeller blades. In December 1914, French pilot Roland Garros approached Saulnier to arrange for this device to be installed on his aeroplane but it was not until March 1915 that he took to the air with a forward-firing Hotchkiss 8 mm (.323 in) machine gun mounted on his Morane-Saulnier Type L. In addition to the armoured blades, Garros's mechanic, Jules Hue, attached deflector wedges to the blades. While this reduced the chance of a dangerous ricochet, the wedges diminished the propeller's efficiency. On 18 April 1915, having shot down three German aircraft, Garros' plane was forced down in German territory. Before he could burn his aircraft, he was captured and the gun and propeller were sent for evaluation by the Inspektion der Fliegertruppen (Idflieg) at Döberitz near Berlin. Armour is protective clothing intended to defend its wearer from intentional harm in combat and military engagements, typically associated with soldiers. ... Roland Garros Roland Garros (October 6, 1888 – October 25, 1918) was an early French aviator and a fighter aircraft pilot during World War I. Garros was born in Saint-Denis, Réunion. ... 1915 (MCMXV) was a common year starting on Friday (link will display the full calendar). ... The Hotchkiss machine gun was the standard machine gun of the French Army during World War I. It was made by the French arms company Hotchkiss et Cie, which was set up by American engineer Benjamin B. Hotchkiss after he moved to France in the 1860s. ... The Morane-Saulnier Type L was a French parasol wing one or two-seat aeroplane of the First World War. ... A ricochet is a rebound, bounce or skip off of a surface, particularly in the case of a projectile. ... April 18 is the 108th day of the year in the Gregorian calendar (109th in leap years). ... 1915 (MCMXV) was a common year starting on Friday (link will display the full calendar). ... The Idflieg (Inspektion der Fliegertruppen - Inspectorate of Flying Troops) was the bureau of the German War Office that oversaw German military aviation prior to and during World War I. Categories: | | ... Berlin is the capital city and one of the sixteen states of the Federal Republic of Germany. ...

Fokker's synchronizer

Popular accounts claim that Dutch aircraft designer Anthony Fokker was then asked to reproduce Saulnier's deflectors and proceeded to invent the synchronization system in a matter of days — according to some accounts,^{[attribution needed]} Fokker was given the problem on a Tuesday evening and presented a working system on Friday. However, Fokker's team, including engineer Heinrich Lübbe, had been working on a synchronization mechanism since late 1914, probably based on Schneider's patent. Indeed in 1916 LVG and Schneider sued Fokker for patent infringement — the battle continued until 1933 and though the courts repeatedly found in Schneider's favour, Fokker refused to acknowledge the rulings. Anton Herman Gerard Anthony Fokker (April 6, 1890 – December 23, 1939), was born in Kediri (Dutch East Indies, now Indonesia) and became a Dutch aircraft manufacturer. ... Heinrich Lübbe (12 January 1884–14 March 1940) was a German engineer working for Dutch aircraft designer Anthony Fokker during the First World War, invented the interrupter gear which enabled a machine gun to fire through the arc of a fighter aircrafts propeller without the bullets striking the... 1916 (MCMXVI) was a leap year starting on Saturday (link will display the full calendar). ... It has been suggested that civil trial be merged into this article or section. ... The examples and perspective in this article or section may not represent a worldwide view. ... 1933 (MCMXXXIII) was a common year starting on Sunday. ...

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 that later German fighters used

Fokker's team adapted their system to work with the new Parabellum lMG 14 machine gun fitted to a Fokker A.III unarmed single-seat monoplane (a military version of the Fokker M.5K) usually flown by Leutnant Otto Parschau. This aircraft — the first example of the five M.5K/MG production prototypes for the Fokker E.I — was demonstrated on 19–20 May 1915 and shipped to the Western Front on 30 May 1915. Image File history File links Download high resolution version (1000x569, 19 KB)Diagram of Anthony Fokkers machine gun synchronisation gear. ... Image File history File links Download high resolution version (1000x569, 19 KB)Diagram of Anthony Fokkers machine gun synchronisation gear. ... Airframe of the prototype Fokker M.5 The Fokker M.5 was an unarmed single-seat monoplane aircraft designed and built by Anthony Fokker in 1913. ... A monoplane is an aircraft with one main set of wing surfaces, in contrast to a biplane or triplane. ... Airframe of the prototype Fokker M.5 The Fokker M.5 was an unarmed single-seat monoplane aircraft designed and built by Anthony Fokker in 1913. ... Max Immelmann of Feldflieger Abteilung 62 in the cockpit of his Fokker E.I. The Fokker E.I was the first successful fighter aircraft, entering combat with the German Army Air Service in mid-1915 which marked the start of a period known as the Fokker Scourge during which the... (Redirected from 19 May) May 19 is the 139th day of the year in the Gregorian Calendar (140th in leap years). ... May 20 is the 140th day of the year in the Gregorian calendar (141st in leap years). ... 1915 (MCMXV) was a common year starting on Friday (link will display the full calendar). ... May 30 is the 150th day of the year in the Gregorian calendar (151st in leap years). ... 1915 (MCMXV) was a common year starting on Friday (link will display the full calendar). ...

The solution used a cam attached to the propeller shaft that pressed on a long rod running to the trigger of the guns. The cam was set such that the propeller was horizontal when it pushed on the rod, and the rod in turn pressed the trigger to fire a bullet. The trigger operated by the pilot pulled the rod into position over the cam. monkey ...

The first victory using a synchronized gun-equipped fighter is believed to have occurred on 1 July 1915 when Lieutenant Kurt Wintgens of Feldflieger Abteilung 67, flying the Fokker M.5K/MG serial number 'E.5/15', forced down a French Morane-Saulnier Type L east of Lunéville. However the plane landed in French territory and the victory could not be confirmed. The first confirmed victory went to Max Immelmann flying a Fokker E.I on 1 August 1915, forcing down a Royal Flying Corps B.E.2c. July 1 is the 182nd day of the year (183rd in leap years) in the Gregorian calendar, with 183 days remaining. ... 1915 (MCMXV) was a common year starting on Friday (link will display the full calendar). ... The Morane-Saulnier Type L was a French parasol wing one or two-seat aeroplane of the First World War. ... Lunéville is a commune in the French région of Lorraine. ... Max Immelmann Max Immelmann (September 21, 1890 - June 18, 1916) was a German World War I Flying ace. ... August 1 is the 213th day of the year in the Gregorian calendar (214th in leap years), with 152 days remaining. ... 1915 (MCMXV) was a common year starting on Friday (link will display the full calendar). ... The Royal Flying Corps (RFC) was the over-land air arm of the British military during most of World War I. Origin and Early History Formed by Royal Warrant on May 13, 1912, the RFC superseded the Air Battalion of the Royal Engineers. ... The Royal Aircraft Factory BE.2 (Blériot Experimental) was the first military aircraft put into service by Britain. ...

Sole possession of a working synchronizer enabled Germany to dominate the Western Front skies in a period known as the Fokker Scourge. Initially lacking a synchronizer, the Royal Flying Corps relied on pusher aircraft such as the Vickers F.B.5 Gunbus and the Airco D.H.2 which did not have the problem of firing forwards through the propeller. Germany was protective of the synchronizer system, instructing pilots not to venture over enemy territory in case they were forced down and the secret revealed, but by 1916 the Allies had developed various synchronizer mechanisms of their own, usually based on cams and links, like the Fokker mechanism.because it was bad Combatants Belgium, British Empire, France, United States, other Western Allies of WWI Germany Commanders No unified command until 1918, then General Ferdinand Foch Kaiser Wilhelm II Casualties ~4,800,000 Unknown though considerably higher Following the outbreak of the First World War in 1914, the German army opened the Western... The Fokker Scourge, a term coined by the British press, was a period of time in World War I in the summer of 1915. ... The Royal Flying Corps (RFC) was the over-land air arm of the British military during most of World War I. Origin and Early History Formed by Royal Warrant on May 13, 1912, the RFC superseded the Air Battalion of the Royal Engineers. ... A British WWI-era F.E.2b pusher. ... The Vickers F.B.5 Gunbus was the first operational British aircraft purpose-built for air-to-air combat, making it debatably the worlds first true fighter aircraft. ... The Airco DH.2 was a single-seat biplane pusher aircraft which operated as a fighter during the First World War. ... 1916 (MCMXVI) was a leap year starting on Saturday (link will display the full calendar). ...

Further development

The first British aircraft to use a synchronizer gear was the Sopwith 1½ Strutter which arrived in April 1916 equipped with the Ross synchronizer, although some other service types were retrofitted with synchronised guns about this time, including the Nieuport 12 and the Bristol Scout. The main problem with early mechanical synchronizers was that the rate of fire of the machine gun was dependent on the engine revolutions, and was slowed, especially when the engine was throttled back. The mechanical linkages were also very liable to failure, resulting in the unfortunate pilot shooting away his own propeller. Sopwith 1½ Strutter The Sopwith 1½ Strutter was a British one or two-seat biplane multi-role aircraft of the First World War. ... 1916 (MCMXVI) was a leap year starting on Saturday (link will display the full calendar). ... The Bristol Scout was a simple, single seat, rotary-radial engined biplane that functioned as one of the very first UK-built and designed fighter aircraft for the British armed forces in the first two years of World War I, even though it was originially intended to be a sporting...

Eventually all British aircraft were equipped with the superior hydraulic Constantinesco synchronization gear (or "CC" gear), invented by Romanian engineer George Constantinesco) which used impulses transmitted by a column of liquid instead of a mechanical system of linkages. This was not only inherently more reliable, but delivered firing impulses at a much higher rate, so that a synchronised gun now fired at more or less the same rate as a normal machine gun, regardless of engine revolutions. The gear could also be easily fitted to any type of aircraft instead of having to have type-specific linkages designed. The Constantinesco gear remained in use with the Royal Air Force until the Second World War, the Gloster Gladiator being the last British fighter to be equipped with it. Table of Hydraulics and Hydrostatics, from the 1728 Cyclopaedia. ... George (or Gogu) Constantinescu (1881 - 1965) was a Romanian scientist, engineer and inventor. ... The Royal Air Force (RAF) is the air force branch of the British Armed Forces. ... Mushroom cloud from the nuclear explosion over Nagasaki rising 18 km into the air. ... Gloster Gladiator photographed in England in 2002 The Gloster Gladiator was a biplane fighter, used by the Royal Air Force and the Royal Navy, as well as a number of other air forces, during World War II. The aircraft had a top speed of around 414 km/h. ...

A pilot would usually only have the target in his sights for a fleeting moment so a concentration of bullets was vital for achieving a kill. The obvious solution was to increase the number of guns. The final version of the Fokker Eindecker, the Fokker E.IV, came with two Spandau machine guns and this became the standard armament for all the German D-type scouts starting with the Albatros D.I. Fokker experimented with mounting three machine guns on the E.IV but the extra weight rendered the aircraft virtually unflyable. The Allies did not field an aircraft with twin synchronized guns until the Sopwith Camel and the SPAD S.XIII came into service (mid 1917). The Fokker E.IV was the final variant of the Fokker Eindecker fighter aircraft that was operated by Germany during the First World War. ... MG08 with optical sight. ... The Idflieg designation system was used to generate German military aircraft designations prior to the end of World War I. Each designation consisted of one of the following letters, followed by a roman numeral. ... The Albatros D I was a German fighter airplane used during World War I. It was designed by Thelen, Schubert and Gnädig, in an attempt to create an airplane superior to the then-dominant Nieuport 11 (Bébé) and Airco D.H.2. ... The Sopwith Camel Scout was a British World War I single-seat fighter aircraft that was famous for its maneuverability. ... SPAD S.XIII The SPAD S.XIII was a French biplane fighter aircraft of World War I, developed by Société Pour LAviation et ses Dérivés from the earlier highly successful SPAD S.VII. It was one of the most capable fighters of the war, and one...

Turrets

With the introduction of the "high speed" bomber came a need to protect the gunner from the elements and to give protection but retain the wide firing arcs and so the power driven multi-gun turret evolved. One of the first instances was the single nose mounted turret of the Boulton Paul Overstrand that served with the RAF, and the almost simultaneous introduction of the much more advanced Martin B-10 with the US Army Air Corps. The Boulton Paul P.75 Overstrand was the last of the twin_engine biplane medium bombers of the Royal Air Force, a series that had begun during the First World War with the likes of the Vickers Vimy and Handley Page Type O. The Overstrand only saw brief service in the... A B-10 being flown during a training session at Maxwell Field. ...

For maximum efficiency the bomber turret needed to be able to rotate in all directions and cover as wide a range of elevation as possible - this meant that there would be some combinations of elevation and direction where the turret was aiming at some part of the aircraft itself. To prevent the guns firing an electrical system was used. The guns were fired by solenoids and by introducing a break in the electrical power to the guns that coincided with the forbidden arcs of fire the aircraft would be safe from its own guns. The Boulton Paul design used a brass drum and brush contacts that corresponded to the direction of the turret and angle of the guns. Where the brass was removed and replaced with insulating material the electrical circuit would be broken and the guns prevented from firing. Various solenoid actuators from Trombetta Motion Technologies A solenoid is a loop of wire, often wrapped around a metallic core, which produces a magnetic field when an electrical current is passed through it. ... Boulton Paul Defiant Boulton Paul Aircraft Ltd was a British aircraft manufacturer that operated between 1914 and 1961. ...

The End of Synchronization

Synchronization gears finally became totally redundant when jets replaced propeller-driven fighters - but their use, even in piston engined aircraft, had already declined - especially after 1940. It was no longer practicable to mount guns with their firing mechanisms within the cockpit, which eliminated one of the reasons for having guns mounted in the fuselage in the first place. The importance of locating the guns in front of the pilot also diminished, as aircraft gunsight technology improved and the requirement for heavier armament increased. Cantilever monoplane wings provided much more space than the fuselage to mount armament - and being much more rigid than the old cable braced wings they provided a much steadier mounting. The result was that many fighters of the World War II era had all their guns mounted in the wings outside the propeller disc - their direction of fire "harmonised" to converge at a preset distance. Nevertheless, German and Soviet fighter types in particular were slow to abandon fuselage-mounted guns, usually in addition to wing mounted guns. A Pratt and Whitney turbofan engine for the F-15 Eagle is tested at Robins Air Force Base, Georgia, USA. The tunnel behind the engine muffles noise and allows exhaust to escape. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000...

The last synchronizer-equipped aircraft to see combat action were the Lavochkin La-11 and the Yakovlev Yak-9 during the Korean War. The Lavochkin La-11 (NATO reporting name Fang) was an early post-World War II long-range piston-engined Soviet fighter aircraft. ... Yak-9 Yak-9D The Yakovlev Yak-9 was a single-engine fighter aircraft used by the Soviet Union in World War II. Like the Yak-3, it was a development of the earlier Yak-1. ... Combatants United Nations:  Republic of Korea,  Australia,  Belgium,  Luxembourg,  Canada,  Colombia,  Ethiopia,  France,  Greece,  Luxembourg,  Netherlands,  New Zealand,  Philippines,  South Africa,  Thailand,  Turkey,  United Kingdom,  United States Medical staff:  Denmark,  Australia,  Italy,  Norway,  Sweden Communist states:  Democratic People’s Republic of Korea,  Peoples Republic of China,  Soviet Union Commanders...

References

• Woodman, Harry, "CC Gun Synchronisation Gear", Aeroplane Monthly, September 2005
• Jarrett, Phillip, "The Fokker Eindeckers", Aeroplane Monthly, December 2004
• "The Electro-Hydraulic Turret", The Aeroplane No: 1654, February 1943