Oerlikon FF
Encyclopedia
The FF were a series of 20mm autocannon
introduced by Oerlikon
in the late 1920s. The name comes from the German
term Flügel Fest, meaning wing mounted, fixed, being one of the first 20mm guns to be small and light enough to fit into a fighter aircraft
's wing. The FF series inspired many 20mm cannon used in World War II
, including the French Hispano-Suiza HS.404
(adopted by the British and U.S.), the German MG FF
, and the Japanese Type 99 cannon
.
The original design, introduced as the FF, fired a 128 gram 20x72mm round with a muzzle velocity
of 600 m/s at a cyclic rate of 520 rounds per minute. The gun weighed only 24 kg. The low muzzle velocity was of some concern, so additional developments led to the 30 kg FF L using a longer 20x101mm round which gave 750 m/s, and the 39 kg FF S firing a 20x110mm round at 830 m/s at a slightly slower 470 rounds per minute. The original guns became known as the FF F from this point on.
The MG FF, like all pre-World War II Oerlikon guns, was an API blowback recoil-operated
weapon and embodies certain features which are not found in other automatic cannons. The most important of these are: 1) a barrel which does not recoil; 2) a heavy breechblock which is never locked against the breech and actually moves forward when the gun is fired.
The FF F was licensed by the Japanese and produced as the Type 99-1, along with the FF L as the Type 99-2. Hispano-Suiza
built the FF S as the HS.7, and slightly improved HS.9. This design was later abandoned by Hispano-Suiza. In the 1930s, Marc Birkigt
designed an entirely new gas-operated
cannon with a locked bolt, the HS.404, which became one of the best 20 mm weapons of the war. Ikaria in Germany started production of the FF F with a slightly more powerful 20x80mm round as the MG FF, but later introduced a new Minengeschoss round. The resulting MG FF/M was a common weapon until about 1941. Starting in late 1940 these were replaced by the very different Mauser MG 151/20
.
Autocannon
An autocannon or automatic cannon is a rapid-fire projectile weapon firing a shell as opposed to the bullet fired by a machine gun. Autocannons often have a larger caliber than a machine gun . Usually, autocannons are smaller than a field gun or other artillery, and are mechanically loaded for a...
introduced by Oerlikon
Oerlikon Contraves
Rheinmetall Air Defence AG is a division of German armament manufacturer Rheinmetall, created when the company's Oerlikon Contraves unit was renamed on 1 January 2009 and integrated with Rheinmetall's other air-defence products...
in the late 1920s. The name comes from the German
German language
German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....
term Flügel Fest, meaning wing mounted, fixed, being one of the first 20mm guns to be small and light enough to fit into a fighter aircraft
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...
's wing. The FF series inspired many 20mm cannon used in World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, including the French Hispano-Suiza HS.404
Hispano-Suiza HS.404
The Hispano-Suiza HS.404 was an autocannon widely used as both an aircraft and land weapon in the 20th century by British, American, French, and numerous other military services. The cannon is also referred to as Birkigt type 404, after its designer. Firing a 20 mm caliber projectile, it delivered...
(adopted by the British and U.S.), the German MG FF
MG FF cannon
The MG FF was a drum-fed, 20 mm aircraft autocannon, developed in 1936 by Ikaria Werke Berlin of Germany. It was a derivative of the Swiss Oerlikon FF F cannon, itself a development of the German World War I Becker 20 mm cannon, and was designed to be used in fixed or flexible mountings, as...
, and the Japanese Type 99 cannon
Type 99 cannon
The Type 99-1 cannon and Type 99-2 cannon were Japanese versions of the Oerlikon FF and Oerlikon FFL. They were adopted by the Imperial Japanese Navy in 1939 and served as their standard aircraft autocannon during World War II.-Adoption:...
.
The original design, introduced as the FF, fired a 128 gram 20x72mm round with a muzzle velocity
Muzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...
of 600 m/s at a cyclic rate of 520 rounds per minute. The gun weighed only 24 kg. The low muzzle velocity was of some concern, so additional developments led to the 30 kg FF L using a longer 20x101mm round which gave 750 m/s, and the 39 kg FF S firing a 20x110mm round at 830 m/s at a slightly slower 470 rounds per minute. The original guns became known as the FF F from this point on.
The MG FF, like all pre-World War II Oerlikon guns, was an API blowback recoil-operated
Recoil operation
Recoil operation is an operating mechanism used in locked-breech, autoloading firearms. As the name implies, these actions use the force of recoil to provide energy to cycle the action...
weapon and embodies certain features which are not found in other automatic cannons. The most important of these are: 1) a barrel which does not recoil; 2) a heavy breechblock which is never locked against the breech and actually moves forward when the gun is fired.
The FF F was licensed by the Japanese and produced as the Type 99-1, along with the FF L as the Type 99-2. Hispano-Suiza
Hispano-Suiza
Hispano-Suiza was a Spanish automotive and engineering firm, best known for its luxury cars and aviation engines in the pre-World War II period of the twentieth century. In 1923, its French subsidiary became a semi-autonomous partnership with the parent company and is now part of the French SAFRAN...
built the FF S as the HS.7, and slightly improved HS.9. This design was later abandoned by Hispano-Suiza. In the 1930s, Marc Birkigt
Marc Birkigt
Marc Birkigt was a Swiss engineer who moved to Barcelona, Spain when he was hired as an engineer by Emilio de la Cuadra, founder of Hispano-Suiza automobiles. He created the Dewoitine company along with Émile Dewoitine. Birkigt was nominated for the Car Engineer of the Century prize for the...
designed an entirely new gas-operated
Gas-operated reloading
Gas-operation is a system of operation used to provide energy to operate autoloading firearms. In gas-operation, a portion of high pressure gas from the cartridge being fired is used to power a mechanism to extract the spent case and chamber a new cartridge. Energy from the gas is harnessed...
cannon with a locked bolt, the HS.404, which became one of the best 20 mm weapons of the war. Ikaria in Germany started production of the FF F with a slightly more powerful 20x80mm round as the MG FF, but later introduced a new Minengeschoss round. The resulting MG FF/M was a common weapon until about 1941. Starting in late 1940 these were replaced by the very different Mauser MG 151/20
MG 151 cannon
The MG 151 was a 15 mm autocannon produced by Waffenfabrik Mauser starting in 1940. It was in 1941 developed into the 20 mm MG 151/20 cannon which was widely used on many types of German Luftwaffe fighters, fighter bombers, night fighters, ground attack and even bombers as part of or as...
.