Type 99 cannon
Encyclopedia
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
.
mechanism pioneered by the Becker
cannon, but fired different ammunition: 20x72RB, 20x100RB and 20x110RB, respectively.
Following the import and evaluation of sample guns, the Imperial Japanese Navy decided in 1937 to adopt these weapons. To produce the Oerlikon guns, a group of retired Navy admirals created a new arms manufacturing company, the Dai Nihon Heiki KK. In 1939 this started producing a Japanese version of the FF, initially known as the Type E (because the Japanese transliteration of Oerlikon was Erikon) but from late 1939 onwards formally known as the Type 99-1. A Japanese version of the FFL was produced as the Type 99-2. The FFS was tested, but not put in production.
The 99 in the designation derived from the Japanese imperial calendar year
, 1939 corresponding to the Japanese year 2599. The formal designations were Type 99-1 machine gun and Type 99-2 machine gun. (Japanese
: Kyū-Kyū Shiki Ichigō Kizyū, Kanji
: 九九式一号機銃) and Kyū-Kyū Shiki Nigō Kizyū, Kanji: 九九式二号機銃) The Japanese Navy classified 20-mm weapons as machine guns rather than cannon. These weapons were never used by the Japanese Army -- There was almost no commonality in gun types or ammunition between Army and Navy.
The Type 99-1 and 99-2 were not models of the same gun, instead they had parallel lines of development into several different models. Because of the close technical similarity, several modifications were adopted to both guns simultaneously.
Because it fired a bigger cartridge than the Type 99-1, the Type 99-2 had a higher muzzle velocity but a lower rate of fire, and was heavier. In the first years of the war the IJN preferred the Type 99-1, and it did not operationally use the Type 99-2 until 1942. Towards the end of the war it developed a preference for installing the Type 99-2, presumably to counter the improving performance and ruggedness of US combat aircraft. Compared to rival gun designs, the Type 99 cannon suffered from relatively low muzzle velocity and rate of fire, but the close economic and political ties between the IJN and Dai Nihon Heiki KK ensured that the latter had little competition.
, mounted in the wings of the famous Mitsubishi A6M Zeke or Zero. A flexible version, initially developed for the Mitsubishi G3M
bomber, was inverted to put the ammunition drum below the line of sight of the gunner. Smaller drums (45, 30 or 15 rounds) were used on flexible installations where space was limited.
The limited ammunition capacity was an important disadvantage. The Type 99-1 Fixed Model 3 could be equipped with a 100-round drum, but the size of the drum was itself a problem in fighter installations, although the Model 3 guns were installed on the initial production versions of the A6M3. A more practical solution was provided by the Type 99-1 Fixed Model 4, which featured a Kawamura-developed belt feed mechanism.
.
The Model 4 of this weapon adopted the same belt-feed mechanism as the Type 99-1 Model 4. The Type 99-2 Model 5 resulted from attempts to increase the rate of fire. By modifications that included the addition of strong buffer springs, the rate of fire was raised to between 670 and 750 rpm. But the Model 5 was formally adopted only in May 1945 and may not have seen combat.
Oerlikon FF
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...
and Oerlikon FFL. They were adopted by the Imperial Japanese Navy
Imperial Japanese Navy
The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...
in 1939 and served as their standard aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
autocannon
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...
during 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...
.
Adoption
In 1935, officers in the Imperial Japanese Navy began to investigate 20-mm automatic cannon as armament for future fighter aircraft. Their attention was drawn to the family of aircraft autocannon manufactured by Oerlikon, the FF, FFL and FFS. These all shared the same operating principle, the advanced primer ignition blowbackBlowback (arms)
Blowback is a system of operation for self-loading firearms that obtains energy from the motion of the cartridge case as it is pushed to the rear by expanding gases created by the ignition of the propellant charge....
mechanism pioneered by the Becker
20 mm Becker
The 20 mm Becker was a German automatic cannon developed for aircraft use during World War I. It was first mass produced in 1916 and was installed in a variety of aircraft; the only German autocannon to actually see service in the air during the war....
cannon, but fired different ammunition: 20x72RB, 20x100RB and 20x110RB, respectively.
Following the import and evaluation of sample guns, the Imperial Japanese Navy decided in 1937 to adopt these weapons. To produce the Oerlikon guns, a group of retired Navy admirals created a new arms manufacturing company, the Dai Nihon Heiki KK. In 1939 this started producing a Japanese version of the FF, initially known as the Type E (because the Japanese transliteration of Oerlikon was Erikon) but from late 1939 onwards formally known as the Type 99-1. A Japanese version of the FFL was produced as the Type 99-2. The FFS was tested, but not put in production.
The 99 in the designation derived from the Japanese imperial calendar year
Japanese calendar
On January 1, 1873, Japan adopted the Gregorian calendar. Before 1873, the Chinese style lunisolar calendar had been in use since 7th century. Japanese eras are still in use.-System:...
, 1939 corresponding to the Japanese year 2599. The formal designations were Type 99-1 machine gun and Type 99-2 machine gun. (Japanese
Japanese language
is a language spoken by over 130 million people in Japan and in Japanese emigrant communities. It is a member of the Japonic language family, which has a number of proposed relationships with other languages, none of which has gained wide acceptance among historical linguists .Japanese is an...
: Kyū-Kyū Shiki Ichigō Kizyū, Kanji
Kanji
Kanji are the adopted logographic Chinese characters hanzi that are used in the modern Japanese writing system along with hiragana , katakana , Indo Arabic numerals, and the occasional use of the Latin alphabet...
: 九九式一号機銃) and Kyū-Kyū Shiki Nigō Kizyū, Kanji: 九九式二号機銃) The Japanese Navy classified 20-mm weapons as machine guns rather than cannon. These weapons were never used by the Japanese Army -- There was almost no commonality in gun types or ammunition between Army and Navy.
The Type 99-1 and 99-2 were not models of the same gun, instead they had parallel lines of development into several different models. Because of the close technical similarity, several modifications were adopted to both guns simultaneously.
Because it fired a bigger cartridge than the Type 99-1, the Type 99-2 had a higher muzzle velocity but a lower rate of fire, and was heavier. In the first years of the war the IJN preferred the Type 99-1, and it did not operationally use the Type 99-2 until 1942. Towards the end of the war it developed a preference for installing the Type 99-2, presumably to counter the improving performance and ruggedness of US combat aircraft. Compared to rival gun designs, the Type 99 cannon suffered from relatively low muzzle velocity and rate of fire, but the close economic and political ties between the IJN and Dai Nihon Heiki KK ensured that the latter had little competition.
Type 99-1
The Type 99-1 was adopted by the Japanese for both fixed and flexible installations. The fixed installation was developed first, as a fighter gun fed by a 60-round drum magazineDrum magazine
A drum magazine is a type of firearms magazine that is cylindrical in shape, similar to a drum. Instead of rounds being stored flat, as in a more common box magazine, rounds in a drum magazine are stored in a spiral around the center of the magazine, facing the direction of the barrel.There are...
, mounted in the wings of the famous Mitsubishi A6M Zeke or Zero. A flexible version, initially developed for the Mitsubishi G3M
Mitsubishi G3M
The Mitsubishi G3M was a Japanese bomber used during World War II.-Design and development:...
bomber, was inverted to put the ammunition drum below the line of sight of the gunner. Smaller drums (45, 30 or 15 rounds) were used on flexible installations where space was limited.
The limited ammunition capacity was an important disadvantage. The Type 99-1 Fixed Model 3 could be equipped with a 100-round drum, but the size of the drum was itself a problem in fighter installations, although the Model 3 guns were installed on the initial production versions of the A6M3. A more practical solution was provided by the Type 99-1 Fixed Model 4, which featured a Kawamura-developed belt feed mechanism.
Specifications
- Caliber: 20 mm
- Ammunition: 20x72RB
- Length: 133 cm (53 in)
- Weight: 23 kg (75 lb)
- Rate of fire: 520 rounds/min
- Muzzle velocity: 600 m/s (1970 ft/s)
Installations
- Kawanishi H6KKawanishi H6K|-See also:-References:NotesBibliography* Doubilet, David. "The Flying Boat". Sport Diver Magazine. Volume 15, Number 8, September 2007.* Francillon, Ph.D., René J. Japanese Aircraft of the Pacific War. Annapolis, Maryland, MD: Naval Institute Press, 1995.* Green, William. Warplanes of the Second...
- Kawanishi H8KKawanishi H8K|-See also:-References:NotesBibliography* Bridgeman, Leonard. "The Kawanishi H8K2 “Emily”" Jane’s Fighting Aircraft of World War II. London: Studio, 1946. ISBN 1-85170-493-0....
- Kawanishi N1K
- Mitsubishi A6M
- Mitsubishi G3MMitsubishi G3MThe Mitsubishi G3M was a Japanese bomber used during World War II.-Design and development:...
- Mitsubishi G4MMitsubishi G4MThe Mitsubishi G4M 一式陸上攻撃機, 一式陸攻 Isshiki rikujō kōgeki ki, Isshikirikkō was the main twin-engine, land-based bomber used by the Imperial Japanese Navy Air Service in World War II. The Allies gave the G4M the reporting name Betty...
- Mitsubishi J2MMitsubishi J2MThe Mitsubishi J2M Raiden was a single-engined land-based fighter aircraft used by the Imperial Japanese Navy Air Service in World War II. The Allied reporting name was "Jack".-Design and development:...
- Nakajima J1NNakajima J1N-See also:-Bibliography:* Francillon, Réne J. Japanese Aircraft of the Pacific War. London: Putnam & Company Ltd., 1970 . ISBN 0-370-30251-6....
Type 99-2
The Type 99-2 was a heavier weapon with a stronger recoil, and was not put in use by the IJN before 1942. It was used exclusively in fixed installations, i.e., either in fighters or in power-operated turrets. The Type 99-2 was carried by later models of the A6M, starting with the A6M3 model 22a, and on later Navy fighters such as the Kawanishi N1K-JKawanishi N1K-J
The Kawanishi N1K Kyōfū was an Imperial Japanese Navy floatplane fighter. The Kawanishi N1K-J Shiden was an Imperial Japanese Navy Air Service land-based version of the N1K...
.
The Model 4 of this weapon adopted the same belt-feed mechanism as the Type 99-1 Model 4. The Type 99-2 Model 5 resulted from attempts to increase the rate of fire. By modifications that included the addition of strong buffer springs, the rate of fire was raised to between 670 and 750 rpm. But the Model 5 was formally adopted only in May 1945 and may not have seen combat.
Specifications
- Caliber: 20 mm
- Ammunition: 20x101RB
- Length: 189 cm (74 in)
- Weight: 34 kg (51 lb)
- Rate of fire: 480 rounds/min
- Muzzle velocity: 750 m/s (2460 ft/s)
Installations
- Aichi B7A
- Aichi E16AAichi E16A|-See also:-References:NotesBibliography* Francillon, Ph.D., René J. Japanese Aircraft of the Pacific War. London: Putnam & Company Ltd., 1979. ISBN 0-370-30251-6....
- Kawanishi N1K-JKawanishi N1K-JThe Kawanishi N1K Kyōfū was an Imperial Japanese Navy floatplane fighter. The Kawanishi N1K-J Shiden was an Imperial Japanese Navy Air Service land-based version of the N1K...
- Mitsubishi A6M
- Mitsubishi G4MMitsubishi G4MThe Mitsubishi G4M 一式陸上攻撃機, 一式陸攻 Isshiki rikujō kōgeki ki, Isshikirikkō was the main twin-engine, land-based bomber used by the Imperial Japanese Navy Air Service in World War II. The Allies gave the G4M the reporting name Betty...
- Mitsubishi J2MMitsubishi J2MThe Mitsubishi J2M Raiden was a single-engined land-based fighter aircraft used by the Imperial Japanese Navy Air Service in World War II. The Allied reporting name was "Jack".-Design and development:...
- Nakajima J1NNakajima J1N-See also:-Bibliography:* Francillon, Réne J. Japanese Aircraft of the Pacific War. London: Putnam & Company Ltd., 1970 . ISBN 0-370-30251-6....
External links
- Type 99 cannon, www.warbirdsresourcegroup.org
- World War II Aircraft Gun Tables
- 20 mm Aircraft Cannon Type 99 Mk. II, US Ordnance Report.
20mm Gun Table
| Name | Cartridge | Projectile weight |
Rate of fire | Muzzle velocity |
Gun weight |
|---|---|---|---|---|---|
| (grams) | (rpm) | (m/s) | (kg) | ||
| France | |||||
| HS.9 | 20 x 110RB | 122 | 360-420 | 830 | 48 |
| 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... |
20 x 110 | 130 | 700 | 880 | 60 |
| Germany | |||||
| MG FF | 20 x 80RB | 134 | 520 | 600 | 28 |
| MG FF/M | 20 x 80RB | 92/115 | 540/520 | 700/585 | 28 |
| MG 151/20 | 20 x 82 | 92/115 | 750 - 800 | 800/720 | 42 |
| Japanese Army | |||||
| Type 94 Flexible | 20 x 99RB | 127 | 380 | 675 | 43 |
| Ho-1 Ho-1 cannon Ho-1 was a Japanese autocannon used during World War II. It was a Type 97 20 mm anti-tank rifle adopted for use in bomber turrets.-Specifications:*Caliber: 20 mm *Ammunition: 20 x 125... |
20 x 125 | 144 | 400 | 805 | 45 |
| Ho-3 Ho-3 cannon Ho-3 was a Japanese autocannon used during World War II. It was a drum-fed improvement of the magazine-fed Ho-1 cannon, itself derived from the Type 97 antitank rifle.-Specifications:*Caliber: 20 mm... |
20 x 125 | 144 | 400 | 805 | 45 |
| Ho-5 Ho-5 cannon The Ho-5 was a Japanese aircraft autocannon used during World War II. Developed from the Ho-103 machine gun, it was a version of the American Model 1921 Browning aircraft machine gun. It replaced the Ho-1 and Ho-3 in general service. The Ho-5 was belt-fed using typical Browning-style steel... |
20 x 94 | 96 | 750 - 850 | 715 | 37 |
| Japanese Navy | |||||
| Type 99-1 | 20 x 72RB | 129 | 490 | 600 | 23 |
| Type 99-2 | 20 x 101RB | 128 | 490 | 750 | 34 |
| Great Britain | |||||
| Hispano Mk.II | 20 x 110 | 130 | 600 | 880 | 50 |
| Hispano Mk.V | 20 x 110 | 130 | 750 | 840 | 42 |
| USSR | |||||
| ShVAK | 20 x 99R | 95 | 800 | 750 - 770 | 42 |
| Berezin B-20 Berezin B-20 The Berezin B-20 was a 20 mm caliber autocannon used by Soviet aircraft in World War II.-Development:The B-20 was created by M.E. Berezin in 1944 by chambering his Berezin UB 12.7 mm machine gun for the 20 mm rounds used by the ShVAK cannon... |
20 x 99R | 95 | 800 | 750 - 770 | 25 |
| VYa Volkov-Yartsev VYa-23 Volkov-Yartsev VYa-23 is a autocannon used on Soviet aircraft during World War II.-Development:In 1940, A.A. Volkov and S.A.Yartsev created an autocannon called TKB-201 for the new 23 mm round. It was intended to be the primary weapon of the Ilyushin Il-2 ground attack aircraft... |
23 x 152B | 200 | 550 | 880 | 69 |
| NS-23 Nudelman-Suranov NS-23 The NS-23 was a aircraft cannon designed by A. E. Nudelman, A. Suranov, G. Zhirnykh, V. Nemenov, S. Lunin, and M. Bundin during World War II as a replacement for the Volkov-Yartsev VYa-23 cannon. It entered service in 1944... |
23 x 115 | 200 | 550 | 690 | 37 |