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46-580: J69 may refer to: HMCS  Ingonish  (J69) , a Bangor -class minesweeper of the Royal Canadian Navy HMS ; Sphinx  (J69) , a Halcyon -class minesweeper of the Royal Navy LNER Class J69 , a British steam locomotive class Parabiaugmented truncated dodecahedron Teledyne CAE J69 , a turbojet engine [REDACTED] Topics referred to by

92-554: A 20 mm caliber cannon, known now as the 20 mm Becker using the advanced primer ignition blowback (API blowback) method of operation. This used a 20×70mmRB cartridge and had a cyclic rate of fire of 300 rpm. It was used on a limited scale as an aircraft gun on Luftstreitkräfte warplanes, and an anti-aircraft gun towards the end of that war. Because the Treaty of Versailles banned further production of such weapons in Germany,

138-472: A careful balance between the force of the shell being fired and the operational timing of the mechanism. In the Oerlikon designs, these timing demands resulted in a relatively slow-cycling weapon. As a response to this demand, Oerlikon developed "power reserve loading" action, introducing a gas-operated mechanism to unlock the breech. The gun produced to this design after the close of hostilities of WW2, and

184-621: A convoy escort, Ingonish was deployed with 40 depth charges launched from two depth charge throwers and four chutes. The minesweeper was ordered as part of the British 1940 construction programme. The ship's keel was laid down on 6 June 1941 by North Vancouver Ship Repairs at their yard in North Vancouver , British Columbia . Named for a community in Nova Scotia , Ingonish was launched on 30 July 1941. Transferred to

230-467: A locking mechanism, a fairly heavy bolt must be employed; while to give this heavy bolt sufficient forward speed, a large spring is required (and Oerlikons, distinctively, have this component wrapped around their barrels.) These features will limit the rate of fire of such guns, unless other steps are taken—as in the final model of the Japanese 99 Mark 2 . This unique chamber and bolt design necessitates

276-523: A rate of fire of 500 rpm. And the FFS, which weighed 39 kg, delivered a high muzzle velocity of 830 m/s at a rate of 470 rpm. Apart from changes to the design of the guns for wing-mounting and remote control, larger drums were introduced as it would not be possible to exchange magazines in flight. For the FF series 45, 60, 75 and 100 (and a rarely used 150) drum magazines were available, but most users chose

322-414: A reduced rate of fire (280 rpm). The purpose of this development was to improve the performance of the gun as an anti-tank and anti-aircraft weapon, which required a higher muzzle velocity. An improved version known as the 1S followed in 1930. Three sizes of gun with their different ammunition and barrel length, but very similar mechanisms, continued to be developed in parallel. In 1930 Oerlikon reconsidered

368-468: A refit, which took nine weeks to complete. In May 1944, the minesweeper joined Sydney Force, the local patrol and escort force working out of Sydney, Nova Scotia and remained with the unit until February 1945. The vessel returned to Halifax Force in February and underwent a second refit at Saint John, New Brunswick . Following the refit, Ingonish was sent to Bermuda for work ups and then sailed for

414-493: A second advantage of this unusual arrangement is that after firing the bolt and case have a short, but significant, distance to travel rearwards before the bolt-end re-emerges and the case in turn begins to leave the chamber; and this in combination with the retardation of the rearward travel provides sufficient time for gas pressure to drop to the necessary safe level. This system permits blowback to be used in far more powerful weapons than normal. Nevertheless, compared to guns with

460-493: A total of 2,400 indicated horsepower (1,800 kW) and gave a maximum speed of 16.5 knots (30.6 km/h; 19.0 mph). The minesweeper could carry a maximum of 150 long tons (152 t) of fuel oil . British Bangor -class minesweepers were armed with a single 12-pounder (3 in (76 mm)) 12 cwt HA gun mounted forward. For anti-aircraft purposes, the minesweepers were equipped with one QF 2-pounder Mark VIII and two single-mounted QF 20 mm Oerlikon guns. As

506-600: Is different from Wikidata All article disambiguation pages All disambiguation pages HMCS Ingonish HMCS Ingonish ( pennant J69) was a Bangor -class minesweeper initially constructed for the Royal Navy during the Second World War . Loaned to the Royal Canadian Navy in 1942, the vessel served on both coasts of Canada as a convoy escort and patrol vessel. Following

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552-443: Is free-swinging on a fixed pedestal mounting with a flat armored shield affording some protection for the crew. The cannon is aimed and fired by a gunner using, in its simplest form, a ring-and-bead sight . The gunner is attached to the weapon by a waist-belt and shoulder supports. For this reason, some mountings existed with a height-adjustment feature to compensate for different sized gunners. A "piece chief" designates targets and

598-414: Is required, as with such low-power cartridges the static inertia of the bolt or bolt and slide - the physical tendency of heavy components to resist rapid acceleration - is adequate to ensure that the projectile has left the muzzle and the gas pressure in the barrel is down to a safe level before the breech opens (while the bolt spring also resists the opening of the breech, in practical terms its contribution

644-399: Is too small to be relevant). In contrast, 20mm cartridges are far too powerful, and efficient autocannon barrels too long, for this basic system to be practical; so the Oerlikon uses Advanced Primer Ignition (API) to augment the resistance of the bolt. In API blowback weapons, the firing pin fires the cartridge while the bolt is still traveling forward so that the gas pressure has to overcome

690-448: The 3"/50 Mark 22 gun . It provided a useful increase in firepower over the .50 cal machine gun when adapted and fitted to some aircraft. However, it had some problems with jamming in the ammunition feed. The Royal Canadian Navy popularised the use of the Oerlikon gun as an anti-ship and anti-submarine gun – while it was not effective against the armour of most larger ships, it was used extensively and effectively against U-boats , and on

736-632: The Bofors 40/L60 40 mm gun from 1943, although many squadrons retained a mix of guns until the end of World War 2. Squadrons in the Far East were equipped exclusively with Oerlikons. The Oerlikon gun was installed aboard United States Navy ships from 1942, replacing the M2 Browning machine gun , which lacked range and firepower, and largely superseding the 1.1"/75 caliber gun , which was heavier and had less mechanical reliability. It became famous in

782-597: The Imperial Japanese Navy , after evaluating all three guns, ordered developments of the FF and FFL as the Type 99-1 and Type 99-2 . The incorporation of the improvements of the FFS in a new anti-aircraft gun produced, in 1938, the Oerlikon SS . Oerlikon realized further improvements in rate of fire on the 1SS of 1942, and the 2SS of 1945 which achieved 650 rpm. However, it was the original SS gun which

828-620: The Pacific coast until March 1943, when Ingonish was ordered to the Atlantic Coast of Canada . After arriving at Halifax, Nova Scotia on 30 April 1943, the minesweeper was assigned to the Western Local Escort Force as a convoy escort. In June, Ingonish transferred to Halifax Force, the local escort and patrol force operating from Halifax. That November, the warship was sent to Baltimore , Maryland for

874-513: The Zürich suburb of Oerlikon where it was based, then acquired all rights to the weapon, plus the manufacturing equipment and the employees of SEMAG. In 1927 the Oerlikon S was added to the existing product line. This fired a still larger cartridge (20x110RB) to achieve a muzzle velocity of 830 m/s (versus 490 m/s for the original Becker 20x70RB gun), at the cost of increased weight and

920-565: The fall of France in June 1940, only 109 guns reached the United Kingdom. All Oerlikon guns imported from Switzerland, in 1940, were mounted on various gun carriages to serve as light AA-guns on land. Just a few weeks before the fall of France, the Oerlikon factory approved manufacture of their gun in the United Kingdom, under licence. The Royal Navy managed to smuggle out the necessary drawings and documents from Zürich . The production of

966-556: The 30 or 60-round drum. The 1930s were a period of global re-armament, and a number of foreign firms took licenses for the Oerlikon family of aircraft cannon. In France, Hispano-Suiza manufactured development of the FFS as the Hispano-Suiza HS.7 and Hispano-Suiza HS.9, for installation between the cylinder banks of its V-12 engines . In Germany, Ikaria further developed the FF gun as the MG FF , firing 20x80RB ammunition. And

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1012-529: The Mediterranean. It was also placed experimentally on the battleships Arkansas , Colorado , Maryland , West Virginia , Washington , Massachusetts , and training ship Wyoming . Although guns with blowback action had played an important part in WW2, it was obvious that something better was needed, especially for the universal demand for a high rate of fire. The blowback mechanism requires

1058-635: The Oerlikon cannon were used much more extensively, on aircraft, on ships and on land. In the air, the Ikaria MG FF was used as armament on a number of German aircraft, of which the most famous is the Messerschmitt Bf 109 . The Japanese Navy similarly used their copy of the FF, designated the Type 99 Mark 1 cannon on a number of types including the Mitsubishi A6M Zero . Later in the war, they also equipped fighters including

1104-556: The Royal Canadian Navy, the ship was commissioned on 8 May 1942 at Vancouver . Following work ups , the minesweeper joined Esquimalt Force in May 1942, the local patrol and convoy escort force operating out of Esquimalt, British Columbia . Ingonish was one of the warships added to the west coast patrol force after the Japanese attack on Pearl Harbor . The main duty of Bangor -class minesweepers after commissioning on

1150-666: The Royal Navy, advocated within the Royal Navy to set up an unprejudiced trial for the Oerlikon 20 mm gun, but was unsuccessful. It was not until the Commander-in-Chief of the Home Fleet , Admiral Sir Roger Backhouse , was appointed First Sea Lord that Mountbatten's efforts bore fruit. During the first half of 1939 a contract for 1,500 guns was placed in Switzerland. However, due to delays and then later

1196-483: The United Kingdom in June 1945. The minesweeper was paid off and returned to the Royal Navy at Sheerness on 2 July 1945. Never entering service with the Royal Navy, the vessel was placed in reserve. Ingonish was sold on 1 January 1948 to Clayton & Davie for scrap and broken up at Dunston, Tyne and Wear . Oerlikon 20 mm cannon During World War I , the German industrialist Reinhold Becker developed

1242-667: The West Coast was to perform the Western Patrol. This consisted of patrolling the west coast of Vancouver Island , inspecting inlets and sounds and past the Scott Islands to Gordon Channel at the entrance to the Queen Charlotte Strait and back. The minesweeper was later transferred to Prince Rupert Force, the patrol and escort unit operating out of Prince Rupert, British Columbia and remained on

1288-464: The Zero with the Type 99 Mark 2 , a version of the more powerful and faster-firing Oerlikon FFL. The French firm of Hispano-Suiza was a manufacturer of aircraft engines, and it marketed the moteur-canon combination of its 12X and 12Y engines with a H.S.7 or H.S.9 cannon installed between the cylinder banks. The gun fired through the hollow propeller hub, this being elevated above the crankcase by

1334-540: The application of its gun in aircraft and introduced the AF and AL , designed to be used in flexible mounts , i.e. manually aimed by a gunner. The 15-round box magazine used by earlier versions of the gun was replaced by drum magazine holding 15 or 30 rounds. In 1935 it made an important step by introducing a series of guns designed to be mounted in or on the wings of fighter aircraft. Designated with FF for Flügelfest meaning 'wing-mounted', these weapons were again available in

1380-399: The chamber. To ease the motion of the case, the ammunition needed to be greased, which was a drawback of the Oerlikon cannon. An alternative developed during World War II was the so-called fluted chamber, which had grooves that allowed propellant gas to seep between the chamber wall and the case, taking over the role of the grease. Ammunition feed is typically by a 60-round drum magazine on

1426-553: The decks of larger ships. A handful of corvettes were fitted with the weapon toward the end of the war, but it appeared more commonly on frigates and destroyers at the time. The Oerlikon was also used as the basis for the Polsten gun, designed by Polish engineers in exile in the United Kingdom. The gun went into service in 1944, and was used well into the 1950s, among other uses, on Cromwell tanks and early model Centurion tanks . Romania purchased 45 pieces from Germany during

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1472-518: The design of the gearing. Such armament was installed on the Morane-Saulnier M.S.406 and some other types. Similar German installations of the MG FF were not successful. The Oerlikon became best known in its naval applications. Initially the Oerlikon was not looked upon favorably by the Royal Navy as a short-range anti-aircraft gun. In 1937–1938 Lord Louis Mountbatten , then a captain in

1518-507: The feeder changes exhausted magazines. During World War II, twin and quadruple Oerlikon mounts were developed, both for army and for navy use. The British Navy operated a hydraulically operated twin-gun mount. The US Navy operated a quad mount developed for PT boats by Elco Naval Division, Electric Boat Company, called the Elco "Thunderbolt" mount. Prototypes were built and tested in late 1942 and operationally deployed on several Elco PT Boats in

1564-637: The first British-made Oerlikon guns started in Ruislip , London , at the end of 1940. The first guns were delivered to the Royal Navy in March or April, 1941. The RAF Regiment made extensive use of Oerlikon guns in the anti-aircraft role. These were the principal armament for its light anti-aircraft squadrons in North Africa, the Middle East, Italy, and north western Europe, until the introduction of

1610-513: The first half of World War II. It is still in use today on some naval units, nominally as a last-recourse anti-air weapon, but mainly used for firing warning shots or incapacitating small vessels. Unlike most high-powered autocannons, the Oerlikon and its derivatives have a blowback mechanism: the bolt is not locked to the breech of the gun at the moment of firing. Non-locking, simple blowback designs are commonplace in much lighter weapons, such as small-caliber semi-automatic pistols. No locking

1656-416: The force of the propellant gases until the latter overcome the former and start pushing case, bolt and spring backwards. If the bolt had stopped at the mouth of the chamber as in a simple blowback gun, this momentum would have been neutralized; instead thanks to the continuous movement the momentum acts to counter the propellant gases and slow the rearward travel of cartridge and bolt. Synergistically with this,

1702-399: The forward momentum of the bolt as well, before it can push it to the rear. To facilitate this, the Oerlikon's chamber is longer than needed to contain the cartridge, and the front-end of the bolt, which is the same diameter as the case, actually enters this extended chamber behind the cartridge before firing. As a result when firing occurs, the forward force of the bolt and spring acts against

1748-466: The naval anti-aircraft role, providing an effective defense at short ranges (in practice up to 1.5 km) at which heavier guns had difficulty tracking a target. The gun was eventually abandoned as a major anti-air weapon due to its lack of stopping power against heavy aircraft and against Japanese kamikaze attacks during the Pacific War . It was largely superseded by the Bofors 40 mm gun and

1794-508: The patents and design works were transferred in 1919 to the Swiss firm SEMAG ( Seebach Maschinenbau Aktien Gesellschaft ) based near Zürich . SEMAG continued development of the weapon, and in 1924 had produced the SEMAG L , a heavier weapon (43 kg) that fired more powerful 20×100mmRB ammunition at a slightly higher rate of fire, 350 rpm. In 1924, SEMAG failed. The Oerlikon firm, named after

1840-448: The same term This disambiguation page lists articles associated with the same title formed as a letter–number combination. If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=J69&oldid=1133752752 " Category : Letter–number combination disambiguation pages Hidden categories: Short description

1886-450: The three sizes, with designations FF , FFL and FFS . The FF fired a slightly larger cartridge than the AF, 20x72RB, but the major improvement in these weapons was a significant increase in rate of fire. The FF weighed 24 kg and achieved a muzzle velocity of 550 to 600 m/s with a rate of fire of 520 rpm. The FFL of 30 kg fired a projectile at a muzzle velocity of 675 m/s with

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1932-432: The top of the gun. During sustained firing, the magazine must be frequently changed, reducing the effective rate of fire. Belt-fed versions of the gun were developed to overcome this limitation. A trigger in the right-hand grip controls fire. Used cartridges are ejected from below the breech. Different nations and services operated a number of mounting types for the same basic gun. In a typical single-barrel naval version, it

1978-405: The use of a characteristically shaped cartridge: the case has straight sides, very little neck, and a rebated rim . The straight sides allows the case to slide back and forward in the cylindrical chamber. The neck is not supported while this happens and therefore expands when the case is fired, and the rebated rim allows the face of the bolt, with its extractor claw hooked over the rim, to fit within

2024-609: The war, the minesweeper was returned to the Royal Navy and laid up. Ingonish was discarded in 1948. A British design, the Bangor -class minesweepers were smaller than the preceding Halcyon -class minesweepers in British service, but larger than the Fundy class in Canadian service. They came in two versions powered by different engines; those with a diesel engines and those with vertical triple-expansion steam engines. Ingonish

2070-531: Was of the latter design and was larger than her diesel-engined cousins. Ingonish was 180 feet (54.9 m) long overall , had a beam of 28 feet 6 inches (8.7 m) and a draught of 9 feet 9 inches (3.0 m). The minesweeper had a displacement of 672 long tons (683 t). She had a complement of 6 officers and 77 enlisted. Ingonish had two vertical triple-expansion steam engines, each driving one shaft, using steam provided by two Admiralty three-drum boilers . The engines produced

2116-473: Was widely adopted as anti-aircraft gun, being especially widely used by Allied navies during World War II . This gun used a 400-grain (26-gram) charge of IMR 4831 smokeless powder to propel a 2,000-grain (130-gram) projectile at 2,800 feet (850 meters) per second. The Oerlikon FF was installed as armament on some fighters of the 1930s, such as the Polish PZL P.24 G. Locally produced derivatives of

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