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USS Helena (CL-50)
USS ''Helena'' was a light cruiser built for the United States Navy in the late 1930s, the ninth and final member of the class. The ''Brooklyn''s were the first modern light cruisers built by the US Navy under the limitations of the London Naval Treaty, and they were intended to counter the Japanese ; as such, they carried a battery of fifteen guns, the same gun armament carried by the ''Mogami''s. ''Helena'' and her sister were built to a slightly modified design with a unit system of machinery and an improved anti-aircraft battery. Completed in late 1939, ''Helena'' spent the first two years of her career in peacetime training that accelerated as tensions between the United States and Japan increased through 1941. She was torpedoed at the attack on Pearl Harbor in December 1941 and was repaired and modernized in early 1942. After returning to service, ''Helena'' was assigned to the forces participating in the Guadalcanal campaign in the south Pacific. There, she took ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helena, Montana
Helena (; ) is the capital city of Montana, United States, and the county seat of Lewis and Clark County. Helena was founded as a gold camp during the Montana gold rush, and established on October 30, 1864. Due to the gold rush, Helena would become a wealthy city, with approximately 50 millionaires inhabiting the area by 1888. The concentration of wealth contributed to the city's prominent, elaborate Victorian architecture. At the 2020 census Helena's population was 32,091, making it the fifth least populous state capital in the United States and the sixth most populous city in Montana. It is the principal city of the Helena Micropolitan Statistical Area, which includes all of Lewis and Clark and Jefferson counties; its population is 83,058 according to the 2020 Census. The local daily newspaper is the '' Independent Record''. The city is served by Helena Regional Airport (HLN). History The Helena area was long inhabited by various indigenous peoples. Evidence from the M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barbette
Barbettes are several types of gun emplacement in terrestrial fortifications or on naval ships. In recent naval usage, a barbette is a protective circular armour support for a heavy gun turret. This evolved from earlier forms of gun protection that eventually led to the pre-dreadnought. The name ''barbette'' ultimately comes from fortification - it originally meant a raised platform or mound, as in the French phrase ''en barbette'', which refers to the practice of firing a cannon over a parapet rather than through an embrasure in a fortification's casemate. The former gives better angles of fire but less protection than the latter. The disappearing gun was a variation on the barbette gun; it consisted of a heavy gun on a carriage that would retract behind a parapet or into a gunpit for reloading. Barbettes were primarily used in coastal defences, but saw some use in a handful of warships, and some inland fortifications. The term is also used for certain aircraft gun mou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship Class
A ship class is a group of ships of a similar design. This is distinct from a ship type, which might reflect a similarity of tonnage or intended use. For example, is a nuclear aircraft carrier (ship type) of the (ship class). In the course of building a class of ships, design changes might be implemented. In such a case, the ships of different design might not be considered of the same class; each variation would either be its own class, or a subclass of the original class (see for an example). If ships are built of a class whose production had been discontinued, a similar distinction might be made. Ships in a class often have names linked by a common factor: e.g. s' names all begin with T (, , ); and s are named after American battles (, , , ). Ships of the same class may be referred to as sister ships. Naval ship class naming conventions Overview The name of a naval ship class is most commonly the name of the lead ship, the first ship commissioned or built of its design. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of its active battle fleet alone exceeding the next 13 navies combined, including 11 allies or partner nations of the United States as of 2015. It has the highest combined battle fleet tonnage (4,635,628 tonnes as of 2019) and the world's largest aircraft carrier fleet, with eleven in service, two new carriers under construction, and five other carriers planned. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the United States Navy is the third largest of the United States military service branches in terms of personnel. It has 290 deployable combat vessels and more than 2,623 operational aircraft . The United States Navy traces its origins to the Continental Navy, which was established during the American Revo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fire-control Radar
A fire-control radar (FCR) is a radar that is designed specifically to provide information (mainly target azimuth, elevation, range and range rate) to a fire-control system in order to direct weapons such that they hit a target. They are sometimes known as targeting radars, or in the UK, gun-laying radars. If the radar is used to guide a missile, it is often known as a target illuminator or illuminator radar. A typical fire-control radar emits a narrow, intense beam of radio waves to ensure accurate tracking information and to minimize the chance of losing track of the target. This makes them less suitable for initial detection of the target, and FCRs are often partnered with a medium-range search radar to fill this role. In British terminology, these medium-range systems were known as tactical control radars. Most modern radars have a track-while-scan capability, enabling them to function simultaneously as both fire-control radar and search radar. This works either by havin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Search Radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, Marine radar, ships, spacecraft, guided missiles, motor vehicles, Weather radar, weather formations, and terrain-following radar, terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio spectrum, radio or microwaves domain, a transmitting antenna (radio), antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a radio receiver, receiver and Data processing system, processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds. Radar was developed secretly for military use by several countries in the period before and during World War II. A key development was the ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Search Radar
A surface search radar, sometimes more accurately known as a sea-surface search radar or naval surveillance radar, is a type of military radar intended primarily to locate objects on the surface of lakes and oceans. Part of almost every modern naval ship, they are also widely used on maritime patrol aircraft and naval helicopters. When mounted on an aircraft, they are sometimes known by the British terminology, Air-to-Surface Vessel radar, or ASV for short. Similar radars are also widely used on civilian ships and even small pleasure craft, in which case they are more commonly known as marine radar. As with conventional surveillance radars, these systems detect objects by listening for the reflections of a radio signal off target objects, especially metal. The range of a surface search radar is greatly increased compared to other roles due to several aspects of the sea surfaces and the objects in it. In low sea states, water makes an excellent reflector for radio signals, which h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oerlikon 20 Mm Cannon
The Oerlikon 20 mm cannon is a series of autocannons, based on an original German Becker Type M2 20 mm cannon design that appeared very early in World War I. It was widely produced by Oerlikon Contraves and others, with various models employed by both Allied and Axis forces during World War II. Many versions of the cannon are still used today. Blowback-operated models History Origins During World War I, the German industrialist Reinhold Becker developed 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, the patents and design works were transferred in 1919 to the Swiss firm SEMAG (' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bofors 40 Mm Automatic Gun L/60
The Bofors 40 mm Automatic Gun L/60 (often referred to simply as the "Bofors 40 mm gun", the "Bofors gun" and the like, see name) is an anti-aircraft autocannon, designed in the 1930s by the Swedish arms manufacturer AB Bofors. The gun was designed as an intermediate anti-aircraft gun, filling the gap between fast firing close-range small calibre anti-aircraft guns and slower firing long-range high calibre anti-aircraft guns, a role which previously was filled by older outdated guns. The Bofors 40 mm L/60 was for its time perfectly suited for this role and outperformed competing designs in the years leading up to World War II in both effectiveness and reliability. It entered the export market around 1932 and was in service with 18 countries by 1939. Throughout World War II it became one of the most popular and widespread medium-weight anti-aircraft guns. It was used by the majority of the western Allies and some Axis powers such as Nazi Germany and Hungary. In the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft Catapult
An aircraft catapult is a device used to allow aircraft to take off from a very limited amount of space, such as the deck of a vessel, but can also be installed on land-based runways in rare cases. It is now most commonly used on aircraft carriers, as a form of assisted take off. In the form used on aircraft carriers the catapult consists of a track, or slot, built into the flight deck, below which is a large piston or ''shuttle'' that is attached through the track to the nose gear of the aircraft, or in some cases a wire rope, called a catapult bridle, is attached to the aircraft and the catapult shuttle. Other forms have been used historically, such as mounting a launching cart holding a seaplane on a long girder-built structure mounted on the deck of a warship or merchant vessel, but most catapults share a similar sliding track concept. Different means have been used to propel the catapult, such as weight and derrick, gunpowder, flywheel, air pressure, hydraulic, and steam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stern
The stern is the back or aft-most part of a ship or boat, technically defined as the area built up over the sternpost, extending upwards from the counter rail to the taffrail. The stern lies opposite the bow, the foremost part of a ship. Originally, the term only referred to the aft port section of the ship, but eventually came to refer to the entire back of a vessel. The stern end of a ship is indicated with a white navigation light at night. Sterns on European and American wooden sailing ships began with two principal forms: the ''square'' or ''transom'' stern and the ''elliptical'', ''fantail'', or ''merchant'' stern, and were developed in that order. The hull sections of a sailing ship located before the stern were composed of a series of U-shaped rib-like frames set in a sloped or "cant" arrangement, with the last frame before the stern being called the ''fashion timber(s)'' or ''fashion piece(s)'', so called for "fashioning" the after part of the ship. This frame is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Floatplane
A floatplane is a type of seaplane with one or more slender floats mounted under the fuselage to provide buoyancy. By contrast, a flying boat uses its fuselage for buoyancy. Either type of seaplane may also have landing gear suitable for land, making the vehicle an amphibious aircraft. British usage is to call "floatplanes" "seaplanes" rather than use the term "seaplane" to refer to both floatplanes and flying boats. Use Since World War II and the advent of helicopters, advanced aircraft carriers and land-based aircraft, military seaplanes have stopped being used. This, coupled with the increased availability of civilian airstrips, have greatly reduced the number of flying boats being built. However, numerous modern civilian aircraft have floatplane variants, most of these are offered as third-party modifications under a supplemental type certificate (STC), although there are several aircraft manufacturers that build floatplanes from scratch. These floatplanes have found thei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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