Thursday, February 28, 2013

Avtomat

Captain V. Fedorov of the Russian Imperial Army (later - a general of Soviet Army) started development of the self-loading rifle in 1906. His first rifle was chambered for standard Russian 7,62x54R ammunition, held 5 rounds in fixed magazine and fired only semi-automatically. In this job Fedorov was supported by his apprentice V.Degtyarov (who latter became one of most important Soviet small arms designers of pre-WW2 generation). Fedorov rifle entered trials in 1911. In 1912 the Rifle Commission of Russian Army decided to order 150 more Fedorov rifles for further trials, and in 1913 Fedorov submitted a prototype automatic rifle, chambered for his own experimental rimless cartridge of 6,5mm caliber. This new ammunition was more compact that Russian 7,62x54R, better suited for automatic weapons (because of rimless cartridge) and has less recoil. This experimental cartridge fired pointed jacketed bullet weighting 8,5 gram at initial velocity of 860 m/s(muzzle energy 3140 Joules as opposed to 3600 - 4000 Joules muzzle energy of 7,62x54R ammunition). 6,5mm Fedorov rifles were tested late in 1913 with good results; these rifles still had fixed magazines loaded from stripper clips.Further trials and development were stopped by the start of World War One. In 1915, however, the need for lightweight automatic arms forced Russian Army to order manufacture of Fedorov automatic rifles with detachable magazines of bigger capacity. Since production of the new cartridge was out of question, it was decided to convert 6,5mm Fedorov rifles to Japanese 6,5x50SR Arisaka ammunition which was in abundance, being purchased through Great Britain along with Arisaka rifles. The change of ammunition involved only minimal changes to the rifle, including chamber insert and new range scale for rear sights. In 1916 Weapons Committee of Russian Army decided that it is necessary to order at least 25 000 of Fedorov automatic rifles. In early 1918 orders for Fedorov rifle were limited to 9000 guns, but as result of turmoil of the revolution and following Civil war only 3 200 Fedorov rifles were manufactured in the city of Kovrov between 1920 and 1924, when production was finally stopped.

Fedorov "Avtomat" - the first practical assault rifle ever adopted

It is interesting that at the time of initial orders Russian Army considered Fedorov automatic rifles as substitute light machine guns; although in actual use Fedorov rifles were used as individual armament for infantry soldiers,exactly in the tactical niche of modern assault rifles. Fedorov automatic rifles served with Russian and later with Red (soviet) Army through WW1, Civil war and until late twenties, when it was decided to retire all rifles and machine guns that used non-standard (other than 7,62x54R) ammunition, and Fedorov rifles were put into reserve storage. The last conflict that saw action of Fedorov rifles was Winter war with Finland in 1940, when some Fedorov rifles were withdrawn from storage and issued to elite units of Red Army.

One important note must be made about the name of Fedorov rifle, which is universally known as "Avtomat" (automatic). This name was apparently devised by Russian small arms expert Blagonravov during mid- or late twenties. At the time, this term was used to designate any shoulder-fired automatic weapon, be that rifle or submachine gun. Up until now "avtomat" is unofficial Russian term for automatic weapon. Today this term is most often used for weapons, generally known as "assault rifles", and therefore Fedorov's "Avtomat" can be considered as one of the world's first practical assault rifles. At the time of its peak usage (1918-1924) there was only one practical automatic rifle made in the world which fell into same tactical class - the Browning's BAR M1918. Initially Bar was intended to be used as assault rifle, with individual soldiers firing itfrom the shoulder or hip during assaults on enemy trenches; however, Browning's rifle was almost twice as powerful (comparing muzzle energy of US .30-06ammunition used in BAR and 6,5x50SR used in Avtomat) and exactly twice as heavy compared to Fedorov's rifle. Therefore BAR soon evolved into light machine gun,while Avtomat set the pattern for the whole new class of infantry weapons, which rose to its heights during late stages of WW2 and especially afterwards.

Fedorov "Avtomat" action, removed from the wooden stock. Note that barrel is in full recoil position and locking plates are lowered and bolt isunlocked (right locking plate is visible in front of the round cocking handleknob).

Finally, we shall note that Fedorov's Avtomat was not without flaws. Its recoil-operated action was sensitive to fouling; early production guns suffered from non-interchangeability of parts, including magazines; disassembly and especially re-assembly was somewhat complicated. Despite these flaws, it was a formidable and historically important weapon, and, ironically, its ballistic properties are very close to modern idea of "ideal" assault rifle and its ammunition.

Diagram showing the locking action of Fedorov avtomat. Top - bolt is locked tothe barrel, bottom - barrel is in full recoil, bolt unlocked and partiallyopened
Parts are numbered as follows: 1 - barrel; 2 - bolt; 3 - locking lug (one of two);4 - fixed lug in receiver.

Fedorov's "Avtomat" is short recoil operated, locked breech weapon which fires from closed bolt. The bolt locking is achieved by two locking plates, located at either side of the breech. Those plates are allowed to tilt slightly down and up, locking and unlocking the bolt with special lugs.The barrel is fluted to save the weight and improve cooling. Trigger unit uses a pivoting hammer to fire, and separate manual safety and fire selector levers are installed within the trigger guard. The stock is made from wood, with semi-pistol grip and additional vertical fore grip in the front of the magazine.The curved box magazine held 25 rounds in two rows, and was detachable. A special bayonet was attached to the front of the steel heat-shield below the barrel. Standard open sights with tangent rear were installed on the barrel.

Caliber: 6,5x50SR Arisaka
Action: short recoil operated
Overall length: 1045 mm
Barrel length: 520 mm
Weight: 4,4 kg empty
Rate of fire: 600 rounds per minute
Magazine capacity: 25 rounds

Wednesday, February 13, 2013

Antonov An-2 multi-role light utility biplane

The Antonov An-2 is a multi-role light utility biplane initially produced under the Soviet flag. Despite its 1940's pedigree, the system has continued service and operations throughout the world and production itself has totaled over 18,000 examples as of this writing. The An-2 goes under the NATO codename of "Colt" and is designated in US DoD nomenclature as the "Type 22". The Soviet Union/Russia, Poland and China have all lent a hand in production of local base and specialized variants. Operators are numerous and range from those with military service to those with civilian-minded needs.


The Antonov An-2 Colt biplane was developed to replace the Polikarpov Po-2 in the utility and agricultural roles.

The engine - powering a four-bladed propeller - is held in the extreme forward of the fuselage to which the cockpit is situated directly aft. The cockpit is heavily glazed and observation port windows can be seen along the fuselage sides. The wing arrangement on this aircraft is of a sesquiplane (uneven span) biplane assembly with the top wing noticeably wider than the lower element. Each wing is connected via a single large vertical strut making up a single wing bay and each wing system showcases dihedral (upward angle). The fuselage tapers slightly into the empennage to which is affixed a single large, smooth-edge vertical tail fin and its applicable stabilizers mounted to either tail fin side. Like other aircraft of this classification, the An-2 sports a pair of fixed landing gear legs complimented by a smaller tail wheel. The main landing gear legs feature wheel bogies decidedly angled inwards with each leg braced at two points along the underside of the fuselage. Power is supplied from a single Shvetsov ASh-62IR 9-cylinder, supercharged radial piston engine of 1,000 horsepower. Maximum speed is a reported 160 miles per hour with a listed range of 525 miles and a service ceiling equal to 14,750 feet.
Externally, the An-2 shares many similarities with other light aircraft of this class.



Accommodations are generally made for a crew of one pilot but an observer/co-pilot is preferred. Cabin seating can hold an additional 12 passengers.



Beyond the typical prototype and evaluation models, the Soviet Union/Russia has produced the majority of the existing An-2 variants while Poland contributed as well.


Produced types ranged from basic observation and reconnaissance aircraft to specialized floatplanes, artillery observation, mail carrier, cargo transport, VTOL-minded projects, survey and photographic platforms, fire bombers and firefighters, research and VIP transports. Agricultural versions have seen extended use in for both Poland and China.



China has produced many versions of the An-2 beginning with the Fong Shou-2 ("Harvester-2").


This was the first An-2 built to agricultural specifications. The Nanchang Y-5 is a transport version since taken over in production by Harbin with 727 examples delivered. Nanchang Y-5II was an agricultural form seeing production number 229. Shijiazhuang Y-5A was a light passenger model based on the An-2T and produced in 114 examples. The agricultural derivative became the Shijiazhuang Y-5B based on the An-2 SKh. The PLAAF makes use of the Shijiazhuang Y-5B(T) para-drop model. The Nanchang Y-5C is an amphibious version of the Y-5A while the Nanchang Y-5D is a bomber crew trainer. The Nanchang Y-5K became a VIP passenger transport seating five.



Notable operators of the An-2 include (or have included) Afghanistan, China, Cuba, East Germany (and Germany proper), Egypt, Georgia, Hungary, Iraq, Laos, Lithuania, Macedonia, North Yemen, North Korea, Poland, South Korea, Romania, Russia, Serbia, Somalia, Sudan, Syria, Turkey, Ukraine, Vietnam, Yemen and Yugoslavia.


Despite its fragile appearance, the Antonov An-2 has seen its fair share of combat action.


It was debuted in such a manner during the Korean War (1950-1953) and later in the Vietnam War - the latter by the North Vietnamese. Some An-2's were converted from their traditional crop dusting roles to become make-shift bombers in the Croatian War of Independence (1991).


Specifications for the Antonov An-2 (Colt)
Dimensions:
Length: 40.68ft (12.40m)
Width: 59.71ft (18.20m)
Height: 13.45ft (4.10m)
Performance:
Max Speed: 160mph (258kmh; 139kts)
Max Range: 525miles (845km)
Rate-of-Climb: 700ft/min (213m/min)
Service Ceiling: 14,764ft (4,500m; 2.8miles)

Structure:
Accommodation: 2 + 12
Hardpoints: 0
Empty Weight: 7,275lbs (3,300kg)
MTOW: 12,125lbs (5,500kg)
Powerplant:
Engine(s): 1 x Shvetsov ASh-62IR 9-cylinder supercharged radial piston engine delivering up to 1,000 horsepower.
Armament Suite:
Usually none.

Some may be fitted with defensive machine guns. Crews may carry individual weapons while other An-2s modified for dropping bombs as needed.


Wednesday, February 6, 2013

D 20

The M1955 was developed in the 1950s to late to be deployed in the Great Patriotic War 1939-1945. However this howitzer has shown reliability and power in numerous wars deployed by scores of nations. The Soviet Union design bureau awarded the contract to Petrov Artillery and the M1955 was built in Yekaterinburg a city in central Russia used in WW II to relocate many heavy factories and many stayed after the war.

The D-20 can be towed by a variety of tracked and wheeled vehicles.

The D 20 was placed on an existing carriage used by the D 74 and was a common practice used by the Soviets. The gun proved to be well designed and rugged enough during field trails. An 8 man crew was needed to man the howitzer an AT-S medium tractor was used for towing along with the URAL-375 6x6 heavy truck. The Russian government still uses the M1955/D20 and still field about 1,000 guns in their arsenal. An initiative development was a semiautomatic vertical sliding wedge breech block.

The major copy was from The Peoples Republic of China that produced the Type 66. This variant has been shipped all around the globe. Type 66 was made with few changes making most Soviet parts interchangeable along with using all types of 152 mm ammunition. The barrel was 5.195 m (17ft 0.5 in) long using a double baffle muzzle to reduce the recoil. A shield was mounted to protect the breach and recoil mechanism. The crew also was protected to some degree. A firing pedestal was lowered to the grown before firing and the split tail carriage was also rested on the pedestal, this allowed a full 360 degrees traverse.

The main projectile used by the howitzer was the HE-FRAG that weighted 95.92 lbs which led to the sustained rate of fire to 1 rpm. Special types included an AP shell 107.54 kg that would penetrate 124 mm (4.88 in) of armor at 1,000 m (1,095 yards). Smoke and illuminating projectiles are available along with a shell contained flechettes for use against infantry and another that spread anti personnel mines in flight.

A rate of 5 to 6 rounds-per-minute can be achieved with 1 round-per-minute in the sustained firing role. Range for an HE-FRAG projectile is reported at 19,040 yards while a rocket-assisted projectile can land within 26,245 yards. Elevation of the barrel is -5 degrees to +65 degrees with a traverse of 58 degrees.

Specifications for the D-20 (M1955)


Overall Length: 26.57ft (8.10m)
Width: 7.71ft (2.35m)
Height: 8.27ft (2.52m)
Weight: 6.3 US Short Tons (5,700kg; 12,566lbs)

Armament Suite: 1 x 152mm Main Gun

Ammunition: Varies. Typical 152mm ammunition type is Frag-HE, OF32.

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