BTR - 50 The BTR - 50 ( BTR stands for " Bronetransporter " ( БТР , Бронетранспортер , literally " armored transporter " ) is a Soviet amphibious armored personnel carrier ( APC ) based on the PT - 76 light tank . The BTR - 50 is tracked , unlike most in the BTR series , which are wheeled . The BTR - 50 shares many similarities with two other APCs , the OT - 62 TOPAS and the Type 77 . While the OT - 62 is an improved copy of the BTR - 50 developed jointly by Czechoslovakia and Poland , the Type 77 , based on the Type 63 amphibious light tank developed by the People ' s Republic of China ( PRC ) , is not a copy of the BTR - 50 . Description . Like the PT - 76 , the BTR - 50 has a flat , boat - shaped hull . Unlike the PT - 76 , it has a new superstructure added to the front of the vehicle . The hull of the BTR - 50 is made of all - welded steel with the crew compartment in the front , the troop compartment in the center and the engine compartment at the rear . It has the ability to transport up to twenty fully equipped infantrymen who sit on benches which run across the full width of the troop compartment . They mount and dismount the APC by climbing over the sides of the hull . The driver sits in the center of the front of the hull and has three vision blocks and periscopes located at the top of the sloping glacis plate . During night operations the center periscope can be swapped for the TVN - 28 night vision device which gves the driver clear vision up to 60 meters . The driver also has a small hatch that opens upwards - while it cannot be used to leave the vehicle , it can be opened in relatively safe areas for extra vision . In combat the hatch is closed and the driver can use a vision block . There is an emergency hatch under the driver ' s seat . The commander , who sits on the left hand side of the front of the vehicle , has three vision blocks and periscopes in a projecting bay and a cupola with a vision block facing forward . It is located on top of the projecting bay , opens forward and can be locked vertically . The vehicle can operate in temperatures between - 40 °C and + 40 °C . The torsion bar suspension consists of six evenly spaced large rubber - tired road wheels with a drive sprocket at the rear and an idler at the front . The road wheels are hollow to assist its amphibious capabilities . These wheels increase the APC ' s buoyancy by 30 % . There are no track - return rollers . The first and last road wheels have a hydraulic shock absorber , the steel tracks have a single pin and 96 links each when new . There is a small , thin , horizontal skirt over each track . The BTR - 50 is powered by a V - 6 6 - cylinder 4 - stroke in line water - cooled diesel engine developing 240 hp ( 179 kW ) at 1800 rpm . This gives it a road speed of 44 km / h with a cruising range of 400 km . The vehicle can negoiate 30° side slopes , ascend 60° gradients , cross 1 . 1 m high vertical obstacles and 2 . 8 m wide trenches . The engine has a cooling system and a pre - heater ( intended for ignition when the air temperature is −20 °C or below ) . The APC has a 5 gear manual shaft - type transmission system similar to that in the T - 34 / 85 medium tank . The gearbox has four forward and one reverse gear . The vehicle has a side clutch that enables it to make turns , mechanical transmission and a bandbrake . The vehicle has three fuel tanks , two on the right of the front of the engine compartment and one at the rear . All three fuel tanks carry a total of 400 liters . The vehicle has four mounts for additional external fuel tanks at the rear of the hull . The two mounts on the corners of the hull are for a flat external tank , the two mounts in the center of the rear of the hull are for a drum - type of tank . The BTR - 50 is amphibious thanks to its flat , boat - shaped hull which is hermetical and ensures minimal resistance when the APC is afloat . It can swim after switching on the two electric bilge pumps ; erecting the trim vane which improves the stability and displacement of the vehicle in the water and prevents water from flooding over the bow of the APC . Swapping the driver ' s periscope for a swimming periscope enables the driver to see over the trim vane . There is also a manual bilge pump for emergency use . In the water it is propelled by two hydrojets , one on each side of the hull , the inlets are under the hull , the outlets are at the rear . There are also additional assistant water - jet inlets on both sides of the hull over the last road wheels . The rear outlets have lids that can be fully or partially closed , redirecting the water stream to the forward - directed outlets at the sides of the hull , thus enabling the vehicle to turn . This system was designed by N . Konowalow . It is the same system as the one used in the PT - 76 . The vehicle ' s low freeboard of 15 to 20 cm and lack of a snorkel means it can only swim in the calmest waters . Its armor is composed of homogeneous , cold rolled , welded steel - it is very thin by modern standards , 13 mm at the front , 10 mm on the sides and top and 7 mm at the rear . While its maximum armor protects it fully against small arms fire and small artillery shell fragments , it cannot protect it against large shell fragments and . 50 - caliber machine gun bullets . Although its front armor might protect it against 7 . 62 mm small arms fire , that same fire can sometimes penetrate the sides . The vehicle is equipped with an IR driving light and an IR searchlight . It lags behind other Soviet armored fighting vehicles because it has no fire or nuclear , biological , chemical ( NBC ) protection systems , which significantly reduces its effectiveness . The only variant to have a NBC protection system is the BTR - 50PK . Service history . The BTR - 50 was developed in 1952 and entered service with the Soviet Army in 1954 . It was first shown in public in November 1957 . It served in the motorized rifle regiments of tank divisions and mechanized brigades in the Soviet and East German armies . A typical mechanized brigade consisted of three battalions which each had thirty APCs and one command vehicle . They were replaced in front line service by the BMP - 1 IFV . Command vehicle variants were employed by many Warsaw Pact armies . BTR - 50 " s " were used by Egypt and Syria during the Six - Day War ( 1967 ) , a number of which were captured by Israel . Some vehicles were then re - used by the Israeli Army . Both sides used BTR - 50s during the War of Attrition ( 1968 - 1970 ) . During Operation " Raviv " ( September 8 – 9 , 1969 ) , an amphibious raid across the Suez Canal , three T - 54 tanks and six BTR - 50s were used to wreak havoc behind Egyptian lines . BTR - 50 " s " were again employed by Egypt , Syria and Israel during the Yom Kippur War ( 1973 ) . During this conflict , BTR - 50 " s " , along with T - 54 " s " and T - 55 " s " , were used by the IDF during the fighting in and around the city of Suez . The Yom Kippur War also witnessed Israel capture additional BTR - 50 " s " from the Egyptians and Syrians . Some of Israel ' s BTR - 50 " s " were later transferred to the South Lebanon Army . Variants . Ukraine . Improvements in firepower are achieved by adding one of two new fighting modules ( turrets ) , both of which are armed with one 30 mm ZTM1 or 2A72 autocannon , one 7 . 62 mm KT or PKT coaxial machine gun , one 9K113 Konkurs ( NATO : AT - 5 Spandrel ) ATGM and one 30 mm AGS - 17 automatic grenade launcher . Both main guns are stabilized in the vertical axis ( the second variant has a two axis stabilization ) and have electro - mechanical aiming drives . Both have a maximum effective range of 4 , 000 m and can be elevated or depressed between −10° and + 60° or −4° and + 60° . The vehicle carries 150 rounds ( the second variant carries 350 rounds ) . Both machine guns have a maximum effective range of 1 , 600 m . The vehicle carries 2000 rounds in four batches of 500 , ( the second variant carries the same quantity of ammunition but in two batches of 1000 rounds ) . The ATGM system has a minimum range of 100 m and maximum range of 4 , 000 m with four missiles . The automatic grenade launcher has a maximum range of 1 , 700 m . Mobility is improved by replacing the Soviet - built engine with the UTD - 20 6 - cylinder 4 - stroke V - type water - cooled diesel engine built in the Ukraine , replacing the gearbox with a planetary system and installing hydraulic volumetric transmission . The suspension has also been improved by adding three return rollers . The vehicle has a new system of air intakes and exhausts on the left hand side of the front of the engine deck . This upgrade can also be applied to BTR - 50PU vehicles . This vehicle has a greater combat capability , lower fuel consumption and a higher power - to - weight ratio . The vehicle can operate in temperatures between −40 °C and + 55 °C and has an increased road speed of 75 km / h . As a result of all these changes the vehicle is now higher — 3 , 085 m ( the second variant is 2 , 895 m ) and heavier — 16 . 6 tonnes ( the second variant weighs 16 . 8 tonnes ) . There are also additional improvements which can be carried out at customer ' s request . Those include adding kevlar - type spall liner to improve vehicle ' s protection , navigation system for improving tactical mobility and air conditioning system for improving crew comfort and allowing easier operation in hot climate .