Tank BT-SV (BT-SW-2) was created with the introduction of units, assemblies and systems for BT-7. The main difference between the BT-SV were the construction of the tower and the armored corps, which had armor plates arranged vertically. Compared to the BT-7, the nose of the body BT-SW-2 has not been narrowed, and located in the department of management: a driver — on the right, a radio operator-mechanic — to the left. Under the feet of the radio operator's compartment located emergency landing flap. The crew increment up to 4 people.
The main armament of the tank 45-mm tank gun, 7.62-mm machine gun DT paired with it. Angles pointing vertically equated installation from -5 ° to + 17 °. Ammunition of the tank was 175 rounds for the gun and 1386 rounds of ammunition for the machine gun. Ammunition fit into the 22 machine-gun drive. In the case of the radio station artvystrelov number decreased to 140 pieces. Of the total number of shots, only 7 have been laid in the tower, while others were laying on the sides of the tank and on the floor of the crew compartment. The height of the fighting compartment was equal to 1400 mm in connection with which the loader did not have the ability to work standing up. Gun mounted on the mask two spotlights, providing the opportunity to conduct fire NIGHT MODE.
Armor protection of the BT-SV developed a 2-variants, differing only in width. 1st option advocated by firing projectiles. Maximum thickness of the armor plates turret and hull, running from homogeneous armor "FD" is 50 — 55 mm, providing protection against 45-millimeter shells. The second option armor provides protection from fire 12.7-mm machine gun mnogokalibernogo DC. The thickness of the armor plates, which are used for the production of homogeneous armor steel grade "FROM" was 25 millimeters.
Housing the prototype was made of sheets of structural steel (grade 3) with a thickness of 6 to 12.5 mm, which are housed under bolshennymi angles. The angle of the upper front plate is 53 °, the lower — 58 °, the upper side plates — 55 °, bottom — 15 °, the upper rear plate — 58 °, bottom — 48 °. Conical tower, Stern has no niche, equipped with a common hatch. The taper of the tower was 35 °, and its roof slope to the horizon — 5 °. All the top, corners and bottom hull plates are removable and are fastened with screws. In order to give closure of armor chassis great firmness provided special jumpers (three on each side) between the inner wall of the housing and the lower edge of the sheet.
The power plant, chassis and gearbox were minor configuration in comparison with the base machine. Fuel capacity was reduced to 380 liters. (Not installed aft fuel tank). Progress in store tank on the highway is about 120 km. Turning capacity of the tank down as the steering angle of the front rollers was 12 °. Chassis locked armor, mines spring front suspension units have reverse slope at an angle of 38 °. In contrast to the BT-7 Engine cooling system BT-SW-2 worked in the 2-modes: marching and fighting. Blinds in firing position locked tightly by the driver, with all this carried through the air intake feeding air pockets in the stowed position air comes through the side opening blinds and shutters through a feed air outlet.
In a radio operator-minder in the hull of the tank was installed mock radio station 71-TK-1 (3).
Factory tests the BT-SW-2 reins in winter 37 — 38 years in the spring, and then a commission under the chairmanship of Kulchytskyy NIBT tested at the site. In total, the car has passed 1 285.00 miles. As a result, the principle of reservation used on this machine, acknowledged applicable. With all of this was noted that the chassis BT-7 provided a real booking the BT-SW-2, and the growth of its mass to 24-25 tons of very weak. It was assumed that for practical verification of the reliability of the body, and its impact on the work of running in combat criteria will be given a standard tank having a real book for the test firing. But since the first of the 38th, was arrested NF Ciganov, all work on the tank was stopped.
It should be noted that in the following specifically given rational distribution of armor plates was used by an experienced TA-20, and later on the T-34.
The properties of light tank BT "Turtle":
Combat weight — 25 tons;
Crew — 4 people;
Hull Length — 5620 mm;
Cabinet width — 2800 mm;
Height — 2175 mm;
Ground clearance — 380 mm;
Caliber gun — 45 mm;
Machine gun — DT 7.62 mm;
Mark — M-17T;
Engine power — 500 hp. s.;
Road speed — 51.9 km / h;
Cross-country speed — 22 km / h;
In store down the highway — 120 km;
In store travel cross country — 110 km;
Gradeability — 32 degrees;
Surmounted the wall — 900 mm;
Trench — 1650 mm;
Fording — 1200 mm