The Nuts And Bolts of Tanks - Tank layout

The Nuts and Bolts of Tanks: Tank Layout Tank layout. What’s the best way to design a tank? Where should the crew members be located? How should the engine be positioned? How should the main gun and machine guns be mounted? When the first tanks went into action on the battlefields of World War I, these were still open questions. The first tanks resembled huge steel boxes on tracks with the engine inside, roughly in the centre, and with guns and machine guns located either in the hull or in sponsons — special projections from the side of the hull. The interior was unbearably hot and was subject to deafening vibration. Sustained firing of the guns caused propellant gases to build up, sometimes causing crew members to pass out. So the early tanks were problematic machines with limited effectiveness. The improvement of tanks began right after they first appeared. In the British Mark A Whippet medium tanks and the German LK-1 and LK-2 light tanks, designers placed the engine in the front of the vehicle and screened it off from the crew compartment with a metal bulkhead. This made it more convenient for the tankers to perform their duties and battle performance increased. Many vehicles had their engines situated at the front after that; however, by the end of World War I this layout had become rare. The French became the trend-setters in tank design with the introduction of the Renault FT-17 light tank in 1916–1917. At first glance, this vehicle did not seem terribly impressive in comparison with its heavy and medium counterparts. However, the FT-17 was a milestone in tank building, incorporating, for the first time, the basic layout that would soon become standard. Designers Jean Baptiste Estienne and Louis Renault positioned the driver in his own compartment at the front. The fighting compartment was at the centre of the tank. A traversing turret was mounted above the fighting compartment. This provided a 360-degree field of fire for the main gun. In the rear of the vehicle was the engine compartment, containing the engine, fuel tanks and transmission—the mechanism that transmits the torque from the engine shaft to sprocket wheels and tracks with the help of gearboxes. This arrangement is still used in the present day, with some variations each of which have their pros and cons. The classic arrangement with the transmission in the rear is typical of most Soviet tanks of that time. The pros are quite obvious: the engine and transmission are protected from incoming fire hitting the tank’s front; the crew can be isolated from the heat, noise and exhaust fumes generated by the engine; and it’s easier to ventilate the tank components. The drawback is that the turret has to be moved further to the front to make room for the large engine and transmission compartment. The tank’s centre of gravity also shifts forward, so the front wheels are under a greater load and the vehicle has a greater tendency to rock, making it much less accurate when firing on the move. By the end of the Great Patriotic War this problem was moderated by situating the engine crosswise to the hull. The variation of the classic arrangement with the transmission at the front was favoured by German designers for a long time, appearing in tanks such as the Pz. III, Pz. IV and Panther. American tanks with the transmission in the front included the M4 Sherman, M5 Stuart, and M3 Lee. With the driver sharing the front compartment with the transmission, it became possible to arrange the fighting compartment and the turret at the center of the hull. This allowed a more equal distribution of the tank’s weight and simplified the construction of the steering gears. However, tanks with frontal transmissions tended to have a higher profile, because the drive shaft of the engine went over the floor of the fighting compartment. The frontal transmission could be knocked out with a hit to the vehicle’s front. Additionally, a damaged frontal transmission was more difficult to repair. Let’s summarize: Today, most tanks are laid out according to a classic scheme: the driver’s compartment at the front of the hull; the fighting compartment and turret at the centre; and the engine and transmission compartment at the rear. Of course, it’s not enough just to build a tank’s hull. The tank must be able to move around the battlefield. In the next episode, we will tell you about tanks’ running gear.