. . . . The forest ended and the river was close about 100 metres. Sergeev stopped his tank, to the back closed two other machines, he jumped out and called the commanders of both vehicles to him. Together with them he came to feel the terrain. There was a battle not far from here. The sounds of artillery bombardment were close. There were seen explosions. Tankists came to the river. The nearest bank was high and the water was deep about 2 metres. The far one is low and, is as far it is seen in the darkness, not muddy. Then there was a mead, then forest, behind which, as tankists knew, were positioned our forces. They were not far at all. But how to cross the river? To find the other better place of river is impossible - the enemy is too close: the motor roars and tracks are too noisy. Crossing the river from a such hill is impossible for tanks. The small squad could not break through the enemy positions - it was too badly outnumbered. To left machines and return by foot - never! And then Lieutenant Sergeev remembered that when he studied in the tank school, teachers told the students about the jumps on the fast tanks BT. He read this in newspapers also. What is possible in time of peace - is a must in war. So, the resolution was chosen - to jump! And the first one would be ridden by the platoon commander. But for the safety of lives of people, he ordered all, but drivers, to cross the river by swimming. Sergeev took the place of mechanic-driver and started the tank motor. After a few seconds of 100m path the tank's velocity was about 50km/h. Then it flew through the air, drew the curve and fell into the water near the opposite coast. Column of water nearly covered the tank. But the water was not deep there and the tank jumped to the coast due to inertia. Sergeev drove it to the shrub. Inspired by their commander's jump, the others follow his example. Everything was going fine. Crews took their places in machines, which not spotted by the enemy entered the forest. The were no Germans in the forest. And after a half of an hour the scouts were happily met by our warriors."
In the middle of 1930's the tank in USSR the possibilities of so-called dynamical obstacle crossing by tanks. That meant also jumps over trenches and narrow rivers. Only fast light tanks BT could complete this tasks successfully.
On proving grounds BT-2 and BT-5 tanks jumped with the 50km/h speed more than 20m through the air.
These experiences also tested dynamical elements of tanks transmission. Thanks to them T-34 was later equipped with the most reliable transmission. These datas also helped to count other transmissions for tracked vehicles. No other army in the world did make such tests. . . .
