Generally, when the propeller rotates, according to the principle of reaction force, it will naturally produce a torque opposite to the direction of the engine, which will make the engine rotate in the opposite direction and make the aircraft roll over in the opposite direction.

Double counter-rotating propellers can also solve this problem, but at the cost of more complicated transmission system, higher failure rate and increased weight.

General single-engine propeller aircraft can balance this torque by adjusting aileron. Generally, two-engine or four-engine aircraft can also be designed so that half of the propellers rotate in the opposite direction to offset the torque of the other half, so it is rare to choose double counter-rotating propellers.

The reason why Tu -95 uses double-reverse propeller is because its engine power is very high and it is the largest propeller engine. Generally, there are three ways to exert the high power of its engine: 1, increasing the diameter of the propeller; 2. Increase the propeller speed through the clutch; 3. Increase the number of blades. However, increasing the blade diameter and increasing the blade speed have the same consequences, that is, the linear speed at the blade tip will be greatly improved. When the linear velocity approaches and exceeds the speed of sound, the tip airflow will cause sound barrier, which will greatly reduce the propulsion efficiency of the tip. Therefore, in the case that the blade diameter and rotation speed cannot be further improved, the number of blades can only be increased, so two groups of four-blade counter-rotating blades are simply used. Due to the high power of tu95 engine, its flight speed is close to that of jet bomber. At this speed, two sets of blades are used. Similarly, at the end of the propeller era after World War II and the beginning of the jet era, some high-power, high-speed single-engine propeller planes also used counter-rotating propellers, but of course they just passed by.