It's probably worth starting with the definitions. And already they will set the further development of the theme of our story.
So, today no one needs to explain what self-propelled artillery units (ACS) or self-propelled guns are. And self-propelled?
"Self-propelled" - they walk by themselves. "Self-propelled" - they move themselves. The whole difference between the words "walk" and "move". To walk is to travel considerable distances. Self-propelled guns and walked next to the tanks, where it was ordered. Moving guns are those that could move on their own.
Moving guns in a combat situation is a rather complicated procedure, which, moreover, takes a lot of time. And it requires pulling power, no matter what it will be, horses or tractors.
The most striking example: a sudden attack by enemy tanks on the positions of the battalion where it was absolutely not expected. The use of anti-tank artillery is simply impossible instantly, since the guns do not only need to be assembled, you also need to adjust the draft force, hook and move. And the enemy does not wait …
In fact, the first step in this direction was made already in 1923 at the Leningrad plant "Krasny Arsenalts".
Designers N. Karateev and B. Andrykhevich developed a self-propelled chassis for a 45-mm cannon. Inside the lightly armored body of a design called "Arsenalets" housed a boxer gasoline engine from a motorcycle with a capacity of only 12 hp.
The motor accelerated the chassis weighing a little less than a ton to 5-8 km / h. It is unlikely that with such driving characteristics "Arsenalets" could keep up with the troops on the march, so the caterpillar track was supposed to be used only for moving directly on the battlefield.
No seats were planned for calculating the gun. The driver simply followed the Arsenal and controlled it with two levers.
A prototype self-propelled gun was presented for testing in 1928. Of course, the military was interested in the self-propelled chassis for field artillery, but the design of the "Arsenalets" did not provide any protection for the crew and did not have acceptable speed and maneuverability. The cross-country ability was all right. However, after testing, the project was closed.
The Arsenalets self-propelled gun, which is undoubtedly one of the first projects in the world, rightly belongs to the class of self-propelled artillery mounts. Precisely because at the time of its development, there were simply no serious ACS projects yet.
At the same time, later self-propelled guns of domestic and foreign production were armored chassis with weapons and means of protection for fighters installed on them.
The idea of "Arsenalets" was not forgotten. And the idea of a self-propelled gun began to be developed at the FF Petrov Design Bureau even during the Great Patriotic War.
In 1946, the D-44 85 mm anti-tank gun was adopted by the Soviet Army. This weapon turned out to be very successful, so much so that the D-44 is still in service in a number of countries around the world.
In 1948, engineers K. V. Belyaevsky and S. F. The developers completed the project of a self-propelled cannon, which was approved, and in 1949, plant No. 9 began to manufacture a prototype.
The next few years were spent testing, identifying and correcting deficiencies. In November 1954, the self-propelled gun was put into service under the designation SD-44, that is, "self-propelled D-44".
When developing a self-propelled gun, the designers of OKB-9 took the path of least resistance. The barrel group of the original D-44 cannon did not change in any way. A monoblock barrel with a two-chamber muzzle brake and a breech has remained the same.
Only the gun carriage has undergone a solid revision. A special metal box was attached to its left frame, inside which was located a M-72 motorcycle engine with a power of 14 hp. Engine power was transmitted to the drive wheels through the clutch, gearbox, main shaft, rear axle, cardan drive and final drives.
The gearbox provided six forward gears and two reverse gears. The driver's seat is also fixed on the bed. At his disposal there is a steering gear that controls an additional, third, cannon wheel, mounted at the end of one of the beds. During the transfer of the gun to the firing position, the guide wheel was thrown sideways upward and did not prevent the bed opener from resting on the ground.
A headlamp is also installed there to illuminate the road at night.
Hollow carriage frames were used as fuel tanks.
In the stowed position, the SD-44 gun weighed about 2.5 tons. At the same time, it could travel at speeds up to 25 km / h, and 58 liters of gasoline was enough to overcome 22 kilometers.
The main method of moving the gun was still towing with other equipment with more serious driving characteristics.
It is noteworthy that the SD-44 equipment included a self-recovery winch. In the stowed position, its cable was stored on a bulletproof shield, and, if necessary, it was fixed on a special drum on the axle of the driving wheels.
The winch was driven by the main M-72 engine. The transfer of the gun from the combat position to the stowed position and vice versa for the calculation of five people took no more than a minute. With the advent of the An-8 and An-12 military transport aircraft, it became possible to transport the SD-44 cannon by air, as well as to parachute it.
And quite naturally, the main paratrooper of the USSR Vasily Margelov laid his eyes on the cannon, who realized that a weapon capable of being moved by an airplane or a helicopter and at the very least to leave the landing zone was worth it.
The performance data of the SD-44
Caliber, mm: 85
Barrel length, calibres: 55, 1
Weight in firing position, kg: 2250
Angle GN, city: 54
VN angle, degree: -7; +35
Initial projectile velocity, m / s: 793
Max. firing range, m: 15820
Max. self-propelled speed, km / h: 25
Projectile weight, kg: 9, 54
Maximum firing range of OFS, m: 15820
Rate of fire, rds / min: up to 15
Calculation, people: 6
In the movement mode, the gun moves with the barrel back, while it is possible to place a calculation and a part (small) of ammunition on it.
SD-44 is capable of overcoming rises up to 27 °, fords up to 0.5 m deep and snow drifts with a height of 0.30 … 0.65 m. The power reserve on a hard-surfaced road is up to 220 km.
A total of 704 SD-44 guns were produced, both new and converted from D-44.
In addition to the USSR army, the SD-44 was in service with the armies of Albania, Bulgaria, the German Democratic Republic, Cuba and China.
Here's a story. Once again, Soviet engineers showed that they can outplay the whole world.
