After creating a number of improvised and not always successful designs of light tank destroyers in 1943, German designers managed to create a self-propelled unit that successfully combined light weight, strong armor and effective armament. The tank destroyer was developed by Henschel on the basis of a well-developed chassis of the Czechoslovak light tank TNHP, which had the German designation Pz.Kpfw.38 (t).
The new self-propelled gun had a low hull with a reasonable inclination of the frontal and upper side armor plates. Installation of a 75-mm gun with a barrel length of 48 calibers, covered with a spherical armor mask. A 7,92-mm machine gun with shield cover is placed on the roof of the hull. The chassis is made of four wheels, the engine is located in the rear of the body, the transmission and drive wheels are in the front. The self-propelled unit was equipped with a radio station and a tank intercom. Some of the installations were produced in the version of a self-propelled flamethrower, while the flamethrower was mounted instead of a 75-mm gun. The production of self-propelled guns began in 1944 and continued until the end of the war. In total, about 2600 installations were produced, which were used in anti-tank battalions of infantry and motorized divisions.
From the history of the creation of the tank destroyer 38 "Hetzer"
There is nothing surprising in the creation of "Jagdpanzer 38". The Allies successfully bombed the Almerkische Kettenfabrik factories in November 1943. As a result, damage to the equipment and workshops of the plant, which was the largest manufacturer assault artillery Nazi Germany, which formed the basis of anti-tank divisions and brigades. Plans to equip the anti-tank units of the Wehrmacht with the necessary materiel were in jeopardy.
The Frederick Krupp company began to produce assault guns with a conning tower from the StuG 40 and the undercarriage of the PzKpfw IV tank, but they were quite expensive, and there were not enough T-IV tanks. Everything was complicated by the fact that by the beginning of 1945, according to calculations, the army needed at least 1100 units per month of seventy-five-millimeter anti-tank self-propelled guns. But for a number of reasons, as well as because of the difficulties and metal consumption, none of the mass-produced machines could be produced in such quantities. Studies of existing projects have clarified that the chassis and power unit of the self-propelled guns "Marder III" are mastered and the cheapest, but its reservation was clearly insufficient. Although, the mass of the combat vehicle without significant complication of the suspension made it possible to increase the chassis.
In August-September 1943, VMM engineers developed a sketch of a new type of light cheap armored anti-tank self-propelled guns, which was armed with a recoilless rifle, but, despite the possibility of mass production of such vehicles even before the bombing in November 1943, this project did not arouse interest. In 1944, the Allies almost did not raid the territory of Czechoslovakia, the industry has not yet suffered, and the production of assault guns on its territory has become very attractive.
At the end of November, the VMM company received an official order with the aim of manufacturing a delayed sample of a “new-style assault gun” within a month. On December 17, design work was completed and wooden models of the new vehicle variants were presented by the “Heereswaffenamt” (Directorate of Armaments of the Ground Forces). The difference between these options were in the chassis and the power plant. The first was based on the PzKpfw 38 (t) tank, in the small-sized conning tower of which, with an inclined arrangement of armor plates, a recoilless 105-mm gun was mounted, capable of hitting the armor of any enemy tank at a distance of up to 3500 m. The second is on the chassis of a new experimental reconnaissance tank TNH nA, armed with a 105-mm tube - an anti-tank missile launcher, with a speed of up to 900 m / s and a 30-mm automatic gun. The option, which, according to experts, combined the successful nodes of one and the other, was, as it were, the middle between the proposed versions and was recommended for construction. The 75-mm PaK39 L / 48 cannon was approved as the armament of the new tank destroyer, which was put into serial production for the medium tank destroyer "Jagdpanzer IV", but the recoilless rifle and rocket gun were not worked out.
Prototype SAU "Sturmgeschutz nA", approved for construction
On January 27, 1944, the final version of the self-propelled guns was approved. The vehicle was put into service as “a new type of 75 mm assault gun on the PzKpfw 38(t) chassis” (Sturmgeschutz nA mit 7,5 cm Cancer 39 L/48 Auf Fahzgestell PzKpfw 38 (t)). April 1, 1944. mass production began. Soon the self-propelled guns were reclassified as light tank destroyers and they were assigned a new index “Jagdpanzer 38 (SdKfz 138/2)“. On December 4, 1944, their own name “Hetzer” was also assigned to them (Hetzer is a huntsman who feeds the beast).
The car had a lot of fundamentally new design and technical solutions, although the designers tried to unify it as much as possible with the well-mastered PzKpfw 38 (t) tank and the Marder III light tank destroyer. Hulls made of armor plates of rather large thickness were made by welding, and not by bolts - for the first time for Czechoslovakia. The welded hull, except for the roof of the combat and engine compartments, was monolithic and airtight, and after the development of welding work, the labor intensity of its manufacture compared to the riveted hull decreased by almost two times. The bow of the hull consisted of 2 armor plates with a thickness of 60 mm (according to domestic data - 64 mm), installed at large angles of inclination (60 ° - upper and 40 ° - lower). The sides of the "Hetzer" - 20 mm - also had large angles of inclination and therefore well protected the crew from bullets from anti-tank rifles and shells of small-caliber (up to 45 mm) guns, as well as from large shell and bomb fragments.
The layout of the tank destroyer “Jagdpanzer 38 Hetzer"
Click on the diagram to enlarge (will open in a new window)
The layout of the Hetzer was also new, since for the first time the driver of the car was located to the left of the longitudinal axis (in Czechoslovakia, before the war, the right-hand landing of the tank driver was adopted). The gunner and loader were placed in the back of the driver's head, to the left of the gun, and the place of the self-propelled gun commander was behind the gun guard at the starboard side.
For the entry and exit of the crew on the roof of the car there were two hatches. The left one was intended for the driver, gunner and loader, and the right one for the commander. In order to reduce the cost of serial self-propelled guns, it was initially equipped with a rather small set of surveillance equipment. The driver had two periscopes (often only one was installed) for viewing the road; the gunner could see the terrain only through the periscope sight “Sfl. Zfla”, which had a small field of view. The loader had a defensive machine gun periscope sight that could be rotated around a vertical axis.
Tank Destroyer
The commander of the vehicle with the hatch open could use a stereotube, or an external periscope. When the hatch cover was closed during enemy fire, the crew was deprived of the opportunity to survey the surroundings on the starboard side and stern of the tank (except for the machine-gun periscope).
The 75-mm self-propelled anti-tank gun PaK39 / 2 with a barrel length of 48 calibers was installed in a narrow embrasure of the front plate slightly to the right of the longitudinal axis of the vehicle. The pointing angles of the gun to the right and left did not match (5 ° - to the left and up to 10 ° - to the right) due to the small size of the fighting compartment with a large breech of the gun, as well as its asymmetrical installation. It was the first time in German and Czechoslovak tank building that such a rather large gun could be fitted into such a small fighting compartment. This was made possible largely due to the use of a special gimbal frame instead of a traditional gun machine.
In 1942 - 1943. engineer K. Shtolberg designed this frame for the RaK39 / RaK40 gun, but for some time it did not inspire confidence in the military. But after studying the Soviet self-propelled guns S-1 (SU-76I), SU-85 and SU-152 in the summer of 1943, which had similar frame installations, the German leadership believed in its performance. At first, the frame was used on medium tank destroyers “Jagdpanzer IV”, “Panzer IV / 70”, and later on the heavy “Jagdpanther”.
The designers tried to lighten the "Jagdpanzer 38", due to the fact that its bow was quite heavily overloaded (the trim on the bow, which led to the bow sagging up to 8 - 10 cm relative to the stern).
On the roof of the Hetzer, above the left hatch, a defensive machine gun was installed (with a magazine with a capacity of 50 rounds), and was covered from shrapnel by a corner shield. The service was handled by the loader.
"Praga AE" - the development of the Swedish engine "Scania-Vabis 1664", which was mass-produced in Czechoslovakia under license, was installed in the power department of the self-propelled guns. The engine had 6 cylinders, was unpretentious and had good performance characteristics. Modification "Praga AE" had a second carburetor, which raised the speed from 2100 to 2500. They allowed to raise, along with increased speed, its power from 130 hp. up to 160 hp (later - up to 176 hp) - increased compression ratio of the engine.
On good ground, “Hetzer” could accelerate to 40 km / h. On a country road with hard ground, as shown by the tests of the captured Hetzer in the USSR, the Jagdpanzer 38 was able to reach a speed of 46,8 km / h. 2 fuel tanks with a capacity of 220 and 100 liters provided the car with a cruising range on the highway of about 185-195 kilometers.
The chassis of the prototype ACS contained elements of the PzKpfw 38 (t) tank with reinforced springs, but with the start of mass production, the diameter of the road wheels was increased from 775 mm to 810 mm (the rollers of the TNH nA tank were put into mass production). To improve maneuverability, the SPG track was expanded from 2140 mm to 2630 mm.
The all-welded body consisted of a frame made up of T-shaped and corner profiles, to which armor plates were attached. Heterogeneous armor plates were used in the hull design. The car was controlled by levers and pedals.
The bottom of the armored hull of the tank destroyer "Hetzer"
The Hetzer was powered by a six-cylinder overhead valve in-line liquid-cooled engine of the Praga EPA AC 2800 type with a working volume of 7754 cm XNUMX3 and a power of 117,7 kW (160 hp) at 2800 rpm. A radiator with a volume of about 50 liters was located in the rear of the car behind the engine. An air intake located on the engine plate led to the radiator. In addition, the Hetzer was equipped with an oil cooler (where both engine and transmission oil were cooled), as well as a cold start system that allowed the cooling system to be filled with hot water. The capacity of the fuel tanks was 320 liters, the tanks were refueled through a common neck. Fuel consumption on the highway was 180 liters per 100 km, and off-road 250 liters per 100 km. Two fuel tanks were located along the sides of the power compartment, the left tank held 220 liters, and the right one 100 liters. As the left tank emptied, gasoline was pumped from the right tank to the left. The fuel pump "Solex" had an electric drive, the emergency mechanical pump was equipped with a manual drive. The main friction clutch is dry, multi-disc. Gearbox "Praga-Wilson" planetary type, five gears and reverse. The torque was transmitted using a bevel gear. The shaft connecting the engine and gearbox passed through the center of the fighting compartment. Main and auxiliary brakes, mechanical type (tape).
Details of the interior of the tank destroyer "Hetzer"
Steering "Praga-Wilson" planetary type. Final drives are single-row with internal teeth. The external gear wheel of the final drive was connected directly to the drive wheel. This design of final drives made it possible to transmit significant torque with a relatively small size of the gearbox. Turning radius 4,54 meters.
The undercarriage of the Hetzer light tank destroyer consisted of four large-diameter road wheels (825 mm). The rollers were stamped from a steel sheet and were fastened first with 16 bolts, and then with rivets. Each wheel was suspended in pairs by means of a leaf-shaped spring. Initially, the spring was recruited from steel plates with a thickness of 7 mm and then plates with a thickness of 9 mm.
After creating a number of improvised and not always successful designs of light tank destroyers in 1943, German designers managed to create a self-propelled unit that successfully combined light weight, strong armor and effective armament. The tank destroyer was developed by Henschel on the basis of a well-developed chassis of the Czechoslovak light tank TNHP, which had the German designation Pz.Kpfw.38 (t).
"Praga AE" - the development of the Swedish engine "Scania-Vabis 1664", which was mass-produced in Czechoslovakia under license, was installed in the power department of the self-propelled guns. The engine had 6 cylinders, was unpretentious and had good performance characteristics. Modification "Praga AE" had a second carburetor, which raised the speed from 2100 to 2500. They allowed to raise, along with increased speed, its power from 130 hp. up to 160 hp (later - up to 176 hp) - increased compression ratio of the engine.
