Whitepaper

Armoured Sd Kfz 251 can be divided into force branch located in front of the machine, and located him fighting compartment, which housed the crew (a driver and commander) and soldiers assault or any weapons (mortars, antitank gun, etc. ). Inside was the fighting compartment and special equipment (a radio station or a night vision device).
Housing

Case APC consisted of a skeleton, which by riveting or welding installed armored corps. On the Sd Kfz 251 armored personnel carriers used heterogeneous armor – their outer surface was firmer than the inner. Frontal, side and aft armor thickness was 14.5 mm, and the bottom and the roof – 8 mm.

In the power pack housed the engine, fuel tank, steering front wheels, etc. During the fire wall was a control post, where were the places the driver and the commander of the armored personnel carriers. On the dashboard in the driver’s seats have been installed instruments, controlling the parameters of the engine (the thermometer sensor, oil pressure, tachometer, fuel indicator), speedometer and control bulbs. Office armored personnel carrier was carried out using the steering wheel and pedals (clutch, gas and brake). To the right of where the driver had two levers, shift lever and handbrake.

The right side of the wheelhouse was located Commander APC. On some models, such as Sd Kfz 251 / 9, the place of the commander of armored personnel carriers (at the same time the commander of the calculation) was transferred to the stern of the crew compartment.

On each wall the crew compartment installed benches for the soldiers landing. At the armored vehicles of the first modification (Sd Kfz 251 Ausf. AC) benches were covered with leatherette, later used a simple bench in the form of a tubular frame with a pull on it with canvas. We used the wooden seats. On the walls of the crew compartment had been provided for mounting assault weapons: machine guns Mauser 98k caliber 7.92 mm submachine gun MP 38 and MP 40 caliber 9.0 mm.

We specialized models Sd Kfz 251 armored fighting compartment was converted to accommodate the additional radios, guns, or a night vision device. Do ambulances were equipped with racks for installation of the litter. In APCs Sd Kfz 251 Ausf. And in the fighting compartment sides were peepholes, closed bulletproof. The front wings were parking lights. Nearby were installed floodlights (spotlight). At the stern of the APC located positional lights. The antenna was located or from the body (Sd Kfz 251 Ausf. A) or on the wall of the crew compartment (other modifications).
Propulsion

On the Sd Kfz 251 armored personnel carriers mounted engines Maybach HL 42 TURKM. Carburetor six-cylinder engine with liquid cooling Maybach HL 42 TURKM had the following haraktristiki: cylinder diameter – 90 mm, stroke – 110 mm, working volume – 4171 cm3. Engine power – 73.6 kW (100 hp) at 2800 rpm (maximum – 3000 rpm). Specific power (Sd Kfz 251 Ausf. A mass of 9000 kg) – 8.27 kW / ton (11.1 hp / t). compression ratio 6.7.

The radiator is in front of the cylinder block. The mouth of the radiator was put out. On the upper armor power pack (Sd Kfz 251 Ausf. A and B) were abstracted grid vent. On machines later modifications of this hole was removed. Fuel – leaded petrol OZ 74 octane ones of 74 – was placed in the gas tank capacity of 160 liters. The fuel tank was located between the engine and control station, in front of the fire wall. Fuel consumption: 40-55 liters per 100 km on the highway and 80-85 liters per 100 km on rough terrain. Muffler aboard armored personnel carriers between the wheel and caterpillar.

On the Sd Kfz 251 armored personnel carriers mounted a two-chamber dvuhpoplavkovy carburetor Soleks 40 JFF II. Two-plate dry clutch Fichtel & Sachs Mekan PF 220 K with a hydraulic output torque from the engine to the gearbox Hanomag O21-32785 U50. Transmission planetary type, four forward and one back. For movement on the highway and cross-country transmission had different gear ratios. By road: I send – 1:3.47, II transfer – 1:1.80, III transmission – 1:1.01 and 1:0.63 IV transfer, and cross-country: I – 1:8.63, II – 1:4.47, III – 1 : 2.52 and IV – 1:1.58. Rear transfer ratio was 1:9.80. The driver shifts gears by means of two levers to the right of its location. Office armored personnel carrier was carried out using the booster, the current front-wheel drive tracks. Auxiliary air brake with pads Kletrak acted on the front wheels and the main air brake – the driving wheels caterpillar mechanism.
Electric equipment

Electrical single-wire, 12 V, was fed from the generator Bosch RKCN 300/12-1300 power 300 Watts. In addition to the generator source of current is the two lead-acid batteries Bosch voltage of 12 V and capacity of 75 Ah. Battery in the battery compartment located under the seat commander APC. Electric ignition, the ignition sequence of the fuel-air mixture in the cylinders: 1-5-3-6-2-4. In addition to electric starter motor can be run using the handle passing through the hole in the frontal armor and connected directly to the motor shaft.

Power supply had control devices, alarm, spotlights mounted on the wings, radio, positional lights. In armored personnel carriers, military gun, electric powered lights were a sight and trigger gun. On machines Sd Kfz 251/20 was installed, the additional supply night vision device.
Armament

Most of the APCs were armed with machine-gun Rheinmetall-Borsig MG 34 or MG 42 caliber 7.92 mm, set in front of the crew compartment. In APCs Sd Kfz 251 Ausf. BD gun was closed broneschitkom 6 mm thick. In the rear part of the crew compartment was mounting for an additional machine gun MG 34 or MG 42. The machine gun was adapted for firing at air targets. Ammunition usually amounted to 2,010 rounds. In the special versions of ammunition generally was smaller.

Armoured Sd Kfz 251 / 2, were armed with mortars WgGr 34 caliber 80 mm, and the Sd Kfz 251 / 9 – short-barreled cannon 7.5 cm KwK 37 L/24 75 mm caliber and barrel length 1765.3 mm. For the gun used the following types of ammunition: Smoke (weight – 6.21 kg, muzzle velocity 455 m / sec), high-explosive Sprenggranate (5.73 kg, 450 m / sec) and armor-piercing K Gr rot Pz (6.80 kg, 380-415 m / sec at a distance of 1000 meters armor-piercing shell pierced the armor of thickness 35 mm). In addition to the guns 7.5 cm KwK 37 L/24 used cumulative ammunition Hohladungsgranate 38 HL1 / A, HL1 / B and HL1 / C weight of 4.40, 4.57 and 4.80 kg and initial speed 450 m / sec. At the 100-meter HEAT projectiles pierced the armor, respectively 70, 75 and 100 mm (normal-piercing shells K Gr rot Pz at this distance was making only 41 mm!). 25% of the standard ammunition were armor-piercing shells, 10% smoke and 65% explosive. In parts of the grenadier ammunition usually 80% were high-explosive and 20% armor-piercing projectiles.

Armoured Sd Kfz 251/10 equipped with antitank gun Pak 35/36 L/45 (1665 mm) 37 mm. For this gun was used armor-piercing projectiles 3.7 cm PzGr weighing 0,685 kg, the initial velocity of 745 m / sec. At a distance of 1000 meters PzGr shell pierced the armor thickness 22 mm.

Armoured Sd Kfz 251/17 were armed with anti-aircraft gun 2 cm Flak 38 L/112.5 caliber of 20 mm. The gun fired projectiles weighing 0.100 kg. Advanced bronetranspotrery this version armed with a machine gun MG 34 or MG 42.

Armoured Sd Kfz 251/22 Ausf. D equipped with an anti-gun 7.5 cm Pak 40 / 1 L/46 75 mm caliber, and Sd Kfz 251/23 – Gun 2 cm KwK 38 L/55 caliber 20 mm caliber machine gun MG 34 7.92 mm, set in a standard tower Hanglafette 38. The gun fired different types of ammunition, including armor-piercing projectiles 2 cm PzGr weighing 0.100 kg.

At the armed branch of grenadiers, who carried bronetrasporter, was a machine gun MG 34 machine pistols MP 38 and MP 40 (since 1944 also automatic MP 43/44) and pistols P-08 and P-38 and other weapons (such as Panzerfaust).
Chassis

Armoured Sd Kfz 251 had a half-track chassis. The front wheels were for steering, and the caterpillars provide high throughput. Half-track scheme has significantly simplify the design bronetranspotrtera (did not need sophisticated airborne transmission and clutches) with a relatively good cross-country machine.

The wheel of the landing gear consisted of a worm type steering mechanism Hanomag or ZF Ross 600, and was podressorena transverse perevidnoy sprung. For movement over rough terrain using wheel size 190×18. Tire low-pressure type Continental or Michael. Front track – 2775 mm.

When cornering at an angle of 15 ° control bronetranspoterom was carried out as conventional cars. For more cornering special mechanism freeing the inner track and simultaneously transfer of power (from 56 to 100%) on the outside.

The first outdoor series of road wheels consisted of three rollers, the inner row – four, and the average number of – of the six drive wheels. Under normal conditions, the load fell on the inner and middle row of rollers, took a number of external load only at overcoming obstacles.

The first support roller in the right lane was a 140 mm shifted to the stern of the APC. This was due to the peculiarities of torsion suspension. Last wheel, located in the rear of the car, was directing. To track tensioning screw used spanning mechanism. Road wheels stamped out of sheet thickness of 8-12 mm, had eight round holes and were obrezineny. Driving wheels – cast. Caterpillars razdelnozvennye odnogrebnevye odnoshkvornevye equipped depreciation ¬ ziruyuschimi rubber gaskets (Gummipolster). Step caterpillars – 140 mm, length – 7700 mm (left track) and 7840 mm (right track). Track Width 280 mm. Left track consisted of 55 units, right – of 56. Gauge – 1600 mm. Length of tracks – 1800 mm. Clearance – 320 mm.
Radioequipment

Standard Sd Kfz 251 armored vehicles were equipped with ultra short wave transceiver FuG Spr Ger af prutovoy antenna with a length of 2 meters. Radios provide communication at a distance of up to 3 km and was located on the right of the place – the commander of armored vehicles in front of the machine. In addition to radio communication and alarm systems in armored personnel carriers was a set of signal flags and rocket launcher LP (Leucht Pistole) or LP-42 (pistol) caliber 27 mm and a set of signal and illumination flares. At the armored vehicles used as vehicles of communication and command vehicle used other types of radios.
Optical equipment

Do gun MG 34 and MG 42 no scopes. They used a conventional rifle sights and sometimes concentric (for firing at air targets). Sd Kfz 251 / 9, the main gun of 7.5 cm KwK 37 caliber 75 mm, were equipped with scopes SflZFlb / Rblf 36 giving a fivefold increase in the operating range up to 2000 meters and the field of view of 8 °. Gun Pak 35/36, is the main armament bronetranspotrerov Sd Kfz 251/10 was equipped with a sight ZF 1×11. Anti-aircraft guns were equipped with standard sight ZF 3×8. This sight was at the gun Pak 40 (Sd Kfz 251/22) and a flak Flak 38 and MG 151. In the frontal armor of the fighting compartment were two peepholes, closed bulletproof. Similar cracks were smotorovye and sides of the wheelhouse. In bronetranspotrteov Sd Kfz 251 Ausf. D construction inspection of cracks has been simplified. Do transporters Sd Kfz 251 / 1 Ausf. And in the fighting compartment sides were six (three on each side) viewing slits. For observation also used different artillery sights and binoculars.
Optional equipment

Additional equipment consisted of the instruments attached to the sides of cars and being in the side containers (Kasten). In bronetransportrerov Sd Kfz 251 Ausf. D-sided containers have been built and is a single structure with sides. On the sides of armored personnel carriers transported demining tools: crowbars, axes and shovels. Inside the crew compartment at the front door was attached to a fire extinguisher and first aid kit. In addition to armored personnel carriers was a canvas tent, which could stretch over the open fighting compartment during rain or snow.

At the APCs had a standard set of spare parts, fuel pump and jack. Sanitary vehicles were equipped with a barrel of drinking water, which was fastened on board the crew compartment. In addition to the barrels of water on the ambulance was an increased supply of medicines and bandages. Inside Sd Kfz 251 / 8 were adapted to accommodate stretchers with wounded.

Besides all the above items into the extra equipment included cans of fuel and water, bucket, blankets, etc.