Tank Start-Up

Tank start-up procedure undertaken by the "Tank Museum Team" of ever so competent Englishmen, as demonstrated on Tiger I #131 at The Tank Museum, Bovington, UK.

NOTE: The German word “Durchdrehanlasser” quoted in this video is not the correct original German terminology, instead it should say “Schwungkraftanlasser” - in English: "manual inertia starter". One should be mindful of the fact that this video was not published by The Tank Museum.

Once started, the pre-selective gearbox throws a slight tantrum when upshifting into 2nd gear … .

More competent (?) Englishmen at The Tank Museum, Bovington, UK, explain and demonstrate the process of operating the manual inertia starter on the Tiger Tank in detail:

Manual inertia starter

The manual inertia starter was a device used to start up the Tiger’s Maybach tank engine specifically in case of a dead battery. This was a likely scenario, especially during winter fighting on the Eastern Front.

The starter mechanism works by accelerating a heavy flywheel (separate from the engine flywheel) to high speed, using a reduction gear driven by a hand crank. Once sufficient rotational speed is achieved by hand-cranking, a clutch is engaged manually to mesh the starter flywheel with the engine flywheel. After clutch engagement, the inertia stored in the rotating starter flywheel carries the entire crankshaft train and engine internals with it. By rotating the crankshaft and moving the pistons up and down, ideally enough downdraft is generated in the carburetors’ cold start circuits to actually start the engine – after the magneto has developed sufficient voltage to generate a spark, by that same rotational speed. Regrettably, the gear set, and the entire mechanism the manual inertia starter is comprised of, is in fact liable to seize up - especially in the winter time, when it is needed most.

Only 2 decades prior, starting an engine by hand-cranking was still the normal method. Chauffeurs routinely faced the occupational hazard of suffering a broken wrist, caused by initial engine backfire. This is why you would grab the crank handle without wrapping your thumbs around.

Compared to hand-cranking of a normal car engine, operating this type of manual inertia starter poses less of an injury hazard from backfire. However, you would surely not want to hold the crank handle at the moment the freewheeling flywheel is being meshed with the crank train of the engine. The dead weight to be carried is rather substantial.

The same procedure untertaken in the field, by a team of professionals - and true sportsmen at that: King Tiger start-up by working the manual inertia starter (a task otherwise liable to bring even the hardiest of men to well-nigh exhaustion) ...

There are some noteworthy modifications of the manual inertia starter fitted to this "King Tiger", as compared to the original design used on the Tiger I.

By operating the hand crank, the flywheel is accelerated to very high rotational speed. As seen clearly in this footage, the crank is then pulled out to disengage from the gear mechanism used to achieve such high RPMs. Immediately thereafter, a second operator reaches into the cavity to mesh the freewheeling flywheel with the crankshaft. Once engaged, the flywheel's inertia carries the entire crankshaft train with it. Pistons move up and down in the engine's cylinders, causing air to be drawn past the carburetor jet nozzles. This creates the air/fuel mixture to be compressed inside the engine, before it is set to ignite and generate motive power.

At the same time, the magneto "Bosch Zündmagnet, Part No. JGN6R18" hopefully begins to generate enough voltage to create an ignition spark at each of the 12 spark plugs. The magneto generates high-voltage electricity and supplies it directly to the ignition system - bypassing the generator and battery setup. This is why the engine can start and run, even with a completely dead battery.

But even if one managed to get the flywheel moving, and engaged with the crankshaft, there is still a lot to go wrong before the "Maybach HL 230" engine fitted in the King Tiger actually roars to life. Just imagine what a fuel-flooded intake manifold, caused by malfunctioning carburetors - or arching ignition wires - can do. Not to mention deep-frozen batteries suddenly being subjected to charging voltage.

Plenty of opportunity for a "spanner thrown into the works" (UK English), or "monkeywrench in the machinery" (US English). The latter referring to the type of wrench Germans called "Engländer" ... perhaps with some derision at that:

Monkeywrench ("Engländer") used for Imperial nut/bolt sizes

The T34 tank, by comparison, was a completely different animal. The elegance and ease of the starting process on this diesel-powered tank is just one of the reasons why the T34 was a coveted trophy among German troops. Many of these Soviet main battle tanks were placed into service with Wehrmacht units.

The T34, once running, was remarkably quiet. This video shows a specimen with the larger modern turret, in service with the Polish military until well after the war:

Primed for start-up

T34 start-up ... you first hear the retrofitted electric fuel pump priming (the original design featured a manual lever-type fuel pump, used to pressurize the fuel system to 3-4 PSI prior to cranking of the engine).

Starting could be done by electric starter, or in case of a dead battery, by compressed air stored in air reservoirs (bottles) while the tank was previously running. No need to disembark from the tank for emergency starting in the cold …

Listen to the (retrofitted) electric fuel pump, priming from minute 00:20:

Compressed air starter

The T34 used a compressed air starting system to push air into the cylinder at high pressure, and crank the engine over. This type of compressed air starter, using the “Direct Starting” principle, was pioneered by American diesel engine manufacturer Waukesha. It was adapted by the Soviets in the 1930s - as were many things in the course of the lively and lucrative trade relationship between US and USSR prior to WW2.

As quoted from the T34 operator manual: "The engine can be started by an electric starter or by compressed air. The electric starter is fitted to the gearbox. An air distributor is attached to the front part of the engine for compressed air starting. From the air distributor, compressed air is conveyed trough a steel tube to the starting valves fitted inside the cylinder head." ... "The system of starting the engine by compressed air consists of two compressed air bottles, a reduction valve, pressure gauge, air distributor to cylinders (mounted on the engine), pipes from the air distributor to cylinders and twelve outlet valves (one for each cylinder)."

The system was even designed to allow refilling of the air bottles by external means, without having to remove the air bottles themselves. The 2 air bottles and associated T-manifold pipework were located in reach of the driver in the front portion of the hull.

Tanks operating under extreme cold conditions were always liable to encounter trouble starting their engines. This applied regardless of whether they were powered by a diesel or petrol/gasoline engine. As engine oil thickens to a sludge and the batteries are drained, it becomes that much harder to turn over the engine using an electric starter motor.

The T34’s compressed air starter allowed the tank to operate in as low as minus 36 degree (Celsius) temperatures before Moscow in 1941. Under these conditions, German vehicles were unable to function because their oil and coolant had frozen. This frequently caused engines to seize up, rendering the matériel useless in its entirety, while providing endless headaches for "Inst." (Instandsetzung) workshop crews working rearward in the field.

The M4 Sherman has gotten a bad rap over the decades. Despite the far-reaching standardization efforts undertaken as America prepared for war, a hodge-podge of different engines were installed to power this prime mover of a battle wagon for the US Army. This particular specimen, a Sherman M4A1E8 HVSS 76mm restored in Bastogne by the team at the War Heritage Institute, is powered by a Continental R-975-C4 radial engine originally designed for airplanes:

Stalin ordered a Diesel

All of Stalin’s modern tanks had diesel engines. He insisted on this and those tanks produced by America for the Soviet Union under Lend-Lease were made special order for Stalin. As a result, all Lend-Lease Shermans sent to the Soviet Union were equipped with diesel engines.

This included the vast quantities of M4 “Emcha” Sherman tanks supplied via Murmansk and Tehran. After the surrender of Nazi Germany, these tanks empowered Stalin to evict the Japanese from Manchuria in the final days of WWII.

Stalin's engineers and military planners – well ahead of “the West” already at that time – had figured out that diesel power is the way to go in a tank.

Despite the cold-starting issues that diesel engines by design will have, they settled on diesel rather than petrol/gasoline power. The compressed air starter used in the T34 greatly alleviated any concerns about starting a tank under freezing conditions, with a dead battery.

Building a tank powered by a petrol/gasoline engine is of course complete lunacy, on all fronts. Nearly all other Sherman tanks, as in fact most other tanks at the time, had petrol/gasoline engines. This included of course the enormous Maybach Tiger tank engine, and the other German tank designs. This mode of propulsion, specifically the type of fuel used, greatly diminished the survivability of the crew. One is puzzled that this practice was continued well into the 1960’s.

Whiskey in a barrel

The father of General Herbert Norman Schwarzkopf Jr. was stationed in Tehran to coordinate Lend-Lease supplies to the Soviet Union. Gen. Schwarzkopf’s book is a worthwhile read, as it includes second-hand accounts of the situation on the ground, which he relays from stories his father told him, and letters received by his mother.

One such account details how Lend-Lease M4 “Emcha” Sherman tanks were supplied with whiskey bottles hidden in the gun barrel. This was surely meant well, a kind gesture by Rosy the Riveter and her colleagues (comrades?), saluting their brothers and sisters in the Soviet Union, as they packed up those tanks in Detroit, to be shipped to the Soviet side of the Eastern Front.

But more than once the Red Army soldiers receiving these tanks did not think to look inside the breech, or even bother to clean the barrel. The end result was of course the same as if pouring sand down the muzzle. Glass being made from molten sand, this proved a reliable way of destroying the M4’s main weapon.

So to prevent this, General Schwarzkopf’s father had to take care and remove the whiskey bottles already in Persia, prior to loading the Sherman tanks placed in his care onto railway cars at Tehran, destined for the Soviet Union. We may rest assured that whiskey was put to good use, as Schwarzkopf Sr. suffered terribly from endless tooth aches - with not a single dentist on hand, near or far in the highlands of Persia.

The T34 was an advanced Soviet evolution from originally American designs, namely by noteworthy tank engineer Christie. The US Army had no use for his designs. But Soviet generals and designers saw the potential of a fast lighter tank. It seems they put the idea of mobile armored warfare into practice while great strategists like Guderian were still thinking about it (?).

The Christie design was reincarnated by the Soviet war machine as the type BT-5 tank. In this video, one of them is being salvaged from the bottom of the river Neva:

Very impressive, and of historic interest is this T34 – one of many captured by Wehrmacht forces, and fitted with German markings. Here it is being pulled out from the swamps in the year 2000, somewhere in Ukraine: