As the Western allies were assaulting the beaches of Normandy
in June of 1944, a new type of vehicle could be found driving around the fields of Surrey, near the Fighting Vehicle
Proving Establishment at Chobham. This vehicle was to set
the standard for Western tank design for years to come. It was Heavy Cruiser A.41, to be known as “Centurion”. The genesis for A41
dates back to October of 1943. The British concluded
that by this point, between domestic cruiser
manufacturing and the imports coming in
from the United States, that they could quit poncing around with half-arsed modifications
to extant equipment, and instead build a proper tank to modern specifications. Immediate needs would be met by the continued production
of Comet series, with its reasonable enough gun and incremental improvements
over the Cromwell. For the A41, though, they would throw out the rulebook, and start from scratch. The first rule they threw out
was the requirement that the tank
be transportable by rail. This was a legacy holdover
from the early war period when the technology of the time
was such that pretty much you needed to railhead a vehicle somewhere. However, it was thought that they could soon enough
develop a transport truck to transport the new tank. This became the Antar, and in the meantime, the new tank
should be reliable enough that if necessary it could get
to wherever it needed to go under its own power. The next requirement was that it be given
a large turret ring. Up until that point,
the British designers were faced with a choice. You could either put a powerful gun in a horrible turret design, such as Challenger or Firefly allowed, or you could put a moderate gun in an acceptable turret design,
such as Comet. By increasing the turret ring size to 74 inches vs, say,
Sherman’s 69 and a half, they made enough room that this tank
could comfortably take the full-power 17-pounder gun. Now, five inches
may not sound like very much, but it really does have
a large effect. Protection
against the German 8.8cm gun was mandatory, which resulted
in good sloped hull armor and a well-designed cast turret. After a little bit of mucking around
with a 20mm Polsten cannon (Polsten is an acronym,
Poland and Sten) in the Mk1 tank, they decided this was
pretty much a waste of space and subsequent marks
dispensed with the 20mm and you just had the coaxial 7.92 Besa. The next variant dispensed with the 17pounder
and replaced it with a 20 pounder. This was the Mk3, and it became
the defacto British production tank. The Mark 4 was a close support version, the Mk5 was basically a Mark 3 except they replaced the 7.92mm Besas with Browning .30 calibre machineguns. We are at the Australian museum
of armor and artillery in Cairns to have a gander at their Centurion. The first Centurion
arrived in Australia in 1951, but this was simply
a British Army vehicle for tropical trials. Australia was
the first foreign country to order Centurion in 1950, however the order
was diverted to Korea upon the onset of the Korean War, and given to the British Army. The first sixty Australian Centurions
finally did arrive in February of 1952. Over time 117 vehicles
would be delivered, 96 of them would be upgraded
to Mark 5/1 standard. The difference
between the various marks: The Mark 5/1 saw
the addition of hull armor, the Mark 5/2 saw the replacement of the 20pounder with the 105mm gun. If both modifications were applied, the vehicle became a Mark 6. As you can see,
this vehicle does not have the additional hull armor,
making it one of the few vehicles which never made it
from Mark 5 to Mark 5/1. We start the tour
at the front of the tank as always. As you can imagine with a vehicle
with a service life like centurion, there were a lot of variations
on the theme. When the vehicle
was first put into service it would have had a stowage bin for the driver’s winshield
on the top left, and spare track over on the right. A lot of photographs, particularly from Vietnam, you would see
two roadwheels mounted on the glacis instead. This particular vehicle
has obviously had those removed, we have a small splashboard,
and multiple headlights. Sometimes you could also find
just single headlights. One unique feature about this tank
you don’t often see on others is located more or less
at the front of the roof over the driver’s compartment, and that is the fillerport
for the drinking water tank. And doubtless,especially
in the Australian environment, a very well-received feature. Other than that,
not too much here. You have the towing lugs and I will draw attention to the rather simple method of attaching the idler wheel by bolts to the font of the hull. There are 108 track links per side, 24 inches wide,
5 ½ inch pitch, single pin. To check it you want
to neutral steer to gather all the slack
on the return run on the side you want to check. Once you’ve done that, you then make sure
that the droop or the sag between the two center rollers isn’t more than an inch
to an inch and a half. Now, obviously you can imagine
that if the side-skirting is attached to the tank,
you have to unbolt that and remove it
as well which is a little bit annoying. Actually adjusting
the track itself, though, is easier than most vehicles. All you have to do
is simply remove a retaining clip, or in this case,
there’s a little pinch bolt to loosen, and then you get your large wrench and screw backwards or forwards. Unlike a lot of the vehicles
I’ve been looking at recently, they’ve moved the screw
towards the end of the idler arm, not down at the fulcrum. Provides a lot more leverage,
makes it theoretically easier. However, there is
a bit of a design flaw. It was noticed
that on occasion after throwing track, the track could be so tensioned that they couldn’t break track, and they couldn’t even loosen the track due to the tension
being applied to the tensioning system. The solution here was to cut the track, either by use
of an oxy-acetylene torch, or by blowing charges. There would be two linear charges
per armored recovery vehicle. You would set the charges
and literally blow the track apart. It is actually
the longest sequence in the manual. It is the process
of how to do this complete with all sorts of safety warnings, and I do note that it specifies
that in the event of a misfire, the officer in charge is the one
who must take “The Long Walk”. And it does emphasise
in block capitals, “alone”. I was never very good
at that sort of thing myself, I had this terrible habit of
investigating bombs with my soldiers. I guess it kept them company,
but in hindsight it may not have been
the most sensible thing ever. The British have now abandoned the Christie suspension system, and gone with bogies
to save on the interior space. They are an improved Horstmann design. There are three coil springs
in each bogie. Two major ones to deal
with the bulk of the load, and an additional third one to take up that extra effort when the first two get compressed. Doubtless changing bogie springs was a task looked forward
to by all crewmen. Not all the bogies are the same. The lead and trail bogies have additional shock absorbers
in the system, they’re up behind this housing here. Roadwheels, obviously
mounted in pairs, two pairs per bogie, three bogies per side,
that’s 24 roadwheels per tank. Check ‘em every 250 miles. The entire system
will cross an 11-foot gap, and scale a 3-foot wall. As you move up on the side,
it’s all about the stowage. Lots of deep stowage bins
for all your pioneer tools, tank repair equipment,
and what have you. You have also
on the sides of the turret the characteristic
turret stowage as well, usually this is going to be
more for your personal gear. Further forward you can see
the smoke grenade launchers and towards the back all you can see is the tow cable
and one of the exhaust pipes. Just inboard of the exhaust pipe you can see one of the marker lights, lifting eye, and underneath this appendage you’re going to get
the usual assortment of towing pintle, towing lugs,clevices and the like. The appendage itself,
this marks the vehicle as a Mark 5 LR, LR standing for “Long Range”, we’ll talk about that
when we get onto the engine deck. This is much easier
without the side skirting in the way. So as you can see we’re now
on the engine deck of the tank, and to open it the louvres, you have to spin the turret
like in most tanks. Unfortunately, unlike most tanks, 90 degrees isn’t going
to cut it with this, because of the large stowage bins
on turrets sides, you have to go all the way around
to about the 5-o clock, and unfortunately it’s hot and I’m doing
the manual traverse thing. In the real world, of course, you’ll just put it in power mode
and spin around, it’s not all that bad,
only in the museum. We’ve opened up
the transmission compartment first, and underneath me
you can see the entire steering, transmission, braking system. All the linkages are mechanical, you can see the inputs here
for the steering, the brakes, the gearbox. Steering is performed
by use of the steering brakes, the inside pair
of the two sets of brakes, but unlike
earlier generations of tanks where the brake
would slow down a track, what this does is it stops
the relative slip inside the transmission itself. As a result, it is powered steering on a fixed radius,
and that depends on what gear you’re in. In first gear,
it’s about 16 feet, in fifth gear it’s about 140. Access to the clutch itself is through a panel
on the base of the tank, in the belly. You can also see that to access
the transmission compartment, we’ve had to lift up the radiators, and this is a similar design
you would have seen this as far back as the Matilda II infantry tank
of 1940. Just as I close up
the transmission housing I will point out the filler point
for the coolant, 33 gallons of coolant were required. These aren’t as heavy as some,
but they’re still not light. So this is the famous
Rolls Royce Meteor, the V12 1649 cubic inch plant, which, limited to 2,550 rpm
would crank out 650 horsepower. This is enough
to get the tank going along at a pretty reasonable clip,
21.5 mph forward, 7.4 in reverse,
which is much higher than most tanks of the time,
in fact, almost double the speed. The high reverse speed was specifically requested
by British tankers building on the experience from Italy
where in the constricted terrain, frequently the only way out of trouble
was to put her in reverse and go as fast as you could. Directly underneath me
is the charging set engine, in American terms
it’s the auxiliary motor, which you would run
just to keep the electrical systems in the tank operating,
the batteries charged, without using the fuel drain
of the main engine, and fuel was a problem. It used 80 octane or better, there are two fuel tanks
in the engine bay, one on the left,
one on the right, 59 and 62 gallons accordingly. Now, people keep asking me
why do give measurements in imperial, well, it’s because
that’s what the tank was designed with. I do a German tank
I’ll do it in metric. Internet is your friend
if you want conversions. Anyway, the 121 gallons,
according to the manual, will get you approximately
34 miles cross-country, 65 miles on road. This is absolutely pathetic,
especially when you bear in mind that refueling was done
by hand-held jerrycans. The British Army’s
Bulk Refuelling System didn’t enter service until 1975, you can imagine
how laborious a process filling up your fuel tank would be. The solution to this
was the monotrailer. This was a 200 gallon trailer, with a single pivoted wheel
at the rear. This basically extended
the length of the tank by half, was entirely unpopular
with the crew, and was eventually
removed from service, actually pretty quickly. It was replaced
by a 100 gallon external fuel tank mounted straight
onto the rear of the tank. That is the extended long range tank we have mounted
on this particular vehicle. So we’re going to close up now, start off with the cooling system
for the 14 gallons of engine oil, close up the louvres, spin the turret back to the front, and I’ll see you for part 2. This is going to be
one of those days, isn’t it? Lifting eyes... underneath, behind
this little extension here you’re going to have
the usual assortment of clouds. That was much better.
All right.
