In the mid-1930s the British Army,
which was always fairly forward- thinking in terms of AFV design,
although not necessarily so in practice mainly due to financial constraints,
decided to reevaluate their tank categorizations.
The idea of having a heavy tank
to work with the infantry and blow through the lines
and a light tank to go marauding
dates back at least as far as Mark IVs and Whippets of World War I.
However, the development was such that the Army's light tanks
were becoming lighter and smaller,
and the ability for them to do any significant marauding was starting to drop.
Plus you had the additional problem
that you were more and more likely to find something
that was going to shoot back.
So, they moved on to infantry tanks and cruiser tanks.
The infantry would, well, work with the infantry tanks
and the cruisers will be the ones doing the exploitation.
The task for designing the cruiser tank fell to Vickers
and their genius designer John Carden in 1934.
The mission given to him was to come up with something cheaper
than the A7E3 or the A8 then under consideration.
What he came up with was the A9,
which entered service as the Cruiser Tank Mark I.
Welcome to the Tank Museum, Bovington,
and the start of the story of the A9’s brother, the A10.
The A9, by most standards was a modern tank.
You have the driver up front, you have a powered three-man turret,
you got the drivetrain at the back with the sprockets.
There were a couple of problems, though, which prevented it
from being the world leading tank at the beginning of World War II.
Firstly, it was riveted.
Secondly, you have these anachronistic machine gun turrets,
which lead to all sorts of design problems afterwards.
Most importantly, though, the thing only has a half inch of armour,
and it was becoming very obvious that this was no longer going to cut it.
The Armored Corps decided that, well, ok,
the A9 may be good enough for the tank brigades,
but for the army tank battalions you still needed something a little bit heavier.
So, they put the word back down:
Give us something that has an inch of armor.
Carden, reasonably enough, simply took their new A9 design
and added armor to it.
This brings us now to the A10,
which, as you can see, has a strong family resemblance.
By ditching the twin machine-gun turrets at the top,
this reduced the amount of volume that had to be protected by armor
and it also allowed the tank to be a tad shorter.
As a result, A10, with about twice the effective armor thickness of its sibling,
ended up being a little under 2 tons heavier.
Initially it had a very nice sloped front with a little housing for the driver.
However, somebody at the war office decided
it might actually be a good idea to have a bow machine-gun.
As a result, the driver was shifted off to the side, interestingly to the left,
and the machine gun position added to the right,
and the box superstructure was added to cover everybody up.
It's the price you pay for interior volume,
although it destroyed the nicely sloped armour it used to have.
There is still some sloping, mind,
and I would note the horizontal ribbing, which has a couple of effects.
Firstly, it actually does add a little bit to the effective armor value.
Secondly, it stops ricochets from coming up into the driver's face,
and thirdly, and most importantly,
it stops people from slipping off the tank in wet weather.
Construction is of a riveted and bolted type, as you can see,
but there was a bit of a tweak with the A10.
It was built with what was known as composite armor.
Now, what you would do then is you'd start with the frame,
you would rivet a softer steel skin to the frame
and then you would attach on top of that softer skin the actual armor plate.
And what you have is sort of a face hardened effective equivalent
or if nothing else, the soft steel would be a spall liner.
The idea was it would make it easier to repair and build.
Now, the initial tanks did not come with the hull machine gun,
because at the time the coaxial in the turret was a Vickers 303.
So now if you're trying to talk about mixing
303 and 7.92 in the same tank, you're just asking for trouble.
As a result, the bow was simply blanked off.
Now, later on production changed, the turret got the Besa,
this allowed the Besa to be installed into the hull.
And this brings us to the nomenclature issue,
which in typical British period practice was absolutely horrible.
All the A10s were Cruiser Mark IIs.
If you had the Vickers coaxial, you were a Mark 1.
If you had the Besa, you are a mark 1A,
but because this particular tank has the 3.7 inch mortar
(people call it a howitzer, but it's actually a mortar),
this is now the close support variant.
So what we're looking at is Cruiser Mark 2, A10 Mark 1A, CS.
Isn't that fun?
Other items on the front, well, you're gonna see
the headlights of course are large, as was typical at the time.
You've got your little hooks here for towing or lifting
and, well, that's pretty much it,
although I do note the little marker lights on the corners.
Track tension is incredibly basic on this vehicle.
It is a ratchet and pawl,
so if you wanted to loosen the track tension
you would have to release this little locking nut on the pawl,
lift it up and then you would insert levers into these slots here
and manually crank upwards or downwards as appropriate.
Now, if you're tightening it, you don't even need to loosen the pole,
because of the shape of it you simply tighten
and the little ratchet will lock into place.
No specific level of tension is given in the manual,
however, it does say that up to 2 inches of movement
in the track return between the return rollers is acceptable.
Coming around to the side of the tank
brings us to the distinctive bogie suspension.
The bogies are mounted two per side on the lower hull side,
and as you can see, the lower hull side is actually angled a little bit.
This was a deliberate attempt to increase the armor protection,
although, interestingly, the angling continues outwards
as you go up into the upper superstructure,
unlike the inwards of a lot of other vehicles.
The suspension is officially known as the slow motion suspension,
although it is also very often known as the Bright Idea, designed by Carden.
It consists of a 24-inch front wheel two 19.5-inch rear wheels.
The 19.5s are on a little independent bogie to the rear,
the 24-inches on its own independent pivot point.
The 24-inch is also identical to the idler wheel,
so you have a little bit of exchange there as well.
The advantage to having this rather obscure design
is that you can have a large wheel for getting over obstacles,
but the smaller rear wheels are, a) lighter,
and b) they take up less room, so you can have more wheels,
more pressure points in a certain length of area.
Of course, over time this proved to be perhaps not the best compromise,
the idea was dropped, but there you go.
The tires are not actually molded onto the wheels,
they're held in place by this bracket. The bracket is bolted on separately.
The bracket also performs a wear plate function for the guide horns.
The tracks, well, there are 73 links per side,
this is down five off of the 78 of the A9.
They are cast of a malleable iron and are of a double pin type.
Now, the pins are lubricated, but not in the manner, say,
you would find on a German half-track.
They were lubricated once upon assembly and then when you put it together,
rubber seals were supposed to keep the oil in and the dirt out.
Note the use of the word “supposed”, the people who actually used it
probably have their own ideas on the effectiveness of the system.
As you move to the upper hull, I'm gonna start at the front right corner
with this ludicrously complicated arrangement of plates
that all had to be fitted together.
I counted 12 of them, all within a one-foot radius of this point here.
Fire extinguisher located here, there is the builders plate
on the outside of the vehicle, which is a little bit unusual,
and a wonderful amount of stowage for personal kit or the tank issue equipment.
Finally, of course, we come to the air intake.
The 14-tooth sprocket,
which as you can see has a little bit of rubber on it as well,
is driven by an AEC type A-179 engine.
This is a 9.6-liter 6 cylinder, cranks had 150 horsepower at 2200 rpm.
Now, this is all mounted on the four-point system as a single unit
with the clutch and gearbox for easy maintenance.
It is not what you would consider a power-pack today, though,
because it does not include the steering or braking mechanisms.
The engine is a dry sump system, uses seven gallons of oil.
The cooling system is nine gallons of coolant,
which is one more than that found on the A9,
which is basically the same engine.
The brakes, you will note, are on the outside of the vehicle,
which is a little bit unusual.
Has some advantages and one or two disadvantages.
Advantages, well, firstly, they are on the outside of the tank,
so you don't need to have room inside the armored hull:
Space saver and weight saver.
Secondly it is very easy to repair these brakes:
You simply pull off the housing
and there are your brake pads ready for replacement.
Third advantage, cooling the brakes is really easy,
because you have all the air on the outside,
and that's why these ribs are here
to add a little bit more surface area and to help it cool down faster.
The really big disadvantage, though, is that the brakes are on the outside
and this means that they can be easily damaged.
Now, the solution was to add an armored housing
to the outside of the brakes to help protect against incoming fire
or really large rocks or something which might damage the brakes,
but as subsequent developments showed,
it proved not to be the best idea of the lot,
and after Valentine the idea was basically dropped.
There are two fuel tanks in the rear hull by the engine
and they are both on the near side.
One will often hear nearside and offside when talking about cars,
but it's the first time I've ever read these descriptions in a tank manual before.
For those who don't understand,
the nearside is the side of the vehicle nearest to the curb,
so in this case, because it is a British vehicle,
that means the left-hand side of the tank.
Each fuel tank is thirty-three and a quarter gallons,
bringing it up to a total of 66.5,
which is a little bit less than that found on the A9.
However, there is a third fuel tank by the driver in A10,
bringing the grand total up to 98.
Filling up the fuel tanks of a British tank at the beginning of World War II
would not have been so simple,
because one used what were known, reassuringly, as ‘Flimsies.’
These are two-gallon or four-gallon cans,
which had a very nasty tendency of leaking a lot.
By the end of the war,
the British had moved on to refueling together with the Americans
with jerrycans—a design shamelessly stolen from the jerries,
and quite arguably is the German military's greatest contribution
to world war technology, and one which is very often overlooked
in favor of bigger and flashier things.
Anyway, that brings us to an end of the A10 exterior.
Join us for part two, we'll be back for the inside.
Repairing the brakes is really, really easy,
because all you do is you just pull off the squeaky thing and…
come on through.
It's a tad slow and underpowered,
and there was something else wrong with it.
I hope you found the tour of the A10 interesting and informative…
and you're holding your face in your hands,
you're obviously not having a good time at this,
so something has screwed up somewhere…