When WW2 kicked off,
the epitomy of US tank design
was Medium Tank, M2.
This was basically
a self-propelled machine-gun nest
which happened to have a 37mm up top
do deal with anti-tank work.
However, in 1939, Ordnance Branch
did some experimentation to see
if maybe a 75mm cannon
might not be a little better
at the anti-infantry role,
and the answer was
“Well, actually, yes, it is”.
Come 1939 also,
and shortly thereafter,
a slight altercation kicked off in Europe,
and the Americans,
watching the goings-on in places
like France and Poland
started to come to the conclusion
that perhaps the 37mm
wasn’t going to cut it in the anti-tank role,
and you needed something a bit bigger.
Well, that something bigger was the 75mm.
Now, ordnance had done experimentation,
as I said, previously,
you look at the T5E2
which was basically an M2 medium,
that had a 75mm pack howitzer M1
mounted on the right sponson.
This proved to be somewhat successful,
and as a result, orders for the M2A1
were curtailed, and the M3 medium
went into production.
This was just going to be an interim vehicle
while they figured out the problems with the T6,
which would soon become
the M4 Sherman, which had the 75mm,
of course, in a fully rotating turret.
Now, Ordnance Branch were originally quite happy
to make a turretless tank
with the 75 in the hull,
pretty much like a Sturmgeschutz.
However, Infantry Branch still had a lot of sway
in tank development at the time, and they were insistent
upon retaining the 37mm.
Now, I’ve not actually seen
any reasons as to ‘why’,
just that they did,
at least according to General Barnes.
The only thing that comes to mind, perhaps, is the ability
to have close-in protection
against infantry, with canister rounds,
basically big shotgun shells,
which were not available for the 75.
By doing all this,
however, they reduced the amount of machineguns
on the vehicle,
and they really did want
to have this thing turn into the anti-infantry death-blossom
machine-gun vehicle of doom.
As a result, they decided
to put another cupola
on top of the turret, with another.30 cal.
This made an already-tall tank
even taller.
Went into production in March 1941,
and was known in British service
as Medium Tank, M3 Lee.
The British, however, were not incredibly enthralled
by either the height of the turret,
or the fact that the commander
didn’t have access to the radio.
They requested
that a new turret be designed.
Mounted on the same turret ring,
it was a little bit lower, a little bit longer and deeper,
and it had a bulge for the radio mount.
In British service, of course, this was known as Medium tank M3 Grant.
Not General Grant,
the official documentation
from Churchill was very clear
not to use the word “General”,
but in practice,
it turned out that people started calling it that anyway.
Entered production both in the factory
of the Pullman Standard Car Company,
which was famous for making
luxurious passenger cars (coaches)
for railroads, and also
the Pressed Steel Car Company,
famous for making slightly less luxurious rolling stock.
So we are at the Australian Museum
of Armor and Artillery
in Cairns, Queensland,
and they’ve been nice enough
to let us wander around their M3 Grant.
It’s going to go in the traditional manner,
we’re going to go wander around the outside in Part 1,
talk about the running gear,
the engine and so on,
and then in part 2,
we’re going to hop inside
and see how much fun
the six or seven lads inside had.
So, starting off at with the hull,
we can of course see that this is
one of those of riveted construction.
About 300 cast-hulled vehicles
were built by Alco,
and another 350 welded-hull by Baldwin,
but the vast majority of M3s
were of course, rivets.
This was the heaviest and most time-consuming
form of construction,
and you also had the minor hazard
that rivets could pop off
and become projectiles inside the tank.
However, it was the level of technology,
and so many tanks of the era
were riveted as it was.
The armor itself is pretty reasonable for its time.
You have about two inches
for the upper slope,
one and a half down here sloped at 53,
and the 3-piece transmission housing
is about 2-inches.
You also have the large bulges
for the final drive.
Now, the great thing about
the final drive housing/transmission housing
for the M3 which was kept on
to the M4 was how easy it was
to access the transmission.
You simply unbolt the housing,
pull it off, two guys
could do it with a crane.
If you compare that
to a lot of other vehicles of the time,
this was an amazing piece
of user-interface, shall we say.
It made life so much easier.
Other features you have on the front,
there would be behind the brush guards,
of course, service lights and siren,
plug in in here,
and a point of amusement, shall we say,
is the twin machine-gun ports.
Now, of course, remember the Americans
loved machineguns on their tanks,
they really did,
and having the cupola on top
just wasn’t enough.
So they put the two here,
they were fixed in traverse,
they were aimed by moving
the entire hull.
They were adjustable in elevation.
However, there are some immediate problems.
Can you imagine being
the gunner on the 75 or the 37
trying to service the target,
and the tank is doing this
because the driver’s having
a whale of a time trying to spray
things with machineguns.
Well, this proved to be
pretty much a complete waste,
very quickly one machinegun
was deleted and they installed a plug
to fill up the hole.
However, pretty soon thereafter,
they decided to get rid of the second one
as well as a complete waste of space,
and although pretty much
every M3 you see will have the ports
for the machineguns, in actuality
you’ll see that they’re welded over,
and it’s pretty rare to find a picture
of one in service with machineguns.
They did come with tripods,
they were stored in the back,
and you could dismount them
and use them as a regular tripod-mounted.30 cal
if you so desired.
Oddly, the machineguns were kept,
some of the earliest M4 Mediums
also had the twin hull machineguns,
but very quickly they decided this was a really stupid idea,
they saw the light,
and got rid of it.
As you keep on moving around
to the left, obviously you have
the large driver’s hatch,
it has a periscope inside it,
of course, we’ll have a look at it
from the inside, 75mm gun M2,
you will note that it stops
short of the tracks.
This was a ‘thing’
in tank design of the time,
they really didn’t want the gun
to go any further than the track.
Well, suffice to say,
that turned out to be
a rather silly idea,
and later production vehicles
had the 75mm gun M3,
which was longer,
had a higher muzzle velocity,
better for anti-tank work.
You will see on some photographs
of M2-equipped tanks
a large counterweight
on the end of the muzzle.
This was used for the stabilization system,
the longer M3 cannon
just didn’t need it
because the gun was heavier.
You then continue around the side.
The running gear was basically held over
from the M3 Medium.
This was a factor
in quickly ramping up production.
The old-fashioned vertical
volute bogies, two wheels per bogie,
bolted simply onto the hull.
Now, the advantage, of course,
to the bolts, it was very easy
to make replacements,
you just unbolt it,
and put a new one back in.
Another advantage was
it took up no space inside the hull,
unlike a lot of other suspension systems
such as Christie.
Downsides, however,
you had a lack of mobility,
relatively speaking,
because you didn’t have
the range of motion for the wheels
that you would have on other vehicles.
Center roller on the top of the bogie.
It is what you would call now
a light-duty bogie,
the heavy duty bogies
would have a return ramp for the track
and also the return roller was located
a bit further to the rear.
The tracks were
another mobility-reducer,
they were only 16 inches wide.
Now, the thinking at the time
was that if you made wider tracks,
then the entire track system
would be heavier, as well as the tank,
and you had a slower tank,
and they decided that speed
was more important than floatation.
In hindsight, this can be argued
to not having been the best decision
and of later on you had
the duckbill end connectors,
and of course later on you got
the horizontal volute suspension
which was much wider,
had twin bogie wheels.
The tracks are 79 links per side.
These particular ones
are rather worn examples of T41s.
These were simple rubber pads
that if you ran them bald on one side,
you could flip them over and then
run the rubber on the other side.
Of course, it’s incredibly inconvenient
and I can only imagine taking off
each and every one of these end connectors
and flipping them over.
Later the T41 was replaced by the T51
which had a double-thickness
of rubber on one side, so you still
had the same service life of the track,
but you didn’t have to go through all the hassle
of flipping it over.
Other patterns,
you had rubber double “I”s,
and you had chevrons,
both steel and rubber.
Primary access into the hull,
of course, was through these large doors.
Inside each door, and you’ll also see
scattered around through the hull and turret,
are these pistol ports.
This was again another concession
to the fact that you no longer
had machineguns in sponsons,
so the idea was that you could take
your Thompson.45 and just shoot out
this if there was any infantry
that got too close.
The door was, of course,
a bit of a liability
to the armor integrity of the vehicle,
so by late production vehicles
they had deleted this,
so the only access to the hull
would have been down through the turret basket
or through the hatch
which was retained in the hull roof
just behind the main gun.
Just coming back from the door
you can see one of the unit markings.
If you haven’t figured it out,
the British had a system
of shapes and colors,
which would tell you
the squadron and troop that the vehicle was in.
Another thing
that the British usually used,
and the Americans you don’t see so much,
are the sandshields.
Of course the British were operating a lot in North Africa,
in the desert, and these were
simple sheets of metal which covered
the return run of the track
and was supposed to keep the dust down.
In actuality, of course, the things
fell off very quickly
and were discarded,
nobody bothered to replace them.
As you come back to the back,
we see again the traditional idler wheel setup of the time,
just like we saw on the M10.
So you would have these locking bolts her,
undo these, you would then
screw in the spreader bolt,
this would then loosen the clamp
around the idler arm.
Pull off this retaining plate,
under this clip,
you just hammer it off this way.
You have now released the serrations,
the teeth here.
You then take Little Joe,
that big massive wrench,
and lever the wheel forwards
or backwards to tension the track.
Slap on your retaining plate,
under the clip,
release the spreader bolt,
tighten the clamps, and you’re done.
We have the exhausts.
The radiator air comes out of the hole
above the rear hull,
the exhausts, of course, are on each side.
Behind the doors we can see
the Wright Cyclone 975 radial engine.
It’s angled a little bit forwards and down
to allow the power train,
the propeller shaft,
to clear underneath the hull
as much as possible.
Little hole up here,
it’s for your hand crank.
It’s not used for starting the engine,
but what you want to do
and this is common for any radial engine tank,
is before you get going
you want to turn the engine
a couple of revolutions
because all the oil is probably pooled
at the bottom of some of the cylinders
and you probably have hydrostatic lock.
So you cycle the engine a couple of times,
and then you’ll be able to start it.
The engine, as mentioned,
it is a 9-cylinder radial, pumps out about 400hp.
Burst speed is about 24 mph,
sustained speed closer to 21.
Has 185 gallons of 92 octane petrol
will get it maybe 120 miles.
There are four fuel tanks.
Two each of 32 ½ gallons
are mounted vertically
at the front corners
of the engine compartment,
and the other two, each of 60,
are located a little bit more
to the rear over the sponsons.
Although you can access the engine
for general maintenance purposes
back here, if you really want
to do some heavy work or pull the pack
I’m afraid what you’ve got to do
is unbolt the engine compartment deck,
lift that off with a crane, and then
you can lift up and out the radial.
Eventually they figured out
a better way of doing it,
if you look at an M18,
the engine will actually slide out backwards.
So that’s it for the engine compartment really,
so let’s hop on up to the back deck.
When you come up onto the engine deck itself,
which actually wasn’t all that hard
because you have all the handholds
to climb on to the side door
and you just make a right
instead of going into the vehicle,
bear in mind this was
an air-cooled vehicle.
So it’s not as if you need any ports
for the cooling system.
As a result, the only hatches here,
and there are five of them,
are for the five fuel tanks.
Four for the main engine,
and one for the auxiliary motor.
Confusingly, this is also
sometimes known as Little Joe.
The grille here is the air intake
for the radiator.
The air is sucked in here,
blown directly over the radial engine,
and then out that gap
above the rear hull.
The engine air intake
for the actual combustion
comes in through the hull,
the fighting compartment.
You can also see back here
another one of the pistol ports,
aiming to the rear, you can see
another pistol port for the side of the turret,
again this is all for the.45,
and you can see the distinctive bulge here
for the radio on the Grant turret.
And, of course, I am sitting
on one of the sponson boxes
for the stowage of tools and whatnot.
Of course a lot of them would be mounted in the fixtures
and fittings on the back of the engine deck.
While I’m still on the outside here,
I’m going to point to a couple of things
at the front of the vehicle.
We have now come to the hull roof,
and if it wasn’t for the fact
that there were a lot of people
on this tank, there would be a lot of room for sleeping.
On the right hand side,
again I’m directly over the 75,
you have the main hatch door here,
on some of the cast hull versions,
the hatch would actually
be sloped downwards.
You can see here also
the mechanism for the primary sight
for the 75mm gun.
Of course, it’s a casemate,
so as the gun traverses
to the left or right,
the entire sight itself
has to have room to swing
around this pivot point as well.
The 37mm gun was also stabilized,
and much as you wanted
a counterweight on the M2,
there was also a counterweight
which could be fixed here.
It looks like a recoil cylinder
when it’s mounted.
It’s not, it’s just a lump of metal
designed to balance the system
for the stabilizer to take effect.
Again, a lot of photographs
you’ll see that it has been removed,
they’re just not using the stabilizer.
Now, whether or not the stabilizer
was a good thing is another matter.
It is frequently known
that a lot of units
just didn’t use them,
they said it didn’t work.
Looking into
Armored Board’s investigations
into the matter,
they realized that there were two or three problems.
Firstly, the early stabilisers,
yeah, they didn’t work very well.
They eventually fixed
those relatively quickly.
The second problem was
that they were so classified
that nobody taught the crews
how to use them and how to maintain them.
As a result, they didn’t work
when they tried to use them
and this led to a loss of confidence.
There were a couple of units
that actually did do
their digging and figured out
how to use them, they swore by them.
They had better performance
in the field than even Armored Board
said that the stabilizer was capable of.
But it’s just another example
of “It’s not just the equipment,
you also have to know how to use it”
So anyway, that brings us
to a conclusion of the exterior
of the vehicle, part 2,
we’ll be back and we’ll hop inside
and see the six positions.