We’re a little bit East of Los Angeles in a place called Tankland.
It’s a lovely warm sunny day perfect for having a look at an open-topped vehicle
like the one behind me.
The story for it starts in October of 1948 in Fort Monroe.
An anti-tank panel was established,
and during the course of the deliberations
they decided that they needed a self-propelled,
high-velocity, small caliber anti-tank weapon
which could be air transportable and used to protect airheads.
This was sent up to the Army Airborne Panel in 1948 December.
They endorsed the idea, they kicked it up to Ordnance.
Ordnance sat on it until the 27 April 1950,
at which point they started the project for the T101,
and they then gave Cadillac the contract to build two pilots.
Now initially the idea was
that they were gonna make this thing transportable by an aircraft
with a payload of up to about 16,000lb.
However perhaps recalling the M22 debacle they changed the requirement a little bit
so that they could throw it out of the back of the airplane on a parachute.
When fully kitted out with six parachutes and all the assorted extra equipment,
the aircraft had to lift a payload of about 20,600lb.
However, undeterred by this the project continued for 83 months
and 2.5 million dollars in development.
The final product was the M56 Scorpion,
also known as the “SPAT”, Self-Propelled Anti-Tank.
The manual describes the vehicle as, and I quote:
“a highly maneuverable
and mobile 90mm gun mount qualified to traverse muddy
or marshy terrain, snow and sand.
Its light weight enables it to be transported in a heavy assault glider
or cargo aircraft, and to be airdropped”
Well, as you are looking at it,
the first thing you’ll see is that it’s a tad lacking in the protection department.
Hence, “light weight”.
In fact, there is no armor on this thing what so ever, except the gun-shield,
and the only thing stopping the vehicle from being completely deformed
if it should run accross anything more heavily armored than a bush
is the reinforcing ribs,
and this guard plate at the front here.
The other unusual feature about the vehicle
that you will very quickly notice is the unusual running gear,
so we might as well start there.
Four pneumatic road wheels are mounted on torsion bar suspension on each side.
Now, pneumatic road wheels were chosen because they were lighter.
The tires are 7.5 x12 12-plys.
They are inflated to 75psi, and they are run flat,
the manual states they’re good for about 15 miles at 15mph.
To take the weight of the vehicle, there are six torsion bars,
but only four road wheels.
What’s going on?
Well the answer is that the standard weight of the vehicle is ordinarily taken up
by one torsion bar per wheel,
but the front and the last road wheels each have an additional torsion bar.
It’s hollow, it goes around the standard torsion bar,
and that takes the extra weight from the shock of hitting bumps or from firing.
There are also shock-absorbers on the front and the last road wheels,
and the vehicle needs them.
The tracks themselves consist of eight 44” long sections,
which are bolted together.
They consist of two bands of rubber and steel,
they are connected by steel grousers, with rubber track-pads.
20” wide, they give a ground pressure of only 4.5 pounds to the square inch.
Ground clearance is 15”.
It’ll cross a four foot trench, scale a 30” wall,
and it will ford to a depth of 42” or with preparation 60”.
Track tension is conducted of course at the idler at the rear of the vehicle.
Moving up on the hull, storage compartment, antenna mount, grenade box,
and forward of that we’re gonna have the batteries, they are on the left front.
They are under the exhaust.
To access it you actually have to undue the clamp,
rotate the exhaust up and over,
and then you can access the battery compartment.
Of course the battery is removed in this vehicle.
Moving further forward we’ve got the left headlight set,
service drive, infra-red, markers and black-out.
Which now brings up to the engine compartment,
front and center of the vehicle.
So one of the nice things about having a vehicle
has no armor what so ever,
is that accessing the plates is actually a much easier prospect,
it’s not very heavy.
Holding the hood down is a locking lever on each bottom corner.
There is a hinge at the top,
so in theory this will open up like the regular hood of a car,
there is a little prop-stand inside to keep it open.
However, the hinges on this one are broken,
so by the magic of editing we’re gonna make this one just vanish.
The engine itself is a Continental AOI-402-5.
That actually all means something,
so A — air cooled, O — Opposed Cylinder, I — Fuel Injection,
402 — surprise, surprise 402 cubic inches, -5 means it’s the fifth one in the series.
The front of the engine is determined by where the accessories are.
In this case the accessories are at the rear of the engine compartment.
So the front-right of the engine,
or the left rear of the engine compartment is where you’ll find your oil filler and dipstick.
Takes 13 quarts of oil.
The six cylinder engine itself is rated at 200hp at 3,000rpm,
355 foot/pounds of torque at 2,750rpm,
and it runs on 80-octane gasoline.
Forward of the engine compartment, transmission as you’d expect.
To access it pull forward the travel lock.
There’s another locking lever, and simply lift up the transmission lid.
Underneath is the Allison CD-150-4 transmission.
Again it all means something.
CD — cross-drive, 150 — input horsepower, -4 the fourth model of the series.
“Now hang on a second” you’re probably saying to yourself.
“The engine is 200hp, but the transmission is only 150 input. What’s going on?”
Well, engines are usually rated as a gross hp,
so you say it’s a 200hp engine that is true.
But once you add on all the accessories and so on,
the net hp is substantially less.
In this case, the Continental — gross 200, net is only rated at 155.
So that’s why there’s only 150 or so coming into the cross-drive transmission.
The transmission itself is a torque converter.
It’s got two speeds forward, low and high, neutral and reverse.
Steering is controlled by control disc clutches, also the brakes.
Transmission oil at the front.
13 quarts, and it appears to be in a relatively good condition.
Now, I guess I should detour a little bit at this point
and respond to a couple of comments
that keep coming up on the videos in the past.
They are along the lines of, “Why do you keep telling us this?
Why do I care whether or not this thing take 13 quarts of oil,
or how you tension the track?
Tell us how awesome the gun was and how it performed in battle.”
Well it is certainly true
that you are probably not likely to ever need to know
how to operate a museum piece.
What I’m more trying to get across though,
is what it takes to operate a vehicle.
We tank crews take a lot of time taking care of our tanks,
so that for the small amount of time that we are fighting,
the vehicle is taking care of us.
And there’s all this support that goes into it,
it’s a lot more complicated
than you think from just operating your car.
And things like combat history you can probably find pretty easily on-line.
So anyway, that little detour made I’m gonna close up here
and we’re gonna keep going around.
Right hand side of the vehicle, another head-lights set.
The horn ordinarily would be here — appears to have been disconnected.
Moving further back we have another storage box,
the ramming stuff will go in here for example.
Moving further behind the stowage compartment
on the right side we’re going to have our mounting point
for a hand held fire extinguisher, marker-light tail-light…
And this brings us to the rear of the vehicle
where there isn’t that much on the hull itself.
There’s a tow pintle, a couple of clevis mounts,
and a rack for the pioneer tools.
That’s it for the hull. We’ll be back in part II with crew positions.
Firing this gun would have been… we’ll call it an adrenaline rush.
You can see how quickly the round will come out,
and hit you if you weren’t…