The M18 Hellcat is a well known tank destroyer from the second world war.
With a combination of mobility and firepower it fit well into the American doctrine of
the time.
Often forgotten is that this vehicle was not just used as a tank destroyer and saw a variety
of uses during and after the war.
Some of these include the turretless chassis used for troop and ammo transport all the
way to the bizarre M18 T55 hybrid created decades later.
In this video we won’t be looking at either of those, although both do deserve their own
videos in the future, but rather we'll be looking at a project which could have seen
service had WW2 lasted longer.
Today we delve into the story of the Super Hellcat.
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Now let’s get into what you clicked on this video for.
There are many factors that go into whether or not I will include a vehicle into this
series.
Oftentimes I pick tanks that have failed due to specific issues with their design that
caused them to be either useless on the battlefield or prone to breakdowns.
Other times I choose designs so outrageous they never left the paper they were drawn
on.
In between those two extremes is what I would consider probably the most common reason for
a vehicle to be considered “Cursed by Design”.
That being an upgrade to an existing vehicle which later ends up being unnecessary.
Many times these designs were not necessarily bad but due to either the end of a war or
better alternatives the project never got off the ground.
Today’s topic is a perfect example of this.
With its excellent performance on the battlefield the M18 Hellcat is by far one of the most
advanced armored vehicles from the second world war.
Featuring thin armor and a powerful 76mm cannon capable of defeating just about anything it
faced, these tank destroyers packed quite a punch and could deliver that firepower wherever
it was needed most.
However, as you may recall from previous videos it’s rare for any vehicle, no matter how
effective, to be left alone with the quest for increased firepower never ending.
For the Hellcat this came in late 1944 from the 12th Army group who requested several
improvements to the machine.
This included greater frontal armor, a coaxial .50 cal, a turret roof, and a more powerful
main armament.
The Tank Destroyer Board after studying the proposal came back with a result quite similar
to what I’m sure most of you are thinking right about now.
“The ideal requirements means a vehicle of basically different design from the M18.
If all are met, these requirements will result in a vehicle of entirely different employment
characteristics, in effect a tank.”
This is without even considering the fact that as I mentioned just a moment ago the
M18 was already able to handle pretty much anything it would likely encounter.
So the need for a bigger gun was far from urgent.
Nevertheless it was decided that looking into the idea further couldn’t hurt since if
the war did drag on for longer the firepower of the vehicle may need to be increased.
This was clearly shown by the steady increase in firepower up to this point of the conflict.
With tanks such as the Tiger II beginning to appear this was certainly a possibility
worth considering.
The main problem with this however is that the M18 had by now finished its production
cycle, and to fit the larger cannon into the existing turret would require almost a complete
redesign to it.
Although further production was proposed if the war dragged on, modification of current
vehicles would not only take them out of commission during the upgrade process, but with most
of the vehicles already overseas it would be quite expensive.
All hope was not lost though and with the successor to the M10 having just entered production
under the designation M36 a potential idea was formed.
Not only did the M36 already feature a 90mm cannon but following some measurements of
the turret and M18 in February 1945 it was decided to see if the turret swap could be
done.
This was finally put to the test several months later after the M36 turret they were allowed
to use for the project had finished its testing.
There are some conflicting dates given for when exactly the conversion took place with
photographs of the completed swap being dated as June 27th 1945 but other records stating
it occurred in July.
More than likely the photos were misdated but regardless we know for certain that by
the end of July the conversion had been completed.
Overall the turret swap was done without major issues, only needing a few parts of the M18
chassis to be adjusted slightly to accommodate the new turret.
This included some trimming to the driver's hatch to prevent it from being blocked by
the turret.
With these changes made the tank had gained around 3000 pounds (1360 kgs).
Despite this increase in weight the tank still maintained its mobility with only a slight
change in stance caused by more weight towards the rear of the TD.
Finally the moment of truth came and the 90mm cannon was loaded for testing.
It was found that the tank would definitely require a muzzle brake after it was found
that the tank would roll back 22 inches (56 cm) if the gun was fired with the brakes not
applied.
When testing was done with the muzzle brake fitted this was reduced to less than an inch.
Next the tank was subjected to a 1000 mile (1609 km) endurance test.
Thinking the increased weight could cause the tank to sink into the ground, some experimental
21 inch T82 tracks were used instead of the original ones.
However, after these quickly broke the remainder of the trial was done using the original tracks.
Overall the tank was found to be satisfactory and was considered worthy of further development.
Not only that but the upgrade could be easily done in the field with it requiring no major
changes to either the hull or turret.
That being said, as any of you who know your WW2 timeline will by now have figured out,
the war in Europe had already been won by this point.
With that the last report for this project came in January of 1946.
This particular project would not be the last time the M36 turret was used to upgun another
tank but that's a topic best left for another video.
As for the Super Hellcat we do have one final mystery I could not solve.
Despite my searches I was unable to find the origin of the nickname.
I reached out to The Chieftain who quite literally wrote the book on American TD’s and he was
also unsure of where it came from.
My first thought was that it came from World of Tanks players since several other nicknames
for tanks have come from that game.
However, searches on google predate the games release by at least 5 years.
The earliest mention I could find of the name seems to come from some modelling sites including
one piece of box art featuring the name.
If you happen to know anything more about this unofficial name which has attached itself
to the tank please let me know in the comments because I would really like to know.
All that being said the Super hellcat designation was never officially used to refer to the
tank as it was never accepted for production.
As we can see the M18 with 90mm GMC M36 turret was a good upgrade at the wrong time.
Had it entered service we can likely assume it would have performed quite similarly to
the original M18.
Had the war dragged on for longer in Europe it’s entirely likely this tank could have
seen use in the field although with the M36 itself reaching the warzone it's hard to say.
In my opinion I could see this being used as a way to keep the turrets from damaged
M36 TDs in service although with the M18s and M36s not being used in the same units
as far as I know, so it's debatable how often this might have actually occurred.
Anyways that wraps up the story of the Super Hellcat.
As always let me know what you think of this design down in the comments, I love reading
what your opinions are of the tanks I research.
If you’re a fan of the M18 be sure to hit the subscribe button because I plan to make
some more videos very soon on both the original tank as well as other bizarre variants of
it.
In the meantime if you want to learn more about the specific details I left out of this
video I encourage you to pick up a copy of Can Openers which covers the development history
of US tank destroyers.
I’ll leave a link to where you can get the book down below as it was one of the main
sources I used for this video.
Thanks again to Call of War for sponsoring this video.
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Thanks so much for watching and I’ll see you in the next one.