M18 Hellcat, the Unwanted Success | Forged for Battle

Seek, strike, and destroy; that was the motto  of the US Tank Destroyer battalions during the Second World War commonly seen in the black cat  patch used by those units. This illustrates the doctrine behind these vehicles with their intended  use being to intercept and destroy enemy tanks, as opposed to waiting for them to come to you.  With this doctrine in mind, a design would have no need for excessive protection at the cost of low  speeds, but rather something exceptionally fast and packing

the firepower to match. While this can  be seen in many different tank destroyers during the war no doubt the pinnacle of this design  philosophy is our topic today, the M18 Hellcat. To truly understand the design process which  eventually led to the M18 we need to first travel back around 7 years before the first prototypes of  what would eventually become the M18 Hellcat were delivered. The reason for this is that in 1936 the  US Infantry Board would create the first set of characteristics for

a vehicle which would closely  resemble later US tank destroyer designs. While not a tank destroyer, and in-fact it predates the  Tank Destroyer branch itself by several years, this marked one of the early attempts by the  US military at producing a sort of tank support vehicle and indeed tested it to see its capability  in an anti-tank role. This development would be rapidly sped up by the creation of 53 Tank  Destroyer battalions as well as the shifting of existing anti-tank battalions into T

ank  Destroyer battalions. However for the Hellcat the most important part of this was the creation  of the Tank Destroyer Tactical and Firing Center led by Lieutenant Colonel Andrew Bruce. This  would not just be in charge of developing the doctrine for existing and future tank destroyers  but also the development of those future designs. At this point many of the tank destroyers being  fielded consisted of halftracks such as the M3 Gun Motor Carriage, but this would soon change. The  design an

d introduction of the M10 tank destroyer not only somewhat resembles the attributes of  the earlier M2 based design mentioned earlier but would be the first to actually enter service. The  M10 itself is deserving of an entire video of its own, but for the purposes of this video we will  briefly discuss some of those characteristics. The first of these is obviously the open-topped  turret which was done for several reasons. For one it improves visibility for the crew but it  also helped to keep t

he fighting compartment free of fumes or smoke from firing the gun. Secondly  while it was built on the M4 Sherman chassis it had its armor protection reduced allowing for a  lighter weight than the original Sherman. Finally it featured a more powerful 3 inch, or 76.2mm, gun  than its Sherman cousins making it far deadlier in its intended role against enemy armor. While it  does share some general similarities to the M18 the M10 was primarily an expedient solution  to the need for a tank destroy

er following the US entering WW2. The problem with the M10 in  the eyes of now General Bruce was that it only marginally improved in mobility over the Sherman.  In order to solve this a new platform was needed, and indeed another was already in the works. The development path which would eventually lead to the M18 actually began slightly before the  design process for the M10 beginning November 7th, of 1941, 18 days prior to the T35 project which  eventually progressed into the M10 GMC with the

T35E1. This alternative design called the  37mm Gun Motor Carriage T42 was to be a modified version of the T9 light tank armed  with, you guessed it, a 37mm gun. It should come as no surprise that the idea of a 37mm  gun as a main armament for a tank destroyer in late 1941 quickly was thrown out replacing  it with the more powerful 57mm and with that we come to the next stop in our journey to the M18. This next tank was known as the 57mm Gun Motor Carriage T49. While many aspects of the design a

re  still far from the M18 already some similarities can be found primarily in the running gear.  However it would be the next tank, the 75mm Gun Motor Carriage T67, where we finally reach  the true predecessor to the Hellcat. Featuring an open-topped turret armed with the 75mm M3 cannon  this design would be the final step towards the design known as the T70 which would become M18.  While the test bed for this new design was little more than the T49 prototype hull with a new  turret slapped on

top and the bow machine gun removed there were few changes left in order  to reach the conclusion of this development process which had now been ongoing for over  a year. Which finally brings us to the T70. With our journey to the M18 finally reaching  its destination we also reach the question of what did the US actually get for all that time  spent? Taking aspects of the previous designs leading up to it the 76mm Gun Motor Carriage T70  featured a lighter version of the 76mm gun with 45 rounds

of ammunition. Finding an exact firerate  for the vehicle has proven difficult with the only concrete information I could find being from a  Soviet test giving it a maximum of 11.4 rounds per minute. The only other number I could find was 20  rounds per minute which is an uncited claim in the wikipedia article so I cannot verify the validity  to that. As for the hull it was redesigned to accommodate the Continental R-975-C1 9 cylinder  air cooled radial engine. With the larger radial engine now

taking up much of the space in the  rear, the transmission and final drives were moved to the front of the vehicle. The turret was also  redesigned to mount the 76mm finally being given a protrusion on the rear to act as a counterbalance  for the gun creating the recognizable shape of the M18s turret. The suspension and running gear were  also altered massively switching from using coil springs on the previous designs to now relying  on torsion bars. As for armor there isn't much to say as ther

e wasn’t very much on the vehicle.  While it did have a good amount of angling along the hull front with only half an inch of armor,  or 12.7mm, it wasn’t going to stop much besides shrapnel or small arms at longer range. The turret  was not much better with the thickest point being between ¾ and 1 inch thick, 19-25.4mm. Although this thin armor did result in less protection for the crew, the lightweight of  under 20 tons allowed the T70 to reach incredible speeds. According to the manual this s

hould  be limited to a maximum of 55mph or 89kph, but the true top speed the vehicle could achieve  was even higher. This made it quicker than all its potential foes and even its own allied  forces which actually led to some problems in combat as we will discuss later. As for the crew the tank destroyer was to be operated by a 5 man team. Two men would  sit in the hull front acting as a driver and assistant driver with the remaining three  being in the open topped turret performing the duties of

gunner, loader, and commander. Roughly 1 year after the very first wooden mockup of the T49 the first prototype of the  T70 would be completed in April, 1943 shortly followed by an additional 5 for a total of 6.  These 6 tank destroyers would be tested at both the General Motors Proving Grounds at Camp Hood  and Aberdeen Proving Grounds. While these did find some problems with the design overall they  performed well being placed into production by the Buick Motor Car Division of General Motors

in  June of 1943. From the initial testing alterations to these production vehicles included shifting  the gun 2 inches to the right of the centerline of the vehicle to give the gunner more room  and the addition of a second shock absorber alongside the existing one on the first roadwheel  to reduce the speed of wear. Rapid wear was also a concern in regards to the tracks leading to  a series of improvements to resolve that issue. In yet another display of the United State’s  immense manufacturi

ng capabilities the production quota of 1,000 vehicles by the end of 1943 was  fulfilled in January of 1944. Meaning from the time of the first prototype to 1,000 production  units was barely 8 months, and by the time production ended in October of 1944 that number  had jumped to 2,507. To put this in perspective the entire production run of the Japanese Chi-Ha,  which was one of their most produced tanks of the war, was around 2,100 and took them from  1938-1945. As for the Germans, a fairly co

mparable design to the M18, the Marder III, saw  around 1700 units produced from 1942-44. While production numbers alone do not make a vehicle  great and a number of other factors including how many vehicles were ordered vary by vehicle it is  still incredibly impressive how quickly the US was producing vehicles not just in large quantities  but ones with excellent quality and reliability. The T70 would officially become the M18 in March  of 1944 being standardized as the 76mm Gun Motor Carriage

M18. The first units would begin to  arrive to troops in the field during the spring of 1944 in Italy. However, a problem quickly  arose, the crews didn’t want them. Given it had good firepower and better mobility than anything  else the US was fielding at that time what caused this? Well it came down to a few factors which  you can probably guess. One of these was the fact that up to that point the crews had been  serving on M10s in North Africa as well as the Italian front. When you combine t

he inherent bias  we humans have towards what we know with the fact that the new replacement featured significantly  thinner armor without any significant increase in firepower it's understandable why they may have  been a bit hesitant towards the M18. This was not the only concern though as being an entirely new  design also brought with it the unavoidable fact that it was new to everyone and because of that  both Axis and Allied troops had yet to see it in the field. With the M18 featuring a m

uzzle brake,  larger road wheels, and a hull shape that looks somewhat like the German Panther the chances of  friendly fire increase dramatically. One method used to help prevent this was to not only show  troops what the new vehicle looked like but as we see from this image the muzzle brakes of at  least some M18s were painted red. Due to most photos being black and white and a lack of further  information we cannot say how many had this done or for how long but we do know that it was done. Th

e T70 was briefly considered as a light tank for the US army as a whole but due to the limited  protection this did not progress further. It was not just the US forces who were initially  unimpressed with the M18 either with the Soviets having a similar disinterest towards potential  lend lease of the tank destroyer. This was for more than just the lack of armor protection,  although that is noted as a concern. The other factors leading them to not want it were high  fuel consumption, poor offro

ad performance, and the fuel it used causing it to be more  fire prone. Before you rush to spread these around as reasons for the M18 actually being  a terrible vehicle though bear in mind that the environment the Soviets were fighting in, as  well as their doctrine, was different from that of the US. So while some of these, such as not  using diesel fuel thus being more fire prone, are valid concerns other flaws such as the vehicle  being unable to effectively tow similar weight vehicles or the

loaders position being cramped  were either non-issues under US doctrine or were resolved through changes to the vehicles. It  should also be noted that the Soviets pointed out a number of good characteristics about the T70  including its reliability, gun characteristics, and comfortable positions for most of the  crew. The example they received was a very early production T70 as well meaning many of the  early upgrades had still yet to be introduced. While the M18 would not see service on the 

Eastern front it would see widespread use in the West as well as some use in Italy and the  Pacific. The first of these, as mentioned earlier, would be given to troops in Italy as the  Normandy landings had yet to occur and user feedback on the designs was highly desired. Much  of this feedback, as we have already discussed, largely echoed the concerns put forward by  the Soviets. Light armor, difficulty in mud, and poor placement of the ammo racks were all  found to be problems with the design

. Even the smaller size of the M18 compared to the M10  led to concerns about the crew space being more limited. This would lead to the commander of  the 894th Tank Destroyer Battalion to not deploy them alongside their M10 cousins, rather utilizing  them as part of the reconnaissance company where they reportedly performed well. This hesitation  towards putting the M18 into combat persisted even to the Normandy invasion with only three  of the nineteen self propelled Tank Destroyer Battalions i

n England being equipped with them.  This was not just due to the lack of armor or other factors we have already mentioned as much  as a hesitation towards introducing a new vehicle type into an already complex operation. This  same hesitation is partly responsible for the US lacking the more powerful armaments on their  Shermans during the Normandy landings which is without a doubt one of the biggest mistakes  made during the early invasion of Europe. As the war progressed we can see the somewh

at  icy reception of the M18 begin to thaw. While the light armor remained an ever present concern  as the more powerful Panzer types were encountered more and more frequently the potential benefits  granted by the M10 grew fewer. Some of these are expressed by a Hellcat commander by the name of  Sergeant Joseph Tetreault who heaped praise on the tank destroyer. He even brings an interesting  point up regarding the armor protection of the M10 and M18 against German guns stating “Unless we  have

at least ten inches of armor on our tanks, we may just as well not have any armor of more  than two inches.” He then goes on to say the lighter armor of the M18 actually was better in  that regard as the thinner armor would result in less fragmentation than the thicker armor of the  M10 leading to an overall better outcome when hit. This praise was not without criticism though  as despite the fast speed of the Hellcat its actual mobility was found to be similar to that  of the other vehicles alo

ngside it. In fact in some cases shortages of M18s saw knocked  out vehicles replaced by 76mm armed Shermans which could reportedly keep pace with the M18s  under battlefield conditions. I caution against taking this as gospel truth though as various  other accounts note the M18s superior off road capabilities with it crossing terrain where  M4s instead bogged down. The speed did in some cases prove to be an issue however as M18s could  easily leave their supporting recon and security units behi

nd. This problem with outrunning their  supporting forces did result in an interesting proposal though. A fully M18 powered unit. The theory for this was to create multiple variants of the M18 to have a full platoon made up  of them. These variants included a command recon vehicle, an armored personnel carrier, an armored  ammunition carrier, an armored prime mover for artillery, a general purpose carrier, and one with  an anti-aircraft mount. In the end this idea would not result in a fully M18

powered platoon but  the existence of the M39 Armored Utility Vehicle does give us a glimpse into what may have been. Other potential improvements to the M18 based on feedback from the crews were attempts to add  additional armor to the tank destroyer as well as some sort of roof for the turret to prevent  grenades from easily being tossed in as well as to keep the weather out. Other complaints were  made regarding the .50 cal mount and the fact that the commander needed to fully expose himself

  to enemy fire in order to operate it. This led to a variety of experimental forms of protection  including a hinged dome and conical cover but none of these were adopted. The largest of these  modifications though was the T7 swimming device to allow the M18s to perform water crossings. By  using floats, side skirts, LVT-style grousers, and even a gun stabilizer this would give the M18  both amphibious capabilities as well as granting them the ability to fire effectively while doing  so. This a

nd some other similar designs created later did achieve success in their goal to make  the vehicles float but were not used in combat. Back to their combat use the M18s would see good  success during the Battle of the Bulge where they got to fulfill their intended purpose of rapid  response to armored breakthroughs. In this they reportedly performed well with the 705th Tank  Destroyer Battalion reaching and supporting the 101st Airborne Division. The 705ths M18s  successfully prevented German ar

mored advances, knocking out many of the German panzers at the  cost of relatively few Hellcats. This is in essence exactly what the updated Tank Destroyer  doctrine called for with TDs being employed to halt the advance of enemy tanks by supporting  infantry. By doing this they reinforced the infantry while also gaining the benefits of  having those infantry protect them from enemy infantry. To fully discuss the Tank Destroyer  doctrine and its many flaws would take far too long to include in t

his video but if you would  like to learn more I recommend reading “Seek, Strike, and Destroy: U.S. Army Tank Destroyer  Doctrine in World War II” which will be linked below. Nicholas Moran also has a number of videos  discussing tank destroyers and doctrine on his youtube channel “The Chieftain” which are worth  watching if this is a topic you find interesting. The performance of the M18 in the European theater  generally appears to have been fairly good. It still struggled with the heavier arm

or of the  newer German Panzers but thanks to the mobility they could still knock them out by flanking  them. As for their limited use in the Pacific this appears to be a bit less impactful. Tank  destroyers in general were of little use in a theater where the most heavily armored tanks  were already easy pickings for the Shermans. With the suicidal anti-tank tactics utilized  by the Japanese the open top and thin armor of the M18s also placed their crews in far more  danger. I should note thoug

h that I was able to find one report which echoes the praise for the  M18s mobility we see from the European theater. While it doesn’t mention it by name referring to  a Self Propelled 76mm gun the description leads me to believe this is almost certainly referring  to the M18 and the M18 is mentioned by name later in the report. It reads, and I quote “The SP 76mm  gun proved to be the most mobile self-propelled weapon on the battlefield. Its relatively light  weight, maneuverability, and low sil

houette proved very successful. The enemy did not succeed in  knocking out any of these weapons in the 77th Division. Those located by the enemy were  quickly shifted before they could be hit.” While it certainly performed well there is no  denying that the M18 was lacking in firepower for a tank destroyed by the end of the war. A  short lived project to mount a 90mm gun on the M18 did have the potential to solve this but  the war was over by the time it had completed testing. If you’d like to l

earn more about that  vehicle I have covered it in a previous video. The end of WW2 would not mark the end of the M18  in combat although it would not be used by the US forces in the war in Korea with only the M39  Utility vehicles being used. Several nations would end up taking M18s for themselves though with the  Yugoslavian, Bosnian, Serbian, Italian, Greek, Venezuelan, Iranian, and Taiwanese militaries all  receiving some. M39s were also used by several other nations with the West Germans, J

apanese, and  Netherlands receiving small numbers of them. Out of all these the only ones to actually see combat  are those within the Balkan nations. These were used in a variety of strange ways including as  part of an armored train by Serbian forces and as part of the infamous M18/T54 Hybrid created by  the Bosnians. Other odd modifications were made to keep these aging vehicles in service such as the  ones you see on screen. Another attempt to keep them in service was done by Taiwan who moun

ted  the M18 turret on the hull of a Duster anti-air vehicle. The last of the notable variants of the  M18 is the modernization made by a company in Venezuela during the 90s. The engine was swapped  to a diesel with it also receiving night vision equipment and a thermal sleeve for the 76mm gun.  This vehicle is commonly known as the M18A2 but it is unclear how many of these were actually built. The legacy of the M18 is a bit of a strange one in the world of armored vehicles. While it certainly 

is not a failure I’m not sure if we can consider it an outright success. We cannot blame it for the  shortcomings of the doctrine it was placed within but the question still remains, was it really  necessary? While at the time of its introduction it did feature more firepower than the standard  M4 Sherman as more 76mm armed Shermans arrived its firepower advantage was nullified and the  mobility it had remained its sole advantage. The introduction of the M36 furthered this as  now there was a co

mpeting Tank Destroyer which packed a bigger punch. Perhaps the M18 armed  with a 90mm could have proven to be an even more capable machine but we will never know. In  my opinion I think the M18 was a vehicle somewhat ahead of its time which caused it to be put into  a somewhat awkward position. Just a few decades after WW2 we began to see vehicles with a similar  premise to the M18 where firepower and mobility were prioritized over armor with tanks such as the  Leopard 1. While I would not go a

s far as to say the M18 was some sort of early main battle tank  I do have to wonder if it might have been viewed more favorably by all if it had come about in a  post-war world. Either way, while you could make a somewhat compelling argument for this to have been  an episode of “Cursed by Design, I feel that would be a disservice to the vehicle and crews which  when combined proved it was a capable and deadly machine. Again though, those are just my thoughts  so please don’t take them as factua

l statements. So what do you think about the M18, let me know  down in the comments below, and while you’re down there don’t forget to try World of Tanks using  that link and the code COMBAT to get your special starter bonus. Thanks again to them for supporting  my content, it’s only through support from all of you and my sponsors that I can make these videos  for you full time. I want to once again give a shoutout to Nicholas Moran’s book “Can Openers''  which is an amazing resource for the dev

elopment of these US tank destroyers. Of course as always  a big thanks to all of you for watching and to my conelyfans who generously support my content.  If you enjoyed this look into the M18 Hellcat I highly recommend watching my previous videos on  the Nashorn and Firefly as those two vehicles show ways that other militaries tried to solve the  tank destroyer question, hope to see you there.