Monday 28 June 2021

Long-Awaited Success

The last two years of WW2 were difficult for American tank building. Their first few wartime tanks were quite modern and even surpassed those of leading tank building nations of the time, but a wave of failures followed, resulting in them falling behind. Mass production of the planned replacement of the Medium Tank M4 only began in November of 1944, and officially this was a heavy tank to boot. This article tells the tale of the M26 Pershing, a tank with a complex but ultimately successful history.

Aiming to reinforce

The spring of 1943 was a difficult time for American tank building. To start, work on the Heavy Tank M6 finally came to an end on March 25th, 1943. Development of the Medium Tank T20 family stalled to the point where the variant with an electromechanical transmission designated Medium Tank T23 suddenly took the lead. The T23 was the leading choice for the replacement of the Medium Tank M4, but the void formed by the departure of the Heavy Tank M6 could not be filled. The Ordnance Department decided to take the traditional route: why build one tank when you can build three?

A prototype of the Medium (by now, Heavy) Tank T26, Detroit Tank Arsenal, October 1944.

On May 6th the Ordnance Committee recommended the production of 250 Medium Tanks T23. In parallel, 40 tanks would be built with the 90 mm T7 gun that had the ballistics of the M1/M2 AA guns. Work on this gun started in 1942 and was initially meant for the M6, but it no longer had a home after work on that tank ended. However, the M6 wasn't the only vehicle that could use it even by the end of 1942. The gun was installed in a GMC M10 tank destroyer, and it turned out that it fit quite well. The idea of putting it in a medium tank came up around the same time. The Medium Tank T23 with a 90 mm gun was designated Medium Tank T25. 10 more tanks analogous to the T25 but with armour on the level of the Tiger would be built. This would give the Americans a medium tank with the protection of a heavy one. The "thick-skinned" T25 was designated Medium Tank T26.

The tank was supposed to be based on the Medium Tank T25, but in the end it was different in many ways aside from the armour thickness.

Initial requirements for the Medium Tank T26 called for a mass of 36,287 kg. This was the largest mass the electormechanical transmission could support. Since it was clear that the stock suspension of the Medium Tank T23 would simply crumble under such pressure, designers suggested using the torsion bar suspension that was being tested on the T20E3. However, even this estimate was quite optimistic. Further work showed that the weight of many components was simply underestimated. The torsion bar suspension was also heavier than the bogeys and the design used on the T20E3 was quite unreliable. The turret was also heavier. Even the basic T23 ended up heavier than expected, and by the fall of 1943 the mass of the Medium Tank T26 reached 39,916 kg. The mass would continue to increase.

Watch the result of weight gain. Here the tank is called medium...

The increase in mass led to a review of the order for the tank. The Ordnance Committee decided to order just two tanks instead of ten on December 23rd, 1943. In parallel 10 Medium Tanks T26E1 would be built. Like the T25E1, these tanks would have a torque converter and an Alisson Torqmatic planetary gearbox. Work on the Medium Tank T26 dragged on for so long that the order was reduced to just one tank on May 6th, 1944. Even this tank took a long time to finish and thus appeared much later than the T26E1. It was no longer a medium tank by that point. The Medium Tanks T26 and T26E1 were upgraded to heavies (in case of the T26 it started using the designation on August 1st, 1944). This was a reasonable decision, as both tanks confidently crossed the 40 ton mark. At the same time the designation didn't mean much. The tank was heavy by mass and medium in everything else.

...and here it's a heavy.

For an number of reasons, the Heavy Tank T26 with registration number U.S.A. W-30128307 was only delivered on October 26th, 1944. There was no longer a need for this vehicle by this point, but it was hard to stop the bureaucratic machine once it's started. The tank weighed 43,141 kg, which was considerably more than the Heavy Tank T26E1. The hull was supposed to be the same as on the Medium Tank T25, but it turned out to be different. The front hull was supposed to be 102 mm thick and cast, but it was actually rolled with only some cast elements welded on it. The running gear was largely borrowed from the Heavy Tank T26E1 (one of the tanks tested at the Aberdeen Proving Grounds) including the 610 mm wide T81 metallic tracks. The turret with 102 mm of front armour and 76 mm of side armour was also taken from the T26E1. This was already a late model turret with a port for throwing out spent brass. 

Location of tools in external toolboxes.

The Heavy Tank T26 was sent to Fort Knox on October 28th, 1944, and trials started on November 30th. The goal was to compare how the tank with an electromechanical transmission compares to those with torque converters. In total the tank drove for 2560 km, the engine worked for 279 hours. The results were mixed. The transmission once again showed itself to be a complex system, especially when it came to servicing. On the other hand, the advantages of the T23 were demonstrated yet again. The electromechanical transmission was easier to use during off-road driving than the Torqmatic on the Heavy Tanks T26E1 and T26E3.

Inside the fighting compartment.

The trials didn't shift the balance much. Each variant of the transmission had its own advantages and drawbacks. The fears that the extra weight would overload the transmission were unfounded. The tank turned out to be quite reliable. Effectively the final word fell to the mechanics. The electromechanical transmission was judged to be too complex, so it was discarded.

Conditionally acceptable

The strangely slow process of building the Heavy Tank T26 is not surprising. The Americans were not as relaxed as it would appear. The cause for this was the disappointing result of Medium Tank T23 trials. The situation around the Medium Tank T26E1 developed much faster in the meantime. Like the Medium Tank T25E1, the Heavy Tank T26E1 was built by the Fisher Tank Division. This was a logical decision, considering this factory built tanks with torque converters. The factory played it safe and first built the pilot T25E1, then switched to the heavier vehicle once all the issues were discovered.

The first Heavy Tank T26E1 (then still Medium). Aberdeen Proving Grounds, March 3rd, 1944. The two part fenders can be seen.

The first Medium Tank T26E1 was finished in late February of 1944, after which it was sent to the Aberdeen Proving Grounds. Initially it weighed 38,873 kg, a moderate weight considering the increase in protection, especially compared to that of the Heavy Tank T26. Like the Medium Tank T25E1 the hull was cast. Its design was nearly identical to that of its lighter brother, the only difference was armour thickness. As required, the front armour was thickened to 102 mm and the sides to 51-76 mm. The running gear was enough to spot the difference. Due to the increase in mass, the Medium Tank T26E1 received 610 mm wide T81 tracks, giving it an even lower ground pressure. Reinforced road wheels were also used, they were now 152 mm wide instead of 102 mm. Changes were also made to the fenders. They were now wider, and on the first Medium Tank T26E1 they were made up of two parts.

The differences in the hull of the Medium Tank T25 were slight.

The situation with the turret was the same as with the hull. It was the same externally, but the front was 102 mm thick and the sides were 76 mm thick. Some other changes had to be introduced. Since the gun mantlet was thicker, the design of the T99 gun mount had to change, and so it was renamed T99E1. The ammunition capacity remained the same: 42 90 mm rounds.

The same tank from above. Note that T26E1 tanks could look different depending on when they were produced.

The engine was the same: the 500 hp Ford GAF. The power to weight ratio dropped to 12.86 hp/ton. The top speed was reduced to 40 kph. This was not much compared to the tank's predecessor, but still alright for a medium tank, especially since its main opponents were not much faster. The speed of the tank's predecessors also came at the cost of reduced reliability.

Removed power pack. Thanks to a turret-mounted crane replacement could be done by the crew alone.

The tanks were distributed among proving grounds as soon as they were built. As mentioned above, the first tank was sent to the Aberdeen Proving Grounds, as was the second tank. Several tanks were sent to General Motors, another to Fort Knox. The Aberdeen Proving Grounds was the owner of the largest amount of the tanks of this type; up five different tanks came here at different times.

Watch the transformation. Here, the tank is designated as a medium.

Data on the Medium Tank T26E1 differs. Officially, 10 tanks with registration numbers U.S.A. W-30103292-30103301 were delivered by Fisher Tank Division between February and May 1944. Plans indeed called for three tanks apiece in April and May, after which the contract concluded. However, a report written by Soviet commission that visited the Fisher Tank Division in 1944 casts doubt on this completion date. According to them, Fisher Tank Division only delivered 6 tanks by June 1st, 1944. Another tank was delivered by July 11th. Assembly took much longer than expected.

There was another limiting factor in addition to subcontractor delays. Various defects were discovered during trials that were corrected on tanks that were still in assembly. This slowed down production and caused a comical situation where the early tanks were officially medium and the later ones were heavy. Soviet specialists were also confused by the two types of T26 tanks. They did not know that the Detroit Tank Arsenal was building a different tank. The T26 was also still called a medium tank, but the Aberdeen Proving Grounds called their T26E1 heavy as of June of 1944.

Here the tank is already called heavy, although in May of 1944 it was officially still a medium.

Soviet specialists paid no special attention to the Medium Tank T26E1 since there was little new compared to the T25E1. At the same time, discussions with Ordnance Department officers revealed that the T26E1 had the highest chances of entering mass production. The commission also considered the T26E1 to be superior to the T23 and T25E1. It had not only thicker armour but lesser ground pressure, which improved off-road mobility. There was also another advantage: reliability. The designers took no chances and made the suspension with a significant safety margin. This was also noted in the verdict issued by the Aberdeen Proving Grounds. The tank had its own growing pains, but there was no issue with the suspension's reliability, unlike its predecessors.

Fort Knox didn't make a choice. Heavy? Medium? Pick one yourself.

The Medium Tank T26E1 was established as a clear leader when trials at Aberdeen finished on May 21st, 1944. There were still issues, including cooling of the differential and various problems with the transmission and engine group. The ammunition racks were also criticized. An analogous tank was tested at Fort Knox in the meantime, but it was different from its predecessors. Perhaps the difference in mass played a role. According to the report from Fort Knox, their tank weighed 39,621 kg. The list of complaints regarding this vehicle was much longer. The specialists there also noted that the tank should carry 70 rounds of ammunition and that the hatches needed to be reworked to improve splash protection. The ventilation of the turret was judged insufficient.

The Aberdeen Proving Grounds crossed out the type of tank completely.

The list of improvements was long, but not as long as on other tanks. The Ordnance Department understood this. On July 25th, 1944, the Chief of Ordnance Major General Levin Campbell Jr. gave the order to rename the Medium Tank T26E1 to Heavy Tank T26E1. Even in June the tank was often called "medium-heavy" in correspondence. Work began on improving the tank so that its design was perfected by the time it entered production. The laborious two year long process to produce a replacement for the Medium Tank M4 was coming to an end. The Americans took the same path as the Germans, building a heavy tank to replace a medium one. This tank was officially classified as a heavy for almost two years.

Joint trials of the T25E1 and T26E1. It turned out that the heavier tank had fewer issues. The choice was obvious.

The ten pilot Heavy Tank T26E1 had different fates. Most of them were used in various trials to improve the production tank design. One tank served as a parts donor for the Heavy Tank T26. Finally, the first Heavy Tank T26E1 was converted into the T26E4. It was the only truly heavy American tank that saw front line use. Not a single tank survived to this day, but all live on in the last American wartime tank.

Long awaited series

The American military began thinking about the Heavy Tank T26E1 going into production back in January of 1944. Initially contract T-8244 signed with Fisher Tank Division called for 250 tanks, not 10, but the fiasco with the Medium Tank T23 forced the Americans to hold their horses. The issue of mass production was revisited in the summer. The revised version of contract T-8244 required Fisher Tank Division to produce 260 tanks (10 of them were T26E1, then the main series followed). The tank had to be improved before that. As mentioned above, the Heavy Tank T26E1 was not satisfactory as it had a number of design defects.

Assembly of the Heavy Tank T26E3 at Fisher Tank Division.

Even the situation in Normandy had little effect on the plans to produce an improved Heavy Tank T26E1. In his infamous memoir Death Traps, Belton Cooper harshly criticized this delay, but the reason for it was simple. Putting such a raw tank into the field was a bad idea. Considering the 250 T23s that were unsuitable for combat, the plans to deliver the first 10 tanks in November of 1944 seemed reasonable. It was expected that Fisher Tank Division would scale up production later: 20 in December, 50 in January of 1945. Documents still called this tank T26E1.

A finished product of Fisher Tank Division, April 1945.

As mentioned above, the improved Heavy Tank T26E1 was put into production without a prototype. The first tank with registration number U.S.A. 30119821 and serial number 11 was already a production tank. It was also renamed: it was now called Heavy Tank T26E3. This designation first appeared in the summer of 1944. The Heavy Tank T26E3 was not radically different from its predecessor on account of these differences not being needed. The most noticeable changes were made to the turret and armament. The M3 gun received a double baffle muzzle brake. The improved gun mount was indexed T99E2. A ventilation fan was added to the turret roof. The loader's hatch changed and an observation periscope was installed in front of it.

A February production tank. It was still called T26E3.

The chassis of the Heavy Tank T26E3 was not visibly different, but there were plenty of changes in the fighting compartment. As requested, the ammunition capacity was increased to 70 90 mm rounds. There were also other changes that improved the tank's reliability and effectiveness. As a result the Heavy Tank T26E3 got even heavier. Its mass now measured 41,497 tons. The top speed was expected to drop to 32 kph. It turned out that even at operational power of 450 hp the tank could run at 40 kph, at maximum power of 500 hp (it could only be maintained for a short time) the speed grew to 48 kph.

The T26E3 were nearly identical to one another. This was the result of waiting a long time before going to mass production.

The first production tanks were sent to trials, including Fort Knox. The results were quite different than the T26E1 gave. The tank was deemed fit for duty and had to be shipped out as soon as possible. The army finally received a tank that could potentially replace the Medium Tank M4.

A May production tank. By this time bit was named Heavy Tank M26.

This verdict had an impact on Heavy Tank T26E3 production. Instead of 20 tanks, 30 were delivered in December, and 70 in January. 132 tanks were delivered in February, and the remaining 8 vehicles to satisfy contract T-8244 were delivered in March. Production continued, this time to satisfy contract T-14674/1 that called for production of 1300 tanks. 172 tanks were built under this contract in March. In total Fisher Tank Division delivered 180 units that month. This was just the beginning: 225 tanks were built in April, 243 in July, 300 in August.

A Heavy Tank M26 being assembled at the Detroit Tank Arsenal, May 1945.

The need for a replacement of the Medium Tank M4 meant that production had to increase. Fisher Tank Division was the only producer of the Heavy Tank T26E3 at first, but the Detroit Tank Arsenal joined in as of March 1945. Contract T-14673 was signed with the factory, and the first 14 tanks were delivered in March. An important event took place at the end of the month: the Heavy Tank T26E3 was standardized as the Heavy Tank M26. Like Fisher, Chrysler was also ramping up production rapidly. 44 tanks were delivered in April, 118 in May, 70 in June, 102 in July, 125 in August. In total Detroit put out 473 tanks with serial numbers 1761-2233 and registration numbers U.S.A. 30128307- 30128779.

A late production tank with T80E1 tracks.

The end of the Second World War meant that production was wrapping up. Fisher Tank Division produced 106 tanks in September of 1945, 46 for contract T-14674/2. Finally, 134 tanks were delivered in October of 1945. In total, 1729 tanks were produced here between November 1944 and October 1945 with serial numbers 11 through 1739 and registration numbers U.S.A. 30119821- 30129485. A total of 2202 M26 tanks were produced. There were almost no changes introduced during production. The most noticeable change was the introduction of a new track link. There were many issues with the lifespan of the T81 track link, and later model tanks received narrower 584 mm T80E1 tracks, the same as the Medium Tank M4A3E8. This was the largest change made during production.

Better late than never

The increase in planned production of T26E3 tank to 40 units in 1944 was no accident. Gladeon Barnes, the head of Research and Engineering at the Ordnance Department, ordered that 40 tanks must be built as soon as possible. Half of them (all tanks built in November and a portion of those built in December) were immediately sent to Fort Knox for trials, the rest went to Europe. This happened before the German counteroffensive in the Ardennes, but no doubt this had an impact on the rate at which new tanks were introduced into service and production volumes. Barnes himself headed the Zebra Mission in France. He arrived on February 9th accompanied by key figures in American tank production, including representatives from the Aberdeen Proving Grounds and the Tank-automotive Center. Colonel Joseph Colby, a key figure in the Heavy Tank T26E3 program, was also here.

Gunnery training, February 1945.

Zebra Mission immediately began preparations for combat. The vehicles were distributed between the 32nd and 33rd regiments of the 3rd Armored Division as well as the 14th and 19th battalions of the 9th Armored Division. Each units received 5 tanks. Crews were trained in the vicinity of Aachen. Supply and service was also organized here. Energetic action yielded results and the Heavy Tank T26E3 units were ready for action on February 23rd.

Turret damage sustained by Fireball on February 26th, 1945 at Elsdorf.

The tanks first saw battle at Elsdorf in Germany on February 26th, 1945. The tanks of the 3rd Armored Division were the first to see battle, and the debut did not go according to plan. A tank with serial number 38 and personal name Fireball from F company of the 33rd regiment (F23) was hit at point blank range by a Tiger tank. The gunner and loader were killed by three hits to the turret. The German tank retreated, got stuck, and was abandoned by its crew. Fireball was knocked out but not destroyed, and two weeks later it was back in action with a gun taken from a GMC M36 tank destroyer. Tank E12 from E company got luckier and destroyed a Tiger tank and two Pz.Kpfw.IV at Elsdorf.

Tank E12 performed well during the combat debut of the T26E3. The tank received additional concrete armour shortly after the battle.

The tank's crews did not ignore the results of the battle. It was clear that the tank was only heavy when it came to mass. Whether on the crew's initiative or the repair detachment's, E12 received a reinforced concrete addition to its front armour. This modification was carried out by Belton Cooper's battalion. This was an exception, and the repair crews spent most of their time tending to damaged tanks. The T26E3 was quite lively, only one tank was written off after battle (serial number 25). The tank took a direct hit to its lower front hull. The crew survived, including the driver, as the shell passed between his legs. The tank was partially burned out and still technically repairable, but it was used as a source of spare parts.

Tank with serial number 22 knocked out during the fighting for Cologne. This was one of the first tanks to use the T80E1 tracks. It was later repaired.

These tanks played an important role in battle, even though there were few of them. For instance, the most famous battle where the Heavy Tank T26E3 participated in took place at Cologne. Tank E3 with registration number 30119836 from E company of the 32nd regiment of the 3rd Armored Division destroyed a Panther tank that lay in ambush near the Cologne cathedral. The battle was caught on video and became famous. These tanks also played a part in the fighting for Ludendorff bridge in Remagen. Fighting in March showed that the tank was a success. There were, however, some issues with the engine. Another issue was rapid wear of drive sprocket crowns and road wheel tires. The latter was the fault of metallic tracks. A similar issue was observed on the Medium Tank M4.

A tank from E company, 32nd regiment, 3rd Armored Division, Cologne. This photo was taken during the famous duel.

The result of the use of the T26E3 in combat with the 3rd and 9th Armored Divisions was not only the standardization of the tank as the Heavy Tank M26, but also an urgent order for more tanks of this type. 40 more arrived in late March and 310 arrived in total before the fighting ended, 200 of which were issued. If they had arrived half a year earlier they could have made a larger impact on the course of events, but history doesn't know the word "if". As mentioned above, there were good reasons for this delay. At least they arrived in Europe in time to fight, unlike the Pacific. The new tanks were supposed to be used at Okinawa, but only arrived by the time the fighting ended. 12 tanks were sent to the UK where they were nicknamed "Pershing". One of these tanks is currently on display at the Bovington Tank Museum. As for tanks of the "first wave", one survives to this day. This tank carries serial number 35 and fought in A company of the 14th Tank Battalion, 9th Armored Division. This tank is currently on display in Wolfeboro, New Hampshire, bearing its original markings.

200 Heavy Tanks M26 were issued before the war ended.

The end of WW2 led to a cut in defense spending, including tanks. This lead to the Heavy Tank M26's five year tenure as the USA's best tank. It was renamed to Medium Tank M26 in 1946, a reasonable move, considering it was not so heavy compared to the Panther and Centurion. Work continued on modernizing existing tanks. A rubber-metallic T84E1 track replaced the T81 and T80E1. These tracks were much better and did not chew on the road wheel tires. The next step was modernization of the armament. The 90 mm M3A1 gun with a single baffle muzzle brake and a fume extractor was introduced in 1948. These guns were installed in the M67A1 gun mount. Modernized tanks received the index Medium Tank M26A1.

No longer a heavy: the tank was renamed Medium Tank M26 in 1946.

These tanks were used in Korea, although there were also plenty of ordinary M26es there. The Pershing played a significant role in stopping the North Korean offensive. Over 300 tanks of this type were used in Korea in 1950. The vehicles were criticized for low mobility and reliability. The M26 was quickly replaced with its direct descendant, the Medium Tank M46 or Patton. This tank had a more powerful engine and thus became more mobile. The armour of there tanks proved insufficient and their losses were high.

An M26 tank in Korea.

New types of tanks slowly forced out the M26 from service. This didn't mean that their careers ended, as plenty of other nations were interested. For instance, the French, who were trying unsuccessfully to develop their own AMX 50 tank. The first tanks of this type were received in 1952 and they served for quite a while. Belgium also received these tanks starting in 1951. Finally, the largest foreign user of the M26 was Italy. The first tanks began arriving in 1951 for a total of 270 units. They served until the 1960s. All of the aforementioned nations used both the M26 and M26A1.b

M26 and M26A1 in the Italian army, 1950s.

Despite its growing pains, the M26 was a true success for the Americans. Creating the tank was hard, but other nations did not fare much better. Unlike the Centurion I or T-44, the M26 managed to see battle and showed itself well. The concepts set by this tank became dominant in American tank building for 30 years. What can serve as a better indicator of the Pershing's success?

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