T70 Gun Motor Carriage - Soviet Trials

Would you like to see the Soviet T70 GMC
  • Yes
  • No
0 voters

imageT70 Gun Motor Carriage - Soviet Trials
image
The “T-70 destroyer-tank” at the NIIBT proving grounds, spring of 1944.

Introduction and History:
The T70 Gun Motor Carriage was the prototype form of what would become the American M18 Hellcat tank destroyer. Developed in 1942-43 as a high speed tank destroyer, the T70 was designed with an emphasis on mobility and firepower, using the powerful 76mm M1 gun and a lightweight chassis to reach high speeds.

In 1943, a small number of T70 vehicles were sent to the Soviet Union under the Lend Lease program for testing and evaluation. Soviet engineers were intrigued by the torqmatic transmission and the high power to weight ratio, which gave the vehicle exceptional speed and agility. However, their assessments noted serious drawbacks: the armor was extremely thin, providing little protection, and internal space was cramped, especially around the gunner’s position. Additionally, visibility from within the fighting compartment was limited.

image
Shipping record of tank destroyers that arrived at Molotovsk and the equipment that accompanied them.

Unlike the GMC M10, which was formally accepted into Red Army service, the T70 never moved beyond the trial stage. After testing, the vehicles were not adopted or widely used, likely due to the Red Army’s preference for more robust and better armored self propelled guns like the SU-85 and SU-100. The T70s quietly disappeared into obscurity, remembered mostly as a footnote in the broader story of Allied cooperation and experimental vehicles evaluated by the USSR during World War II.

Overall, the T70 GMC’s armament was solid for a tank destroyer of its class, but the chassis left much to be desired and ultimately led to its rejection.

The Soviet evaluation concluded:

The American T70 SPG could not be recommended for import for the following reasons:

  • Poor armor, which only protects against small arms fire and shell fragments.
  • Excessive fuel consumption, several times higher than comparable SPGs under the same conditions.
  • Reliance on high octane gasoline, increasing the risk of fire.
  • Poor visibility from within the vehicle."

As noted earlier, the T70 prototypes were later refined and standardized into the M18 Hellcat. It seems the Americans were aware of these shortcomings as well. However, the upgrades were relatively minor and did little to address the vehicle’s fundamental flaws especially its poor off road performance. Similar issues appeared during trials of the T26E3 Pershing, which also used a torque converter and demonstrated the same high fuel consumption.


Specifications:

General Information

  • Origin: United States of America
  • Crew: 5 (Commander, Gunner, Loader, Driver, Assistant Driver)
  • USSR Received for testing: 2

Dimensions

  • Weight: 17.7 metric tons (39,000 lbs)
  • Length: 5.3 m
  • Width: 2.9 m
  • Height: 2.5 m

Armament

  • Primary: 76mm M1A1 Gun (45-60 rounds)
  • Secondary: 1 × .50 cal (12.7 mm) M2HB machine gun (roof mount)

image
The penetration of the GMC T70’s gun had no issues.

  • Photo #31: penetration of the left side with a 76 mm shell from the American M1A1 gun from a range of 2000 meters.
  • Photo #32: Diagram of the penetration of the left side with a 76 mm shell from the American M1A1 gun from a range of 2000 meters.

Armor

  • Thickness: 6.4-25.4mm (0.25-1 inch); mostly 12.7mm flat plate
  • Armor type: Rolled homogeneous steel (RHA), welded construction

Engine and Performance

  • Engine: Continental R-975-C4 9-cylinder radial
  • Horsepower: 400 hp (298 kW)
  • Top Speed: 89 km/h (55 mph) on road (high for the standards of that time)
  • Range: 160-175 km (100-110 miles)
  • Power-to-Weight Ratio: 22.6 hp/ton

More images
image
The mudguards on the tank destroyers were quickly lost.

image
This placement of ammunition was risky, but made reloading quicker.

image

image
Fuel consumption on dirt roads increased drastically.

image
When driving off-road, the light tank destroyer consumed more fuel than some heavy tanks.

image
Hill climbing trials.

image
Driving at a tilt.

image
The tank destroyer is fording a river.

image
Component layout of the GMC T70.

image
Diagram of the transmission on the American tank destroyer.

image
Armour diagram. As you can see, there isn’t much of it. The armour was sacrificed for high mobility.

image
Placement of crew members within the fighting compartment. Soviet testers had many issues with it.

image
Visibility from the T70.




Sources

M18 Hellcat - Wikipedia
https://www.reddit.com/r/TankPorn/comments/ris943/the_76mm_gun_motor_carriage_t70_m18_hellcat/
Redirecting...
Tank Archives: Hellcat: Highway Tank Destroyer
The M18 Hellcat Tank Destroyer - The Army Historical Foundation
M18 Gun Motor Carriage (Hellcat) Self-Propelled Tracked Tank Destroyer (TD)

3 Likes

I think this would fit great as a lowbie squadron vehicle, maybe prem/BP

Premium or event only, but still +1.

3 Likes

+1, sure, why not? I agree with others’ saying that this could be added as a squadron, premium, or Battle Pass vehicle.

Just a small correction regarding the engine:

It’s noted that the first 1,350 M18 Hellcats were equipped with the R-975-C1 engine, which produced 350 net horsepower. Only vehicles with serial numbers 1351 and higher received the R-975-C4, which had an output of 400 net horsepower.

The Soviet-trialed T70 GMC appears to have carried the registration number 40108549, based on the image provided. If that number is accurate, its serial number would be below 1351, meaning it was fitted with the R-975-C1 engine, not the -C4.

Therefore, it should be corrected to R-975-C1 with an output value of 350 net hp or 355 ps.

You should update the (P/W) ratio accordingly based on the corrected horsepower value.

source:  M18 Tank Destroyer World War Two Production Statistics

2 Likes

Thanks, I was somewhat confused about the engine part.

soviet m18? A capable light tank at mid brs to help me spawn the yak9ut faster? Absolutely sign me up!

2 Likes

absolutely not. The last thing we need is more copy and paste to further dilute the pool of american vehicles in every single tech tree.

2 Likes

It’s not copy and paste

4 Likes

In general this is true but the USSR does not have normal light tanks for this BR. I think the T70 could fill it.

+1, only for the event.
At least Soviet T70 sounds better than T86 at Normandy '44, which never showed combat at the Western Front or Normandy. :/

Maybe best suited for the ‘Victory Day 2026’ reward?

Also, if Gaijin ever dreams about adding this for Tech-tree, nah, not for tech-tree.

T34-85 does this things job just fine -1 just more copy and paste for events and battle pass stuff what next a american tiger 2 ?

2 Likes

Should be a nice addition depending how it’s implemented.

1 Like

-1 for two reasons:
1: It’s a vehicle that only underwent trials and was never actually used by the USSR.
2: It’s a copy paste vehicle.
At most, this should only really fit as an event vehicle, otherwise War Thunder will just further wash out the techtrees.

4 Likes

Agreed. Tech tree vehicles should only be vehicles used in mass such as Churchill