R-39 - An Amphibious Failure

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Hello !

Today, I’d like to suggest the addition of the R-39 light amphibious tank, also known as the Object 101.


The R-39 shares an uncanny resemblance to the PT-76. In fact, the latter would improve the former’s design.

History

Spoiler

Drawn from the Soviets’ experience with river crossing and the use of scout tanks during the Second World War, the requirements of the next generation Soviet light tank were largely focused on giving it more tactical and strategic mobility.

In 1947, Soviet engineers were given one task : to make an amphibious light tank with characteristics on par with the T-34-85. Reasonably, a compromise had to be made as such a tank could not have the armament, the armor and the mobility of the T-34-85 while being amphibious.

In early 1948, technical requirements were lowered. The tank would weigh 11 to 13 tons, have an armor of a max thickness of 12 mm of steel, a max speed of 55 km/h and a 76 mm gun replaced the requirement of an 85 mm gun.

The tank designed by the Krasnoe Sormovo factory received the name R-39 and the index 101, while the APC based on the same hull was named R-40 and 102. By mid-July 1948, the factory was ordered to build the tank by June 1949. Meanwhile, the OKB-92 worked on the 76 mm LP-76 gun, specifically designed for the R-39. However, many of the components came late : the engine made in Chelyabinsk came a few months late, as well as the radiators and the electrical equipment. A tell-tale sign of what was to come.


The R-39 as built before the summer of 1949

Mobility trials began on the 29th of May, 1949. Speeds of 52 km/h and 9 km/h were recorded, respectively on ground and on water. The tank was noted to have a tendency of throwing tracks and many parts were not working as expected.
The second prototype was built in June, trying to fix the issues encountered on the first prototype. It used foldable hydro jets but this didn’t quite change anything.

The tanks were deemed unsuitable for anything else and the factory would have to produce new prototypes for the 1950 state trials.

However, Soviet higher-ups thought that it’d be a better solution if all the work was transferred to the VNII-100 in Chelyabinsk.
Work on the project was then stopped as more promising (and less awful) projects came to be, notably what would become the PT-76.





The R-39 going for a swim



The first R-39 had a steel plated welded at the front and floats at the rear to deal with buoyancy issues





Trials of the first R-39 in May-June 1949




More generic views of the tank and a blueprint

Specifications

Crew : 3

  • Driver
  • Gunner - Commander
  • Loader

Armament

  • One 76 mm gun LP-76T (Ammo : 30)
  • Sights : TShK-66
  • Elevation : -1°45’ / +26°

Dimensions

  • Weight : 15,35 tons
  • Length : 6.805 m
  • Width : 3.34 m
  • Height : 2.16 m

Mobility

  • Engine : V-54-300 (300 hp @ 1500 rpm)
  • Top speed : 53 km/h (7,3 km/h on water for the 1st prototype, 9,5 km/h for the 2nd) / -7,5 km/h
  • Transmission : 5 forward / 1 reverse

Armor

  • Turret front : 20 mm
  • Turret sides and rear : 10 mm
  • Hull front : 12 mm
  • Hull sides : 10 mm
  • Hull rear : 5-6 mm (Educated guess)

Sources

1 Like
2

Cool event vehicle +1

3

Would be fun event vehicle!

4

+1, -1 gun depr will be very tricky though.

5

cool proto vehicle, would fit in as a lower BR light tank in a slot where i think the USSR needs one for its TT