"To the Chief of the 3rd Department of the BTU, Military Engineer 1st Class comrade Afonin
Summary report of experimental work performed at factory #183 in March 1941
- Trials of cooling fans: three types of cooling fans entered trials.
- 1st variant: instead of blade supports special ribs were used. A vehicle with this fan travelled for 800 km. Trials will continue in April.
- 2nd variant differs from the production type only in the riveted rim that is the same as the BT-7M type. A vehicle with this fan travelled for 400 km. rials will continue in April.
- 3rd variant: production fan attached to the flywheel with a friction clutch to slip in cases of rapid changes of RPM in the driveshaft. A vehicle with this fan travelled for 80 km. Trials will continue in April.
- Trials of the constant mesh gearbox were completed. This gearbox shows no advantages over the production type, and the top speed in 4th gear dropped by 5 kph, which is not desirable. There were also a number of defects found in several parts. It is pointless to implement this design into production.
- New types of cast driver's hatches with different types of thermal treatment were tested by fire. One type showed good results in terms of ballistic resistance. The decision to put it into production is being made by the BTU.
- Trials of a new type of turret ring with a different bearing runner to tighten tolerances. Trials showed that tolerances are tighter, but the turret can jam. Work on other variants is being performed.
- 8 types of air cleaners were produced. One of the types showed the best results (95% clearance) and was sent to Leningrad for government trials.
- Reinforced Hadfield steel tracks were produced and tested. The assembled tracks made it to 2500 km after which the pin eyes were severely worn and the tracks began to break, the same thing as with production tracks.
- Major modernization of the T-34: the model is complete. The design bureau is producing blueprints for the experimental design.
Military Representative of the GABTU, Military Engineer 3rd Class, Alekseev"