I report that the proving grounds trials of the T-50 produced at factory #174 cannot be completed in the timeframe allotted by your order #009ss issued on January 7th, 1941, due to a series of design defects discovered in the trials process.
The main defects are:
- Unsatisfactory lifespan of track links (cracks in the track eyes and breaking of the track teeth). Track links start to break at 300-400 km.
- Weak design of the drive wheel (destruction of the hub, high wear and cracks on the crown after 250-300 km).
- Destruction of the bevel gear and pinion and bending of the 3-4 gear fork on the gearbox after 1500 km.
- The hull floor is insufficiently robust (it vibrates and there is a sagging of 11 mm) and the turret platform roof bends.
- The installation of armament and observation devices was not performed in accordance to notes made by the Model Commission (no new turret was designed).
- Insufficient thickening of the observation device prisms (poor visibility, easily covered in snow.
- Installation of electrical equipment is poorly laid out, which creates radio interference and does not protect the wiring from mechanical damage.
- Radio communication at maximum range and the intercom were not tested.
- It is difficult to shift from 2nd to 3rd gear.
- The oil temperature in the gearbox is high (100-115 degrees at an exterior temperature of -15 to -19 degrees).
- Order the factory to correct all known design defects by February 10th of this year and provide a new turret for penetration trials from February 10th to [cut off].
- Increase the length of warranty trials to 2500 km for more thorough testing of assemblies, the transmission, and suspension after changes made to their design.
- Extend the Commission's deadline to February 15th to compete the trials and test the communications equipment.