ETO armor

Test Report Moskau Automotive Test Institute, ETO SO series transmission.

Test Report Transmissions SO Series, Moskau Automotive Test Institute


Product Description

Test Report Transmissions SO Series, Moskau Automotive Test Institute

Test Report gear type transmission, ETO SO series.

Description: Transmissions put to the test. Comprises of  complete:

  1. Pair of 100: 1 gear reductions with 2 motors 480 series.
  2. Micro gear reductions with a ratio of 1: 75 available with 2 motors 480 series.
  3. Final drive gears made of 4 16 tooth hardened steel gears.
  4. Screws M4 and M2.
  5. Fasteners for gears socket head set screws.

The adjustable output shafts for Tamiya models.

Parts are of course much more simple than in the Tamiya transmissions and they are much more difficult technically, but the transmission assembly is as simple as the AK-47. Power parts which are attached to the output shafts are made of hardened steel 16T gears of 10 mm thickness which power steel shafts with flats under the gear set screws (shafts and universal, but more on that below) and ride on 6 5×10 sealed bearings of very high quality with rubber seals, steel helical gear 4 pcs., tapered with the crown, and fasteners. Helical gears are made very high quality.

The photo submitted shows the motor/gear reduction assembly. You can easily replace the motor with any that have shaft diameter of 2.3 mm to 3.2 mm. Motor pinion is brass, it can be drilled out to a desired diameter without problems. or you can buy a ready module 0.5 with the number of teeth as the old.

Tests for durability and trouble-free operation:

Motor temperatures were measured with an infrared thermometer.

Gearbox was installed on the test stand, load immediately was put 6 kg / cm (33 lb./inch), power to motor was provided at 7.2v. Motor working with this load was lukewarm while working 72 hours continuously.

Next, 9 kg / cm (49 lb./inch) – while working 72 hours nonstop, the motor was 43 C.

Next, 12 kg / cm (66 lb./inch) – 72 hours nonstop, the motor was 53 C.

Next 15 kg / cm  (83 lb./inch) Р72 hours nonstop, the motor was 58 C.

Next, 18 kg / cm (98 lb./inch) – 48 hours nonstop, the motor was 75 C, temperature rose but not much, but tests had to be stopped because the beginning to smell overheated windings.

Then, on the shaft of the gearbox was installed strap (at the end of the shaft) and it was loaded slowly to 15 kg (33 lb.), in order to identify the amount of load to cause the shaft to break or bend, with the strap wound on the shaft lifting the load from the floor level to the level of 1 meter. The test was completed without breaking the any shafts (although doubts have been thought and a couple of shafts were on hand to replace broken shafts if needed), weight was taken and even more to 17 (37 lb.) kg.

Next gearboxes were installed in a tank that is used on the cross-country tests on the road (100 m diameter circle around the parking lot). The tank drove 48 laps spending 4 Akka 12,000 mAh of 50 planned (not enough charge and 1 ACC was given for other purposes). Failures were observed, although these were jammed tracks (2 times stone fell into the hole for the ring gear and scored it) resulting burnout fuse for the motor for one side track. But all these breakdowns did not affect the transmissions, who worked and worked.

After, I disassembled gearboxes and photographed result. As expected tempered gears working like new, gear reduction bushings appeared almost imperceptible but of course, I noticed them just because I remember what was the play on the new gearbox. Helical gear not worn. Gear reductions were washed, oiled and re-assembled – test passed.


  1. The gearbox is very reliable and can provide motive power for a tank up to 12 kg (27 lb.) of at least 15,072 m (9.04 miles) without significant loss of their qualities.
  2. The design of the built-in capability for its universal use in tanks for long and for short shaft tanks.
  3. In the case of a repair needed the gear can be removed separately from the output shafts, which is very convenient.
  4. The motor gear reduction may at any time be replaced by a similar one.
  5. With the final drive shaft gears, we immediately noticed both output shaft can be adjusted slightly to eliminate  different distances from the hull side to the edge left and right track assemblies.
  6. The rigidity of the structure is excellent, no hint of “play” of the gearbox housing.
  7. Bearing Units are standard and common, and in the case of breakage may be easily replaced. There are two bearings in each output shaft support which 3 bearings support each shaft going the drive sprocket.
  8. Transmission is of highest quality. All parts fit correct. We test Tamiya, Mato, Waltersen, DKLM, Impact and ETO. ETO is best quality and best for performing.

Kuriokov, Y. T. Director.

Translated Russian-English Skorova E. E. 17.10.14