Gearbox reduction set

Ord.No. 870/74

If you want to use the mechanics from an X-Treme trainer helicopter in a full-fuselage helicopter with a rotor disc Ø of 1780 - 1810 mm (2-blade) or 1 680 mm (3/4-blade), this gearbox reduction set is absolutely essential. The appropriate gearbox reduction ratio results from the use of a toothed belt clutch bell with 30 teeth and a 72-tooth belt pulley in the first gear stage.
In the second gear stage you should use the combination of 84 : 18 teeth (870/84 and 870/18) with the toothed belt 870/100.
This means the basic requirements for employing X-Treme mechanics in models such as the UH-1D, Bell 212 / 412, big AIRWOLF and Bell 230, using a scale rotor head.