... spec MOD1 112T CNC helical main gear and MOD 1 tail drive helical gear to increase gear mesh area, and minimize gear noise during flight. ... effect, and improve overall power output.12. Brand new gear box with more streamlined design also allows for simpler ... : 281mm7.Motor Drive Gear:12T8. Main Drive Gear:112T9. Autorotation Tail Drive Gear: 104T10. Tail Drive Gear: 22T11. Drive Gear Ratio: 1:9. ...