Abstract: In a high-loaded, light-weight, compact, multi-stage gear transmission unit with at least one stage with non-parallel shafts, and a transmission ratio between approximately 70 and 150, like a helicopter transmission, said angle transmission generally forms the weakest link. By adoption of a face gear/cylindrical pinion-stage instead of the commonly used bevelled-stage, not only a more reliable drive is possible, but its efficiency is higher, due to less friction, its size is smaller, its adjustment is simpler such that straight forward replacement becomes possible, and - not in the least - the transmission ratio of said angle drive tends to high ratios in contrast to known bevelled-drives which tend to low ratios. In many cases one or even more stages less become possible, providing a further important reduction in weight and size.

Abstract: In a high-loaded, light-weight, compact, multi-stage gear transmission unit with at least one stage with non-parallel shafts, and a transmission ratio between approximately 70 and 150, like a helicopter transmission, said angle transmission generally forms the weakest link. By adoption of a face gear/cylindrical pinion-stage instead of the commonly used bevelled-stage, not only a more reliable drive is possible, but its efficiency is higher, due to less friction, its size is smaller, its adjustment is simpler such that straight forward replacement becomes possible, and--not in the least--the transmission ratio of said angle drive tends to high ratios in contrast to known bevelled-drives which tend to low ratios. In many cases one or even more stages less become possible, providing a further important reduction in weight and size.