A helicopter rotor assembly with vertically staggered blades is disclosed. Each blade travels in a rotational path which does not cross the rotational paths of the other blades. This arrangement reduces noise because each blade travels in a path which avoids turbulent or disturbed air from the preceding blades. In one embodiment, the blades are arranged from the lowermost blade to the uppermost blade such that each blade following the lowermost blade will be above the blade in front of it. Since each blade pushes air down to create lift, this vertically staggered arrangement allows the blades to travel through less disturbed air.