Main and Tail Rotor Tip speeds
The S-92 rotor speed was increased from 100% (258 rpm) to 105% (271 rpm) over the period of it development to accommodate for increases in both empty and maximum gross weights. At the same time the main rotor diameter was increased from 53.66 feet to 56.33 feet. These combined increases in rotor diameter and rotor speed have resulted in a corresponding increase in main and tail rotor tips speeds.
The S-92 in its present configuration have main and tail rotor tip speeds of 799 fps and 719 fps. This is well in excess of what Mr. R. Prouty recommends as a maximum in his text Helicopter Performance Stability and Control due to potential noise problems. At –3 degrees Celsius and 165 knots the S-92 main rotor advancing tip speed approaches mach 1.0 . This would require that the S-92 be operated at a reduced airspeeds during winter operations in noise sensitive areas.
By comparison the main and tail rotor tip speeds for the Super Puma are 738 fps and 691 fps and the main rotor tip speeds for MD902 and EC135 are approximately 690 fps. The later two meeting the world's latest helicopter noise signature requirements