Main and Tail Rotor Tip speeds
The S-92 rotor speed increased from 100% (258 rpm) to 105% (271 rpm) over the period of the its 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 presently has a design tip speed in excess of what is recommended as a maximum in R. Prouty’s 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 will be at exactly 1.0 mach. This would require that the S-92 be operated at a reduced speed during winter operations in noise sensitive areas. 140 KIAS may put the S-92's rotor tip speeds in the .95 mach or greater region. This could potentially creat noise issues around and below the helicopter in flight.
