What is the decibel level of a Sikorsky CH-3C helicopter?

The vortex noise decibel level of Sikorsky CH 3C helicopter is calculated in different parameters of the five rotatory blade revolutions per minute (rpm),thrust,sound pressure level (SPL),angular velocity radians per second, etc.

At 183 rpm at 13400 pound thrust it is 78 db,for 20,500 pound trust it is 82 db. Similarly at 213 rpm rotor speed at 20000 pound thrust the noise level is 83 db.