To: tu154
In a previous post I indicated that the rotor would behave as described under ideal conditions.
I don’t know if this is still true for Sikorsky rotor systems but it applied to those Sikorsky helicopters that I am most familiar with. Most Sikorsky rotor masts are (were) tilted forward by three degrees.
Many Sikorsky rotor control systems compensate for tail rotor translation so in a stable hover the disc is tilted 7 degrees to the left. This means that the helicopter fuselage will act like a pendulum and hang down three degrees tail low and seven degrees down to the right. The compensating 7-degrees is in effect 7-degrees of left cyclic so, in a stable hover there will be some leading and lagging. The advancing blade leads and the retreating blade lags. The advancing blade in this case is flying from the longitudinal centerline over the left quadrant.
One of the checks that can be performed on a Sikorsky rotor system is a check for a bad damper. This test can be performed in a hover by rotating the cyclic stick rapidly in the direction of blade rotation. This induces leading and lagging so that if there is a bad damper it will manifest itself in a lateral shuffle or beat.
Nick Lappos can be the final arbiter on this.
