I think it's about right!
It needs to be borne in mind that the blade cannot be thought of as a single wing like that of an aeroplane because of the variance of airspeeds seen by the blade from root to tip (very high speed near the tip, very slow near the blade root). That is why the blade is designed with twist and sometimes with profile and size variations along its lentgh.
As soon as the helicopter moves away from the hover, the blade on the retreating side is experiencing a reduction in airspeed and the inner portions / elements will very soon reach a stalled condition folowed by a reversal of airflow i.e. negative airspeed.
To put some simple figures on that (the only type most pilots like):
Rotational velocity = circumference of circle times rotor rpm = 2 x "pi" x R x N
"pi" = 3.142, R = distance from centre of rotor hub and N = rotor rpm.
A blade element 1 foot out sees 14.3 mph
A blade element 2 feet out sees 28.6 mph
A blade element 20 feet out sees 286 mph
It should be seen that the inner part of a rotor may be stalled or very close to it even in the hover! Once the helicopter moves into forward flight the stalled area expands outwards. An area of not only stalled blade but with a reversed airflow follows it outwards from the centre as the forward airspeed increases. Retreating blade stall is very definitely not a sudden phenomena.
It is of even more complicated than this! The airflow is of course modified by the induced flow which affects the angle of attack of each blade element, and at low speeds this is significantly different from "front to back" of the disc with regard to the direction of travel (looks like we are into inflow roll and flap-back next!).
Just thought I'd remind folks of this.
ShyT
[ 04 August 2001: Message edited by: ShyTorque ]