Helimut:
Static droop is a function of engine governing (as opposed to permanent droop being a built in rotor droopcharacteristic of the rotor sytem type).
As torque is increased, the tendancy is for the N2 and hence the Nr to droop. The governor compensates by automatically increasing N1 to keep the N2/Nr constant. Conversly when decreasing torque, the N2/Nr will tend to temporarily (static) increase (overspeed) thus commanding the governor to decrease N1 to compensate.
Hope this helps.
Cheers, OffshoreIgor
