초록

The invention concerns method and apparatus to obtain accurate tracking of rotor blades, as for example helicopter rotor blades, despite the existence of conditions transiently altering rotor angular velocity.

대표청구항 ▼

In the method of determining out-of-track condition of the baldes of a rotor driven in rotation by a drive, the rotor and drive subject to transient forces that tend to vary angular frequency, the steps that include (a) providing a display means and operating same to repeatedly display corresponding

In the method of determining out-of-track condition of the baldes of a rotor driven in rotation by a drive, the rotor and drive subject to transient forces that tend to vary angular frequency, the steps that include (a) providing a display means and operating same to repeatedly display corresponding portions of the rotating blades to have selected spread positions in space, and (b) adjusting the repetition rate of said displaying as a function of transient force induced variation in drive angular frequency caused by said transient forces, thereby substantially to maintain said selected positions in space, (c) said (b) step including employing a first sensor located to sense the frequency f1 of the drive at a location where f1>>f2, f2 being the angular frequency of the blade rotor, (d) said (b) step also including employing a second sensor located to sense f2, (e) and using said sensed f1 and f2 to control the display means to have an output whose initial frequency, once each interval related to rotor revolution, is controlled by f2, and whose subsequent frequency following said interval is controlled by f1.