Helicopter rotor balancing apparatus and method
AssigneeChadwick-Helmuth Company, Inc.
InventorsWilliam F. Wilson, James R. Chadwick, James G. Helmuth
Life of this patent
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Abstract
The method of balancing a rotor having multiple blades and defining an axis of rotation, and wherein structure proximate the rotor is subject to vibratory motion due to dynamic unbalance of the rotating rotor and an out-of-track condition of the rotor blades, the method employing two vibration pickups, the method including: A. operating the pickups to produce vibratory signals corresponding to up and down vibratory motion of the structure at port and starboard sides of said axis, B. combining said signals to produce a resultant oscillatory output signal characteristic of rotor vibratory motion due substantially to only one of said conditions, C. using said resultant output signal to alleviate said one condition.
Claims12
In the method of balancing a bladed rotor having multiple blades and defining an axis of rotation, and wherein structure proximate the rotor is subject to vibratory motion due to a dynamic unbalance condition of the rotating rotor and an out-of-track condition of the rotor blades, the method employing two vibration pickups, the method including
- a. operating the pickups to produce vibratory signals corresponding to up and down vibratory motion of the structure at port and starboard sides of said axis,
- b. combining said signals to produce a resultant oscillatory output signal characteristic of rotor vibratory motion due substantially to only one of said conditions,
- c. using said resultant output signal to alleviate said one condition.
In the method of balancing a bladed rotor having multiple blades and defining an axis of rotation, and wherein structure proximate the rotor is subject to vibratory motion due to a dynamic unbalance condition of the rotating rotor and an out-of-track condition of the rotor blades, the method employing two vibration pickups and a stroboscope, the method including
- a. attaching the pickups to said structure at generally opposite sides of said axis and operating the pickups to produce vibratory signals corresponding to the outputs of the respective pickups,
- b. combining said signals to produce a resultant oscillatory output signal characteristic of rotor vibratory motion due substantially to only said dynamic unbalance condition,
- c. triggering the stroboscope in synchronism with said resultant output signal and directing the stroboscope at the rotor to produce flashes repeatedly illuminating a target rotor blade at a characteristic angularity with respect to said axis, and
- d. varying the weighting of the rotor as a function of the magnitude of said signal and said characteristic angularity to achieve substantial balance.
In combination with a helicopter rotor having multiple blades and defining an upright axis of rotation and helicopter structure proximate the rotor subject to vibratory motion due to a dynamic unbalance conditions of the rotating rotor and an out-of-track condition of the rotor blades,
- a. a pair of vibration pickups attached to said structure at locations at port and starboard sides of said axis to produce vibratory signals corresponding to up and down vibratory motion of the structure at said locations, and
- b. means for receiving and combining said signals to produce a resultant oscillatory output signal characteristic of rotor vibratory motion due substantially to only one of said conditions.
Dependencies are inferred from the claim text.