The Process of Static Balancing:

Marvel manufactures a series of balancing arbors that are designed to balance loads ranging from one pound up to 3,500 pounds. Each of these

arbors can be used for multiple applications merely by changing balancing adaptors. 

 

Two types of adaptors are available:  thru-shaft mounting and under slung mounting. 

Thru-shaft mounting will accommodate thru-shaft and splined propellers and thru-shaft main and tail rotor assemblies. 

Under slung mounting will accommodate flange mounted propellers and those rotor assemblies whose design does not permit thru-shaft mounting.

The balancing arbor is a vertically suspended device upon which a load to be balanced is horizontally mounted. The arbor features an extremely

high degree of sensitivity and accuracy. Its design virtually eliminates internal wear surfaces and internal frictional resistance. Therefore,

there is no requirement for the replacement of worn parts - only routine reconditioning and inspection.

 

The characteristic response of the suspended balancing arbor to a load in a state of imbalance is a tilting action. This action occurs through an

internal flexible solid suspension element located at a predetermined point on the arbor suspension rod. This suspension rod is encased in an oil

filled shaft.This oil filled reservoir provides a dash-pot for dampening excessive oscillation of the sensitive balancing mechanism. The degree of

oscillation dampening is regulated by raising or lowering the oil level in the reservoir or by varying the viscosity of the oil used.

 

The arbor is free to tilt about the suspension rod to the extent necessary to indicate direction and relative magnitude of the unbalancing forces

inthe load. This displacement is observed as an eccentricity between an indicator bushing and a black indicator disc. A perfectly balanced load

will be indicated when the indicator bushing is perfectly concentric within the black indicator disc. If the load is slightly out of balance, but

within allowable balance tolerance, one edge of the black indicator disc will be slightly eccentric with the indicator bushing. If the load is out of

balance to its maximum allowable balance tolerance, one edge of the black indicator disc will be exactly even with (i.e. tangent to) one edge of

the indicator bushing. If the load is out of balance beyond its maximum allowable balance tolerance, one edge of the black indicator disc will pass

under the edge of the indicator bushing.

 

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