Also referred to as "Blade Matching", this process is the analysis of the
configuration of each blade in comparison to each of the other blades. In order to be
considered in correct geometric balance each measured position on the blade should be the
same as the identical point on each of the other blades (within tolerance). Due to the
number of analysis points available and the fact that the propeller is electronically
measured in three dimensions the Hale MRI is the ideal
method of matching propeller blade geometry. Our measuring method records the actual blade
pressure surface offsets therefore allowing contour to be measured and displayed.
- An important requirement of all rotating machinery is that the
rotation axis coincides with one of the principal axes of inertia of the body. After a
wheel has been manufactured, modified or repaired, it must be balanced to satisfy this
requirement, especially for higher speed vessels. The condition of unbalance of any
rotating body may be classified as static or dynamic unbalance.
- Static Balance is the mechanical balance of the
propeller in the plane of rotation. This can be measured by inserting a special arbor into
the bore and placing this assembly onto a stand wherein the rotation of the propeller is
in the vertical plane
- and the arbor rests upon bearings. Because the propeller is allowed
to freely rotate the heavier blade(s) will rotate to the downward most position. Weight is
either added or removed until the propeller will remain static in any rotational position.
- A propeller may be in perfect static
balance and still not be in a balanced state when rotating at high speeds.
- Dynamic unbalance is a "couple" or a
"twisting" force in two separate planes. Because these forces are in separate
planes, they cause a rocking motion fore and aft -or- side to side. A perfectly good
propeller (geometrically) that is unbalanced will cause mechanical vibrations and a
decrease in bearing life and efficiency due to unnecessary forces. The only scientific
manner in which
- to accurately measure and therefore correct dynamic unbalance is
through the use of a true multi-plane dynamic balance analyzer.
- At Hale Propeller we offer the customer the option of having their
propellers dynamically balanced using the
- Dynamics Research 602 Multi-Plane Computerized Dynamic Balance
38" Diameter 5 Blade being Dynamically
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