Thread: old days
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Old December 14th 06, 10:28 AM posted to rec.aviation.rotorcraft
boB[_2_]
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Default old days

Stuart & Kathryn Fields wrote:
I'll try one: What are the sources of 2/rev vibration in a two bladed helo?
I know that I don't have any significant 2/rev in hover, but do in forward
flite.



Stuart, you are definitely more current than I on blade tracking so let
me try to remember. A 1 or 2 per rev vibration which is constant
throughout the rpm range should require PC link adjustments. I hope I
remember, I did a bunch of these, a vibration which increases as RPM is
increased should require a trim tab adjustment. A flag is the easiest
way to adjust the blade track although if you have a vibrex you can get
it fine tuned. Tomorrow I'll go find my -20s for the OH58, UH1 and AH1
and see if my memory is bad.

--

boB
copter.six

P
U.S. Army Aviation (retired)
Central Texas
5NM West of Gray Army/Killeen Regional (KGRK)