"Stu Fields" wrote in message
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"RogerN" wrote in message
m...

"Stu Fields" wrote in message
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"Roger Haar" wrote in

Roger: You are dead right. On the Helicopter, the
first move is to track the blades. aerodynamically. Out
of track blades on the helo will cause a 1/rev vertical
vibration that can confuse a balancing operation if the
operator isn't paying attention.
On our ship we put two different color grease pencil
marks on each blade. When the rotor is spun to full
speed, my wife takes a pole with the center cardboard
tube from a paper towel roll attached to the top of the
pole and carefully brings the paper towel roll in until
it just ticks the blade ends. We get two different color
tick marks of one blade is higher than the other. We
adjust until we get just one color combined from the
two. This doesn't guarantee good aerodynamic tracking at
cruise speed on the helo since aerodyanic differences of
the two blades can cause a "climbing" blade. Helps to
have a fearless wife...


I do something sort of similar on my R/C helicopters. I
use 2 different color tape strips near the tip of each
blade, hover the helicopter and look at it from the side,
you can see if one color of tape is flying higher than
the other. When the blades are out of track it causes a
lot of vibration.

RogerN

With our bigger ships, a tracking tip light was invented
where you install a red LED on one blade tip and a white
LED on the other. The LEDs are pointed at the pilot. The
first time I tried these, I was nervous about them coming
off in flight and creating a hellatious vibration. While
running up I noticed a red streak and a white streak and
thought "This is Great". Then at flight rpm the lights
disappeared. No vibration so they must have both left at
the same time. Slowed back down and there the lights were
again. Great design. Centrifugal force pulled the little
battery away from the LED. Tremendous idea though. It
eliminated the need for a passenger operating a strobe
light to check track during cruising flite. One design
used centrifugal force to turn the LEDs on...

Perhaps you are refering to 'centrifugal reaction' ? ;))
Sorry, couldn't resist.... phil