balancing act

Hi Stuart & Kathryn,

What kind of helicopter are you talking about here?

Please excuse a wild guess from someone who has "very" little experience in
the experimental world but......... since you're not finding anything
overtly loose in the drive system or tail blades, I have to wonder about
something like a bearing going south on you? It might not be anything
you'll feel just moving a static system round but could start causing
problems when under load. Is there any kind of preload put on the system
during assembly? If so, is it even?

As I said, I'm just guessing here so if I'm totally out of line, please
excuse the reply! ;-)

Best of luck & fly safe,
Steve R.


"Stuart & Kathryn Fields" wrote in message
.. .
Here's one for the pros: I was balancing my tail rotor and had it down to
0.27 ips and still had just a touch too much weight where I had added it.
So still needing to safety wire a bolt that is located in the center of
the tail rotor output shaft, I chose to safety it to a hole 180 degrees
from the weight. The safety wire was small, 0.025, so I didn't expect to
see the ips go to zero, but I hoped they would decrease maybe to 0.20.
Well it didn't. All of a sudden I had 0.9ips, so I shut down and removed
the wire and ran again. This time I got 0.5 ips. The balancer reading
did not even come close to repeating. The phase angle was also different.
In an experiment, I would run up from idle to full chat and take 4
averaged readings, come back to idle and go up to full chat again for
another 4 readings. Never repeats. Can't find anything loose in the
drive or on the blades. If I pull a set of readings at 2500, 2600 and
2700, all the readings pretty much agree with the exception of ips
increasing a bit with rpm. However if I take it to idle and come back up,
I get a different set.
Any ideas?
--
Stuart Fields
Experimental Helo magazine
P. O. Box 1585
Inyokern, CA 93527
(760) 377-4478 ph
(760) 408-9747 publication cell