Date: Sun, 23 May 1999 01:36:42 -0400
From: Rick Argente <RickArgente@compuserve.com>
Subject: Aileron Vibration
Sender: Rick Argente <RickArgente@compuserve.com>
To: "lancair.list@olsusa.com" <lancair.list@olsusa.com>
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So far, I have about 10 hours on N360ZR.    I have a couple of small bugs
to sort out 
here and there but one nagging problem I have is the left aileron, it
vibrates!  The right aileron
looks quite solid looking out from the canopy but the left has this small
up and down vibration 
which can be felt on the control stick.  Part of the vibration is probably
being transmitted from
the engine/prop but I'm not sure.  I will have to prop dynamically balanced
next week and 
will also install the new engine isolators.  

Here are the facts:
 1 . It vibrates at both high and low speeds, more vibration at higher
speed, less at lower speeds.
 2. The vibrating aileron has a mac servo inside for the trim tab (piano
hinge tab).
 3.  The aileron control system has almost zero slop, it is quite tight and
no binding whatsoever.
 4.  Both ailerons are over 100% balanced but the trailing edge of the
right aileron moves UP 
         MORE (about 1/4") when hanging from the hinges, detached from the
control rods.  The left
         aileron only moves up about 1/8"  inch.   
  5.  Yesteday, at around 160 knots IAS, it applied full left trim and held
the stick at neutral, the 
         vibration ceased.  So, loading up the aileron stops the vibration
but I don't know what 
         that means exactly.
  6.  The top skin of the right aileron is flushed to the top main  wing
skin throughout the aileron span.
         But the middle portion of the left aileron has a small dip.  The
dip is about 1/16" wherein
         the aileron top skin is lower than the wing skin.  Can't remember
exactly how wide the 
         dip is but I will estimate a around 5".    I'm wondering if air
flow is somehow broken here 
         and causing the vibration.

I added more weights to the left aileron to equal the 1/4" over-balanced
condition of the 
right aileron.  Haven't flown yet since this mod.  

If that doesn't reduce or eliminate the vibration, I plan to eliminate the
middle dip of the top
skin of the left aileron by increasing the thickness of the skin using some
duct tape 
temporarily.  

I'm kinda of running out of ideas and don't really know if what I'll be
doing will help any.
Any other ideas out there??  Please feel free to voice them out as I'm
getting a bit
frustrated.

Oh yes, another thing, during one of our flights, the CHT's reached
450-degrees during
initial climbout with full power, @120 knots.  I thought that the CHT
problem has been 
solved but I guess not.  It's getting warmer here now, much warmer than
when we first
did the inital test flights, around 75 to 80 degrees.   I am contemplating
on adding another
vent hole at the bottom of the cowling to increase exit air volume.  Any
other ideas on 
how to reduce my CHT's.  Oil temps are at 170 degrees.


Thanks
Rick Argente
N360ZR    
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