Posted for "Bill Wade" <super_chipmunk@roadrunner.com>:

 Re: aileron trim tab (LIVP)Jeff and others-   Thanks for the tips- I'll keep
them for when I get to that point, years from now :-(
 
 One question- is the carbon in contact with the aluminum? From what I've read
carbon accelerates corrosion of aluminum. One reference that came up in a
Google search is pages 659-70 of ASM Handbook Volume 21: Composites. Anodizing
seems to be a good solution but fretting can wear away the coating over time.
The rivets might be more vulnerable than the hinge.
 
  An alternative might be to use sheet material made from E-glass. Spray or
paint PVA onto a sheet of plate glass then lay up as many thicknesses as
desired, topped with a layer of peel ply. A layer of Glad Wrap (Saran can be
used but it's a bit stiffer) covers all and extends past the edges of the
layups. The whole thing is rolled (I use a rubber ink roller) so excess resin
is forced to the edges, removing air and sealing the Gladwrap. The result is a
dense sheet that has a glassy surface on one side and is prepped for bonding
on the other. While partially cured, one or more edges can be bent upward to
form flanges if desired. Good stuff for making subassemblies like brackets,
battery boxes, etc.  -Bill Wade
   
 
 ----- Original Message -----
  From: Jeffrey Liegner, MD
  To: lml@lancaironline.net
  Sent: Saturday, December 06, 2008 10:46 PM
  Subject: [LML] Re: aileron trim tab (LIVP)
 
 
 I installed the standard size, and the test pilot said it was too small and
under-effective.  So we increased the size off the hinge.  The
hinge length is standard, only the width is increased.  Carbon fiber sheet.
 
  Jeff L
  LIVP
 

      Can anyone give me some information on the size of their aileron trim
tab. I used an 8 inch long piece of hinge. It seems like I need a little more
mass, as fuel burns off on one side I do not have enough trim left. Its pretty
effective most of the time. I installed per book for the LIV. Help!Brad
 
    I ended up riveting a flat plate of AL to the original tab to almost
double the number of square inches of tab surface area. The builder's manual
recommendation is too small. Also it helps to keep your wings balanced to
within 10 gallons for trim reasons. Many aircraft have lateral fuel imbalance
limitations for this reason--the Cirrus SR 22 is one.
 
    I'm not sure about the IVs, but on the ESs we have added between 50% and
100% to the trim tab area by riveting on a piece of aluminum.  Because of the
thickness of the trailing edge of the aileron, the hinge alone doesn't do
much.