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<< Lancair Builders' Mail List >>
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In a message dated 7/3/2001 11:27:32 PM Pacific Daylight Time,
lancair.list@olsusa.com writes:
<< After a few months of flight on my Lancair 360 (MK II) I have noticed that
in level flight the leading edge of the elevator (the counterbalance area)
is about 1/4" or 3/8" above the horizontal stabilizer.>>
Matt -
If your CG is more forward, you would need more down force off the horizontal
tail, thus the trailing edge of the tail should be more "up" to generate that
extra tail down-force. You have the opposite condition -- you need trailing
edge down to get less down-force at the back end of the airplane. Therefore,
your suspicion that the forward CG is not the cause is correct.
You probably think you have more drag because of the deflected elevator, but
then again, you might have less drag overall because the tail generates less
downwards lift, you pay for that with less induced drag off the tail, plus
your main wing has to generate less lift to compensate for the down force, so
there's less induced drag off the main wing as well. But probably you have
the same down-force, gotten by having an elevator deflection because the
stabilizer is too nose down.
Frankly, I don't think you could measure any of those effects on your
airspeed indicator. But you could run an experiment where you shift CG to
get a different elevator trim position, and see if you notice a change in
speed.
Is the elevator position a problem, other than the obviously hideous
appearance which makes your flying Lancair painful to look at? (Major joke
here...) Or do you just want it level for aesthetic reasons?
Concerning the stick position, I suspect there is some ability to shorten
your forward elevator pushrod to bring the stick aft and closer to vertical.
If there's insufficient adjustment, I think you'll have to make a new
pushrod, or cut some threads off the existing threaded rod ends. Make sure
you can't push a safety wire through the witness holes in the rod end bearing
(but you know that). Other than that, I see no problem in adjusting it.
You could probably make the aft pushrod a little shorter as well, as long as
you leave adequate clearance for the bob-weight. But I'm less certain about
this as I haven't gotten that far yet.
- Rob Wolf
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