[NSRCA-discussion] triangulation trimming

[Derek Koopowitz]

I finally got some time to do some meaningful setup and trimming on my
plane... out of the box without checking any incidence/thrust the plane
pulled quite a bit to the canopy in up and downlines.  I also had downtrim
in the elevator and just didn't feel good about the plane in the lines.
Rolls were fine.

During this past week I found out the thrust/datum line from the designer
and then set the wing to a little less than 1/2 deg pos. and the stab at 0.
Got to the flying field - checked CG range (good) - checked weight (good)
and then filler up and took off.  I never touched elevator trim it was that
good.  I had to change aileron trim a little (expected) but now the plane
flew like it was supposed to.  The upline pull to the canopy was just about
gone and so was the downline pull.  I did mix in some down trim with low
throttle to fix the downline.  I did find that one of my elevator halves is
slightly misaligned even though it is flush with the tips - this caused a
loop/pull/push to change direction slightly.  KE left rudder caused a push
to the belly and a slight roll to the right - right rudder was a very slight
pull to the canopy and a slight roll to the left.  It was blowing about
10mph pretty much down the runway while trimming.

After landing I adjusted the left elevator half by going out 2 full turns on
the clevis.  I flew one more time and the loops were now perfect but I had
to add down trim now to fly level (and adjust aileron as well).  The slight
pull to the canopy in the upline is still there but I'm going to increase
wing incidence a little more now to fix that.  I'll probably be a little
over 1/2 deg. positive on the wing when I try again.  Overall the plane is
tracking/flying a lot better now.

By the way... I did not change thrust at all on the plane.  It comes
standard with 3.5 deg. right and 0 down and thats the way the designer built
it and flies it successfully - top 10 at the WC's.

On Sun, Mar 16, 2008 at 7:17 PM, <shinden1 at cox.net> wrote:

> Lance you need to find out exactly where the wing  inc . is.
> I think if you move your c/g back a little it will help take some of the
> up trim out But you prob need more pos inc, in the wing so we need to know
> where you are at right now to determine exactly where to go
> Bryan
>  ---- Lance Van Nostrand <patterndude at tx.rr.com> wrote:
> > Bryan,
> >
> > The discussion list moves faster than I can try this stuff out.  Too bad
> I
> > have to work...
> >
> > I first only moved my CG forward significantly and have improved overall
> > tracking.  It was windy Saturday and wind penetration were good.
>  Bryan's
> > suggestion was correct on CG movement to make this improvement.  However
> > with the forward CG (and resultant uptrim)  it pulls to the canopy
> slightly
> > on downlines.  At this point I noticed that during inverted flight,
> rudder
> > input caused a pull to the belly (plane rose).  This was weird.  I then
> > raised the incidence 2 turns and it fixed the inverted flight problem
> but it
> > seemed to make the canopy pull worse.  Interestingly, KE flight was not
> > noticeably affected.
> >
> > The other affect is that inverted 45 downlines drop toward earth faster
> than
> > upright 45s (which track nicely).  Before this change, both 45s were
> fine.
> >
> > Is this the expectation?
> >
> > --Lance
> >
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