Re: S-Tec 50 Autopilot

["Tim Crawford" <crawford@atdd.noaa.gov>]

Hi Ricardo!


Thanks for your info on the S-Tec.  I worked most of the day on just this
issue.

For N6Q, Pitch cntl was fine but I had an extreem wing rock.  First I
reduced the roll gain by changing the feedback resistor from 15K to 9.8K. 
That maid it better but did not fix the wing rock.  Next I shortned the
arm on the roll servo.  It was originally set up with hardware sent by
S-Tec.  The final mechanical gain reduction did the trick.  Now I get just
a little rock on a roll command and a very slight (nearly not noticable)
rock at high speed.  So my conclusion is you need to reduce the gain as
much as possible BOTH mechanically and electronically.  

BTY  In level flight today, N6Q made a clean 180kts.  So now it is 5 kts
faster than my long!  In time, I expect to find at least another 5 kts. 
The rest of the story is that I had to turn 2840 RPM @ 21.1".  I really do
not want to work things that hard just to fly faster than my Long!  But it
is nice to know I can out run myself <g>.



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      >-}     Tim        {-<
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 Long EZ N3R           Velocity N6Q