Trimming Question

[Ihncheol Park]

Trimming QuestionYou can not be sure if this is a incidence problem.

Try knife edge.  If it does the same thing,
Moving CG forward, Decreasing wing incidence, or Mix up elevator with
Rudder.
Also, check Decalage, Incidence checking in the trim chart.

http://www.nsrca.org/trimA.htm

My plane does this too, but the incidences are correct.  CG is fine.  So, I
mix the elevator with rudder.
BE Very sure to check both side knife edge flights.
Trimming often takes very long time.  Every adjustment is affected by CG
changes.
Thus, CG is the most important thing.

By the way, have you checked the CG with & without Fuel?
I do both.
Hope this helps,


Ihncheol Park


  -----Original Message-----
  From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On
Behalf Of Larry Diamond
  Sent: Thursday, May 01, 2003 7:13 AM
  To: NSRCA
  Subject: Trimming Question


  I am sorting out an H9 Aresti 40 that I intend to start with Sportsman
until I get another plane sorted out.

  CG appears to be very close. It holds a 45 degree upline straight and
needs a touch of elevator to start the pull through the 1/2 Reverse Cuban 8.
Inverted flight only requires a touch of down elevator.

  My tank location was modified from the intended location and is on CG, to
be read, "The front of the fuel tank is about 1/4 inch forward of the
leading edge. I have mounted a YS 63 and has unlimited vertical after 4
tanks of fuel. CG is currently located at 4" back from the LE per the
instructions (aft range). This tank location result in outstanding ground
handling on grass. Zero tendency to nose over, not even close...

  The problem is in level flight it pitches to the belly with rudder input.
Made for an interesting landing when I corrected with a touch of rudder for
cross wind.

  Is this an incidence problem? I haven't tried a power off dive yet to
check it out due to time. What else could I look for?

  Engine - YS 63 New (2 tanks for break in and 4 flights)
  Prop - APC 11x8
  Max RPM - 11,400 (slightly rich still)

  Thanks,

  Larry K. Diamond
  Program Manager, KEG

  Phone:  (812) 634-4286
  Pager:   (877) 575-4163
  Fax:      (812) 634-4007
  E-Mail:  ldiamon at kimball.com
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