REFLECTOR: TruTrak Automatic Trim

[Brett Ferrell]

Bob,


I don't know if the GRT autopilot does or not, but the Trio does, and we've
installed it.  I've verified it on the ground, but we haven't tested it in
flight yet.  When we do, I'll report back.  Since the folks at Trio are EZ
fliers, I hope it won't dump the nose, but we'll see.  ;-)


Brett


	-------Original Message-------
  From: Bob Jackson (Jax Tech)
  To: 'Velocity Aircraft Owners and Builders list'
  Subject: Re: REFLECTOR: TruTrak Automatic Trim
  Sent: 01 Jan '12 12:27

  Ours worked well for more than a year, but it's been 'down' now for
several
  months for unknown, at least as yet, reasons.  We haven't had time yet to
do
  all the troubleshooting TruTrack has asked for to isolate the problem...

  When it was working correctly, the only problem we used to have was in
  trimming fast enough during the big transition while slowing from high
speed
  cruise (~180 KIAS) to approach/landing speed, which requires a very large
  trim change from full nose down to full nose up, often in less than a
  minute's time.  You can help it out by just holding down the nose up trim
  button, but if you don't help enough, the elevator servo clutch will slip
  and 'dump' the nose, which can be a very disconcerting event and feeling
  when you're shooting a an actual approach IMC and low to the ground.

  The Velocity has very high pitch stick forces when slow because the
canard
  doesn't have all that much surface area, which necessitates (in my
opinion)
  very high elevator deflections in the landing configuration.

  All in all, though, I think the TruTrack Auto Trim module is a very
  worthwhile addition to autopilot operation.  Works very well if you don't
  make rapid speed changes.

  I'm curious if GRT has something similar out now, or how (and how well)
they
  handle rapid and large pitch trim changes.  If we were configuring over
  again now, I think we would be looking very closely at the GRT autopilot
  system and it's components.  We are very happy with the GRT EFIS, even if
  it's human interface is not very 'sophisticated' or easy to use.

  Bob Jackson
  Turbo Cross Country XL/RG
  N2XF
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