REFLECTOR: TruTrak Automatic Trim

[Bob Jackson]

Thanks Brett -- hope your Trio works well for you.  I also liked the Trio
(especially the user interface), when we were looking a couple of years ago,
but there was no full interface for it with the GRT EFIS.  

 

And we have so much EFIS redundancy already in our plane, that the value of
integrating a full TruTrak or Trio autopilot (with its own integrated gyro)
seems like overkill -- especially now that GRT is selling autopilot servos
for their EFIS.

 

Bob

 

PS  Great job, again, and thanks for organizing the calendar design this
year!

PSS  One 1542 SM, 5.6 hour, 77 gal leg from KAPA (Denver) to X04 (Orlando)
with 30 to 60 kt tailwinds (http://flightaware.com/live/flight/N2XF --
notice the great circle route curvature!) -- the Velocity is amazingly
efficient!

 

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From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Brett Ferrell
Sent: Sunday, January 01, 2012 12:41 PM
To: bobj at jaxtechllc.com; 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: TruTrak Automatic Trim

 

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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