REFLECTOR: GRT Displays overheating - Anyone else see this?

[Brett Ferrell]

Scott - As I mentioned, Yes, I already tried a small computer fan, and Yes,
I already tried running one of my two fresh air lines from the nose NACA
directly the back of the screen where the heat sink is located, and neither
helped really at all.


Larry - It comes back within a "few" seconds, basically shutting the
display off removes the heat and a few seconds later it reboots.  I'm not
sure how cool it must get to restart, but it seems to cool pretty quickly.
The good news is that if it detects airspeed it goes right into flight mode
(you don't have to press accept as you normally would).  Both AHRS were
still up, so any screen that was up still had all air and heading data.  If
it takes 12-15 seconds to reboot (haven't timed it, that's just a guess),
I'd say they were down about 20-25.  Each of my 3 screens did this at some
point.


I'd previously had one shut off valve in the oil line (actually, a 3 way),
but took it out when I put in hoses to replace the hard AL line.  My
rationale was that if I didn't block the supply and the return that extra
cooler would be exposed to, and eventually obtain,  the hot oil temperature
anyway.  Yes, having oil  flow through it will get it there more quickly,
but without air flow it is only transferring heat to it's surroundings by
raditation, so it's final temperature is all that is really important.
That means two valves or pull the cooler.  Since my plane is a little nose
heavy anyway, I'll probably pull the cooler.


All - Back to my questions, has anybody else seen this?  Do most folks have
vents in their glare shields already?


Brett


	-------Original Message-------
  From: Lawrence Epstein
  To: Brett Ferrell , Velocity Aircraft Owners and Builders list
  Subject: Re: REFLECTOR: GRT Displays overheating - Anyone else see this?
  Sent: 09 Jul '12 05:28

  Brett-


Was it just the display?
Did it come back on spontaneously, or did you have to shut it down and
restart later.
How long before it recovered?


I also though about having a second radiator in the nose for Winter heat. I
was thinking to have a shut off valve so that it wouldn't have any flow in
the summer.


Larry


On Sun, Jul 8, 2012 at 10:36 PM, Brett Ferrell <[LINK:
mailto:reflector at velocityxl.com] reflector at velocityxl.com> wrote:


We've had quite a string of hot weather here in SW Ohio as of late, and on
the last couple of flights we've had issues with our GRT HX screens
overheating and shutting down in flight.  We've got backup dial gauges, but
needless to say, it's disappointing when you lose the fancy readouts, and
though we've been planning to fly to Airventure we will likely won't if we
can't quickly find a solution to the issue.  Has anyone else seen this
behavior?  If so, how did you resolve it?


GRT tell me that the screens should run 'about 30 degrees' above ambient.
They will shut down at 160 F, and you can see the internal temperature by
going to setup menu (Display Maint, Analog Input page).  It's been right at
100 F here for the last few days, and I can confirm that on the ground they
warm right up to 130.  We went around the pattern and in less than two
passes they were shutting down!  I went to the setup page, and sure enough,
they were reporting in the mid 150s.


GRT believes that if I add vents to my glaresheild the issue will resolve
itself, but I have already tried a large (68 cfm) computer fan aimed at the
back of the displays, which only relieved about 1 degree F of temperature,
and tried routing cooling air from the nose fresh air vent to the back of
the displays to no effect (the screens still shutdown in flight).  I
believe my situation is unique because I mounted a second oil cooler in the
nose for winter recirculating air usage (rather than cold outside air), and
have checked this cooler is, in fact, getting quite hot.  On my last flight
it was over 200 F even though the one on the nose NACA was below 180, so I
think this cooler is just filling the nose area with hot air.  Net, I'm
going to pull that cooler, and at some point put vents in the glaresheild,
but that's a fair amount of effort the way I have it mounted.
Brett
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