I have been flying with the original GRT EFIS now for a bit more than two years, and have been extremely happy with the system. When Grand Rapids announced that they were working on a High Resolution screen, I didn’t give it a lot of thought, being satisfied with the original resolution screen which satisfied all of the functions that I needed. However, the newer screens are a bit brighter, and that is always attractive – even though I picked the GRT’s at Oshkosh several years ago after doing direct sunlight readability comparisons to the other systems available at the time, and finding that GRT was the best (to my eyes).
A couple of weeks ago, I was chatting with Mark at GRT about beta-testing their new RAIM GPS module, and he asked if I thought I could put two of the new displays in a vertical stack in the RV-8 panel. The new display bezels are a half inch higher than the old ones, making for a total new height of an inch. I told him that I thought it would be tight, but that I was willing to give it a try. The first step was repackaging my annunciator panel to fit in an empty spot on the right side of the panel, as I was going to need that 5/8” strip across the top. I dropped the bottom edge of the EFIS units about 1/16”,and took the rest out of the top of the stack – I had to trim the panel attaching flange just a touch to allow clearance, but that was easily reinforced.
A box with two new HS displays showed up on my doorstep on Friday, but since Louise was in town, I put them on the bench so that we could enjoy a flying trip on Saturday. After dropping her off at Hobby on Sunday morning for her SWA flight home (the weekend was too short for the RV to work for the long trip from D.C.), I headed to the airport with the new toys. Of course, the weather was nice enough to fly a bit, so that came first, then it was time to get to work! The panel came out in about 5 minutes, and out came the old displays. I enlarged the main EFIS hole and drilled for new nutserts where the HS displays needed them. Interestingly enough, the bottom pair of holes was in the same place, and all the rest “missed” the holes for the old displays, so I left those nutserts in place as well, so I could swap back and forth if I wanted.
Cutting the hole for the new annunciator was straightforward using a cut-of wheel on the Dremel, and after two hours work, the panel mods were pretty much done. I transferred the ARINC and RAIM GPS modules from the old displays to the new ones, and opened up the cases to move the SD cards that hold the terrain database as well. I had previously backed up the old unit’s configuration files to thumb drives, so I uploaded those configs to the new units using the bench-top power supply. I spent a half hour replacing some of the harness cable ties with lacing cord, “just because”, and then remounted the panel in the plane.
The only small problem I encountered was with the deeper HS cases (about ¾”), the connector back shells interfered with the mount for my AHRS (mounted directly ahead of the display units). I removed the back shells, added a strain-relief loop to the cable, and the assembly was back on track. I’ll look for short back shells in the future. A quick “power up” test confirmed that the units were not only working, but were properly configured (although the new displays offer a few options that will want to make me reset some defaults to make the most use of them), so all of the elements of the avionics system (EFIS, EIS, GPS, A/P, etc) were talking. The new annunciator checked out perfectly, and I was ready for a trip around the pattern. The only thing not yet up and running was the RAIM GPS, and I probably have some additional configuring to do to get that on line. (It ran fine on the ground after finding the right settings, but I noticed that it wasn’t outputting position in the air – I probably just haven’t fiddled with it enough!)
My initial impression of the displays are quite positive – clear, crisp, and bright! While I still think that the original displays are quite adequate, the new ones are better, and allow a strip of engine instrumentation to be placed underneath the PFD – very useful. My other favorite new feature is the ability to look at both the CHT and ET time graph’s simultaneously – once you’ve used these plots, the old fashioned bar graphs will just never do. Leaning with a time-graph of the EGT’s is just so intuitive (at least for an engineer!).
The bottom line is that you CAN fit two HS displays vertically in an -8 panel, and there is sufficient structure to make it work. The new displays are bright and crisp, and because they have a little more real estate, they allow a little more information on each page. Best of all….while the HS displays use the same processor as the older Horizon 1’s, they will share display bezels with the newer HX displays that have a faster processor. So once you have built the panel to accommodate the HS displays, the new HX’s will slip right in….subject to CFO approval, of course….
More to come when I have some real flight experience behind the new displays!
Here's a close-up of the displays:
You can go HERE for a few more pictures of the panel with different displays if you're curious. There are an awful lot of potential combinations of data - this is a very tiny sampe!
(You can go to my "virtual hangar" page to see a "before" picture)
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