Saturday, April 9, 2016

Trim Wiring Vindication & Avionics Learning Curve

Being a nasty snowy day, decided to stay home and work on the April 15th deadline, but first want to mention a few items discovered after powering up the DOG Aviation’s RV12 avionics for the first time.

One of the first things completed after the initial powering of the avionics was to install the SkyView version 13 software from the Van’s site along with a few configuration files Van’s supplies with preset configurations for the RV-12. The software can also be downloaded directly from the Dynon site, but it will contain no presets unique to the RV-12 forcing the user to run through all the menu settings manually.

The configuration menu shows the system items on the SkyView’s buss, but there are a few items that do not show up because they are connected separately to the serial ports such as the transponder, GPS250 or 2020, ADS-B, and the Garmin GTR 200 Radio, ect.  Interestingly, I only saw an entry for the GPS250 (which I assume came from the Van’s configuration files) but do not see the GPS2020 that is installed … it was also NOT in the list of possible devices.

Thinking the red X for the GPS may be appearing because the airplane was inside, yesterday afternoon between snow storms the fuselage was rolled outside of the hangar and the avionics powered up … after waiting quite a while, the red X for the GPS did not go away. By doing a little more reading, it appears that the new GPS 2020 antenna is ONLY supported beginning with SkyView version 14 … so that is likely the main issue since the system does not see the GPS 2020 antenna.

Dynon released version 14 earlier this year but there were some unsavory issues created with older SkyView screens, so Dynon temporarily suspended version 14 to make the necessary corrections to the software. Recently, Dynon began distributing SkyView version 14 again. I could download version 14 now directly from Dynon … but will opt to wait for Van’s to post version 14 with configuration files unique to the RV-12. I have plenty to do in the meantime with fitting the cowling and finishing off the engine compartment … so can afford to wait for a little while in the hopes Van’s posts their preconfigured version of Dynon’s SkyView 14 on their website soon.

Yesterday, I also performed the Garmin radio software update to the latest version 2.7 … it is easy to do. Starting with the radio powered off, just place a micro SD card with the latest software file on it into the micro SD slot on the front of the radio … then power up the radio. The radio will identify the software version on the micro SD card and compare it to the version in the radio … and if the SD card is newer, it will ask to upgrade the radio … select yes and a minute or so later it is done.

Frequent readers know I plan to use a couple of switches on the Tosten CS-8 control grips to control the Garmin GTR 200 radio. One switch will be used for swapping between the active and standby frequencies. The second switch will cycle through a user saved table of up to 20 stored frequencies. I ran into a little problem here. I remembered there are quite a few configuration menus but could not get into them at first. The pilot’s guide that comes with the radio DOES NOT show the user how to get into the configuration menus. For the most part, it only shows how to get into the audio settings by pressing the menu button which brings up a settings menu that allows the user to change various audio options. My radio did not come with an instillation manual, so needed to download one to my phone while at the hangar to discover the “mystery” of how to get into the GTR 200 radio’s configuration pages. For those builders interested … the procedure to enter the configuration menus is: With the GTR 200 radio powered off, press the center button on the right knob and keep it depressed … then power up the radio. After a few seconds the radio will allow access to a grouping of configuration menus. There is a discrete configuration menu there which is where the two discrete inputs can be configured. I configured Discrete Input 1 to swap between the primary and standby frequencies. Discrete Input 2was optioned to cycle through the user stored frequencies.

Of course, I couldn’t wait to see if the wiring change I made for the trim motor was correct … so I was eager to try the trim switch mounted on the panel. Vindication!!! The trim motor worked precisely as I predicted it would back on March 5, 2016 in this post:

When pressing the panel mounted trim switch calling for nose down trim, the anti-servo trim tab on the stabilator moved up … just as it should. I also checked the trim switches on the control stick to make sure the trim tab moved in the appropriate direction and it does for those as well! So there is definitely an error in Van’s plans on page 31B-04 step 2. I can’t speak for all RV-12’s, but those builders building with the intent of installing the SkyView Autopilot & Knobs Panel modules during construction phase will do themselves a favor if they place the wire identified as  +Tab Up on pin 32 of the fuselage connector and NOT pin 31 as shown in figure 1 in section31B-04. Doing it now will save you from going into the connector later and extracting the wires and rolling pins 31 & 32.

The built in run-away trim protection built into the AP panel module also worked as advertised … it will allow the trim motor to run four or five seconds then stop. Releasing the trim switch momentarily will reset the trim circuit and the trim motor will move again when the switch is activated again. A nice safety feature in case a trim wire becomes shorted to ground.