A Week Of Minor Setbacks

Earlier in the week on Tuesday evening Mike T. was at the airport watching his mechanic perform an annual on his airplane and we got to talking about things left to do prior to a first flight and conditioning the brakes was one of the items still left to do. After Mike’s mechanic decided to call it quits for the evening to resume the following morning, Mike gave me a hand temporarily installing the upper forward fuselage skin with a few screws.


It was getting late (almost dusk) and we felt it was a good time to make Banzai taxi runs up and down the taxiway because the likelihood of having other taxing aircraft to contend with would be slim to none at that hour.  The goal for the evening was to condition the RV-12’s brakes as suggested in the Matco brake manual. The DOG Aviation RV-12 was rolled out of the hangar and started. After letting the oil temperature warm up, two fast taxi runs were performed along the long taxiway adjacent to the hangers while dragging the brakes the whole way in an effort to heat them up as suggested in the Matco manual.


After the high speed taxi/brake conditioning was completed, the airplane is to sit for at least 15 minutes to let the brakes cool. By the time the brakes cooled it was, for the most part, getting dark so decided to roll the RV-12 back into the hangar. After hooking up the tow bar and about to push the RV-12 back into the hangar, I noticed the S-1207 bushing was missing from the nose cone. This is the bushing that the pitot tube pokes through on the tip of the spinner …. what the heck? !!! .


Yep, the bushing was flat out missing. The bushing is glued in place using blue Locktite 242 which, at the time I thought was odd, but that is what Van’s calls for in the plans … guessing to make the bushing easily replaceable. Thus far, I have not heard of any RV-12’s losing the S-1207 bushing, so guess this is unique to me. I know I followed the directions precisely and roughed up the mating surfaces with coarse sandpaper as instructed, and even cleaned the mating surfaces with both Acetone and Isopropyl alcohol prior to assembly.


Of course, by now it was totally dark outside and while Mike used his golf cart with lights on to run up and down the taxi area, I was walking around with a flashlight. At one point, I also had a car following me with its brights on and we just could not locate the bushing. So I decided I would call Van’s in the following morning and have a couple of bushings overnighted … so if it happens again, I will have a spare (they are inexpensive $6 each). So prior to heading to the hangar the following morning, a call was placed to Van’s and the two bushings were ordered for overnight delivery.


As luck would have it, the next morning Mike rolled his airplane outside to warm it up for a compression test and his mechanic noticed this strange looking round object on the asphalt and said to Mike “look at this strange looking thing I just found here on the asphalt”. Mike told him it was the bushing from my airplane that we were looking for the previous evening.

The recovered S-1207 bushing that came out of the RV-12’s spinner. Amazingly, it does not look as though it suffered any damage whatsoever. Even so, I will replace it with a new bushings.


I have decided to NOT use Loctite 242 to secure the replacement bushing onto the spinner. I figure the bushing will not come out on its own if I use a glue that is a bit more tenacious.  Silicone was considered briefly, but if the spinner is to be painted, the silicone will certainly guarantee a problem getting the paint to stick in that area. Finally decided to use fuel tank sealant. Granted, it will make replacing the bushing much more of a challenge if it ever needs to be replaced … but I don’t care. The main thing is it will not be parting company with the spinner on its own accord anytime soon … theoretically at least. After scuffing up the bushing with coarse sandpaper, I mixed up a small batch of fuel tank sealant.


I did not get crazy with the fuel tank sealant, just placed a very thin film on the bushing and under the lip on the bushing. Also placed a very thin film of the tank sealant on the inside of the hole in the spinner (this may have been a bad idea from the standpoint of easy removal). After pressing the S-1207 bushing into the tip of the spinner, the tank sealant was spread along the base of the inside of the spinner and then up onto the side of the bushing … theoretically, this should prevent the S-1207 bushing from backing out unless the tank sealant is cut away from the sides of the bushing.

We have been having some cold nights here at DOG Aviation so brought the spinner home so the fuel tank sealant can cure where it is warmer. The S-1207 bushing set on the S-1201 spinner in a thin bed of fuel tank sealant.

The inside of the S-1201 spinner with fuel tank sealant spread around the base of the hole in the spinner and up onto the side of the bushing to keep it in place.


The other setback, which was totally my fault, was breaking one of the vacuum gauges used for balancing the carburetors on the Rotax engine. Yep, dropped it Wednesday while going to a different length of mounting screw and really hosed it up bigtime. Had it sitting on my leg while sizing a screw and it slid off onto the hangar floor and broke the glass cover, along with displacing the movement internally so badly, the gauge is unusable. Fortunately, I was able to find a supplier that had the gauge in stock and had it shipped to me and received it yesterday … so it should not hold up progress. I do want to give the fuel tank sealant two full days to cure, so will not attempt starting the engine until Sunday at the earliest … but Sunday is forecasted to be a rainy day, so may have a little weather delay thrown into the mix as well.


The only shining light of the week … the Dynon 470 ADS-B unit was received back from Dynon late yesterday evening. Dynon gave me an exchange unit under the warranty rather than having me wait for the one I sent in to get repaired. So the project for later today is to install the ADS-B unit and hope it works like it should.

A Bump In The Road To First Flight

Yesterday, while fine tuning the audio system to my satisfaction,  I decided to also update the Dynon SkyView’s mapping database. While in the setup menu, I took a closer look at the settings for the ADS-B receiver. Ever since the instillation of the ADS-B 470 receiver, there has been a notification in the warning box saying “ADS-B IN OFFLINE”. Because of the insurance donut hole (mentioned a few posts prior) I have been powering the SkyView up inside the hangar and figured I was just not receiving the ADS-B signal … and that may be true, but the result in the status menu will be “No Signal” not “Offline”. Having never gone through the process of installing an ADS-B receiver before, I had not really picked up on the fact that there was an issue with the ADS-B 470 box.


What really got me to the conclusion that something was drastically wrong with the ADS-B 470 box was when I dug into the menus and had a look at the ADS-B status menu ... where it said “Not Found”!!! That’s not good. I had noticed when looking at the serial port setup menu that the receive counter for serial Port 2 was always 0 and not incrementing, but figured that was because I was inside a hangar and not receiving data …. wrong! I have since come to understand even though there is no ADS-B signal being received, that counter should be clicking away continually because the ADS-B box is always being polled by the SkyView.

The RX counter should not be zero … it should be steadily incrementing.

I placed a call to Dynon's tech support and left a message, a short time later I received a call from Mike at Dynon support and proceeded to explain to him what I was seeing. Mike said the issue appeared to stem from no received data from the ADS-B 470 box. Mike wanted me trace the continuity of the wires between the ADS-B box and the SkyView (Mike said it is a common mistake to flip-flop the wires) … then give him a call back with the results. For those RV-12 builders that need to go through this process, I can save you some time. The Van's configuration file and wiring harnesses for the RV-12 is wired and configured to place the ADS-B 470 on SkyView's serial Port 2. As such, the DB-9 connector that plugs into the back of the ADS-B 470 box is wired for the RV-12 as follows:


Pin 2 of the ADS-B 470's DB-9 connector goes to Pin 6 of the DB-37 connector that plugs into the back of the SkyView …. and Pin 3 of the DB-9 connector goes to Pin 5 of the DB-37 connector.


(As a side note for builders that have not configured the Dynon ADS-B 470 on serial Port 2 … table 47 on page 14-5 of the SkyView System Instillation Guide Version 11 shows where to wire  the ADS-B 470’s transmit and receive wires to the SkyView's DB-37 connector depending on which serial port is desired).


In my case,  much to my relief, the wiring buzzed out OK. So there were no wiring errors to contend with. This leaves only two possibilities … a bad serial Port 2 in the SkyView or a bad ADS-B 470 receiver. I called Mike at Dynon and informed him the wiring was indeed correct. At this point, we discussed a plan to verify Port 2 in the SkyView was working. That plan involved configuring for a loop back test.


For the loopback test, the ADS-B 470's DB-9 connector is left removed from the ADS-B 470 box and Pin 2 of the DB-9 connector is connected to Pin 3 using a jumper. The DB-37 connector is reconnected to the back of the SkyView and the SkyView is powered up. For the loopback test, serial Port 2 is temporally reconfigured by changing the device name from SV-ADSB-470 to NMEA basic device and making sure both serial in and out ports are configured as NMEA basic. What this does is transmit a known data string pattern on the transmit wire from Port 2 and the loopback at the DB-9 connector sends the data string back to the Skyview’s Port 2 on the receive wire.


The above is achieved by changing the settings for serial Port2  at the location listed below:


SETUP MENU > SYSTEM SETUP > SERIAL PORT SETUP > SERIAL PORT 2 SETUP.

After making the above change for the loopback test, I could see both transmit and receive counters incrementing steadily with no errors …. Meaning, serial Port 2 in the SkyView was in good shape and capable of sending and receiving data … so the failure was definitely inside the ADS-B 470 receiver box.

A fine example of infant mortality in the world of electronics. This ADS-B unit was broken the day it was installed, I was just not savvy enough to pick up on it. Failures are most likely to occur early on … if an electronic device lasts 30 days or so, it will likely give many years of trouble free service.


I packaged the ADS-B receiver up and sent it out to Dynon for a quick exchange, so hope to have the unit back by the end of the week. I think at this point I’m inclined to hold off on the first flight until I get the ADS-B unit back so I do not have to deal with installing, removing and installing the upper fuselage skin. Because as fellow RV-12 owners know, this can be a chore when the canopy is installed.

Cockpit Interior Completed - Almost

Finished up installing the RV-12’s interior and discovered two minor issues. The piece of carpeting that covers the center tunnel in the area under the instrument panel has a recess cut into the forward edge of the carpet for the wiring bundle … unfortunately, that recess is not big enough because of the much thicker brake lines, the additional tube for the static line going to the backup instruments and the ADS-B coax cable. As such, the carpet can’t be placed as forward as necessary so the edges that should be close and parallel to the firewall are not. Because of the alignment issue I did not attach the Velcro strips for that piece yet. Will need to take the carpet piece to a tailor at some point in the near future and have the recess made both a little wider and deeper.


The other issue involves the interior trim piece that covers the air vents. This piece has a cutout for the air vent but it is completely covered with a fine mesh material. Installing the trim piece will require cutting a slit in the mesh for the lever that controls the position of the vent. This, in and of itself, is not a big deal but the mesh is fine so I feel it will really significantly cut down the airflow. So at this point, I left the piece off until I make a decision … leaning towards removing the mesh all together. Guess I could fly the plane without the piece in place and see just how much air the vent produces then install the panel and compare the airflow with the mesh in place and go from there.

Seats and interior carpet in place in the cockpit area.

Photo of the interior carpet under the instrument panel. These pieces are just loosely set in place because the center tunnel piece needs to be tweaked as mentioned above. I didn’t realize it at the time, but the issue with the wiring bundle can’t be seen in this photo. One of the previously mentioned air vent can be seen to the right of the right control stick.


One of the few remaining tasks that needed to be accomplished was adjusting the takeoff trim position that is displayed on the EMS. I was searching for the words “trim” calibration or some such thing and couldn’t find it listed on the EMS calibration page. That sent me on a tangent referring to the SkyView documentation with no joy   … well it IS there …. it is listed as “elevator” and not trim. The calibration wizard can be accessed by going to SETUP MENU > HARDWARE CALIBRATION > EMS CALIBRATION> ELEVATOR. Calibration is easy …. the SkyView has the user run the trim motor full down and full up then has the user place the trim in the takeoff position to complete the calibration. Based on what other builders have suggested, I set the trim takeoff position to 1 7/8". This is done by moving the control stick full aft and measuring the distance from the aft edge of the anti-servo tab to the aft edge of the stabilator. This should be a safe initial starting point and can always be readjusted later if desired.

Photo posted on the VAF forums by John a builder in Texas that shows a good starting point for setting the position of the trim tab for takeoff.


While the SkyView was still powered up, decided to pre-set some frequencies into the Garmin GTR200 radio following the Garmin User manual. Also decided to adjust the blaring stall warning sound down from a mind-numbing screech to a level louder than any of the other audio signals, but not blaring. The Garmin radio has two audio inputs … AUX 1 is for the stall warning tone and AUX 2 is for annunciations coming from the Dynon SkyView.


To reduce the stall warning sound level, the adjustment was made at the Garmin radio using the volume adjustments for the AUX 1 input. There is also an adjustment potentiometer on the AV-50000 module as well, but I did not play with it.


I discovered a little background noise in the headsets coming from the Skyview …feel it is originating from the SkyView because the sound is in sync with the clock seconds. It was getting late evening so decided to leave this for the next work session … will try turning down the EFIS potentiometers on the AV-50000A module a bit to see if it helps since the radio has tons of gain available for the audio input. This may be a sound that is being transferred from wires running adjacent to the music inputs. I still have the music inputs muted so will need to do a little experimenting to find out what the deal is.

Inspection Panels & Interior Installed

Frequent readers may have been wondering when the first flight of the DOG Aviation RV-12 will occur ….. soon, very soon.


As mentioned in the previous post, it was necessary to remove the wings to install the F-1228 cover. Two Sundays ago after the MAPS museum’s pancake breakfast, Bernie and Mike K. gave me a hand removing the wings so the F-1228 seat floor cover could be installed down over the flap handle. Now that we have done it a couple of times, the process was a snap … it took far longer to get all the screws in the cover plate than it did to remove and replace the wings.


While I had the flap handle disassembled, I used the opportunity to remove ½" from the VA-114 spring inside the flap handle. This makes the button far easier to push and reduces the likelihood of pinching fingers or thumb on the button. This was done in accordance with Van’s Notification 15-10-01.


Then the monsoons hit …. it rained every day last week, so I didn’t get much done. I figured there was no urgency, so why spend time in a cold damp hangar listening to the defining sound of rain hitting the metal roof if it is not necessary? However, the time was not entirely wasted in that custom made checklists were printed out and laminated.


This week during the last few work sessions all the covers for the center tunnel and baggage bulkhead have been installed along with most of the interior pieces. I did run into a small issue installing the F-1230 tunnel cover. This is the cover that readers may recall needed to have the slot for the wiring harness cut out a little larger (this was done months ago during a trial fitting). Then installing the cover I had troubles getting it to seat correctly … it would not slide down low enough around the bundle of wires and brake lines. One of the brake lines was interfering with the cover. Further investigation revealed the stiffness of Bowden cable for the parking brake was the root of the problem … in that, it was preventing the brake line from moving downward. The cable for the parking brake had been routed behind the brake lines going to the parking brake and prevented the brake lines from moving. The solution was to reroute the Bowden cable on top of the brake lines in the valley between the two lines. This solved the issue and actually made for a better instillation but sucked up most of an afternoon in the process. Unfortunately, I did not take any photos.

Installing the F-1227 seat ramp cover, and the remaining baggage floor covers and the modified F-1207F baggage bulkhead went smoothly, but took a toll on my knees and legs because of the position necessary to lean over the cross brace to gain access to the screws in the baggage area.


At this point, I was planning on balancing the audio, but got sidetracked and decided to install most of the interior carpet and side panel kits. Mainly because I did not want my shoes to scrape up the paint when pushing on the rudder pedals. At first I was only going to install the one piece of carpet but decided to just go for it and install them all in the cockpit area. All went smooth for the most part, but it took much longer to install the Velcro strips than I thought it would. But the end results look nice.

Working on installing the carpet over the seat pans.

I discovered there is a long piece of Velcro that needs to be installed underneath the spars. Not going to happen now … so I just have it laying there stuck to the carpet for the time being because I am not removing the wings just to install a strip of Velcro. Will make a note of it so the next time the wings come off, I can install the Velcro.


Note to fellow builders that have purchased the carpet kit. While you have the wings off to install the cover plate that goes over the flap handle do yourself a favor and install the carpet for the seat pans at this time.


The side panels are installed by placing a bunch of Velcro strips on the inside of the fuselage skin and setting the panels in place. The panels are a very snug fit and shaped perfectly … nice job Abby!

Installing one of the side panels on the right side of the DOG Aviation RV-12.

Did not have enough time to finish installing the arm rests, so will finish that up first thing during the next work session. I have a carpet kit for the baggage area as well but will hold off on installing that until my knees recuperate a bit.