Autopilot Roll Servo

Time: 2 Hours

One of the items delivered today was the second autopilot servo that will function as the role component of the autopilot. To install this is exactly the same as the servo I put in for the pitch. One thing I found was that I made an error in the D sub pin layout way back when I installed the servo wiring harness when I was wiring the fuselage. It was not the same layout as what Dynon called in their installation manual, so I needed to correct this. It was the same in the pitch servo harness and I will correct that one as well shortly. So I needed to remove all the pins from the housing and reinstall them in the correct holes.

After inserting the pins correctly i laced the wires and reinstalled the housing.

I had to add pin and housing to the servo wires as well. The process was the same and ended with lacing and the install of the housing.

The install of the servo into the right wing is pretty easy, just three bolts hold it in place followed by two bolts holding the servo arm connected to the aileron bell crank. After torquing all the bolts and applying torque seal I powered up the Dynon Skyview to configure the network for this new servo. The system worked perfect and now I have expert autopilot controls including a flight director.

Dynon Heated Pitot

Time: 8 Hours

I finally got back to working on the RV. When I built the wings one of the items I planned for was the Dynon heated pitot, for the non pilots it’s the tube that measures the air pressure to determine airspeed and angle of attack. I had installed the mast that would hold the pitot since it needed to be riveted and the hole cut into the wing so it made sense to install this early on. I had also wired for the pitot which includes the power, ground and indication wire. The wiring is for the heat controller that allows the pitot tube to keep ice from forming as you fly through moisture which could freeze on an I heated pitot and block it’s function. First task was about getting the pitot attachment screws drilled, tapped and countersunk.

This pitot has a special function in that it has one hole on the tip to measure pressure indicating airspeed but also has one in the angled face. This hole compares pressure between the two and as the angled ones pressure increases and the tip decreases it can measure the angle of attack, the angle of the wing relative to the air it’s traveling through. This angle of attack or AOA is used to determine when the wing stalls or no longer produces lift.

First up was to determine where the screws need to go. The pitot has some thicker sections on the wall to allow for the screw holes. I transferred where those would line up on a piece of tape I put around the edge so that I could reference them onto the mast.

I also used some electrical tape to help make the fitting tight. I put the pitot tube in place on the mast and used the reference lines on the blue tape to transfer those marks onto the mast. I then used those marks to drill the initial holes after removing the pitot.

I then returned the pitot tube back to the mast and used the previously drilled holes to mark the pitot tube itself. This way I could remove the pitot tube and drill in a more controlled environment as you need to be careful to not drill too deep and hit Bart if the inner tubes or wires.

With the holes drilled in the pitot I could then use my tap for 6-32 screws. I then countersunk the mast to accommodate the screws to be flush.

Once the pitot was secured into place with its new countersunk screws I marked the ends of the aluminum tubes inside the wing so that I would have good clearance. I need to transition from the aluminum tubes to the plastic SafAir pitot/static hose that I had installed a few years ago. I removed the pitot again so that I could cut the aluminum tubes to the final length. I decided to stager them to help with installing the pitot with the fittings installed. I needed to flare the the aluminum tube to work with a compression fitting that allows to transition to the push-to-connect fitting that allows the plastic hose to connect.

The next step was to mount the heater controller. I searched several websites prior to this and decided that I would mount the controller directly to the access panel. This allows for easy installation and removal as needed. So I took some measurements and decided exactly where to mount it on the panel. I made some reference marks and clamped the controller to the panel so I could drill the four mounting holes.

After I had the holes drilled in the panel I went to work on the attachment hardware on the controller. I decide to use nutplates to make installation of the controller as easy as possible. This included drilling for the nutplate rivers and countersinking for the dimples that would be in the panel. Once all cleaned up I riveted the nutplates and dimpled the panel for the #8 screws. Overall a pretty easy process just time consuming.

Now I needed to figure out exactly how to route the wires to make sure they don’t interfere with the aileron bellcrank or the edge of the rib. Once that was decided I started lacing the wires so that they would lay correctly. I also added a couple of adhesive zip tie attach points to help secure the wires.

I laced up the wires that come off the pitot so they look good as well.

The last task is to cut the two plastic lines inside the wing. I had left these long when I installed them a few years ago since I wasn’t sure how they would be routed in the final install. I made some marks where I thought the should end up and cut them about an inch long to start with. After a few trial fits I removed a little at a time to get a perfect fit. I decide to go with two 90° push connect fittings versus bending the aluminum tubes which will all for easy removal of the pitot should it need replacing.

just need to order and install some edge guard along the rib lightning hole to protect the tubing. I also did a pitot test with a 12cc syringe and some surgical hose following the HomeBuiltHelp technique from this video: Leak Testing. My system stayed pressurized and a constant indicated airspeed help for several minutes which tells me I have no leaks. I will test the static side after I crawl into the tail to add a tee fitting. I then tested the heating function of the pitot by powering up the RV and flipping the Pitot switch on. I watched the VP-X screen to see the AMP draw increase indicating the that controller and pitot are drawing power. The indicator I created on the Dynon screen turned green, that’s how I programmed it, to give an indication that the pitot was turned on and is functioning properly. I also tried to use a laser thermometer to see if the probe was actually heating. I could get a good reading so I quickly touched it with the back of my hand. It was hot but not so hot to burn me so that was good enough for me to say it’s working. One more task done on the RV!

Pitot Staic Line

Time: 8 Hours

I needed to run the pitot(airspeed) and AOA(angle of attack) lines inside the fuselage and the left wing. I decided where I wanted to run the lines and drilled for two snap bushings at each bulkhead as they went aft from the fuselage side where they will make a 90° and exit to go into the left wing. Once I had the bushings in I ran the lines and secure them with zip ties as needed to keep them out of the way of things like the flap push rod. 

I also needed to reroute the two lines in the wing as I had originally followed the tooling holes in the ribs. The problem with this is it puts the lines exiting the wing too close to the wings spar. Glenn had already figured this out so I adjusted mine like his. I just change the location of the innermost rib snap bushings. In between the last two ribs I rerouted the lines to exit in a better location.  I used a #6 adel clamp to secure the lines to the rib. These lines will be cut to a perfect length once we reinstall the wings for the final time and slide thru the snap bushings in the fuselage side. They will attach to the two elbows that will be inside the fuselage. 

While I was working on the right wing and the pitot/AOA lines I decided to work on the wiring that I needed to run to the pitot and wing tip. On the right wing I will need a 3 wire harness to the tip for the land/taxi lights, a 3 wire(with shielding) harness to the tip for the NAV/Strobe and a 3 wire harness to the pitot tube for pitot heat. At the wing root I used plain Molex connectors as this area should be sealed up from moisture with the rubber seal that will tie the flashing to the fuselage side. Out in the wing tip I might get moisture thru the hinge that I have holding them on so I used Seal-All connectors form McMaster Carr to help prevent corrosion. With the NAV/Stobe I carried the shielding thru the wing root connector and left it un-terminated at the wingtip as per AeroLED’s recommendation.  I started with all the Molex connectors at the wing root and secured them with a adel clamp. 

When we go to attach the wings for the final time I left enough length on the fuselage side to be able to connect the wires with plenty of space as we slide the wings in place. Then as the wings slide into place the extra wire will be pulled into the fuselage and out of the way under the passengers foot wells. 
Once I had the wing root wires secured I moved to the outboard end to work on the weather proof ends. They work just like a Molex except the have a rubber seal that you put on the wire before crimping. Once the wire is crimped you crimp the seal to hold it in place. 

These seals fit nicely into the back of the connector and prevent moisture from getting in.

 Then there is a back peice that snaps into place to hold the wire and seal in place. 

I completed this process for both the land/taxi lights and the NAV/strobe lights and secured them with an adel clamps and zip tied the remaining parts in their bag to the harness so I don’t loose them for later. Then when I get my lights bought I will complete the mating end of the connector on the wires from the lights and make them long enough to connect them as I install the tips. 

I also ordered the Dunon ARINC module, the device that talks between the Skyview system and a certified GPS, so that I could drill and mount the nutplates to the bracket I made a while ago. I really didn’t need this part but I wanted to rivet the bracket to the fuselage and I needed the nutplates to be drilled first. 

So that’s where I stopped and called it a day.