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!

Wings Back On

Time: 6 Hours

We have been busy getting all the things done in the new home to make it ours. Like ripping up old ceramic tile to make way for new hardwood. That was not a fun project but it’s all ripped up and ready for the installers. In-between that work I have been doing little projects in the hangar to get it organized. I also got my hands on the RV to start building again. One of the items I was unhappy with when I put the wings on the first time was the length of the wire bundles coming out of the wings. I found them to be a little short to work on with the tight space you end up with when the wings are on. So since I had the wings off again I decided to add 12″ to each of the bundles to give me plenty of length. I also figured that I would finish up the little bit of fiberglass tasks to the control surfaces, the rudder and elevators. I just needed to fill some pin holes and smooth the transitions out a little. A composite pro I am not and hope to get some help when it comes painting time to make these perfect. I used some filler primer to identify the holes and used Super-Fil to make the corrections. With the rudder pin holes taken care of and a coat of primer on I put the rudder on the vertical stabilizer and bolted it in place. I also put the AeroLED tail light in as well.I then spent two hours putting in the new close tolerance bolts in to secure the wings…again. The process was just the same as before, I froze the bolts and used LPS lubricant. The rivet gun at low pressure worked to drive them into position. The hardest part of the whole ordeal, as before, was to torque the bolts. I worked one bolt and then took a little break as leaning over the side wall of the fuselage even with padding was not very comfortable. So that’s a good start to being in my very own hangar that’s ten feet from my back door! I can not wait to be able to just walk out and go for a flight or a trip.

Wings On!

Time: 6 Hours

This morning I had breakfast with my buddy Glenn in preparation for helping me put my wings on. Now that the RV is at an airport I can put the wings on permanently so that I can continue to work on stuff while I wait to save up for my propellor. Since we have had my wings on and off two times before the process was pretty easy for us. We used the temporary bolts initially to hold the wings in place while I prepped for the final close tolerance NAS bolts. I had put all the bolts in the hangar freezer in hopes that they would shrink ever so slightly. I also picked up a can of LPS-2 lubricant that Vans recommends. Then I laid out several different tools, hammers and my rivet gun with the flush set in place. I started with the hard to get bottom bolts with the larger ones first. I pulled a bolt from the freezer and sprayed the shank with the LPS. Then I inserted it by hand as far as they would go followed by a few hits with a mallet. Then to drive them all the way I used my rivet gun and flush set with some duct tape on the face to drive the bolt thru. I just used a low PSI setting and it worked really well. I drove the two lower large bolts then the top followed by the two smaller bottom bolts then the top two. This process worked pretty slick and only took an hour.

Now the fun job of putting a washer and nut on all these bolts and torquing them. The large bolts get torqued to 520-630 in/lbs and the smaller ones to 80-100 in/lbs. not much to show on that process other than is was very time consuming and a pain to do. It didn’t help that it was 91° today and a little humid. After I finished I put some orange torque seal on to show that they were torqued.

There are also two AN-4 bolts that screw into nutplates from the aft side of the center section, I torqued those as well.

Fun day and felt good to sweat and swear a little while working on the RV! It’s been a while and I’m glad to be back at it. I have so many projects and tasks to do now that the wings are on and I’m excited to get at it!

Wing/Fuselage Flashing

Time: 8 Hours

With the wings removed I can finish up the work on the holes drilled for the flashing that closes up the wing/fuselage gap. The holes were drilled with the wings in place but you don’t have enough access to finish the work that is required. All these holes will eventually have a acres in them to hold the flashing in place but allow easy removal for work. All of the holes will get a nutplate for a #8 screw. The flashing holes will be dimpled for flush screws so all the underlying skins on the wing will either be dimpled or countersunk depending on the area. The fuel tank edge can be dimpled as well as the bottom wing skin. The top has to be countersunk since it has three layers due to the extra wing walk material that beefs up the area to walk on. I started with the fuel tanks working on both wings. 

I used one winged nutplates for the two spots where the fuel tanks reach the wing spar. You could remove the fuel tank and have access to rivet a normal two winged nutplates. With the one winged nutplates I could rivet them without removing the tanks. Thanks again to Glenn for having his wings here so that I could eyeball them when I was scratching my head on how to rivet the normal ones. Once I had all the tank ones done I moved to the single nutplate that falls on the wing spar flange. I countersunk the rivet holes for the nutplate and grabbed my rivet gun and bucking bar and set those rivets. With the nutplate in position I countersunk the screw hole with a #30 bit. This bit head will fit inside the nutplate screw hole and keep it aligned. 

From here I worked my way up the bottom skins which just needed nutplate rivet holes drilled and dimpled as well as the #8 holes dimpled. 

All the holes on the top skin will be treated like the wing spar flange and had the nutplate riveted in place and the. The screw hole countersunk. 

With all these holes done I can put the wingtips back on and store the wings for later work, landing/taxi light wiring and install, and out of the way. 

During a break I ordered and ran to pick up a couple boxes of screws from McMaster Carr. I wanted to get some black 8-32 torx screws 1/2″ long for my instrument panel. I thought these would look cool vs the gold colored ones that I already had. 

I though these looked so cool I ordered a box of black 8-32 phillips flush screws for my armrests and side panels from MicroFasteners.com as they carry 100° head screws in black and stainless. 
 My girl and the kids got me a Aircraft Spruce gift card for Father’s Day so I used that yesterday and ordered the Dynon autopilot control head that sits next to the intercom on my panel. I wanted this now so that I could test my trim buttons on the grips as well as the trim motors like the one I just installed for the roll trim. That should be here by the weekend for me to install. Thanks T, Drake, Chandler, Ellie and Cody.