New EGT Probes

After I hit the 170 flight hour mark I started to see some fluctuations on my number one cylinder EGT(exhaust gas temperature) gage. It started with slow but ended up showing an extremely high temp them going to zero. This happened on two separate flights. On the second flight the number three cylinder started showing similar signs.

So off came the edging cowl to inspect the probes and their wiring. First I checked all the wires for any signs of chaffing or cuts. Then the connections to make sure they were tight and intact. Last thing I did was to remove the number one probe from the exhaust pipe and bingo there it was. So I removed the number three probe as well and it looked the same.

Here is what they looked like when I removed them:

Luckily we have a Aircraft Spruce location an hour away. I looked up the part numbers and they were in stock so I made a drive down there and picked up four new probes. Figured I would replace all four since I was at it. Good thing because the other two looked similar to the first two. l

This photo is of a new one and you can see how the probe is supposed to look. Not sure if this is a normal wear pattern for the Dynon probes but will do a little research

After replacing all four probes and a quick run up on the engine we are back in business and indications are all normal.

Uavionix AV-30

Time: 6 Hours

All along during my build I was planning on using a portable attitude indicator from Dynon Avionics called a D-3. This device is around 3” x 3” and 1” thick. It’s portable and powered by an internal battery. The purpose for this was to be a tie breaker. I have two Dynon screens each with their own computer that produces the attitude display. The computers can run either screen and provide redundancy. Say one of them failed and was only producing a picture of a climbing left turn for example with the airplane actually flying straight and level. The system is smart enough to say to the pilot that the two items, in this case the attitude, are showing different things. So you hit one button and both displays pop up side by side for you to examine which allows you to disable the faulty one. But how do you know which one is right? Well you could use several things to help you determine that…say the turning picture was the correct one you would expect to see the heading indication change as you turn. The altitude would change as well if you were in a climbing turn. Those items take the brain a bit of time to register and decipher what is going on. So to hep expedite the issue you can have a third independent system that you can use to compare. The D-3 was going to fill that job but at Sun N Fun I looked at the Uavionix AV-30 system and was real impressed. This is not a portable system and needs to be wired for power and have the airspeed tubing, pitot, attached. The instrument fits in a 3 1/8” hole and provides everything that the Dynon does all in a compact design. So I ordered one from Aircraft Spruce and started the process of how to run my limes.

First up was to determine the routing for the pitot line. I would run a T off of the line that comes from the left wing and run it forward along the center section through an existing hole and up through the right hand gear tower. This will provide the required airspeed indication. This would also require another line to run to the static line in the tailcone. The airspeed is displayed as the difference in static air pressure vs air pressure at the tip of the pitot tube under the left wing. As the airplane moves faster the pressure increases compared to the static pressure and indicates a faster airspeed. I didn’t want to run a line for the static all the way back so I will use the air pressure behind the instrument panel for the static source. This will likely cause a slight difference in indicated airspeed as that static pressure will differ from the aft tailcone one. Not a big deal and I might be able to adjust that in the system as a correction factor.

I printed a full size photo of the instrument to see how it will look. I will place it centered on the panel just below the 10” screen. It looks a little off as the instruments are all placers for how they look when powered on.

Once I had the pitot line roughly run and was sure I could get it from point A to B to my liking I started on the electrical. My my setup I’m going to run the power from the fuse block in my battery compartment rather than to the Vertical Power box. This will allow the AV-30 to run right of the battery, as long as the battery master is on, regardless of what’s happening to the Vertical Power system. The AV-30 only needs a power and ground input and optionally can add a audio output, a GPS input and outside air input. I’m only going with the power and ground as I’m only using this as a backup/emergency system. It uses shielded 22g wire that grounds the shield to the back shell of the connector. The back shell is also grounded to the airframe within 8”.

Now that the pitot line was run behind the panel and the electrical part run I started to hole cutting in the instrument panel. I removed all the connectors from the electronics behind the panel and removed the panel from the plane. I knew the fit would be tight so I measure several times to make sure I had it right. I borrowed the hole punch designed specifically for this procedure from my buddy Glenn. With all the measurements done I drilled a pilot hole with a 5/8” drill bit. This allows the centering bolt to go through the panel and allows the other half of the punch to be bolted on. I used a file to enlarge the 5/8” hole to get the punch to line up just perfect. Once satisfied with the position in tightened the nut a little which causes it to “bite” into the metal and securing it in position. I then secured the panel in the padded vise and slowly tightened the the bolt/nut until it punched through. This thing made a perfect and clean hole right where I wanted. Glenn also let me borrow the screw hole jig which you use after you punch the hole. It has ridges that sit inside the just punched hole and all you have to do is square up the jig and drill the four holes. I cleaned up the inside edge of the hole as the punch leaves a little burr. I scratched the paint a little so I decided I will sand it all and put a new coat of paint on it.

As the paint was drying I plugged the AV-30 in to test the electrical connections. I also plugged in the pitot line and did a syringe pressure test on the pitot tube to make sure there were no leaks and the I had airspeed indication. After the paint was dry I installed the avionics back into the panel. I put the panel back in its place and reconnected all of the cables.

I turned on the master switch and wow it looks great!

This instrument has a lot of options to configure and will make a great stand alone item or a backup to my main screens.

Now time to fly!

Canopy Lock

In the original plans Vans gives you the option to put a lock similar to the forward baggage door to secure the canopy. I just didn’t like the look of that lock and never installed it. One other option to secure the canopy is with a locking mechanism on the aft end of the canopy using the canopy rail. The gang over at has one that fit what I wanted. The idea is that you drill a small #28 hole in the rail at just the right spot. Then slide there lock mount along the rail going forward. There is a pin that screws up and down allowing it to slide into the hole you drilled and preventing it form sliding fore/aft. Then you can add a lock, which they provide, and lock the mechanism in place. I added a small piece of the soft half of a Velcro strip to pad the canopy from the new lock.

It works great and is easily removed and hidden away in my tool bag. I won’t need to use this very much but nice to have when I will be away from the RV for longer periods of time at unknown airports.

Canopy Crack

On our trip to Nebraska we landed in Shenandoah Iowa for fuel as we headed west. When I got out to fuel I found this:

I have an idea why this happened, when we loaded up in the morning it was still windy and cold at home. After we loaded up I slid the canopy closed loosely just to get the wind off us. When I needed to secure the canopy I just used the latch to pull it closed the rest of the way rather than sliding the canopy aft and sliding it forward with the normal force to get it to its closed position. So I think I added a little of side force on that corner and that plus the rivet hole caused the crack.

So I tried to stop drill it in Nebraska but the drill bit was too dull so I stopped. I figured I would take my chances on the trip home. I reached out to Vans with my game plan and they agreed it was the best plan of attack.

What I decided to do was to drill the hole using a coat hanger heated red hot and melt the hole. This was needed since the crack is right on top of the roll bar frame. After melting the hole I carefully sanded the edge of the hole to clean the edges. I then used my scratch repair liquids to remove the sanding marks and return the area back to clear. Once that was finished I made sure the crack was perfectly lined up and then used Weld-On #3 to weld the two parts of the crack together. Weld-On is an acrylic glue that actually welds the two parts together chemically. This glue is thinner than water and wicks itself into the crack.

After 24 hours I sanded the crack a little to make sure all the edges were nice and smooth and then polished it all up. Even with the crack repair you can still see it as a shadow. So I decided it was time to cover the forward edge of the canopy. This is a common practice to clean up the edge. Some paint it but I decided I would just cut a 3/4” strip of glossy black vinyl and use that to cover it.

You can still see a slight ripple where the crack was if you look just right but most will never see it. They always say it’s not if but when you canopy will crack. If this was “my” crack I will be very happy it happened where it did.

Oil Cooler Butterfly Valve

Time: 8 Hours

Now that I have 20+ hours on the engine it is apparent that I will need better control of my oil temps. Even with a good portion covered I was only able to get the temperature up to 185°. The manufacture of the oil cooler mount/shroud, has a butterfly valve kit now that will allow you to control how much air you want to go to the oil cooler from 100% to 5% based on their website. So I ordered that kit form them as well as a cable and knob from McFarlane Aviation.

I needed to remove the cooler shroud so I would have access to the baffle. The first step is to mount the outboard pivot block that the valve rod rotates in. I measured half way based on the baffle opening and marked where I needed to drill for the screws. Once one was drilled I could use the other hole as a drill guide.

Once the outboard block was screwed in place I could drill the 3/8” hole for the rod using the block as a drill guide.

I removed the outboard block and opened the 3/8” hole to a 9/16” hole for clearance.

That hole got cleaned up and I installed the block again and slid the rod through the block and hole in the baffle. This allows me to level the rod and place the inboard pivot block so I could drill its screw holes.

Once the rod and pivot blocks were in place I could start on the plate that will act as the shutter. The one that came with the kit wasn’t perfect for my opening so I sue it as a template for one I made out of .032 sheet I had. I used the screw holes as a starting point and made extra measurements to get the size I wanted. I decided to do a double bend of sorts to get the lower half to close as much of the opening as possible.

After I had the shape finalized I added a small piece of aluminum tube that they supplied and a couple of washers on either side of the outboard baffle wall where the rod goes through. These keep the valve centered in the opening and keep it from moving sideways.

The way the valve opens and rotates inward into the fiberglass shroud causes a problem with the inboard lower edge of the sheet hitting the shroud. So rather than trim the cover and loss some of it effectiveness in blocking airflow I decided to modify the shroud a little. I measured and trimmed the shroud so that it wouldn’t interfere with the valve. I then created a mold out of styrofoam covered in packing tape and laid up a couple layers of fiberglass to create a bump out. This will hopefully provide enough clearance for the valve to open freely.

While the fiberglass cured I started the work on where to put the cable and pull knob for the control of the shutter. I decided to put it between the cabin heat and the alternate air pull knobs.

Once I decided that location I worked on the route where the cable would run. The first thing was to work on the firewall pass through.

Once that was finished I ran the cable through the gear tower placing the washer and nut on as I thread it through. Then I used adel clamps to secure the cable as I ran it across the engine mount to the oil cooler. Once I had the cable secured I could measure and cut it to its final size. I adjusted the length so that I had the proper through from open to closed on the valve.

I adjusted the cockpit end so that the knob was lined up correctly and tighten the not to hold it securely. I bought the cable and knob from Mcfarlane Aviation and had the custom knob say “Oil Shutter, Pull On” in the clear anodized.

With the cable all run and it’s function tested all I needed to do was prime and paint the valve, finish the touch up work on the shroud for paint.

I cleaned up the valve and painted it with the same silver as the baffles. I finished up sanding the shroud and primed/painted it as well. Once the paint was dry I started putting all the parts back together. I cut a new piece of the rubber seal that goes on the lip of the shroud to seal it to the baffle as it needed to be slightly longer due to the change in the side I made to clear the valve as it opened.

Now all that’s left is to close everything up and test it in the cold Chicago weather!