I wrapped up the heater valve swap by reconnecting the SCAT tubing and control cable and then reinstalled all of the interior aluminum covers and seat pans. Before reinstalling the cowl, I checked the breather vacuum valve in case I needed to clean it. I’ve been checking this every oil change and it never seems to get worse than this.
Before reinstalling the interior, I needed to swap the ADS-B module. Dynon recently contacted me about swapping this because they apparently found a hardware defect and they want to replace all of the units in the field. Although I don’t relish removing all of the interior and baggage wall to get to this, I don’t mind since I really appreciate how proactive Dynon is about resolving issues like this.
The new unit is identical from the outside, so it’s a trivial swap (unlike when I swapped from the SV-ADSB-470 to the SV-ADSB-472).
I recently noticed that my cabin heat wasn’t working. After a quick inspection, I realized the control arm on the heater valve had broken off of the flapper valve. The valve is a stainless steel unit from Plane Innovations which I upgraded to because I wanted to keep all steel components on the firewall. I emailed the company about the best way to repair the valve and they rushed out a new one free of charge. I wish more companies had this kind of customer service.
Unfortunately, getting the old valve out requires pulling a substantial amount of the interior out. The heater valve is behind the tunnel cover which is under the fuel pump cover. The fuel pump cover sits under the forward seat pans, so the seats and carpets need to be removed.
My son helped me remove the nuts holding on the heater valve. This is one of the few items that regrettably I didn’t attach to the firewall with nutplates. It would have made replacing it far easier. Unfortunately, adding nutplates now is virtually impossible, so we just bolted the new one on the same way.
Here’s the failed heater valve. The spot welds simply failed due to the high vibration around the firewall. The new valve has five spot welds instead of four, but I’m not optimistic this will prevent this from happening again.
I wrapped up the condition inspection today. It was too dark to take it up for a test flight, so I’ll have to do that later. Other than the few things I mentioned, I didn’t find anything wrong.
Fortunately, I was able to pop off the extra glass and flox mixture I used for the gear leg fairing attachment.
I then fabricated and epoxied some 0.063″ aluminum strips onto the fairings. I curved the upper ends to follow the curvature of the gear legs.
I drilled some extra holes in the strips and then countersunk them so that the epoxy would flow through and help lock the strips to the fairings. After the glue cured, I sanded everything flush with the strips.
One of the fiberglass ears at the top of the gear leg fairings broke off on the left fairing.
The one on the right is cracked all the way through and is likely to break soon.
I had used electrical tape to hold the brake hose to the gear leg. This broke in most of the spots, so I took it all off. I didn’t get a picture of it, but I just wrapped the electrical tape around the gear leg and then used some zip ties to secure the brake hose.
I pulled the tailwheel fork off to clean and lubricate it. While it was off, I swapped the control arm with one that has a hole for a tie-down hook.
I cleaned out the coking that occurs in the check valve that dumps into the exhaust pipe. It was maybe 20-30% blocked and is easily scraped out.
Since I added the tee into the breather line to add an extra check valve as a safety measure, the hose clamp on the upper side of the tee was rubbing against the engine mount. I shortened the hose below the tee to get the hose clamp to clear the mount.
This allowed me to just use the adel clamps to secure the check valves to each other and to the hose. You can also see that I painted the place on the engine mount that was scratched.
One of the two welded brackets for the heat shield near the alternator also broke. I’ll have to order another one of these.
It’s been a long time since I updated the blog, and I’m trying to fix that. I have around 157 hours on the plane now and it’s time for its second condition inspection. I know it’s Valentine’s Day, but Jenn had a bunch of work to do today, so she joined me at the airport while I got started.
I started by draining the oil.
While the oil was draining, I inspected the engine and baffles. Surprisingly, one of the baffle attachment bolts on the #4 cylinder was missing. Fortunately, this didn’t seem to cause any problems (likely because the plenum keeps everything from moving).
One odd thing I noticed was that a couple of pieces of the chrome plating on the #2 cylinder’s intake valve pushrod cover flaked off. This is just cosmetic, but it’s peculiar that it happened and only happened in just this one little spot.
Dynon released version 12 of their software which adds auto-trim to their autopilot. To enable this, I needed to rewire the trim to go through the Dynon Autopilot Control Panel instead of through the Vertical Power VP-X. This entailed several hours of laying on my back under the panel rerouting wires.
The Autopilot Control Panel needed power and ground to run the trim servos. Fortunately, I still had a few extra power pins on the VP-X, so that was a quick addition. I then needed to reroute the four wires from the trim switch and the two pairs of wires to the pitch and roll trim motors. These eight wires all had d-sub pins or sockets, so I built a new harness that extended the wires from this point.
After finishing up the rewiring and upgrading the software, I ran the trim calibration routine and then flew Jenn to lunch in Half Moon Bay to test it out. The auto-trim worked great and kept the plane in trim the whole flight.
While taxiing in from a flight, I heard an odd clunk. I took off the cowling to do a careful inspection and found that both exhaust supports cracked all the way through right at the bend. Squeezing this tubing flat and then bending it clearly put too much stress in the metal.
The bottom of the support just has a flattened piece of stainless steel tubing bolted to a bent piece of mild steel. The mild steel is much tougher and can withstand the vibration without cracking.
I replicated this arrangement at the other end of the supports. Fortunately, it was a pretty quick fix and this should be much more durable.
The rubber on the lower right wing root fairing came loose and started banging into the bottom of the airplane in flight. I pulled of the fairings, and the rubber easily came off. It looks like the 3M weatherstrip adhesive I used didn’t work well.