Tuesday, December 23, 2014

So I did not post trip reports

I really had the best of intentions when I last posted in May this year, to keep you folks updated on how nice it is to have a flying plane and why one would want to get one started (so they could eventually go to all these cool places we went to). But then I figured that I just did not have the time anymore to sort through all the photos taken and come up with a nice catchy story to bind it all together into a nice blog entry.
I just don't have Dave's inspiration (Schmetterling's Dave) and energy to keep this going on a detailed level... but, hey, this was meant to be a builder's blog anyway, right?

Well, then why am I posting now?

Hm, you might have guessed it if you followed me for a while. A bit more than a year ago I got my "pink slip" and that means that I needed to do an annual inspection of my RV in order to honor my operating limitations.

And so I started over Thanksgiving on this task to disassemble and inspect and to catch up with some SBs and stuff I wanted to change myself.

Taking the cowls off to perform the mandatory oil change (after just 50 hours since the last one at 25 hours) was somewhat revealing. I found that I had no problem with chafing wires but the modification for clearing the left forward exhaust spring was not deep enough. It still has a very slight contact it seems.

Not enough for me to consider another lay-up but I might ever so slightly Dremel it down if it persists.

Then there was a slight oil leak at the oil drain plug. Obviously the crush washer is very delicate in regards to its placement when tightening. It was just a few drops over the 50 hours but due to the vibration got tossed around quite a bit.

All the temp indicators showed that the ignition modules did not get too hot. I also added another indicator on the side of the rectifier/regulator to see if it runs too hot as others have reported quite some problems with the Ducati unit.

After the oil change it was time to put the plane on saw horses. Before that I had removed the wings and put them back in the cradle.

The wheels and brake assemblies came off and I found a slight mark that shoeed some contact between the brake disc and the spacer for the inner pad on the right brake.

I contacted Matco about it and they said not to worry about it if I can clearly determine that it does not make contact with the disc now - which it doesn't. I will keep an eye on this. The linings where pretty worn by-the-way and would not have lasted another 70 hours, so I replaced them.

I cleaned the bearings and repacked them and everything went back together and off the sawhorses. Before that I also retorqued the landing gears bolts which needed absolutely no attention whatsoever. They were in perfect shape.

On to the interior. I took off the floor covers and found absolutely nothing to worry about.

Besides some dust, the tail cone did reveal something though:

It looks like the plastic spacer that is supposed to keep the lower elevator cable from sawing through the bulkhead is worn down quite a bit. I measured about 3mm left and the cable makes no contact with the bulkhead yet. This is something I will keep a close eye on and I might have to replace that spacer some time soon.
The tension of the elevator cable was below spec at 20lbs and so I put that on the list to tighten when the seat pan was closed up.

Back to the engine. I replaced the K&N air filters which started to discolor already with a pair of blue ones from Simota USA. They cannot be worse than the K&Ns and they are a bit shorter too, which gives a tad more room to work with under the hood.

I also had to replace my extra RPM resistor as it had started to show erratic readings again. Its behavior indicated that the crimp was probably loosening and removing it confirmed that suspicion. I replaced it with another crimped installation but I might have to additionally solder the connection or install a wired version to overcome these issues.

Next was some electrical work on the left side, enhancing the headset wiring with a LEMO connector for my Bose headset to get the power from the onboard electrical system.
The cutout for the plug reminded me of a delicate surgery performed with a Dremel tool.

Thanks to Van's we have a power wire in the correct location that just ends dead as the standard plugs do not provide power to a headset. But Van's knew what builders would eventually like to add down the road.

It took a while to get it all separated and then soldered back together without messing anything up. Here you see the wired in LEMO harness all hooked up except for the red power wire.

And then all installed in the fuselage.

It all worked like a charm, with a regular headset or a LEMO plugged in. Noticeable is that the headset power comes on with the Main switch, so the LEMO is powered as soon as you power up the system without needing another switch like the Avionics system or anything.

It was a full weekend worth of work but definitely worth the extra effort.

Then I repaired some things with my backup avionics. The Chinese altimeter had given up about 6 weeks after starting flying. Like so many others had reported before (I just couldn't believe it could be THAT bad) the thing never showed the right altitude after it went bad. The Kohlman dial did not seem to have much of an effect anymore and it was practically useless.
Also my German ASI had come back from repair (my fault when running the leak tests on static and Pitot systems) and I wanted to put it back in the panel again.

Opening the avionics bay revealed .... nothing. Everything looked just like I had left it there.

Out came the crappy altimeter and in the one built by United (yellow-tagged) and in with the ASI as well.

The German plugs are a bit too undersized to use 1/4" ID tube and get a good seal. I tried RTV before with success but this time I did not succeed with it. No big deal, I just used shrink tubing to make them a tad bigger.

Please note that the plumbing in the picture above is actually glued to the glove box using spots of RTV so it cannot move around or vibrate.
The disconnected breaker and the still covered slot above the ASI is for a PCAS unit which I chose not to install yet. I might do that the next time I have the bay open. 

Before closing the avionics bay again I complied with SB 13-12-12 and sealed the avionics bay. Instead of using the awkward suggested method described in the bulletin and smear RTV on the inside of the joint after removing the Dynon from the panel, I used a thin compressible sealant strip behind the row of nutplates to accomplish the same goal which is to keep water from entering the avionics bay.

You can get this wonderful sealing strip in 3/16" width from Aircraft Door Seals in Texas. The product is called VWS 100. I also had a VWS 150 which is 1/4" wide as I did not know back then which size would work best. I used the VWS 150 under the canopy skirt to seal off the minor gap between the skirt and the avionics bay cover to keep water and air out. Sorry no picture from that installation yet.

Next, I closed up the seat pan and went on to tighten the elevator cables. Make sure you have the safety clips for the turnbuckles handy when you cut them open.

I tightened the upper cable as this was the one most loose and it also had the most threads showing out of the turnbuckle.

On to the last two items on my list. I wanted to inspect the gascolator screen and thought it to be  a good occasion to drain the rest of the gas out of the tank to allow for the Dynon tank calibration that I had never done. The Moeller gauge is so easy and reliable that I never felt I needed the Dynon gas level information anyway.

It was also a good catch-up on my still existing gas pressure drop issue when cruising with less than 8 gallons of gas.

With the gascolator bowl removed draining the tank through the gascolator is easy. The pump makes it super fast, so watch the level in the canister!

As you can see above, the pressure drop is a clear mystery to me. This flow is taken at around 2-3 gallons left and the pump on.

There was a bit of debris caught in the screen, a bit of fluff that looked like Scotchbrite fibers but the rest was mainly excess lubricant from the O-ring. As the stuff is fuel resistant, it doesn't wash through the screen. I thought about cleaning the screen but they cost $2.50 at Van's and so I just replaced it.
I also had to replace the O-ring as its inner diameter had extended to match the outer diameter of a new one and would have hardly fit back in. This is the result of ethanol in the gas I am using for the Rotax.

And then on to the final task - installing the turtledeck brace that was added to Section 42C. By itself a very simple task but pushed at the edge of being impossible by the inaccessibility of the tailcone without removing the tank. My aft bulkhead modification allows for easy access only to check the cable tension or maintenance on the ADAHRS and its connections but not really for crawling into the cone while on your back.
Of course, that was exactly what I had to do - and then some.

It was insanely difficult to balance on your side while having only one hand to work on a part that needs to be affixed for match drilling as it only has one cleco point in the beginning.

I eventually succeeded but not without major bodily pains that lasted for two days to remind me to never do that again.

And after an hour of sloshing fuel around (I did mention before how much I enjoy that, right?) I also completed the gas tank calibration task that was part of the PAP.

One thing I found that is not yet resolved. Just when I was closing up the aft bulkhead to go for the maintenance flight I found a hole that looked like a #30 size (years of riveting engrained this particular hole size in my cognitive/perceptive cortex).
A hole that might need a rivet but there was clearly no rivet in place - whence the hole.

You found it? It's on the right side of the angle the tank attaches to. Now clearly this would have to get riveted in from the aft of the bulkhead and I had already put most of the screws in. Knowing that one missing rivet would not cause me to crash and burn I decided to look this up the plans and put it on the list for the next annual inspection.

And here she was after the successful maintenance flight. The RPM was again rock solid after replacing the previous resistor with a freshly crimped one. This time around I only had a 41k Ohms available instead of the 47k I had used before, and it did not seem to matter.

This work was done over more than 3 weeks, with all weekends spent at the hangar and some late afternoons and holidays as well.

Saturday, May 3, 2014

RPM Is Stable Now

The 47kOhms resistor did the trick. No more fluctuations, not even during initial climb out. This has been verified today during 3 hours of flying from AVQ to PAN, from PAN to FFZ and back to AVQ. Payson was beautiful and the restaurant has nice food for around what I pay for a gallon of AvGas at Falcon Field.

Now let's plan for a few days in Sedona!

Friday, May 2, 2014

Cowl Painting Done ... For Now

I completed the paint job this week. As a matter of fact I am having my car sit outside with the painted pieces inside waiting to go to the hangar to install them as I am typing this.
Why am I saying "for now" in the title then?

That is because a few things went wrong and now I know how to do it better - much better, actually - but I do not want to ground the plane for another 2 or 3 weeks to fix it right now.

The oil change is complete, I swapped the RPM line resistor and she's grounded for too long already.

So what went wrong with the paint job?

I used Floetrol at around 10-12% and some additional water of around 10-15% but the paint was still a bit thick for spraying. I went with it because I was more afraid of seeing the paint run off the many vertical areas and creating runs that would have needed sanding.
The way the paint dried with that thick coating was somewhat bubbly which created an orange peel effect even though I threw the last coat on thick and wet. The only way to remove the peel is to sand it down to an evenly dull finish and then build the paint back up with a watery consistency and thin wet coats.
I tried this on the spinner as that is the only small piece that has vertical surfaces and so it was easy for a quick test (and it would have been easy to fix had I created runs). I sanded it lightly with 400 grit wet, not enough to completely remove the peel but enough to reduce it drastically.
Then I used isopropylic alcohol (70% ) and some water to dilute the paint enough to really get down to a watery consistency. I was very aggressive with diluting it this time as I wanted to see if this worked or not.
I sprayed it on and I was able to create a very smooth and even coat in no time. The coat dried very quickly and the result is encouraging. The finish is a lot smoother than before, only disturbed by the peel effect that had not been completely removed.

So what would have to happen to get the even glossy finish that I wanted for the rest of the cowl is to sand it down to a smooth surface and then use heavily diluted paint to build it back up in 2 to 3 thin coats. I will likely do this but not right now. I left the paint surfaces as is and won't apply any wax or anything that could later be a problem when sanding down and repainting. For now I will fly this as is and at the next oil change, I will take a stab at this again. It will likely be winter at that time and the lower temperatures could help extending the drying time and create an even smoother surface than what I saw with the test on the spinner.

I got to the hangar and installed the cowl again. What was proven immediately is that the paint is too soft. I hope it will dry eventually and get a harder surface as it is very tender at this time.

Tomorrow morning we'll go flying!