Panel Power

Most of my work these days is spent fiddling with individual wires here or there, so not a lot to take pictures of.  I do have what I think is the final shot of the area behind the panel though.  I had forgotten to pull the two wires for the defrost fans that live in the canopy frame.  I didn't feel like undoing a bunch of zip ties, so I just added them to the bundles and ran them to the center area of the panel.  I have to provide enough play that they can move around as the canopy is opened/closed.  Once I get the canopy back on, I'll put some protection over them.

I also ran the static air tube to the G5.  I put a T on it to take it to the alternate static switch first.  With the switch off, the static air is pulled from the ports at the rear of the plane.  If I ever need to (unlikely), flipping the switch up opens the valve at the back of the switch and allows cabin air to feed the G5 instead. Once I'm flying I'll have to document what the difference is between the two so I know what to expect in terms of changes in instrument indications with the different air sources.  The only time it would ever be used is if the static ports ice up or get clogged with something - again, unlikely since this plane is not one that I'll get anywhere near icing, and there is a port on each side of the plane, so clogging one doesn't necessarily mean a complete clog.

With all of that base wiring done, I decided it was finally time to flip the switch and bring the panel to life!  I still have to do all of the FWF sensor wiring, but want to at least make sure the rest of the wiring is correct before I get too deep into the rest of it.  When I first flipped the master switch....nothing.  Turns out it's important to actually connect the master relay wire to the relay itself.  Duh.  I had left that off until now, not wanting to accidentally let power through when I wasn't ready.  Once I remembered that and connected the relay, everything powered up right away and all of the smoke stayed in the wires!

So at least I know that all of the devices work.  Now the big hurdle is configuring them to actually talk to each other and read all of the sensors.  The big upside to the AFS setup vs Dynon is that it has a lot more serial port options to allow for more peripheral devices (5 per screen).  The downside is that those serial ports aren't all shared between screens, whereas with Dynon (which only has something like 5 ports total) shares all of the port data with both screens.  That means with Dynon, if you lose one screen, you still have control over all of your peripherals via the other screen.  With AFS, if you lose one screen, you lose the peripherals that are linked to that screen and not shared with the other screen.  It gets even more confusing, because that's just the serial ports.  With AFS, all of the devices that use the "skyview network" are shared between screens, regardless of which screen dies.  So that means you'll always have ADAHRS, com panel, autopilot panel, and engine data info on both screens, even if one screen dies (so basically, all of the "get me on the ground" info is available on both screens - plus also having the backup G5).  Risk mitigation with AFS is just about ensuring you configure the serial ports on each screen so that you have necessary controls on the other screen should one die.  For example, once I put in my IFR GPS and second radio, I will configure one screen to be connected to comm 1 and the Dynon GPS, and the other screen will connect to comm 2 and the IFR GPS.  That way if one screen dies, I still have a comm and GPS input coming through the other screen.  Likewise, if both screens were to die, then the G5 would still show all flight attitude info, and I could still use the radio control on the panel itself (vs controlling through the EFIS).  The only things I could potentially lose completely would be my transponder and ADSB, if that screen they are linked to went belly up.  Neither of those present a flight risk though.

All of that is a long winded way to say that my next step will be to sit in the plane for a few hours and configure each screen.  I'll have to take the install manual out on my ipad and just go page by page through it.  It's a lot of configuration!  Everything from entering in the tail number so it can generate the right ADSB code to entering in all of the flight envelope speeds, sensor types, and hundreds of preferences.  One thing I noticed is that I haven't been able to get a GPS signal in the garage.  I temporarily attached the GPS pucks on the plane, but at least with the garage closed, they haven't been able to connect.  I'll open the garage and see if that makes a difference.  I'll probably go ahead and connect the comm antenna as well (even though all of the antennas will have to come off when I paint), just because I don't want to accidentally hit the transmit button without an antenna attached.  That can blow the control module.

Wiring Never Ends

Most of the wire routing directly behind the panel is cleaned up now.  The only remaining connection to finish is the "front" airframe connector to the ACM.  I just need to pull the field wire from the alternator and pin it in that Dsub, then it'll be all set.

The area forward of the subpanel is getting close.  There are just a handful of random wires to run yet, then it will be as organized as it can be.  While it's not pretty because of the various wire lengths I had to deal with (lesson learned - the next plane will be better), it's all solidly mounted.

To do the rest of the firewall forward wire routing, I needed to get the scat tubing for the heater muff inlet in place.  I temporarily put the right aft baffle in place and got the scat tubing routed around the engine mount.  No matter what I did I couldn't keep the tubing from rubbing against the engine mount though.  I used a couple of adel clamps and put RTV between the tubing and engine mount to minimize chaffing. 

Routing the alternator power and field wire back to the firewall is a little awkward.  I made some steel standoffs and attached them to the engine using the oil sump bolts.  Then I attached the adel clamps to the standoffs.

I used the same approach on the other side of the engine for the starter power wire.

More Panel Wiring

There isn't much I can share that looks different in photos, but I'm continuing to truck through the panel wiring.  Even though I have most of the wiring sorted out now in terms of connections, the fiddly part is in figuring out the routing.  I'm trying my best to keep it as organized as possible.  I'm succeeding in some areas and failing miserably in others.  Except for a couple of remaining connections to the fuse block on the right side, most of the wiring behind the panel is in place and solidly supported.  The left side between the ACM and the PFD is incredibly tight, which makes clean routing next to impossible, but I think I've got it about as good as it can get given the space limitations.

The area forward of the subpanel is a different story.  I still have a lot of work to do there.  Part of the issue is a lesson learned from a year ago when I ran my wiring from the other areas of the plane.  Based on what people had said, I made sure to make the wire harnesses just a little longer than necessary to account for service loops behind the panel.  Knowing what I know now, I don't think I'd do that again.  For one, with modern electrical designs, nearly everything in the panel is easily removed just by unhooking Dsub connectors.  With a slider canopy where the back of the panel is only accessible after you've removed the glass screens, a few extra inches is all that's needed to unscrew them, then reach up and remove the connectors.  With a tipup canopy, I don't even have to do that!  All I have to do is open the tipup, and I have unrestricted access to everything.  So I think this "service loops for everything" idea is kind of antiquated at this point, depending on the aircraft design.  For me, the service loops are causing me nothing but grief.  I don't have any room immediately behind the panel to coil up all of the extra wire from my harness runs to other parts of the plane.  That means that I have to bundle up all of that extra wire in forward of the subpanel.  It creates quite the mess!  I'll be able to tidy it up once I sort through my engine systems wiring and all of wires that need to traverse this area to go to the aircraft ground, but in hindsight, I'd cut all of my harnesses shorter and just make them the right length to get to the panel.  Service loops that have to be forward of the subpanel means that if I ever need to remove or change a wire, I have no choice but to crawl under the panel and cut a bunch of zip ties to find my wire in the sea of loops.  It would be far easier not to have the loops to begin with and have no extra wire length in inaccessible areas.  Oh well, lesson learned.  There's no shortening things up at this stage, and it's fine.  It's just an assault to my senses and an extra pound to the plane.

Taming the Rat's Nest

It seemed like there was plenty of space behind the panel until I actually started filling it with wire harnesses today.  I don't think I quite grasped how full the ACM would be.  By the time I was finished plugging things in, it was so full I had a hard time even tightening the Dsub screws.  The downside of having harnesses from AFS is that they aren't the length I would have made myself.  So some fit perfectly, and others have enough extra that I have to make a tiny loop.

I used the panel stiffeners as a place to put adel clamps and run most of the wires from the right side of the panel to the ACM.  That bundle is going to be really close to where the canopy frame swings when closing and opening, but I think it should clear.  If I find it doesn't, I will rotate the adel clamps around and put the wires on the aft side.

I installed the headset jacks.  The lemo plug is the black one on the outside, and the standard 2 plug headset jacks are the silver ones.

Next up was the wiring for the Pmag switches.  I still need to clean up the routing of those wires, as well as run the wire for the master switch. 

Panel Assembly!

The day has finally come to put the panel together!  I'd love to be able to route all of the wires before anything is on the panel and there's a lot of space to work with, but it's too hard to know exactly where everything will set.  I screwed the panel to the longeron brackets and then screwed the audio panel tray in (screws/nuts). The tray for the backup battery and comm transceiver went in next.

The brackets for the audio panel tray stiffen the panel up quite a bit, but the top still has a considerable amount of give when pushing on it, like you would do when pushing the buttons on the radio or autopilot panels.  Since the panel is already painted, the last thing I want to do is put more screws through it, so I decided to make some stiffeners out of aluminum angle attached to the subpanel and the top reinforcement of the panel.  I countersunk the screws on top - the glare shield sits down flush on it when the canopy is closed.  This really stiffened up the panel, and as an added bonus it gives me more places to attach wires routed from one side of the panel to the other.  I had to cut off a big chunk of the angle of the stiffener on the right side to allow clearance for the Dsub that goes into the autopilot panel.  Not ideal, but also not really a big deal given that this isn't a part that will really handle much stress at all.

Then the fun part came that I've been waiting months for!  I put everything in place and locked it down with black button head screws.  I have to admit, it looks pretty cool!  It's especially cool to know that I did it all myself, whereas most people these days just pay a shop to make the panel, from cutting to labeling and wiring.  The only thing of note that I'm not sure about is the fit of the audio panel.  It was very tight going into the tray and is canted just a tiny bit, meaning I got the tray angled down just a little bit.  I know it can go in perfectly straight since it was when I first fit the panel.  I may pull the panel out tomorrow and loosen up all of the screws of the tray to see if I can tilt it back to level.

The remaining things to do are to install the headphone jacks (wired into the audio panel by AFS, so I couldn't put them in before installing the audio panel tray) and 3D print a cover to go where the future IFR GPS will go.  I also need to route the cabin heat control from the heater box up to the panel.

Once everything is in place, the space fills up pretty quick!  Routing wires is going to be interesting.

Exhaust Hangers & Panel Labeling

The exhaust tailpipes need to be supported with rigid, yet flexible, supports to allow the exhaust to move a little with engine vibration (especially on startup) without moving out of position enough to hit the cowl.  This is accomplished by clamping steel tubing to the exhaust and engine/mount and using high pressure rubber hose to tie the two pieces together.  The space in between the two steel tubes is only about 1/4", and the rubber hose spans that space and allows just a slight amount of movement.

The steel tubing that came with the exhaust kit wasn't long enough for my liking, so I got some of the same stainless steel on Amazon and made my own to the size I wanted.  The tubing is scuffed up, and a slight flare is made on the end to help keep the rubber hose from sliding around too much.

The vertical support goes from the tailpipe up to a bolt on the engine sump.  The horizontal support is a little different than what the plans show.  The plans show that you can tie the left and right exhaust to each other in the horizontal plane, but the new nose gear design with the elastomer doesn't have any space to allow a support to go from one tailpipe to the other.  I verified with other builders that the only real option is to go the opposite direction and tie the tailpipe to the engine mount.  That's not ideal because you're attaching a moving engine piece to a mount that doesn't move, but people say it actually works just fine.  These simple connections took hours to do between the two sides - those tailpipe clamps were far from easy to work with!  The setup is nice and rigid, but with a small amount of wiggle room.

The tailpipes take up lots of space and had to be permanently mounted before I could move on to other things.  With those done, I could put the scat tubing in place for the cabin heat box.  The other scat tube going to the inlet of the heat muff will go in a little later since it connects to the rear baffle that's not in place yet.

I switched gears a bit to see if I could salvage the paint job on my panel.  I wet sanded it and then used polish to try to flatten out the extremely uneven surface I had.  I didn't sand it completely flat in all places, mostly because I was afraid of cutting through the paint.  So it's far from perfect, but it's 1000x better than it was.  I definitely see the value of wet sanding!  It's kind of the secret tool of painting, like a grinder is to a welder.  I didn't polish the surface to a mirror finish because my plan is to spray a matte clear coat over it once the labels are on anyway.  The matte clear will also help hide some of the imperfections in the finish.  The gloss finish is what makes every little detail stand out.

I couldn't help but move right on to applying labels!  I had laid out all of my labels in a vector program and sent them off to be printed as dry rub transfers.  The benefit of spending the time getting all of the measurements correct in a vector program was that they could be printed in exact, true sizes.  That meant I could apply whole blocks of labels at one time vs having to do one word at a time and fight with getting them all straight.  The distortion in the photos make it look like some are crooked, but they're pretty straight for the most part.  Of course, I have to leave some imperfections so there's no doubt that I did the work myself vs farming it out!

The panel color isn't quite as dark as the photo makes it look, and the matte clear will lighten it up a little as well.  I'll spray the clear coat on tomorrow, then once that is dry I can get the panel back in the plane and start putting all of the instruments in!

Heat Muff & Panel Paint

I need to get the exhaust finished up so I can plan out all of the other wire and hose runs for the engine (the exhaust takes up a lot of space, so everything else needs to be planned around it).  I just made a wild guess and made 6 heat sinks to go inside the heat muff.  There is room for more if down the road I find that I still don't have enough heat, but I imagine this will be plenty.  

The heat muff doesn't leave many options for where to put it.  It's about as long as the straight length of pipe it goes on, so regardless of how it sets relative to the engine mount, it's basically going to set where it's going to set.  I'll have to snake the scat tube around the mount.

The weather cooperated today, so I primed and painted the panel and a few other random parts.  I think my HVLP gun has seen better days.  I got it on craigslist for cheap, and while it's a professional gun, the parts it was missing that I scrounged up pseudo fixes for are obviously not ideal.  I will definitely be buying a different gun for the exterior paint.  I think some of my issues with the Stewart Ekocrylic are because the gun can't set a decent fan.  It has leaks around the tip, no matter what I do, and the widest fan that I can get without really messing up the paint atomization is about 4".  That's compared to other HVLPs that can make fans 2-3x that size.  Because of the little fan, it's very difficult to get consistent coverage - easy to go from not enough paint to completely flooding it on.  The gun is fine for primer, but not so great with a finish paint.

It's yet to be seen how the panel turns out.  Since I'm going to spray a matte clear coat over it all once the labels are on, it may not matter how the surface finish looks, as long as it's consistent.

Misc Wiring & Exhaust

Doing some catch up documentation from the last few days of 10 minute here and there build sessions.

I can't remember if I mentioned before, but my 3D printed fan guards turned out very nice, but when I screwed them down onto the glare shield, they curled up around the screws because I had made them so thin.  3D printed guards are probably not a great solution since I want them to be low profile.  I think I'll probably end up getting them cut out of aluminum instead.  I'm just waiting to see if I have anything else I need cut before sending the design to sendcutsend.com.  I went ahead and spliced the fan wiring together so I could just run one pair of wires to the panel.  Once the panel is in place and the canopy back on, I'll figure out how to deal with the slack needed in the wires for the canopy opening/closing arc.

I hooked the fans up to my bench power to ensure they worked.  I'm glad I got the thicker fans.  They actually move a lot of air!

I had already finished up most of the switches in the panel, but there were still a couple of oddballs left to do - the Pmag and Master switches.  Neither of those go through the ACM.  The Pmag setup took a bit of head scratching.  The use of a three way switch for their OFF-ON-TEST functions is a little confusing to wire (mostly because unlike standard mags, the Pmags have a self powering function, which means they have to be able to be grounded in different ways to allow testing of both internal power and ship power scenarios).  One of the requirements of the Pmag is having either a 3A circuit breaker or fuse in the mix.  Usually a circuit breaker is used when a key switch is used for all of the runup testing, because then the interrupted power test can be done by pulling the breaker for each Pmag.  Since I'm using toggle switches, the circuit breakers ($$$) are not really all that necessary.  Pmag specifies that fuses can be used as long as they are the slow blow type, which allows for the potential initial startup surge.  I don't need access to the fuses in normal operations, so I put them on the subpanel above the ACM.

For my future self - these are the fuses I'm using:

I believe all of my panel wiring is in place at this point (but not routed nicely - that's for after I finally install the panel).  That means I can start creating a new rat's nest of wiring for all of the firewall forward connections.  I started pulling wires to/from the EMS module, as well as continuing with the main wiring of the alternator, starter, etc.  Still more to do there because part of cutting those big wires means figuring out their routing around the engine.  I'm getting there, just mulling it over before committing.

One thing I've procrastinated on is installing the tailpipes on the exhaust.  I was waiting on that because I needed to have an idea of where the lower cowl exhaust exit opening would set to ensure I had good clearance around the pipes.  The pipes have an angle in them, so spinning them in place means there's a huge range of where the ends can exit the engine compartment and what the clearance to the fuselage and cowl is.

After a lot of iterations, I got both tail pipes exiting in a fairly symmetrical way.  Perfect symmetry isn't possible because they both have a slightly different angle where they mate up to the rest of the exhaust.  The tail pipes get connected to their feeder exhaust pipes using a clamp that has a 1/4" pin welded on the inside of it that keeps the pipes from moving out of position.  I drilled a 1/4" hole through the pipes to accept that pin and clamped the pipes down.



The right tail pipe will be where the cabin heat muff is.  I need to get this in place next because the bulky scat tubing to and from it will dictate where I can route some of my wires.  The heat muff is just a thin cylinder that goes around the tail pipe, with fresh air feeding in one side and then going out the other end to the firewall cabin heat box.



One of the complaints about this design is that in cold regions it doesn't provide quite enough cabin heat.  Some people put a second muff on the other tail pipe, but I've seen those installs and it adds a ton of scat tubing to an already cramped area.  Instead I'm going with the increased surface area approach.  A common solution to increasing surface area is to stuff steel wool into the muff around the the pipe, but the complaint with that is that it decreases the volume of air that can get through to begin with.  I saw a builder who instead added stainless rings with fingers to the pipe.  He said it has worked really well, once he found the right number of rings to add on (he had too many at first and was cooked out of the cockpit).

A while back I drew up a design and sent them to sendcutsend to cut out.  The muff sets off center around the pipe, so my rings have to account for that.  One thing I didn't account for is a change in design of the muff from when I first saw it - it now connects the two end caps using steel rods that go inside the muff.  Those would get in the way of my rings, so I'll have to chop of some of the fingers to allow the rods to pass through.

My next step is to do some tweaking of my ring material (I didn't get my measurements perfect when designing them), bend them around the exhaust and bend the fingers up.  I think I'll start with 6 of the rings.  Those fingers should pull a lot of heat off of the tail pipe and still let the air pass through pretty easily...I think.