Friday I got the static/transponder test done and that’s now in the logbook. That took a bit, because I had to chase down some leaks. And, somehow, I managed to snap off the hose barb that connects to the EFIS’s AOA pressure sensor. That really, really sucks. Now, once again, I have to dismount the EFIS and take it to MGL to have the AOA sensor replaced. Can’t fix the barb. The good news is that the AOA isn’t really necessary for first flight. Also, my combination AOA/Pitot doesn’t lend itself well to the usual testing method of slipping a hose over the end of the pitot and hooking it up to the test machine. But we worked around it by connecting the test line to the fitting where it connects to the pitot tube, so I’m going to assume it works. We’ll find out.
Static tests eventually worked out OK, and we were able to calibrate using the EFIS’s setup menus. All good! Signed off, sticker in the airframe logbook.
Today was about picking up the pieces and extracting the EFIS backup battery for replacement. I think it got run down too far too often and now it won’t take a charge and tops out at 6v. To do that, I had to relocate the IO Extender module to someplace that would allow me to get to the screw securing the backup battery in its bracket. When I had to move the IOX before to get it out of the way of the canopy, I’d put it on the end of a piece of angle behind the EFIS. This solution was kind of half-assed, and I never actually felt good about it, so this is actually an improvement: I put it on top of the throttle quadrant bracket, up out of the way of everything. I’ll have to dismount the transponder to make changes to the wiring, but that’s OK, it shouldn’t be necessary to change the wiring much. It’s much more elegant, and gives me plenty of room behind the EFIS to do what I need to do, plus it’s more secure.
I did have to extend the power and ground wires for the IOX, but I was able to use the trim position wires as-is. It also enabled a much neater wiring bundle instead of the slightly messy arrangement I had previously.
I spent a little bit of time installing a little air conditioner in the window, the one we’d previously taken out of the guest house bedroom and put in the dining room window while Shelley makes a wedding dress for a friend of ours.
Putting it in the shop window was brilliant… Nice and cool and comfy, in what passes for a heat wave here near the L.A. beaches.
Once that was done I worked on the alternate air for the snorkel. They have you glopping up the interface between the galvanized steel opening hardware and the fiberglass snorkel with a mix of flox and resin. I guess this makes sense, but it seems kind of half-assed. Once that cures, I can sand it smooth and call it done. The snorkel won’t be done-done until I get the air filter opening pro-sealed in, but then it’s another thing I don’t have to worry about again.
With the goop on the snorkel setting up, I wanted an easy win, so I worked on the cabin heat cable. The plans for this thing aren’t real clear about how you’re supposed to route the cable through the cabin, but I worked it out. The knob sits to the right of the throttle quadrant, so the passenger can easily get at it. I also wanted to do this so I’d have an inkling of what I’d be looking at when installing the alt air cable, which is another Bowden-type cable like the cabin heat. This type of cable is similar to a bicycle brake cable, or if you’re old enough to remember, a choke cable.
Mostly a non-issue. Cabin heat door opens and closes with push-pull. Sounds done to me.
Sweet FA got done over the weekend (New Years, hangover, etc, etc.), but today I finished wrapping and securing various wires, as well as rerouting the starter ground in a bundle instead of floating around all by its lonesome.
Only two things left to do, really, and that’s to install the OAT probe and reconnect the IOX when it comes back from MGL in a couple of weeks. For now, i’m not sure whether or not to start the baffling or the FWF sensor wiring.
The COMM antenna is installed. I finally wound up routing it along the longeron and down through the center section channel, then back to about where the seat floor panels join. I was able to keep it from running alongside any wires for very long, but there’s some contact where it has to pass through the spar. I swear, running wires fore to aft in that thing is a pain.
I got the antenna installed in a good spot, it’s more than 2 feet away from anything interesting, but I need to test it with my ghetto ground plane strips, since it won’t have a proper ground plane until the wings are on. Even so, I can hear SMO traffic and with the squelch off, a little bit of ATIS. Pressing the transmit button causes some sensor weirdness, but I imagine that will go away with all the dangling wing wires connected and once the plane is outdoors and not surrounded by metal shop equipment and other various RF-bouncy things.
So next is to finish cleaning up the strobe cables running aft (since I can get to them with the floor panels off), then put my floors back together. Then the flap actuator and the control arms, fuel pump, etc, etc.
Just got back from a 2-week work trip, so I needed a little downtime. Today I got back into it and wired in the EFIS backup battery switch. This was wired before, but it was crap, so I redid it. I also wired the RDAC ground to the engine block, like it says to in the manual. Apparently wiring it to the secured supply on the EFIS is not correct. I also got started on wiring the music input. Took me a second (and the brave sacrifice of a 1/8″ splitter) to figure out which was Tip/Ring/Sleeve, but all that remains there is to drill a hole in the panel, solder the wires on, and snap it in.
I got the EFIS back from MGL on Saturday, with a new display board and the latest software update. I installed it, with a few changes to the panel: I added a power switch for the EFIS and I finally got around to wiring up an alternator warning LED. I have no idea if it works or not, but it’s one less unterminated wire floating around. Everything works fine, with one weird exception: With the IOX plugged into the second LAN port, I lose sensor data after about 3 minutes of operation. Needless to say, this is unacceptable.
First, a little background. The IOX is the IO eXtender, a box that takes a bunch of analog and digital inputs and feeds them to the EFIS. These are used to drive things like a CDI, or in my case, trim position indicators. The RAC trim servo has an output wire that gives you trim position based on potential to ground. This works OK, as long as the radio, the audio panel, and the transponder are off. If any of those are turned on, the sensor data from the AHRS and magnetometer go away after a while. It truly is one of the weirdest things I’ve ever seen. The only thing I can think of is that the secured supply output on the back of the EFIS doesn’t have enough juice to run both the sensors, the RDAC (engine sensor module), and the IOX all at once. Acccording to the docs, all those things shouldn’t add up to more than half an amp, wich is the max output of the secured supply.
When I get back from Seattle, (Redmond, actually), I’ll try connecting the IOX to bus power and see if the issue goes away. I really hope so. This is really driving me nuts, and I can’t have my flight data interrupted, ever.
Another issue I’ve got is that my altitude-encoding transponder seems to be reading data from the EFIS, but it’s totally wrong: There is no way pressure altitude can be -200 after I change the pressure setting on the EFIS to show a reading of 3500ft MSL.
In spite of the fact that the EFIS is still in the shop, I was able to produce actual panel work today. Today was the cleanup of the rat’s nest behind the subpanel. I bundled the wires, organized the loose ends, and finally permanently wired the pilot PTT wire. Not only that, I ran and wired the copilot headset and mic, and connected the remote ident wire for the transponder, and it works on both stick grips. A good day.
I picked up another LED and microswitch, with the intention of actually wiring up EFIS power to the switch so I can power cycle it in flight if necessary. Not doing so initially was stupid on my part, but since the thing is in the shop, it’s not that big a deal. The LED is for the alternator warning circuit. Supposedly if the alternator goes funny, it sends 12v to something to let you know.
I didn’t get a chance to wire the ELT GPS power, that’ll have to wait for another day, but it’s a gimme. Should take no time at all. I have exactly two terminals left, and they’re both spoken for, so I want to have the EFIS back in so I can get the wire length right before I crimp a terminal on there.
Of course, without the EFIS howling into the radio spectrum, I can hear SMO ATIS, which is kind of neat. Hopefully this week I can complete the leftover tasks, because a week from today, I go up to Seattle for two weeks for work.
This is actually from last sunday, but this is the first chance I’ve had to actually write it down. Happy Thanksgiving, everyone. I give thanks for… The fact that MGL Avionics is being unbelievably awesome about fixing my EFIS. Again.
I finished the connections for the SP2 and SP4, wired everything up, and started cleaning up the mess behind the EFIS. I got everything wired in and properly arranged and the whole thing went south in a big hurry.
Over the last couple of weeks, I noticed a bit of flickering across the EFIS display, and sometimes the unit would crash, with the White Screen of Death. This is usually solved by power-cycling the unit. Not today. Today the WSOD came on and stayed on. So rather than a complete and utter freakout, I just resigned myself to sending the EFIS back to MGL for any necessary repairs. There’s still plenty to do.
Most of them, anyway. Turns out I need a couple of different switches. I need a dual-pole on/off switch for the battery master, because I’m deleting the alternator field enable. The idea with the alternator field enable is that if for some reason your alternator goes blooey and starts up with runaway voltage, you can shut off the field before it zaps all your goodies. This is a throwback to the days when alternators sucked, some time in the early sixties, and the chances of you interrupting the field before your fancy MFD’s and other computerized avionics surge out are next to nil. Modern alternators are usually pretty bulletproof, unless you switch the field on and off while it’s spinning. Doing that can reduce the life of the alternator from thousands of hours to hundreds, so the battery master is going to be a DPST switch that engages the battery master and the alt field simultaneously. I had to order another couple of switches from B and C also: the one from Van’s sucks. It has no keyway or tabbed anti-rotation ring, and it doesn’t even have a hex nut on the panel side. So I ordered a DPDT switch for the flaps. I also brain-farted on my initial layout, and forgot the heated pitot switch. Ran the circuit for it, allotted amperage for it, forgot to put it on the panel. So I needed another SPST on/off switch for that, because the one I had originally for the pitot heat was repurposed for the pax enable switch.
Yesterday was a bit of a milestone. I installed the firewall grounding plate, which is a brass plate with a bunch of fast-on tabs on one side. The other side is in contact with the firewall, and a big 5/16 brass bolt goes through the firewall, where it becomes the attach point for the negative battery cable and the braided strap that connects to the engine block. With this in place, I ran the wires for the master battery switch. For the first time, I connected the positive power lead to the battery. When the battery master switch was turned on, there was a satisfying >clunk< from the firewall, which meant that the master contactor was working. I checked the main and endurance busses and read 12.5 volts on the multimeter. I didn't hook up the starter switches. I'm still puzzling out wiring runs, But I'll get to that soon enough.
Redesign of the panel based on some thinking and some comments and suggestions from VAF. Notable changes: Master and alt bus feed are now to the right of the EFIS, putting all the DC power stuff there, safely out of the way of casual bumping. The second is the addition of a start button, eschewing the spring-loaded dual-pole ignition switches in favor of dual-pole on-on switches per the Aeroelectric Connection. The start button will actually be on the Infinity stick grip, but if that wire snaps somehow, I want a way to start the plane. Another significant feature is the addition of the Pax Enable switch, which disables the buttons on the passenger side stick grip and also safeties the connector when the stick is disconnected. There’s no starter enable switch because there’s very little chance of me bumping the starter button in flight. It takes an actual effort to depress the Infinity switches, so I don’t think the risk of accidental starter engagement is enough to merit the complexity of another switch. I guess I could wire an off-on-(momentary on) toggle in place of the start button that would serve the same function, but it puts an extra step in the checklist (disable start) that I don’t think is necessary. Also, in case of an engine out, I want as few things between me and the starter as possible. Phones and Mic have been moved to the lowest point possible on the panel, but i’m not going to put them in the armrest. Eventually I’d like to get the Classic Aero interior, which would cover up any accessible jacks in the armrest. There will also be a wet compass mounted on the glareshield or in the panel, I haven’t decided. Ideally, I’d keep that million dollar view free of obstruction , but I’m concerned about interference from wiring. Also, the buttons have been moved to the top, so that nothing gets shut off or bumped during turbulence, and the transponder has been moved to the bottom of the stack.
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