« Posts tagged wiring

It’s on again.

December 29, 2011 / posted in Electrical, Fuselage / No Comments

12 hours.

That’s today and yesterday.   Shelley helped me rivet on the cover plates to patch the holes in the hull I drilled in search of better antenna locations.  There were 3, total.  One down in the tail, one under the baggage floor, and the original one just forward of the spar under the EFIS.   Since I had her in the plane, i was able to reinstall the transponder antenna properly; I’d taken it out to see if that hole might be a suitable location for the COMM antenna.   It wasn’t.   When we got that done, I went to work on putting the pax side floor back together.  Since I had access, I was able to wrap and secure all the cables going aft under the floor, and I can still access the antenna connection under the seat floor.  After that, I spent a lot of time with cable wrap, securing all the loose wiring running down the tailcone.  I took the advice of someone on VAF, who said something along the lines of “start at the tail and work your way forward, finishing everything you can possibly finish.”   Practical matters preclude me from absolutely finishing the tail section right now, but everything else got done and done.   I torqued down the autopilot pushrod bolts (been driving me crazy for a while), and secured all the wiring of the ELT and strobe pack.  The ELT wiring got secured with a length of shrink tube around the idiot DIN connection (phone cables and stereo connectors?  WTF, ACK Technologies?)  providing NMEA GPS info to the ELT.

Alphabet soup, I know.   We airplane people love our acronyms and abbreviations.

I still have one or two loose ends: I need a special platenut to completely finish the baggage floor, but that should be here tomorrow.

Today I started seeing the end of all the disassembling necessitated by having to wire the aircraft.  I got the flap actuator and flap motor put back in, but this time wired in properly with wires secured in the tunnel.  Lo and behold, I was also able to install the flap arm covers in the baggage compartment, something that hasn’t happened since the interior was painted.    I also cable-wrapped the cables running forward of the spar past the fuel lines and locked those down with cable stays, so nothing’s rubbing on anything.

I also began work on reintegrating the control system on the sticks.   A while back, before I knew what I was doing, I overstretched my trim springs and had to get new ones.   I’ve since gotten them, and was working on getting the sticks all back in order.   I had to paint the steel connectors for the springs, so that stopped while the paint is drying.  I started futzing around with the hard fuel lines on the floor, but didn’t really get anywhere.

Tomorrow I should be able to finish the sticks and see if I can’t get the fuel lines secured (they need a couple of Adel clamps to keep them from vibrating too much) and install the fuel pump permanently.

Antenna installed. Again.

December 23, 2011 / posted in Electrical, Panel / No Comments

5 hours.

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.

Music, ELT, ELT-GPS done.

December 22, 2011 / posted in Electrical, Fuselage, Panel / No Comments

6 hours.

I know there’s been a dearth of pictures lately, but there isn’t a whole lot to shoot.   Mostly I’ve been cleaning up wiring.   Today is a win, though.  The ELT has been a ratbastard since I first clicked ‘Add To Cart’ at ACS in March.  After the interminable wait, I was presented with the need to run a 4-pin phone cable along my central wire bundle.   A cheesy phone cable is not the first thing I’d pick to run the remote head of a potentially life-saving device, but it’s not my call, I didn’t design it.   This phone cable connects to an audio annunciator, and from that, another cable goes to the panel-mount remote control, which lets you fire off the ELT through blood-fogged vision if it hasn’t gone off from impact and you need help Right Now.   Today’s important lesson: Use the right tool for the job.  Well, no shit, but the thought of paying $40 for a tool I’d use on this project exactly once galled me, so I didn’t buy the phone line connector crimp tool.  I should have.  I spent a good while debugging why switching the ELT to ‘ARMED’ produced no beep.  First thing was that there was no battery in the audio module.  This required a CR2-type lithium battery, which the Radio Shack down the street had, thankfully.   The other thing was that without the crimp tool, the connector on the phone cable didn’t exactly work right.   No beep, no nothing.   I had already made one run to the Shack for the battery.  Now I had to make another.   But then I remembered I needed a 3.5mm mini plug extension so I could test the music input.   With products in hand, I went home and got back to it.  Sure enough, my crap connector job on the ELT cable was the problem, so with the connector installed properly and the battery in place, switching the ELT to ‘ARMED’ gave a satisfying beep.

Before I went my 10 rounds with the ELT, I’d soldered the 3.5mm snap-in CALRAD jack to the Music 1 cable, making sure to stress-relieve it with shrink tubing.   Once I had my 3.5mm cable, I was able to hear my iPod playing back Geomatic’s “Bliss” just fine.   Some adjustment may be necessary to increase the volume on the audio panel, but that shouldn’t be a big deal.   The level is also regulated properly by the audio panel.  When a radio transmission comes in, the music mutes, then comes back up after the transmission is completed.  The only thing that bums me out about the GMA340 is that I don’t have a music on/off switch, which means I’ll have to pull the plug if I want the music to just plain go away.   Fiddling with an iPod in flight is not a good idea.

So yeah, today’s a win.   Tomorrow, I need to think about mounting the comm antenna, running the comm wire, and putting my floor back together.  Then when all this avionics BS is done, I can put my flap actuation system and control arms back in.   Maybe even seats!   Then it’s on to the wonderful land of Firewall Forward, but not before a hellacious shop cleaning.

RDAC and Emergency Batt switch

December 21, 2011 / posted in Electrical, Panel / No Comments

3 hours.

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.

The hits just keep coming.

December 5, 2011 / posted in Panel / No Comments

4 hours.

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.

Another round of wiring.

November 28, 2011 / posted in Electrical, Panel / No Comments

5 hours.

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.

Really? Really?

November 25, 2011 / posted in Fuselage, Panel / No Comments

4 hours.

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.

Wiring 3.0

November 13, 2011 / posted in Electrical / No Comments

2 hours.

Yeah, I know, not much.   I got new wiring in for the backup instrument.   I’m trying to minimize my RCA connections, and an ugly Y-adapter to combine both the IO Extender and the sensor package is uncool.   I’ve started on removing the 15-foot rca cable from the sensors, and I hope to have that done today.   While I’m at it, I’ll try to rebundle the wires so they make sense:  data cables in a data cable bundle, power in a power bundle, etc.

This head cold I’ve been incubating hit me like a ton of bricks last night, so the next few updates may look like 19th-century absinthe-ramblings, but instead of absinthe it’ll be one of the various ‘Quils available.

And as an added bonus, i’m going to get the GPS<->ELT connection up and running.   Hopefully I can do this without setting off the ELT.  That would be, um, bad.

Wiring and wing conduit

January 30, 2011 / posted in Electrical, Fuselage, Wings / No Comments

4 hours.

I took a drive down to Earl’s on Hawthorne at the 405 freeway to pick up the fittings I need to plumb the purge line. I wanted to save the 11 bucks for shipping, which is ricockulous considering it’s all of 15 miles away from my house. I’m glad I went. The place is an absolute gold mine of high performance vehicle plumbing. They have everything, including the weird stuff, and best of all, they can custom-make hoses while you wait. Still a pricey run. The stainless steel bulkhead elbow for the firewall was not cheap by any stretch. After I got back, I pulled the wings out of the garage to finish up all the old business, which was fabbing conduit support angles, installing Adel clamps, fitting and plugging in the pitot tube, and wiring the autopilot roll servo. I also spent a good amount of time rubbing off old masking tape glue with MEK. Don’t leave masking tape on anything for too long, especially in a hot, dry place The tape turns brittle and the glue turns solid. On the right wing I got wise and heated up the old tape with a heat gun which let me get most of it off in one piece. The rest came off like the stickers Van’s still puts on every part, which never peel off cleanly. This process took a while and by then I was completely beat. I only got 4 hours of sleep last night for some reason, so I was a zombie all day. I figured I’d nap for an hour and go back too it, but I started reading the last chapter of William Gibson’s “Zero History” and I was asleep before the end of the first page. I woke up two hours later, still exhausted, but I went back out there and wired up the autopilot pitch servo.

Both autopilots got wired using the D-Sub method: Use barrel-crimp d-sub pins and sockets on the wires, then individually shrink-wrap them, then put a big shrink tube around all of them. I did this for a couple of reasons. First, the Molex connectors didn’t have a decent locking mechanism. I’m sure it’s fine, but I didn’t like it. Second, I somehow lost a couple of the pins. Embarrassing, but whatever, this should work fine.

I didn’t get around to plumbing my purge line, and common wisdom seems to be to wait until the engine is hung for this. But the longer I wait, the more stuff is going to be in my way when I do a triple-bypass on the fuel system, so I want to get the tubing roughed in as much as possible.

Heated Pitot done.

January 24, 2011 / posted in Electrical, Wings / No Comments

6 hours.

I finished up the pitot heat stuff, got the heat module mounted and the wires spliced in. When I get the Adel clamps from spruce, that process is done and done. It doesn’t sound like much, but it took some time. I had to use platenuts because I have to plan on an extremely limited amount of access once the skin is riveted on. And as an added bonus to my day, I found that some condensation or spray from the hose left some kind of deposits all over my left wing. This sucks. I might be able to buff it out, but it looks like the lime or whatever is etching the alclad. Flat Olive Drab paint it is.

I also got the MGL com extender mounted, and got a good start on mounting the IO extender, but the 6R8 screws I have are too short, so I need to get some longer screws from ACS. Always with ACS. I want to finish this plane so I can stop buying stuff from them for a while.

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