« Archives in December, 2011

Another productive day.

4 hours.

Bunch of stuff happened today.  Shelley helped me get the fuel lines secured with Adel clamps, and I got the fuel pump reinstalled and wired up.  It works!   I also got the tunnel cover finished, but didn’t get to setting up the cabin heat cable.    The throttle quadrant also went back in.   It’s nice to finally see the ‘damage’ from the avionics install and wiring fiasco put right and parts that were languishing on shelves put back on the airplane.

There is no end to wiring.   I cable-wrapped the antenna  wires and worked on the GS/NAV splitter mounting.  Fortunately, there were two holes ready made for it (not really, they just coincidentally lined up).   But I stopped dead in my tracks when my cable stripper exploded.   I need a new one from Radio Shack ASAP.   But once that’s done, the avionics wiring is just about done.   Finished.  Fin.  The end.

Still have to figure out how to connect the marker beacon antenna.   It comes out of the audio panel as a single shielded wire, but it has to connect to a big, fat length of RG400.   How the hell do I do that?

It’s on again.

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.

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.

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

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.

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.