Matt's RV-7 Project

I've just been adding one wire after another, making a little progress with every work session. This is one of the two big connectors on the GSU 73, specifically the one that includes most of the engine/airframe analog and frequency inputs. Man, these high-density connectors can be tricky to deal with. The bundle of short wires pointing to the right is a collection of pigtails for all the shielded wires, which will eventually be affixed to the connector backshell. Just visible coming out of the D-sub connector is the harness for the config module, which is a little EEPROM device that backs up important calibration settings.

I keep checking little wiring jobs off my to-do list… here's the magneto P-lead. The magneto switch is upside-down, since closing the switch equals "no spark".

Here's the power and oil pressure connections to the Hobbs meter. I know I don't really need a mechanical hourmeter since I have all this fancy electronic stuff to keep track of the airframe time for me, but I feel better having something that absolutely cannot lose time; I had a bad experience with another vendor's EIS product once upon a time.

Forward of the firewall, the wiring for the engine sensors is just coiled up, since I have to finish the cowl and baffling before I can hook things up for good.

More splicing, crimping, soldering, et cetera. This photo shows the wiring for the tach sender and fuel flow transducer:

I also finally got around to uploading a new copy of my electrical system schematic:

Finally, a warm weekend! After taking care of yard work and bills and house maintenance, I still had an entire afternoon to spend in the garage. I did a bunch of cleaning and straightening up, and then finished the last of the wires that runs to the lower connector on the GSU 73 ADC/AHRS/EIS unit. The upper connector is for all the various engine sensor inputs, which I'll begin hooking up soon enough.

Some of these connections need to be spliced six ways to sunday, and you have no choice but to do it right there on the airplane. A helping hand tool is indeed quite helpful for this. Note the heavy heatshrink on the jaws to protect the wires.

Good grief, has it been a month since I updated this thing? I've been trying to work on the airplane a little bit here and there, but between holiday travel, work projects, and cold weather, things have been pretty slow in the airplane factory.

I have, however, managed to get the previously installed antennas on top of the fuselage all wired up. Four lengths of RG-400 coax run down from the panel, through the spar, and back under the floorboards. They penetrate the F-706 baggage bulkhead via snap bushings, then run back and up the F-707 bulkhead protected inside plastic conduit.

I drilled small holes in the J-stringers so I could attach the conduit with tie wraps. On the left side of the fuselage, I used a piece of rubber tubing and some tie wraps to prevent the conduit from chafing on the static line.

The conduits run up either side of the F-707 bulkhead – more small holes and tie wraps – and then the coax emerges to connect to the antennas.

Two wires go forward to connect to the WAAS GPS antennas – one for each GNS 430W. I riveted little tabs of scrap aluminum to the lower flange of the F-787 stiffener, so I could secure the wires with adel clamps. Meanwhile, two more runs of coax go through grommets in the bulkhead and connect to the combo GPS/XM antenna that's just aft of F-707.

Here's another view, looking up from [my very uncomfortable position on] the floor. In this picture, the nose of the airplane is to the left.

Up at the forward end, the primary display unit gets a GPS connection, and the multi-function display gets an XM antenna hookup. Each 430W gets a GPS antenna connection too, although I forgot to take a picture of that.

Not surprisingly, the G3X GPS receiver can get a fix even inside my garage with the doors closed. With a good antenna and a strong receiver, you can't lose.

This doesn't look like much, but it took two days' worth of crawling in and out of the airplane to finish.

I already mounted the dimmers for my cockpit map lights, but I didn't get around to wiring them until today. So here's what one of the LED map lights looks like:

I discovered that the inside diameter of the mounting base is exactly the same size as a cleco, which is really handy for drilling the mounting holes.

I dug the rollbar out of storage, clecoed it to the fuselage, marked and drilled pilot holes for map lights, and clecoed a light mounting base to each of the trangular gussets.

I match drilled the three mounting holes to the rollbar, then enlarged the center hole to 1/4" and drilled the mounting holes for miniature nutplates. I'll rivet these to the rollbar gusset once it's been re-powder-coated.

I like this location… it's out of the way and not likely to get broken off by passengers' feet, but still in a good location to be useful for reading a chart or for illuminating dark corners of the cockpit.

I used a very small grommet to pass the wires through the rollbar gusset:

The dimmer modules came with some miniature potentiometers. I soldered leads to the terminals:

…then used heatshrink over the joints:

…and finally put a piece of bigger heatshrink over the entire component, which should help prevent the wires from breaking off.

I drilled holes in the F-721 canopy decks to mount the dimmer pots:

I used some anodized aluminum knobs that match the ones I used for the panel light dimmer knobs. Eventually I'll make little placards to identify the function of the knobs, which will have the added side effect of covering up the holes for the anti-rotation tabs.

I finished up the wiring for the little dimmer modules and closed up the connectors. The power and ground wires that go to the lights themselves are not connected permanently yet, since I need to do a little further work to route them properly.

However, I did hook up each lamp with alligator clips just to make sure everything was wired correctly. Yup, seems to work:

I have something special in mind for making the connection between the lamps and dimmers, but it's not ready to show off just yet.