Dave’s RV-7A Building Log

Still suffering from a cold, but did a bit of work on the plane between naps. I finished hooking up the power and ground for the flaps. I need to figure out wire routing inside the flap housing before I can finish that end of it.

The only thing left to hook up on the transponder was the antenna. I only needed to crimp on a BNC connector as I ran the wire quite a while ago. I powered it up and made sure it was in standby mode. I certainly don’t want it to start pinging, especially without altitude info. I live under Sea-Tac’s class B airspace and within class D airspace for Renton. I went through the set up menus and changed a few minor things. It seems to be working correctly.

I also pondered a bit on how to hook up the landing light switch. I wanted it to be a 3-position switch, off/flash/both. However, I can’t figure out any way to make that work. The wiring diagram for the CreativAir flasher shows a 3-position switch, flash/off/both. I’ll have to do that, but will need to order a 2-1 switch from B&C. I need to place another order with them eventually, as I’m sure I’ll need more coax and probably 14g wire to run out to the landing lights in the wings.

While I was on CreativAir’s web site, I noticed they’re working on some new wing tip HID lights. Oh, that’s tempting. I’ve never been crazy about making the big holes in the leading edges for the Duckworks, but wasn’t sure the regular wing tip lights provided enough illumination. The new lights are expensive, but look pretty cool.

Despite not feeling well from a cold, I had quite a bit of time for the project tonight. I finished up some wiring under the seats, hooking up the pilot push-to-talk button on the stick. I also fixed two of the trim relay connectors. Tested both, and they are working great.

I’m working on the switches from left to right, so the next two were the pitot tube and autopilot. I hooked up power and ground for both. I don’t have the roll servo installed yet (wings not mounted yet), but I plugged it in just to make sure it’s moving correctly. I powered up the autopilot, checked the settings, and engaged it. It worked! I tested changing the direction left and right. The roll servo was moving in the opposite direction, so I swapped the two wires. Next I engaged the altitude and pushed down on the tail. Sure enough, it tried to push the stick forward a tiny bit. Perfect!!

Julie took Adele to her first clarinet band session, so I had some extra time. I started working on the flaps. I installed the motor that I fitted so many months ago. It’s amazing how one stupid washer can take 1/2 hour to install. Once the motor was in, I routed wires around and hooked them up to the switch. I ran out of time, but temporarily hooked up power and ground and tested them. Also worked!

So far, the electrical has been pretty easy and works on the first try. I guess the careful planning is paying off.

It’s been a long spell of no work on the plane. My parents were in town for a few days from Arizona, so we’ve been doing a lot of visiting and entertaining. That plus the start of school stuff, and soccer, and… I found a few minutes here and there to tinker, but nothing really got done.

My parents left early Sunday, and I spent most of the day on the plane. I hooked up the powers and grounds for all of the avionics. I then spent considerable time debating about the location of the jacks. I put in the seat and side panel on one side, and verified that the recessed jack housing is going to work great. I drilled a small hole in the seat pan and fed the wires up through there.

I also soldered up the headphone and mic jacks. I did a lot of double and triple checking to make sure everything was correct. It sure would be nice if the jacks had fast-on tabs. Soldering the wires on there is unpleasant. Of course I forgot heat shrink on one wire. I’m not going to redo it until (if) it breaks. I attached a couple of 22 AWG wires to the correct tabs of the mic jack to run to the pilot stick. I’m still trying to figure out where to put the copilot PTT button. I didn’t put it on the stick, as I want the stick to be easily removable.

One thing that took some extra time was I cut about a foot off each headphone/mic wire, because they were a little too long. In retrospect, it would have been better to just wind up the extra somewhere. Stark had them nicely prepped for wiring. Stripping the outer sheath without nicking the wires was tricky, and then there’s the shielding to cut back, etc. It took more time than I expected.

With all that hooked up, it was time to test the PS Engineering PMA8000B audio panel and Garmin SL40. I put in fuses for those two items, slid them into the stack, and flipped the master and avionics switches. No smoke!! I turned on both units and was able to pull in RNT, BFI, and SEA ATIS, as well as listen to some chatter at BFI and SEA towers. Of course, I made double sure I wasn’t transmitting accidentally. Very cool. I played with some of the functions of the PMA8000B (recorder playback) and the SL40 (standby monitoring). They are both very nice units. I don’t have the GNS430 yet, so I couldn’t try it out. And the antenna isn’t on the GTX327, so I don’t want to power that up yet. I think the autopilot will be next.

Long day with some very cool results. I put the trickle charger on the battery to top it off again.

The 10 AWG wire from B&C showed up, so I wired the avionics bus via the switch on the panel. Works great. The terminals for the size 10 wire are really, really difficult to crimp. Took 2+ hands to squeeze the crimper handles.

I also broke down and ordered one of B&C’s ground blocks. I knew 24 wasn’t going to be enough, so I went for the 48 tab big boy. The ground block I made had two problems. First the aluminum would eventually oxidize and not conduct as well. Second, the tab blocks from SteinAir don’t have a little hole in them to help retain the Fast-on terminals. The B&C blocks are nice quality, if not a bit over-priced. The tabs have a dimple on them, and they are soldered to the brass base sheet. The really, really fortunate part of the whole thing for me, is that the holes on the B&C ground block were almost exactly the same as the holes I already drilled in the firewall. I just had to enlarge one hole to 5/16″. Took me all of 15 minutes to swap, and now I won’t have to worry about it anymore.

AFS finally posted some new information on the AF-3400/3500 on their web site, although it’s only wiring harness diagrams. Looks just as I expected. Should be easy to hook up once they get here. Speaking of which, it’s about time for my bi-weekly nag call to them. 2 weeks ago they said they’d be shipping the harnesses in 2 weeks. This is starting to get really tiring. I just want to get the stupid engine sensors installed so I can wrap up the firewall forward. I have a feeling that Glasair is taking priority over us loyal customers that have been waiting months for product to arrive. One of the standard panels for Glasair’s “2 weeks to taxi” program on the Sportsman includes AFS screens. I noticed they have some special switch option added to one of the wiring harnesses. I’m about 2 weeks away from cutting a new panel and going back to the Dynon screens.

I picked up some 1″ #6 screws at Lowes and was able to mount the airspeed indicator temporarily. The screws are just barely long enough for the altimeter. I’ll have to use 1-1/4″ screws there. It seems like every single thing in the panel needs a different size mounting screw. At least it’s looking good.

Ran the wire for the Gretz pitot heat display out to the left wing root. The display is just 3 LEDs, green for pitot temp OK, yellow for heating up, red for temp too cold. I’m planning on drilling 3 holes in the panel and mounting the LEDs with some little clips I got at Radio Shack. I also ran some 14 AWG wire out there for the pitot heat power. I’m trying to run all the big wires around so I can determine if I’m going to run out of room in the snap bushings. So far, so good. I’ve been trying to take maximum advantage of the outboard snap bushings in the center spar section.

I also ran some coax to the right side antenna for the SL-40. It’s been a while since I crimped the BNC connector for the transponder, but it’s just like riding a bike. The only hassle was routing the coax around. The thicker the wire, the more hassle it is.

I cleaned up the wiring around the fuse blocks a little more. It’s starting to look much better. Julie inspected my work and approved. I’ve got a bunch more wires to run, but progress has been steady. I think maybe another 2-3 weeks should do it for wiring.

I completed the wiring for the right ignition switch and now I’m out of the clear 1/8″ shrink tubing I’ve been using for wiring. I have a bunch more showing up on Wednesday from B&C. I’ll have to work on something else for a day or two. By the way, I’ve been testing the switches as I hook them up. I use a continuity tester with one end on the fuse block (or ground), and the other end connected to the item being powered (or grounded). I then make sure it’s working correctly as I flip the switch. I don’t have any fuses in the fuse blocks yet, so nothing is actually getting power. Soon.

I pulled out the airspeed indicator (ASI) and altimeter and decided to get them fitted. I knew that the spacing with the Digiflight in the middle was going to be a little tight with the Nulite rings. They say you can take a Dremel to them, so I trimmed a bit (about 1/16″) off one side of each with the belt sander. The ring got pretty warm, so I sanded a bit, paused, sanded, etc. Turned out perfectly. The instructions on the web site say to paint the exposed area with some white acrylic paint, so I still need to do that.

I was going to mount the instruments, but figured out I need #6 screws not the #8 that I ordered. A #8 fits through the holes, but there’s no room to put the nut on. I guess we’re just supposed to know that instruments need long #6 screws. I just placed a big hardware order at Spruce today. It always seems like I end up needing something the day after I place an order. I’ll see if Lowes has some screws that will work temporarily. I want to get everything test fitted into the panel to make sure there are no interference problems.

I spent a little time re-verifying all of the fuse and wire sizes I figured out previously. I don’t want to run the wrong size wire at this point.

I wired the left ignition switch. It’s kind of complicated as a wire needs to run from the fuse block to the switch and then to the P-mag. And then another wire runs from the ground block to the switch and then to the P-mag. And I’m putting labels on both ends of each wire. It’s time consuming, but progress is in the forward direction.

Organized the wiring behind the switches a bit, including shortening one wire and replacing another. I temporarily used some clothes hangar wire to get the switch wires routed how I wanted them. I also soldered the leads onto the starter switch.

Geoff Sharples, a Technical Counselor from the Seattle EAA Chapter, stopped by for an inspection. He said everything looked great. He pointed out a couple of cables and fuel lines that need to be clamped away from the engine mount to avoid chafing. That’s kind of my last step on the firewall forward is to secure everything. We also spent a little time trying to figure out a minor issue with the throttle control. For some reason, there’s kind of a detent about 1/4 of the way up from idle. I knew the problem was there, but just hadn’t gotten back to looking at it. It seems like the swivel joint at the end of the cable is somehow causing the issue, but I’m not sure how. I’m not excited about the prospect of having to remove the cable to look at it. It’s at least a 2 hour operation whenever I touch that stupid throttle quadrant. He looked at the fuselage construction, and said it all looked good. I have him back one more time, possibly down at the airport when it’s all set to go.

The wiring around the fuse blocks was getting to be quite a mess, so I decided to organize it. I drilled some holes for tie-wrap mounts and carefully routed wires around.

There’s about a hundred different wiring tasks I could work on now. I decided to get the more difficult/unpleasant stuff out of the way first. That would be the alternator. Working with the thicker 6 AWG wire is not as fun, and routing stuff forward of the firewall is always tricky. I ran a wire from the alternator back to the panel for a circuit breaker and then from the panel back to the main bus. I haven’t decided exactly where the circuit breaker is going to reside yet, so I left those ends long for now.

I also hooked up the alternator field wire to the switch on the panel. The connector on the Vans alternator is very goofy. The only way I could figure out how to attach the two wires from that connector to the wire running aft was to use a Molex connector. It’s odd to have two connectors in a row, but the Molex connectors are much easier to aquire and use.

The tangle of wires is getting a bit crazy. It’s time to do some organization and tie-wrapping.