Archive for September, 2013

Classic Aero Interior Arrives – 1.5 hr

September 30, 2013 Leave a comment

Monday Sep 30, 2013

Today the Classic Aero seats and interior package I ordered nearly four months ago arrived in three boxes. This is not the cheapest way to build an RV-7A but a nice leather interior really adds to the comfort and appearance of the airplane. Being a week night I did not have time to fully install all the components but I did get to check fit each piece and get a feel for how it will look when it is done. Wow! Even in my relatively poorly lit garage the interior of the airplane was transformed. Click on the pictures to see a larger view.


I had to get in and pretend I was flying. The seats are quite comfortable and I had close to 2 inches of head clearance to the bubble even though I am 6’2″. This is going to be one sweet ride. And the smell of new leather just tops it off.


I still need to order the front carpet. Luke at Classic Aero told me to get the seats in first, set the rudder pedal location and measure the distance my heals hit the floor from the firewall so the rubber reinforced heal pad can be located for best fit. Then order the carpet. So that will be my plan.

Categories: Last 10 Percent

Mostly Pulling Wires – 8 hrs

September 29, 2013 Leave a comment

Sunday, Sep 29, 2013

This weekend I continued to work on electrical wiring challenges – mostly pulling wires through conduit and snap bushings for various systems. I started by making a new cable from the roll autopilot servo connector at the wing root into the fuselage. I soldered the wires to the plug side of the seven-pin Mini-Con-X connector and added some nylon braid and shrink sleeve to provide scuff resistance in the gap between the wing and the fuselage. Here the connector is taped to the side of the skin about where it mates to the wing-mounted connector. Inside I ran the four data wires through conduit to the Dynon network hub behind the baggage compartment and the other three wires (power, ground and AP disconnect) under the seats where they will be connected with the pitch autopilot servo wires.


I drilled some holes in the vertical ribs of the firewall to attach conduit for the wire runs. I installed an Adel clamp on each side at the top to secure to conduit which I split with a razor blade. I also drilled a hole in the rib about half way down for a zip tie to anchor the conduit but I will install the zip ties later after getting all the wires installed.


Behind the baggage compartment I made another cable that starts at the pitch autopilot servo. It is attached to a tie base mounted on the top of  the floor rib.


This cable splits into two groups of wires, four data wires that go to the Dynon Network Hub and three wires (power, ground and AP disconnect) which I ran through the conduit under the baggage compartment and seats to be spliced with the roll AP servo wires. The power and ground will also run forward to the Vertical Power unit and the firewall ground block.


I seems like ages ago since I built up and fitted the aileron trim servo hardware. Today I finally installed it permanently (I hope). You can just make out the servo control arm and the two springs that bias the control sticks in this photo. It’s kinda cool that it makes the control sticks stand vertical now even without the aileron pushrods attached. You can see my pilot and copilot control sticks are also fully installed as well.


Wires are starting to accumulate through the tunnel area of the cockpit. Right now most of them are on the right side but that will change soon. There is still a lot more wiring to do.


Categories: Avionics, Wiring

Installed Connector at Wing Root – 1.5 hrs

September 24, 2013 Leave a comment

Tuesday Sep 24, 2013

When I routed the wires from the autopilot roll servo through the right wing I left a long length of wire taped to the inner wing rib for the eventual routing through the fuselage. I decided I really did not want to wait until I moved the airplane to a hanger and put the wings on to finish routing these important connections because I am discovering that the wire routing under the seats is getting complicated and I want to work it all out now rather than make the work at the hangar more complicated. I also want to minimize the amount of work necessary at the hangar because it is so much easier to work at home in the garage. So I decided to add a connector for the servo wires at the wing root. I found a small seven pin circular connector made by Switchcraft that is intended for harsh environments. It even includes an o-ring to keep moisture out. It looks perfect for the seven wires of the rolls servo. So tonight I decided to cut the excess wire at the wing root and install the connector. There is a panel mount connector with a jam nut and #20 pins which I decided to mount to the wing rib, and a plug connector that I will install on the wires from the fuselage. After I install the wings at the airport, I will only have to mate the connectors. This connector comes in two versions; one with crimp contacts and the other with solder cups. I would prefer the crimp version but the crimp tool is very expensive – too much for one or two connectors. So I opted for the solder cup version. Here is a photo of the panel mount connector soldered to the seven servo wires. I put 1/16 diameter clear shrink sleeving over each wire solder joint, then a two larger pieces of black sleeve over that.


Here is the cable completely terminated to the connector.


I made a small bracket out of .040 thick aluminum scrap to mount the panel connector to the wing rib. I also mounted a wire tie base so the wires route up and around the hole for the aileron pushrod. There is no chance of interference with the pushrod. The connector will be accessible before the wing root gap fairing is installed. Now this is much cleaner than the coil of wires I had hanging here.


Categories: Wiring

Finished Copilot’s Control Stick – 1.5 hrs

September 23, 2013 Leave a comment

Monday Sep 23, 2013

Tonight I finished assembling the copilot’s control stick including termination of the wires to D-sub contacts on an 8-inch pigtail.


Last night I potted the pin side of the molex connector inside the lower control fitting while it was plugged into the socket side which was potted into the upper tube a few weeks ago. So now all I have to do is depress the release button on the side of the fitting and extract the upper tube to physically and electrically disconnect the copilot’s stick and remove it.


Categories: Cabin Area

RF Wiring – 5 hrs

September 21, 2013 Leave a comment

Saturday Sep 21, 2013

Today was my first foray into installing RF connectors on coax cable; BNC and TNC connectors to be specific. I ordered a coax wire stripping tool a long time ago and I finally got to use it. The Paladin LC CST 1255 (ordered on Amazon) cuts the outer jacket, braid, and core insulation at the correct dimensions for the connector. If set properly it will not nick the inner core strands which is important for a strong connection. I started by practicing stripping the wire on the end of the expensive ($2.85 per foot) RG400 coax cable. On the first attempt the tool cut right through the center core. But the cutting blades are easy to adjust and after a couple more tries it made nice clean cuts without damaging the wires. Here is an example.


I referred to the videos on the EAA website for guidance on crimping the pin and collar on the BNC connectors. A very helpful resource. Using the inserts specifically designed for coax crimping I installed my first BNC connector.


This first cable is for the ADSB antenna so I measured out the length I needed and installed another BNC on the opposite end. One cable done.


The ELT unit came with an RG58 coax cable about 5 feet long. I wanted to use it but the BNC connectors would not fit through the snap bushings I wanted to use to route the cable from the antenna to the transmitter. So I cut the connector off one end of the cable, routed it through snap bushings I installed in the baggage compartment, and then installed another BNC connector on the end off the cable I had cut.  The BNC connectors I ordered are compatible with either RG400 or RG58. I strapped the cable to the pitot static line using zip ties to keep things tidy.


The Dynon transponder uses a TNC connector instead of a BNC. Why? I don’t know because the antenna on the other end of the cable uses a standard BNC connector. The bad news is the TNC connector cost $26 each instead of $1.85 for a BNC connector. So I was slightly anxious about getting it right when I installed the TNC on the RG400 cable. Errors can be expensive. The bottom line is the installation tools and process are the same for the TNC as the BNC and since I was already in a groove with terminating these connectors and it was going well I went ahead and installed the TNC. No problems seen.


After measuring the cable and installing another BNC on the antenna end I installed the new transponder and ADSB antennas in the aft fuselage. I am happy to have these done.


The Comm antenna cable runs from the antenna under the pilot’s seat to the radio which is not installed yet. So I decided to terminate the connector on the antenna end of the cable and route the rest of my RG400 cable up to the instrument panel area leaving it long for final terminate later. The antenna is fairly close to the aileron pushrod so I bought a 90 degree BNC connector from SteinAir for this location. That keeps the cable low under the pushrod. This is another fairly expensive connector ($17.50) so again I was extra careful to strip, measure, inspect and crimp the cable to the connector. When I installed it I ran a service loop aft of the antenna so it will be easier to inspect the connector or replace it if necessary. That completes all the RF connections expect the one on the radio itself.


Categories: Avionics

Pilot’s Control Stick – 6 hrs

September 20, 2013 Leave a comment

Friday Sep 20, 2013

The stock tube for the pilot’s control stick is quite long. So long in fact that the control stick with the grip attached can interfere with the throttle. That is a safety issue so I decided to cut the tube down enough to clear the throttle. I measured the dimensions of the Ray Allen G205 stick grip and based on that cut about 2.5 inches off the tube.


I drilled a hole through the tube just below the attachment to the pivot bearing for the stick grip wires to exit. I put it there to get it as close as I could to the rotation axis so the flex of the wires is minimized. I’ll put a grommet in that hole.


I have no pictures of the next few steps but I ran 26 AWG wires from the stick grip switches down through the tube exiting the grommet leaving enough wire length to pull the grip off if necessary to work on the switches. I included a piece of braided sleeving for additional scuff resistance since these wires will be flexing. Then I buzzed out all the wires and attached labels with my P-Touch label maker.


This view shows the wires as they exit the grommet.


Next I crimped D-sub pins onto the wires. I also installed a 4-40 pan head screw through the grip cap and the tube to prevent the grip from turning or the switch cap from coming off. Sorry, no photos of that process. The tube was drilled with a #43 drill and tapped 4-40. This stick is ready to install.


Categories: Uncategorized

Assembling the Panel – 3 hrs

September 15, 2013 Leave a comment

Sunday Sep 15, 2013

Some time ago I decided to have my panel CNC machined instead of punching all the holes myself. I just don’t have the tools to cut the holes cleanly and since this is going to be very visible feature I knew it would drive me crazy to have the edges around the annunciator lights and the Gemini look irregular. I chose to use for the CNC work based on some of the reviews I read on VAF.

I spent many hours laying out my panel design in AutoCad and when I was finally satisfied I sent a .dxf file to Bill Morelli at Up North Aviation. He responded promptly and gave me some good feedback on my CAD file. So I mailed my blank instrument panel to Bill while I waited for my TruTrak Gemini PFD to arrive so I could finalize a few dimensions on the CAD file. The PFD arrived on Sep 9, I made the measurements I needed and sent an updated CAD file to Bill on Sep 10th. The panel was cut on Sep 12th and it arrived back at my door on Sep 14th. That’s pretty quick turnaround.

Today I started working with the panel. Here it is simply clecoed to the cabin before installing any components. The holes and cutouts are nice and clean. It’s much more professional looking than I could achieve without buying special tools.


I started by aligning my radio stack to the cutout so I could match drill the panel to the pre-existing holes in the stack. I also drilled the panel for #6-32 nutplates around the large cutouts for the Dynon displays.


I want to make sure the top edge of the audio panel is flush to the top edges of the two Dynon EFIS frames so I loaded both displays and clamped a straight edge across the top of the displays, to which I aligned to PMA5000EX top edge, then drilled the rib holes to match.


I installed the switches, annunciator lights, 12V power adapter, USB charging ports, and ELT control panel and installed the panel back in the cabin.


For now I just put in a couple of clecos to hold the displays in place and a couple of #6-32 screws for the Gemini PFD. That is everything but the radio which is going to be a Garmin GTR 200 (I changed my previous plans to use an SL 40) and four dimmers which I have not ordered yet, but I had pilot holes drilled by Bill. After hanger flying this for a while I can tell already that I like the layout.


This view is  a peak in behind the pilot’s display. The panel area is pretty crowded here but there is plenty of space for wiring and other stuff.


Categories: Avionics

Received Gemini PFD, Wiring Pilots Stick – 2 hr

September 11, 2013 Leave a comment

Wednesday 11 Sep, 2013

After being on backorder for over a month, my Trutrak Gemini PFD finally arrived. Here is a photo of the unit, manual, and bag of included connector hardware.


I started wiring up the pilot’s control stick today. This is wired differently than the Ray Allen manual recommends for manual control of the trim motor because I am using the Vertical Power VP-X. I only soldered the top four switches with a common connection to the Normally Open terminals. I will solder the other leads after I measure and cut the control stick to the final length.


Categories: Avionics

EGT and CHT Wiring, Annunciators – 9 hrs

September 8, 2013 Leave a comment

Sunday Sep 8, 2013

I been moving more into the electrical wiring work this weekend. For the audio panel I did a test installation of the connector backplate onto the tray to determine how this goes together. The instructions in the PSEngineering installation guide are rather limited.


Next I assembled the second annunciator controller module and tested it. This one is wired to sense two circuits going to ground and two circuits going high to 12V. Everything checked out as expected so these are ready to be installed in the airplane.


The next adventure was cutting and terminating the exhaust gas temperature (EGT) and cylinder head temperature (CHT) sensor leads between the engine and the engine monitoring system (EMS). I hoped this would be straightforward but I stumbled upon some posts on VAF and the Dynon forum about problems with erratic EGT readings and bad crimps seem to be the cause. On further investigation I learned that the thermocouple wire used in these leads is a hard metal and does not crimp well to typical copper terminals. So at least I was alert to the issue. I started by doing a sample crimp on a short piece of scrap wire and sure enough it pulled off when I did a pull test. The EGT wire is seven strands and the gauge is a little small for a 18-22 AWG terminal. So I tried again by stripping the wire twice as long and folding the wire back on itself to double the area inside the crimp. That was too large and would not go into the barrel so I cut three of the seven strands at the mid point of the fold so it effectively had 11 stands in the crimp area. That fit into the terminal barrel and produced a good crimp that passed the pull test. I did not measure the force but I pulled on it pretty hard.

For the CHT wires the strands seem to be slightly finer and the wire would fit into the barrel folded back double without trimming any strands. That too produced a strong crimp.

After experimenting to get this solution I was able to terminate all the EGT and CHT leads on the left side (cylinders 2 and 4). I cut pieces of shrink sleeving to go over each mating pair of Faston connectors but have not shrunk them because I may install some fireproof expandable sleeving over this bundle later. The routing I chose provides plenty of slack for the relative motion of the engine without getting too extreme.


Here is a better view that shows how I spread the terminations out to avoid a big bulge in one region. The Dynon instructions recommend against trimming any of the armored sections of the cables so I did one loop back on the EGT4 cable to keep the terminals in a reasonable region. Otherwise they would have been up inside the firewall pass-through and I was not going with that.


With all the wiring planning I have been doing I was able to get a list of the wires and sizes that route through the fuselage center section. The holes to pass wires through the center section is limited to four snap bushings about .450 diameter each and one of those is filled by the elevator trim cable. When I saw the full list of wires that have to get through there it was clear they were not going to fit with the two pitot hoses (pitot and static) that need to go to the Gemini PFD. So I decided to reroute the pitot hoses under the canopy sills to make more room for wires. This picture shows the static line (white) rerouted from behind the baggage compartment beneath the main longerons through a hole I added to the F-706 bulkhead (as a contingency) when I originally built it.


The hose comes out behind the fresh air inlet  behind the panel which is perfect for routing to the Gemini. I did the same thing on the left side with the green pitot hose. I still need to add a few tie bases to tidy up the routing but I think this will help the wire routing problems considerably.


Categories: Avionics, Engine Sensors

Some Electrical Work – 6 hrs

September 2, 2013 Leave a comment

Monday Sep 2, 2013

This was labor day weekend and I spent some time identifying all the wire types, connectors, and general supplies I need to complete most of the wiring on the airplane. I’m trying to get an order to SteinAir put together. We are also working on the final plans for my youngest daughter’s wedding in less than two weeks so that was a priority this weekend. Who says you don’t labor on Labor Day?

I performed a test of the first annunciator light controller module using a simple 12V DC power module left over from some electronic appliance. I tested each circuit to make sure it lights when the circuit is shorted to ground and when the push-to-test button is pressed. All tests were successful so this module can go into the airplane.


I also started working on wiring up the radio push-to-talk button on the copilot control stick. First you have to wire up these tiny AWG 26 wires to the switch cap. 


Then the cap is inserted into the grip. I crimped two sub-D connector socket contacts onto the wires from the switch. These will be mated to two pin contacts on the wires that go into the stick tube with shrink sleeving installed over each pair. This will allow me to take the grip off later to cut the control stick to the optimum length based on the panel layout.


I want to make the copilot stick easy to remove and reinstall so I can take it out when the wife would like to spread out a little on long cross country trips. The plan is to set it up so the electrical connections are made just by inserting the stick into the receiver tube. SO to this end I crimped two molex connector contacts onto a pair 26 AWG wires about 18 inches long. 


Then I inserted these into a two-pin Molex connector that I trimmed down so it will fit into the control stick nicely. I added some additional shrink sleeving because these wires will be close to the stick release button spring and I don’t want any abrasion of the wires.


The Molex connector will go into the base end of the stick. The idea is that the connector will mate when I insert the stick tube into the control linkage receiver tube. I made a round plug out of scrap fiberglass sheet that is down in the tube under the connector. There is a hole in the plug jut big enough for the wires to pass through and I tacked the plug in place with cement to close off the tube for potting.


I injected clear silicone sealant into the area around the Molex connector to pot it in place. Once this cured the connector was securely held. I will work on the opposite side of this connector in the receiver tube in my next episode.


While I had the crimpers out I crimped D-Sub socket contacts onto the wires of the aileron trim servo motor. 


Categories: Uncategorized