Getting Wired – Old Eyes Need Big Print

Spent some time today with the Dymo Rhino label machine outfitted with heat shrink tubing to create labels for the wiring starting with the pitch servo wires. Discovered 1/4" tubing would just barely fit over the Molex pins already on the autopilot servo wires. Was using small lettering to identify the wire number along with what the function is such as “Pitch Data A”. The print was small but quite legible (although it shrinks considerably with the tubing) but based on comments made by friends Bernie and Mike who dropped in to check on the progress, I decided to use larger print and just identify the wire name such as “F489”. After all, I could barely read it the way it was ... even with reading glasses on … and the eyes are NOT likely to get any better a few years down the road if there is ever an issue with the wiring.

Heat shrink tubing slid over the autopilot pich servo wires ready for the heat gun.

After the printed heat shrink labels were slid over the wires, the dust was blown off the heat gun and label shrinking commenced followed by inserting the wires into a Molex connector.

Inserting the autopilot’s pitch servo wires into a 9 position Molex connector.

Once the wires are inserted in the pitch servo’s 9 position Molex connector Van’s instructs the builder to wire tie the wires to the seat rib the wires pass through making sure the wires don’t chafe on the edge of the hole they are pulled through. Decided it would be a good idea to slip a short piece of heat sink over the wires at this location as an insurance policy.

Heat shrink tubing not called for in the plans was added to location where pitch servo wires pass through the seat rib.

Back view of the heat shrink tubing added to location where pitch servo wires pass through the seat rib.

Install Fans As The Drawing Shows Right? … Redo!

Today connecting the wires to the connectors began along with the instillation of two cooling fans on the instrument panel base. Work began with attaching two cooling fans onto the F-1202B instrument panel. The instructions instruct the builder to attach the fan’s ground wire onto a mounting screw that secures the fans onto the instrument panel base. This instruction is accompanied by a caution warning not to break the tabs on the plastic fan from over tightening. I submit ...  if the fan needs to get its power ground through the mounting hardware … the hardware NEEDS to be tight.

One can see how the mounting hardware could potentially break the unsupported eyelet on the plastic fan while tightening the mounting screw to obtain good grounding for the fan motor.

Builders may want to consider the DOG Aviation solution of using the lower  eyelets on the fans as mounting points for the hardware.

Shorter screws were used to mount both fans utilizing the lower mounting eyelets. Now the grounding screw can be made quite tight without fear of breaking an unsupported eyelet on the fan.

The very long MS51957-36 screws (way longer than they need to be) were substituted with much shorter MS-35206-230 screws which were on hand and placed in the lower mounting eyelets. Now there is not a possibility of breaking off an eyelet while tightening the hardware to develop good ground connections for the fans.

Having been distracted with the screws for mounting of the fans, the two fans were screwed onto the F-1202B instrument panel base using the same positioning as shown in the drawing below. Ultimately that proved to be wrong.

Discovered this drawing in the plans shows an incorrect fan mounting ... the fans need to be flip flopped for the airflow to be per the plans.

Redo ... nothing like creating work for yourself and needing to redo because of not reading an entire paragraph. After mounting the two fans as shown in the above drawing, the next sentence in the instructions says to make sure the arrow on the fan points down on the left fan and up on the right fan. To make the airflow as  per the plans, had to uninstall both fans and flip them over. Lesson learned …. the final result may not always look like the drawing.   Being curious, had a look at older drawings on the Van's site and apparently at some point the fan’s airflow direction was changed … from left fan blows up and right fan blows down (which matches the drawing) … to the new way which now has the left fan blowing down and the right fan blowing up.  Apparently the positioning of the fans in the drawing has not been redrawn to reflect this change. Guessing because the Dynon Skyview sits directly in front of the left fan, it is thought better cooling will be acheived by puling the warm air away from the Skyview.

Continuing on the wiring the three wires for the fuel flow sensor were inserted into a Molex connector then plugged into the fuel flow's connector. This was followed by completing the wiring for the auxiliary audio connector. When wiring the Molex connectors the F-398 left audio wire was placed on pin 1 (tip) and the F-397 right audio was placed on pin 2 (ring) as covered in the previous post.

About to insert the three twisted wires for the fuel flow sensor into a Molex connector.

Connecting the auxiliary audio jack wires to a micro Molex connector.

Small Error In Auxiliary Audio Wiring Discovered

After spending another couple of hours this morning searching for the missing bag containing the multimeter, test lead clips, solder, test jumpers and wiring hardware … the bag was finally located much to my relief.  Although, it was such a nice day today, not much time was spent in the shop … yet again.

That said, the other day while installing the wire harnesses, noticed what seems to be a small error in the prints for wiring the auxiliary audio connector. Today I took the time to investigate … it has been my experience that left channel audio is on the tip and right channel audio is on the ring of the typical 3.5 mm stereo plug used for MP3 players, headsets etc. If wired as per the plans, it appears that the left and right channels are switched at the ES00045 connector. Is that such a big deal? No … but it will make any audiophile cringe.

Aux music jack drawing and ES-000045 fuselage wiring harness connector.

When tracing the wires back they are indeed flip flopped on the drawing. The F397 is connected to the right music input and the F398 is connected to the left music input at the WH-00045 connector … pins 2 and 20 respectfully. I went further and traced the wiring diagram all the way back to the Garmin GTR 200 and all was good … right goes to right and left goes to left.

Using the multimeter to buzz out all the audio wires to the WH-00046 and WH-00045 wiring harnesses.

My suggestion to other builders is consider flip flopping the F397 and F398 wires at the ES00045 connector by connecting F398 (left music input) to pin 1 (tip) and F397 (right audio) to pin 2 (ring) of the ES00045 connector to achieve proper left and right stereo orientation.

Photo of the wiring diagram … zooming in one can see F397 is wired to right music input and F398 is wired to left music input of the WH-00046 harness.

All this got me concerned about the left and right audio for the headsets as well ... because the Garmin GTR 200 has a feature called 3D sound where active and standby radio channels are heard at the 11 and 1 o’clock positions and the co-pilot at 3 o’clock.  Happy to report all is well … according to the wiring diagram, tip (left audio) of the headset jack goes to the left headset audio on the GTR 200 and ring (right audio) goes to right headset audio. Of course, this presumes the wiring diagram is correct and can’t really test that at this time because the instrument kit has not been ordered yet.

WH-00045 Wire Harness Installed

After separating out the WH-00045 wiring harness wires that needed to be run through the upper grommet on the F-1203A bulkhead, they were routed through the grommet then one at a time routed to their appropriate positions within the fuselage. The WH-00045 wiring harness has been, for the most part, distributed to the proper locations within the fuselage. The reason for saying “for the most part” is because the power wires for the landing light and nav/strobe have purposely not been installed. The reason being … those wires are going to be upgraded to shielded cable.

Last batch of WH-00045 wiring harness wires to be routed to their proper locations.

Finishing up on distributing the WH-00045 wiring harness one wire at a time to save room in the grommets and, in general, hopefully avoid a tangled mess. Almost finished!

Now that both wiring harnesses are installed, I took the time to verify there is room in the wiring grommets for the pitot tube which will need to run from the tail cone through the wire grommets to the engine compartment and the wires for the trim servo. Small pieces of cable and tubing were slipped through every grommet to verify there is room for them to be installed later. Although a tight fit at places, happy to report there is still room.

Regarding the shielded cable … honesty, most likely the only wires that will truly benefit from the shielded wiring will be the navigation/strobe circuits. In fact, AeroLED’s now recommends using shielded wiring for the nav/strobe wiring for their units. However, because a second landing light was installed specifically to take advantage of the wig – wag capability, not sure if that too could possibly generate headset noise as has been reported by builders who installed the nav/strobe lighting. Because the RV-12 is being built as E-AB, will take advantage of the liberties E-AB offers a builder and will make a changeover to shielded wires. Also decided to error on the side of potential overkill (a John thing) and will up the ante a bit by utilizing shielded wire for the landing light circuits as well … have the wire, may as well use it.

The DOG Aviation procurement department planned for this moment over a year ago by ordering the necessary pins to install the new shielded wires going to the WH-00045 connector. The landing light and nav/strobe wiring originates at the WH-00045 connector so the shell was removed from the connector and the associated wires were removed using a special pin extraction tool.

Two wires of the four wires extracted from the WH-00045 wiring connector using the special extraction tool. Two down … two to go.

After removing the wires from the connector, forward progress ground to a halt as a search began for some materials purchased over a year ago to no avail. Spent hours this afternoon looking for a couple of items needed. The DOG Aviation supply department has dropped the ball and needs to be chastised. Hopefully, the items can be found tomorrow when I’m in a better mood.

More Wire Fishing - Installing WH-00045 Wire Harness

Work was finished up on pulling in all the wires belonging the WH-00046 wire harness and routing the wires to the specified locations. Two short ground wires needed to be added to the seat ribs on either side of the center tunnel. A hole is in the seat ribs already but the primer needed removing in the vicinity of the hole to insure a good ground. The ground wires will attach to an Adel clamp along with other ground wires which will be installed later down the road.

Was trying to think of a good way to remove the primer without scuffing up the ribs more than necessary so came up with a poor man’s piloted bonding brush by using a drill stop collar that had a piece of crocus cloth attached which was trimmed to the width of the collar. The shaft of the drill bit was slipped through the hole for centering and hand spun to remove the primer.  Worked great!

Crocus cloth cut to the width of the drill stop collar made a good poor man’s piloted bonding brush for removing the primer from around a hole to insure a good ground.

The primer is mostly removed from around the hole but still requires a little tweaking on the right side.

Installed ground wire on the Adel clamp mounted onto the seat rib … bolt not tightened yet because another ground wire will attach here later.

Wires from the WH-00046 were fished through the lower wire grommet in the F-1203A bulkhead and routed either through the seat ribs, all the way aft through the center tunnel or up through the wire hole in the center channel.

Fishing WH-00046 wire harness wires aft through the center tunnel.

After routing the wires of the WH-00046 harness to their proper locations, the outside air temperature sensor was installed and its two wires run all the way aft through the center tunnel.

Next the WH-00045 options wire harness installation began. The grommets in the instrument panel base and F-1202F bulkhead that the WH-00045 harness pass through need to be removed and split to allow a connector that is part of the harness to pass. Builders - do yourself a favor and split those two grommets with a razor blade knife and leave them out until the WH-00045 harness is in its final position in those two areas.

Once the WH-00045 is pulled in through the F-1202 bulkhead grommet, the wires in the harness are split ... some of the wires will run  aft through the lower grommet in the F-1203A bulkhead and continue all the way through the center tunnel. The remaining wires are passed through the upper wiring grommet in the F-1203A bulkhead.

Separating and untangling the wires in my left hand that will run through the lower grommet in the F-1203A bulkhead all the way aft through the center tunnel. Wires in my right hand will go through the upper wire grommet in the F-1203A bulkhead.

The WH-00045 harness wires that needed to go all the way aft were fished through the wire grommets in the center channel's bulkheads one at a time.  A long string was run through the center channel bulkhead's wire grommets and taped onto the wire being pulled in through the wire grommets. The string was cut plenty long so it could be looped over the center channel and taped 6" or so further back on the wire being pulled in.  As the wire was being pulled in through the center channel's bulkhead grommets, it was also pulling the pull string back through the grommets so there would be a pull string ready for the next wire to be pulled through the grommets.

Pulling a wire through the center channel’s wire grommets ... the string used for pulling was looped back and taped onto the wire so the string was pulled back through the center channel wire grommets as the wire was being pulled through the center channel's bulkheads.

Installation Of WH-00046 Wire Harness Continues

Although an abbreviated Holiday work session, some more progress was made on the instillation of the W-00046 wire harness. To insure enough cable slack to route above the rudder pedal assembly Van’s marks the W-00046 harness with two red locating bands which are used to aid in correctly positioning the harness. The red band closest to the connector at the instrument panel end is to be positioned at the grommet in the F-1202B instrument panel base. The second band is positioned at the grommet in the F1202F bulkhead which is aft of the fuel flow sensor. For reference, the first red band is located 23" from the connector and the second band is located 62" from the connector. I took these measurements last week for a fellow builder … now I know why he needed them. If not extremely careful, the red bands have a propensity to snag on the grommets and while pushing the cable, the cable will continue moving but the positioning band can stay hung up … thus messing up the positioning.  Ask me how I know.

The WH-00046 cable forward of the F-1203A bulkhead grommet is in final position. Working the cable further aft, slowly but surely.

Discovered an unexpected, but welcomed surprise. The RV-12 has an external audio jack! … it is located between the seats on the F-1203A bulkhead. Knew there was a 12 volt cigarette lighter type of a power source in that area, but did not realize there was also an audio jack for connecting an MP3 player or other audio source.

Auxiliary audio jack in my hand goes into the hole my finger is pointing to. An unexpected nicety.

Installing WH-00046 Wiring Harnesses Begins

A productive day in the shop for a change … amazing how motivating good weather can be. The finishing touches were performed on the F-1202B instrument panel base. The remaining four nutplates were installed and the two WD-1204 engine mount brackets were match drilled then riveted in place.

I noticed a small issue with rivet holes used to attach the four nutplates onto the web of the F-1202B instrument panel base. The rivet holes for these nutplates are dimpled at the factory and in my opinion, not dimpled deep enough. Frequent readers may also remember this issue was also noticed on the firewall shelf. Fortunately, I still have the C-frame I borrowed from Pete after he finished building his RV-9A, so dimpling the holes again was an easy task. (Thanks again Pete … you will be getting it back real soon).

The CCR-264SS-3-2 pop rivets Vans would have the builder install is on the left and the AN426AD3-3.5 I’m using on the right. Note the existing dimples are so shallow even the CCR-264SS-3-2 rivet sits a little proud.

Using the C-frame outfitted with 3/32" 100 degree dimple dies to tweak the existing dimples in the nutplate rivet holes in the instrument panel base for a better fit.

Those builders building E-LSA will need to disregard this next step. Personally, I don’t like using the CCR-264SS-3-2 rivets unless there is no other way. The F-1202B lends itself well for back riveting the four nutplates … so that is what I did using a rivet gun, back riveting plate and AN426AD3-3.5 solid rivets. The back riveting plate was covered in shipping paper to prevent scratching the primer and riveting tape was used to hold the rivets in place when the panel base was flipped upside down. Turned out looking great!

Riveting one of the four nutplates that get installed on the web of the instrument panel base.

All four nutplates back riveted onto the F-1202B instrument panel base with AN426AD3-3.5 solid rivets.

The F-1202B instrument panel base is the attachment point for the two WD-1204 upper motor mounts. The motor mounts were secured onto the instrument panel base, all rivet holes match drilled, removed for deburring, and then riveted onto the F-1202B instrument panel base. Rivet holes on the forward edge are not riveted at this time.

Match drilling the F-1202B instrument panel base’s forward flange to one of the WD-1204 engine mounts.

Match drilling the F-1202B instrument panel base's web to one of the WD-1204 engine mount brackets.

Riveting the WD-1204 engine mounts onto the F-1202B instrument panel base with LP4-3 pop rivets.

WD-1204 engine mount brackets riveted in place on the F-1202B instrument panel base.

After studying the plans, decided I could hold off on riveting the F-1202B instrument panel base and move forward running the wiring harnesses. Just in case there is an issue, will not be placing the terminations or connectors on the wires at this time (just in case they need to be removed) until the rudder pedals are installed and the panel base has been successfully match drilled into the longerons.

One of the main reasons for holding off putting the side skins on and wanting to continue with running the wiring is because the plan is to install a backup airspeed indicator and altimeter so there is instrumentation to fall back on should the Dynon SkyView have a major malfunction. A static line will be required for the backup instruments, so I need to find a good routing location to run the static line from the tail cone up to the instrument panel. However, at this point not sure if there will be room in the existing wire grommets once all the wiring is in place ... so plan to fill them up now and determine if there is enough room left for a static line.

A while back, all the coax cables with BNC connectors were run through the grommets. The next item to be installed is the WH-00046 fuselage wiring harness. Following a builders tip from the forums, prior to installing the WH-00046 wiring harness, every location that has a lose wire or connector pins was wrapped with tape to prevent the lose wires from snagging while pulling the wires through the wire run grommets. A close look at the following photo one can see various locations on the wire harness have blue tape.

Slowly working the WH-00046 fuselage wiring harness through the wire run grommets in the RV-12’s center tunnel.

Nutplates Riveted Onto Instrument Panel Base

A day of running errands left little time for being in the shop but nevertheless, some more forward progress was made on the RV-12 build. The first order of business was to finish up the riveting of the F-1202M-L&R canopy attach doublers onto the F-1202H-L&R canopy ribs.

Using the pneumatic squeezer to rivet the F-1202M canopy doubler onto a F-1212H canopy rib.

 Finished F-1202 M canopy ribs ready for install.

Keen eyed builders may note the F-1202M canopy doublers have JetFlex finish paint on them … this was due to a moment of mental pause last fall when rushing to get all the parts primed and painted. For some reason that can’t be explained, the canopy doublers were finish painted which is unnecessary because the part will not be seen from inside the cockpit. Oh well … looks good though.

The F-1202B instrument panel base receives 20 nutplates along the aft flange. As usual, each nutplate had a screw lubricated with Boelube run into it prior to instillation. Because the plans call for dimpling the nutplate rivet holes, prior to riveting, all 20 nutplates required dimpling as well.

Running a stainless 6-32 screw lubed with Boelube into a nutplate with an electric screwdriver.

Riveting one of 20 nutplates onto the rear flange of the F-1202B instrument panel base.

All 20 nutplates riveted onto the aft flange of the F-1202B instrument panel base.

The F-1202B instrument panel base receives a few more nutplates but ran out of time so will finish up that during the next work session.

A Day Of Nutplates

The DOG Aviation production facility has been experiencing some wild temperature swings … just a couple of days ago we were in the high 70’s (first time this year) then the next morning, it was snowing. The morning tempratures were in the teens and a light snow continued the entire day and of course, it was cold in the shop once again … which was truly demoralizing after actually being comfortable in the shop for a change. Will this winter ever end? Almost seems like reducing the global carbon footprint is sending us into another Ice Age.

Even though there have not been many posts lately, quite a few little tasks have been completed … none of which truly noteworthy. Decided to give the wiring a little more thought before continuing on ... so in the meanwhile, wanted to continue making forward progress by preparing parts that will be needed in the near future. There are a couple of parts that require some assembly plus the instillation of lots of nutplates.

The F-00026-L&R instrument stack angles receive 7 nutplates each and the F-1201Q-L&R battery mount angles receive one nutplate each.

Using the pneumatic squeezer to rivet nutplates onto the F-00026 instrument stack angles.

Nutplates riveted onto both F-00026 instrument stack angles … note there are two nutplates on each stack angle which are not installed at this time.

The next item worked on today was the F-1202H- L&R canopy ribs. In addition to receiving 10 nutplates each, they also receive the F-1202M-L&R canopy attach doublers and the F-1202Y-L&R canopy strut attach angles (which are builder fabricated parts completed last fall).

F-1202M canopy attach doublers and F-1202Y canopy strut attach angles attached with Clecos onto the F-1202H canopy ribs. Ready for installing the nutplates.

Using the pneumatic rivet squeezer to rivet nutplates onto the flanges of the F-1202H canopy rib. Because of the painted surfaces, a small piece of riveting tape was placed over the rivets to prevent the paint from becoming marred by the squeezer.

Fuel Line Pressure Test Completed

After changing the pressure gauge to one capable of handling higher pressures, rebuilding the manifold, properly torquing the test loop fittings and fixing the last of the small leaks in the test loop … the fuel line pressure held steady. The pressure was brought up to 11 psi and for the last 48 hours the pressure has not gone below 10 psi and is now fluctuating with the temperatures in the shop. This is a good sign and indicates there is now a closed system with no leaks.

After 48 hours, the fuel line pressure is fluctuating between 10 and 11 psi depending on temperatures in the shop.

Now that the fuel lines are holding pressure, feel better about continuing on with more vigor. Admittedly, there has been a fair amount of procrastination taking place as of late while trying to determine the best way to continue with the project. It all hinges around the side skins and wanting to keep them off as long as possible for easier access. Another issue to figure out is the best way to run a static line up to the instrument panel for the airspeed and altitude indicator which will be installed as backups.

Fuel Line Testing Encouraging

It has been a while since the last post but some progress has been on the RV-12 in spite of taking time away from the project to satisfy the annual obligation of funding irresponsible spending at the Federal and to a much lesser degree, State levels before April 15th.

Decided to order a 0-30 psi pressure gauge to try locating the leak(s) using more pressure. Trying to find a leak using between 1 to 2 pounds of pressure was just not working well … plus the soapy water rolled off the fittings after being sprayed on so by the time the bubbles created by spraying dissipated, the solution had as well. While installing the new pressure gauge, the test fixture was completely disassembled and reassembled using a pipe thread sealant as opposed to Teflon tape. I think this solved part of the problem but there was still a pressure drop during a subsequent overnight pressure test.

The terminating cap and loop fittings were then torqued to the proper tightness which made them quite a bit tighter than they were. All of this made an improvement. The lines were pumped up to 12 psi, which is basically twice the pressure the fuel pump will produce on a good day, and there was still a tiny leak.  By moving the fuel valve to the off position after the system was pressurized, the gauge did not show any pressure drop in an overnight test which implied the remaining leak was aft of the fuel valve.

Next, a tire leak solution was obtained from a local tire shop … but after mixing it with water as directed, the solution (much the same as my soapy mix) was just too thin to stick on the fittings long enough to find the source of the tiny leak. Finally, a trip was made to the plumbing section of the local big box store and a bottle of leak detection solution was procured. It appears to be a little thicker and has a slimy feel to it … so guessing it has glycerin in to allow it to stick to fittings better. Plus, there was a dauber so the solution did not have to be sprayed which created bubbles. With this I was able to quickly locate what I hole is likely the remaining leak. So my tip for fellow builders is don't waste time doing what I did ... get a comercial leak detection liquid and save yourself some time.

The vinyl tubing was leaking where it was slipped over the aluminum tube on the aft end of the fuel pump and tightened with a larger than optimum hose clamp.

Actually, this hose leak was a self induced trouble because I knew the hose clamps used for making the loop were larger than they should be and did not apply an even pressure on the vinyl tubing. But when cobbling temporary things together, one tends to use that is lying around the shop at the time. The leak was stopped by adding an additional hose clamp.

The overnight pressure test starting at a higher 11 psi.

After four hours this evening the pressure has dropped from 11 psi to 10.5 psi which I feel is in line because I would expect a small pressure drop as the shop cools in the evening. I’ll know in the morning for sure but have a good feeling the system will hold pressure overnight.