Saturday, August 30, 2014

31B-26 Roll Bar Wiring

This page was just revised before I completed it to include the wire that goes to the new canopy latched switch.  It’s a touch confusing because I have some instructions that assume the new harness (includes the wire) and others that assume I’m doing the retrofit.   The key step in this page was to fish 3 wires through the roll bar and out a #12 hole near the top.  To give you an idea of what this was like, the retrofit instructions describe it thusly: “using a safety wire, fish the 3 wires through the roll bar and out of the #12 hole.  Stop when the wire tips are protruding.  If this technique doesn’t work, imbibe the mellowing agent of your choice and try again with a stiff fishing line.”   I didn’t find it fun, but it wasn’t that frustrating for me (no mellowing agent required.)

IMG 3592

Wire bundle exiting roll bar

31B-24 Floating (Wing Root) Connectors

After finishing up the roll servo connector issue, I returned to working on the wing connectors.  The blue connectors are rigidly attached to the airframe, but they are not rigid themselves.  There’s a deliberate bit of wiggle and slop so they can make minor self-adjustments as the wings are slid into place.  There’s a bracket under each seat that is held in place with 4 screws and that bracket attaches to the connector.  Remember the two holes in the picture on 41-11?  Those are the holes through which the brackets are attached.  Unfortunately, they were too small for the screws to fit through.  The location prevented me from getting a drill or other tool in place, but I was able to actually tap them by hand.  Time consuming, but not horribly difficult.

IMG 3588

Left Floating Connector, without cover plate.

IMG 3589

Left Floating Connector, with Cover Plate

IMG 3590

Right Floating Connector w cover plate

Note the pins on the right connector and the sockets on the left.  The wings are, of course, reversed.  I think that’s pretty clever on Van’s part since they can put one complete set in the wing kit and one in the finish kit.  If they put one gender on the wings and the other gender on the fuselage, they’d have to open each set of connectors they bought and keep separate inventories of male & female.

31B-20 Roll Servo Connector

Ah, now this was an embarrassing page.  When pulling various wires through the rear portion of the fuselage, I found that it was convenient to take several shorter wires and tuck them through a convenient lightening hole while I dealt with some longer ones destined for the aft reaches of the tail cone.  I then came across this page which has me insert that same handful of wires into a Molex 9 pin connect.  Then, and only then, did I realize that the wires were still placed through the previously convenient hole and were no longer able to be removed due to the connector.  Well, damn.

I couldn’t find a thing to use as a removal tool, although I knew what they looked like and how to use them from my previous life as a electronics geek. I tried the usual suspects of Radio Shack and then MicroWarehouse.  No one in those shops had the slightest idea what I was talking about.  Struck out at Advance Auto, since those had been used in cars during the 80’s.  Finally, went to Roush Hardware and got some narrow diameter aluminum pipe/wire.  Viola!  I now have 1 meter of pin removal pipe/wire that can be used for similar boneheaded maneuvers.  I’ll probably post a note on VAF and offer to send someone 6” if they find themselves in the same boat.

Anyway, here’s the connector (not threaded through a convenient hole) for later connection to the servos.

IMG 3586

Roll Servo Connector

Recall that the plane is on its right side, so “up” is directed to the right side of this picture.

40-11 Strobe Noise Filter

This page is a “jump” from the regular sequence, as it deals with installing a capacitor to be a noise filter in the lighting system.  Van’s philosophy was to include most of the wiring harness that is needed for the lighting kit as part of the regular building process.  There’s remarkably little wiring to add when someone puts in lights as a retrofit.  This is one of those things.  Rather than completing the wiring process as per chapter 31B and then coming back to install the capacitor, I’m doing it as I build.

There’s a grounding screw that goes into the space below the pilot’s knees.  The Book intimates that it may be difficult to reach and authorizes drilling another hole in a more convenient location if you so choose.  Rather than taking that easy way out, I spent several hours last week trying to tighten the requisite screw.  Yesterday morning, it took all of 3 minutes.  Go fig...

Anyway, with that pesky screw tightened up, the capacitor just plugs into the harness and needs to be tie wrapped in place.

IMG 3583

Port Wing Root Wiring Connector (loose)


Note the two bright holes in the metal sheet containing the reflection of the black capacitor.  We’ll pay more attention to those holes in a few entries.

Monday, August 25, 2014

31B-17 Headphone Jacks

This page has some problems as written.  There was thread that started about a week ago regarding the questionable logic/questionable instructions for this jack.  Here’s my posting to VAF:

Here's my $0.02 on this page. I think the connector I have in my hand is the wrong gender compared to the instructions. The diagram in the instructions show "ears" which correspond to the connector I received with the jacks pre-wired into it, not the connector I'm trying to use. 

Below is a picture of the Micro Connector I received in my kit. Looking at the photo, pin #1 is in the top left spot and #12 is on the bottom right.

If I turn the diagram around (e.g., swap #1<-->#6, #7<-->#12) then the instructions (colors) match up to the ones in the pre-made harness, and there are wires on both sides of each connector that match (expect for the optional power.)

Another way of stating it: the caption "(VIEW FROM WIRE INSERTION SIDE)" is in error and the image provided is the view from the pin side of what we're supposed to insert but is correct for the connector in the supplied harness.

How have those of you who completed this page interpreted this drawing? Am I trying to use the wrong connector even though it's the correct gender for the pre-wired harness? 



IMG 3574

I only got one reply who essentially agreed with me that the orientation is reversed, and that I should insert the wires according to the number/color indicated, not the position as drawn (e.g., install as per the position as viewed from the opposite direction.)    OK, fair enough.  Let’s see what happens in about a year when I apply power and start ‘smoke testing’ :0)

IMG 3579

Audio Jack connector visible in wing root opening

IMG 3580

Copilot’s Audio Jacks, installed

It’s kind of hard to tighten them up too much, so I put a drop of blue Locktite onto the threads to ward of evil spirits of vibration.

Friday, August 22, 2014

31B-19 Pitch Servo Connector

IMG 3575

Pitch Servo Connector

Remember that PIA spade connector I told you about?  There it is.  As guessed, the instructions call for the connectors to be left together and ignored if you are not installing an autopilot, and to leave them apart (pending further instructions) if you are.  Personally, I’d have the builder strip and crimp on the connector after passing the wire bundle, but that’s just me...

31B-16 12V power outlet

IMG 3571

Back View of 12V Power Outlet

31B-15 Options Harness 45

This guy was a pain in the rear.  I threaded the harness through the panel grommet and did a bad job remembering to not tangle with the brake lines under the panel. I had to fish it back out and re-thread it.  There’s a large gauge red power wire (auto pilot roll servos, IIRC) that inexplicably has a spade-spade junction about 6” from its end.  That damn spade-spade junction is damn near impossible to fit through grommets that already have wires through them!  I’ve delivered 10# babies easier than that!  Oh, well.  At least it’s done now.

The pictures aren’t much, just more of the wing connectors and some more wires.  There’s really not much else to photograph...

IMG 3569

Wing Connector with additional Options Harness wires

IMG 3568

Mid tunnel with both Main and Options harnesses

31B-18 Wing electrical connectors

IMG 3566

Right Wing Electrical Connector

IMG 3564

Left Wing Electrical Connector

Note the white wire is just a stub with a spade connection, and the wire from the aircraft is the mating spade.  These will be connected to a noise reduction capacitor before final installation.

31B-14 OAT probe

IMG 3561

Outside Air Temp Probe

31B-11 completion of Wiring Harness 46

This posting is several days out of date, and I really don’t remember too much about finishing this page so I guess there’s nothing much to say here.


IMG 3558

Aft Tunnel with WH-46 pulled

Tuesday, August 19, 2014

31B-10 wing pin sensors

This was a fun page to do.  Although kind of silly, the plane is designed to tell you that the wings aren’t installed and it will not let you start the engine if they aren’t there.  The way it is designed is that the wings are held in place with some very strong steel pins that go through the F-1204 bulk head and wing spars.  Those pins have a protruding handle that has a magnet installed in them.  The magnets then close reed switches and provide a confirmation that they are in place.  This is wonderful, except for the fact that you can install the pins without the wings, so it’s pretty easy to confuse the plane.  Anyway, on to the installation of the reed switches.  (The magnets have already been installed, back in chapter 30.)

Anyway, these magnets are housed in epoxy, which is housed in an aluminum bullet, which is then housed inside the steel barrel attached to the main pin, which is rotated to bring the barrel into proximity of the magnetic reed switch.  Do you see a problem here?  The magnets are shielded inside the steel barrels. I couldn’t get the switches to close anywhere near their installation position, although they closed just fine out in front of the assembly where the steel wasn’t shorting out the magnetic field.  The book said that the tubes could be shortened 1/32” at a time, up to 1/8” but I ended up shortening them by 1/4” to get them to work.    

Shortening the tubes was yet another learning experience.  I used a grinder to abrade the tubes to the desired length, but then discovered I could place neither the springs nor bullets into the tube any more.  Although I couldn’t see it, I deduced that there was a rounded lip inside the barrel.  That came off with a dremel bit and things went back together again. 

Lastly, I had to twist the bullets 180° to find the best position for the respective reed switches.  The pin assemblies are now marked with red & green tape for port & starboard.  Finally, it was unbelievably challenging to start the nut on the screw that held the reed switch on the left.  Just wanted to let you know that it wasn’t fun.

IMG 3556

Starboard Wing Pin

IMG 3557

Port Wing Pin


The epilogue to this page was that I lost my 1st part out of the kit.  I couldn’t find the 4 little snap bushings that channel the sensor wires through some sheet metal to the conduit.  I had to wait a few days to get $0.48 in parts from Van’s for $5.  <sigh>.  To salvage the embarrassment of ordering such a tiny amount, I ordered some caterpillar grommets to line the sharp edges of the access holes while I work on them. That should make things a bit more comfortable on my arms. 

Friday, August 15, 2014

31B-09 pitch servo connector


IMG 3549

Pitch Servo Connector

31B-08 wing electrical connectors


IMG 3547

left wing electrical connector

Forgive the blurry picture.  It was taken at about 4:30 am.  The plane is currently on its right side, so this is the upper surface.   I’m holding the camera up over my head and aiming without being able to see the screen very well.  ( The pink/purple thing is a sheet I use to keep the dust off when I’m not working on it.)

31B-07 aux music jack

IMG 3545

Aux Music Input Jack

31B-06 fuel flow transducer connection


IMG 3543

Fuel Flow Transducer Connector

Again, the blue tape is a temporary fixating device.

31B-05 CPU fans


IMG 3541

left CPU fan

The masking tape and blue tape are temporary ‘bulking agents’ to keep the respective cables or coax from sliding down their respective holes.

31B-03, antennae cables

It looks like this chapter is going to be a bit boring in the documentation department.  I’ll only be putting in commentary where there is something unusual (like the magnetic reed switches).  The photos should be largely self explanatory.


IMG 3537

Comm, ADS-B and ELT cables


progress in the fuel system!

As you will recall, I left off with the conclusion that the fuel pump was the next suspect, and I was awaiting its replacement.   I had been thinking about how to test the pump and went to the local auto parts store to get some tubing and adaptors so I could pump gas from the gas can back into itself.  I hooked up the old pump and got the familiar low hum and no gas flow.  I hooked up the new pump and got a moderately louder hum but... ... no flow.  Now I was really intrigued (I’d long passed the stage of anger/frustration—now it was a puzzle to be figured out.)  The odds of two bad pumps were so low that it wasn’t worth thinking about any further.  Next step?  The power supply. 

I was using an old battery charger that I’ve owned for a long time.  (You can tell where this is going, eh?)  Pulled out a volt meter and measured 11.5 vdc.  That’s odd, it should be about 14 vdc to charge a 12 v battery.  I put one of the pumps on the charger and still got 11.5 vdc.  Just on a whim I checked for AC and found 35 vAC!  That’s definitely Not Good.

An emergency run to the 24 Hour Aviation Supply Store (a.k.a. WalMart) resulted in their last two 6v lantern batteries (one alkaline, one ‘standard’) and this time I could pump gas through the test circuit!  With both fuel pumps!  From here, it was all down hill (in a good way).  Installed the old pump into the plane, added 2 gal of gas and the ‘short’ between the gascolator and the return line.  It pumped fine and there was good flow out of the return line back into the tank.  I let it run about 10 min with no gross leaks.

IMG 3536

Gas dribbling down return line

(The photo doesn’t show it very well, but there is gasoline dribbling down from the inside of the yellow fill funnel and along the fuel return line.  (I used the yellow fill funnel to keep gas from splashing all over everything.)  Even though it’s a lousy picture, I was still quite pleased with the occasion, so here it is.)

Removed the ‘short’ and let the system pump gas back into the can.  When the tank was dry, I used one of the suggestions from VAF and wedged a steel rod threaded through a funnel to drain the gascolator into the can.  viola!

Now that I finally have figured out that problem, I was raring to get going on the wiring.  I got 6 or 7 pages done in 24 hours, but will have to take another 1 week break and go back to work. 

Alas, not all is completely wonderful.  About 4 hours later I was pulling wires through the belly access plates and noted a wet connector where the forward fuel return line attaches to the bulkhead union.  I’m pretty sure that I cross threaded that connection when I had so much trouble installing it.  I re-installed the connector with a new thread sealant (the one recommended by Bob) and will re-test the fuel system when I’m able to spend a day flipping the plane back onto its belly.  I expect that it’s going to leak and I’ll need to replace that line and the bulkhead union.  Stay tuned!

Sunday, August 10, 2014

31B-02, wiring prep. (Fuel system woes.)

OK, this page says that it’s about starting the wiring process, but it’s really a page where I can bitch about the fuel system.  This was pretty easy page that didn’t involve anything in the tunnel or along the floor, where all the fuel lines are.  You know: the damn fuel lines that aren’t working yet.  Anyway, here’s the progress:

IMG 3500

Modified Grommet in firewall

This is the modified grommet placed in the fire wall.  That’s pretty much it for this page.  OK, back to the bitching.

I’m very determined to get the fuel system working before I add more complexity to the tunnel.  I rebuilt the fuel lines forward of the cutoff valve.  These look much better, as they should since I used up 6’ of pipe trying to get them to look right.  One of the other bits of brilliance I had during the last few weeks was that I may not have put enough gas in the tank to get a good suction from the pump.  This time I added about 2 gallons to the tank.  I actually saw the mechanical gage show a measurable amount.  All looked good.  Power applied to pump and... ...nothing.  Disassembly one step at a time showed fuel just barely dribbling over the upper surface of the fuel outlet on the gascolator.  This looks suspiciously like the same level of fuel in the tank, but I wasn’t thinking well enough to do some tilt testing to verify that assumption.

After a night of wracking my brain to figure out how to drain the tank, I tried tilting the whole ship up as much as I could (about 10-11°) to try to unport the fuel pickup.  I still ended up taking a gasoline shower when I removed the pickup.  damn.  I removed the line from the tank to the pump. I removed the pump.  Both blew fine.  I blew the main line from the gascolator (through the forward tunnel line, the fuel flow meter, the interconnect line to the cutoff valve, the cut off valve itself, and the line from the pump to valve) and made another mess as I ejected fuel out of line that attaches to the fuel pump.  In other words, I’ve removed or blown the entire system. The only conclusion that I can reach at this point is a defective fuel pump.

I ordered it the day I left on vacation and it should be back when I return.  I happen to be posting this from a hotel in Toronto, ON where my wife & son are enjoying a marvelous vacation.  More to follow...