EMS and Ignition Wiring

I removed all of the unused wires from DB-37 connector on the SkyView EMS.  I ended up taking out a couple more after this picture was taken.  This was a surprising amount of weight that I don’t have to haul around without benefit.

Here’s the remaining wires.  I’m only using about half the pins in this connector now.  Part of the reason is that all of the position sensors (aileron trim, elevator trim, and flaps) now connect to the VP-X.

I noticed that one of the BNC connectors on the Light Speed ignition box was loose.  I probably violated the warranty (which is likely expired now anyway), but I popped the cover off to tighten it up.

Here’s the connector in question.  You can clearly see that the lock washer isn’t even compressed.  They simply forgot to tighten it fully at the factory.

By comparison, the other BNC connector was tightened fully.  Now they both look like this and are rock solid.

I decided to reroute the ignition sensor wire so that it takes a more direct route back toward the firewall.  This also keeps the wire away from the snorkel (not yet installed).

The wire follows the starter wire back to the engine mount then will get anchored where my finger is so that it will not interfere with the oil cooler.

It then turns up and follows the CHT/EGT wires through the firewall.  It was a pain getting the connector through the pass-through.  I had to remove most of the other wires as well as the connector housing to squeeze it through.

From there, it follows the manifold pressure back and through the aft adel clamp.

Both then turned upward and connected to the Light Speed ignition box.  You can also see a red and black wire running through the right adel clamp.  These are the wires from pins 1 and 3 of the EMS.  The red wire connects to the battery bus and the black wire connects to the firewall ground block.  Together, they’re used to measure battery voltage as well as provide a small amount of power to a couple of the engine sensors.

Both wires run along side the ignition wires.  The black wire then separates here and connects to the ground block.  You can also see that I connected the two VP-X ground wires to their appropriate pins on the J10 and J12 connectors.  These are 18AWG (vs the 22AWG from the EMS) since they carry power for the flap and trim motors which can draw several amps.

The red wire continues on through the front adel clamp and connects to the battery bus.

The label maker I’m using can print on heat shrink tubing.  I’m using that to label certain wires.  All ground wires in the plane will be black, so there’s no need to label them.  All power wires will be labeled as well as both ends of signal wires.

Demo Seats and Wire Routing

I’m having my interior done by Classic Aero Designs.  I really want to go with the Aviator seats, but I had some concerns about the amount of headroom I’d have.  I spoke with Luke at Classic Aero and he offered to send me out both an Aviator and a Sportsman seat so I could try them out.

The Aviator seat has a rounded top and an integral frame.  It’s also offered with a headrest and looks much more like an automotive seat.

Since it has an integral frame, the back is covered and has a pocket.  There is also an adjustable lumbar support.

The Sportsman seat has a square top (because it uses the Van’s seat back which has a square top).

It also has an adjustable lumbar support, but the back must be un-velcroed from the frame to adjust it.

I installed a couple of nutplates on the B&C voltage regulator and installed it to the right subpanel rib.

There are two bundles of wires on each side of the VP-X that need support.  I also need a way to route wires between the left and right side of the aircraft.  I installed some adel clamps on the bottom of each subpanel rib.  They’re just clecoed on since I’m sure I’ll have to swap them out for different sizes after I know how many wires will run through each clamp.

It’s not clear from this picture, but they’re aligned with each set of connectors on the VP-X.

I also installed a couple of adel clamps on the forward VP-X support angle.  Wires that need to cross from one side of the plane to the other will step up and cross on to of the VP-X through these adel clamps.

Here you can see that the ignition wires cross over the VP-X, down through the forward adel clamp below the subpanel rib and then out through the firewall pass-through.  Once these are zip-tied to all the other wires running along side them, these will very well supported.

Installed Vertical Power VP-X Pro

I didn’t like the strain put on the ignition wires by the tight bend necessary to curve down toward the top firewall stiffener, so I picked up a couple of right angle BNC adaptors from Fry’s.  These were only a few bucks each vs. the $17 each (plus shipping) for right angle crimp connectors.  This creates an extra connection in each line, but they’re on quite solid, so I’m not worried about it.

I received my Vertical Power VP-X empty shell today.  Instead of using the included mounting brackets, I cut a couple of pieces of 0.063″ angle so that the VP-X could be mounted to the bottom of the two subpanel ribs.  This location will create plenty of room on each end for the connections.  It’s high enough that it won’t interfere with the control cables, but low enough (and forward enough), that it shouldn’t interfere with any radios that poke through the subpanel.  The forward mounting angle is 1 7/8″ aft of the top firewall stiffener, which provides plenty of clearance for the parking brake valve arm.  You can also see in this picture that the ignition wires fall naturally along the forward mounting angle (now that the right angle adaptors have been installed).  I’m likely going to use that angle as an anchor point for a forward wiring bundle.

I drilled and attached the mounting angles to the VP-X.

After cutting the angles to length and drilling them to the subpanel ribs, I installed nutplates on the ribs and reinstalled the VP-X.

Here you can see the nutplates that are used to anchor the mounting angles.  This is *very* strong.  The actual VP-X (as opposed to the empty shell) weights 2lbs.  There might be as much as a pound or two of other stuff hanging off these mounting angles.  Even at 6 Gs, that’s no more than 25lbs or so.  This can easily hold twice that, so there is plenty of margin built into this.

Installed SkyView EMS and Lightspeed Ignition Box

I installed some one leg nutplates on the SkyView EMS box because I need to install the screws from the other side in case this box ever needs to come out.

I then installed the EMS on the outboard side of the subpanel support rib.  You can see here why I needed to install the screws from the other side.  The top skin curves down here, so there would be no room to get a screwdriver on these screws if they were installed from this side..

I also installed nutplates on this side to attach the Lightspeed ignition box.

Here’s the Lightspeed ignition box.  You can see the screws that attach the EMS just above this box.  There is another pair just below the ignition box.  These are all reachable without removing the ignition box.  There is just enough room in front of the ignition box for the RG-400 wires to curve downward to run along the top firewall stiffener without contacting the firewall.

Lots of Random Tasks

I zip-tied the EGT and CHT wires to the ignition wires on both sides.  These are just temporary, but I need to get the wires in their final positions so that I can begin cutting things to length.

I then installed the 1/4″ nipples into the EI FT-60 (colloquially known as the “red cube”).  This will be mounted between the fuel injection servo and the spider and will measure the fuel that’s being delivered to the engine.

Here’s roughly where it will be installed.  I will need a 2 3/4″ hose that connects the fuel servo to the input side of the red cube.  Hopefully Bonaco can make one this short.

The output side of the cube has a 90º elbow that points directly at the inner end of the right-side inter-cylinder baffle.  I’ll drill a hole through there to pass the hose that connects the red cube to the spider.

I also removed, re-lubed, and reinstalled the fitting in the spider so that it points straight down.  The shiny area between the cylinders is the inner cylinder baffle where the hole will be drilled.

I removed the right side inter-cylinder baffle so that I could drill the hole.

I drilled a 13/16″ hole…

…that will hold a grommet that has a 1/2″ interior hole.  That is roughly the outside diameter of a 1/4″ hose with firesleeve.  I’ll have to install the grommet over the hose before installing it in the hole, but I wanted to make sure it fits properly.

I stopped by OSH and picked up some #10 brass hardware and installed the SkyView ADAHRS.  The ADAHRS contains a magnetometer, so there can’t be any ferrous metal near it so that it can get an accurate heading reference.

I crawled back in the tailcone (hopefully for the last time) to install the static tubing from the tee on F-708 (near the bottom of the picture) through F-707 and into the front of the ADAHRS.  There is a tee installed here because the static line will also run forward to the TruTrak Gemini that I’m using as a backup EFIS.

One of the things I got in my last order from B&C is the alternator field connector.  I installed a jumper between the terminals and added some heat shrink.

I added a couple of extra pieces to build up the thickness of the single wire.

Then installed a larger piece of heat shrink over the whole thing.

Here’s where it connects to the back of the alternator.

The wire will likely run along the alternator b lead along with the wires for the fuel flow sensor.

Modified Dimmers and Mounted Cabin Light

I ordered three of the solid state dimmer circuits from Perihelion Design.  They’re completely self contained and use a LM317T chip to regulate the voltage to the lights.

The zig-zag trace that connects the outer two pads regulates the minimum voltage.  With this short, the dimmer puts out 1.3V at the low end.  This is too low for the annunciator and cabin lights I’m using.

I broke this connection so that I could solder a more appropriate resistor in place of this trace.

The cabin light needs a 330Ω resistor to set the low end of the voltage range to 5V.  Below that, the cabin light I’m using shuts off, so there’s no point in letting the dimmer go below that voltage.

The dimmer that controls the annunciator lights needs a 150Ω resistor to set the low end of the voltage range to 3V.  The third dimmer will be used to dim the lights that go under the glareshield.

Here’s where I mounted the light.  It’s basically as far forward as I could mount it without interfering with the roll bar.  This is still low enough that it illuminates the whole panel, but far enough forward that I can illuminate my lap reasonably well.  This can also be turned left-to-right as well as angled up and down.  I’ll most likely wire this directly to the battery bus so that I can use it to illuminate the cabin and baggage area when loading/unloading the plane.

Refined Annunciator Control Circuit

I’ve spent the last couple of days refining the annunciator light circuit and laying out a PCB that I’m going to have fabricated by expresspcb.com.  They require a minimum order of three boards, so I’ll have a couple of extra if anyone wants to buy them.  Email me at the address in the left bar if you want one.

I also designed a couple of other simple PCBs to replace the SkyView splitters as well as the interconnect between the SkyView and the other avionics.  I’ll post pictures of the boards when I get them.

Unfortunately, the PCB design software only runs on Windows and is really shitty.  I haven’t had to use Windows this much in almost 10 years, but it was just as bad as I remember.

Designed Annunciator Light Controller Circuit

I’m planning on having 7 or 8 annunciator lights.  Some will be triggered when a signal is pulled to ground and others when a signal is pulled to 12V.  I also wanted a button to test all of the lights and a dimmer so I can reduce the brightness for night flight.  I couldn’t find an off the shelf controller that I liked, so I decided to dust off the old EE degree and design a simple circuit that did what I want.  I prototyped a two light version of the circuit below.  You can sort of see the two lights (red and yellow) near the top center of the picture.  The left switch at the bottom simulates the push-to-test button.  When thrown, both lights should light up.  The right switch simulates one of the circuits that should light an annunciator light when pulled to ground.  This circuit doesn’t handle signals pulled to high because I didn’t have any diodes on hand to do that portion of the circuit.

Here’s the push-to-test switch thrown.  You can see both lights are on.

Here’s the single signal light illuminated.  The lights only require 20mA at 12V, so a simple 2N2222A TO-92 NPN transistor can handle this without even warming up.  The end circuit only needs one diode, one resistor, and one transistor per light.  There’s one additional resistor in the circuit to handle one edge case that could blow a diode if one of the high signal pins were pulled to ground accidentally.

Installed Switches/Buttons in Controls Sticks

After soldering all the wires to the control stick switches, I slipped some expandable sleeving and finished the end with heat shrink.  This is the copilot’s PTT button.

The copilot’s stick is removable, so the PTT switch needs a connector in it at the joint in the stick.  I’m using a small 0.062″ 2 circuit plug.  The wire will exit between the rod ends at the bottom of the stick.  I added a layer of heat shrink around the sleeving where it passes between the rod ends to provide an extra measure of abrasion resistance.

I drilled both control stick grips and epoxied in some small 8-32 t-nuts.

I then installed some 1/4″ long socket head set screws that will be used to anchor the grips to the sticks.

With all of the wire soldered on the switches and buttons, I installed them in the grips.

I slipped some sleeving over the nine wires coming out of the pilot’s grip and then installed it on the pilot stick.  Just like on the copilot’s side, I routed the wires out through the bottom of the stick.  Many builders drill a hole in the side of the stick near the pivot point to avoid routing the wires near the moving parts, but Van’s recommends against this as it will weaken the stick.

Just like on the copilot’s side, I installed a length of heat shrink where the wire bundle passes between the rod end bearings.

Replaced SkyView USB Cable and Worked on Control Stick Grips

The SkyView DB37 connector comes with a long USB cable with a type A female end on it.  The other end connects to pins 16-19 on the DB37 connector.  This cable is kind of useless as the female end can’t be mounted to anything.

I extracted these pins from the DB37 connector so I can replace it with a more appropriate connector.

I picked up this 18″ USB 2.0 A M/F panel mount cable.  I could have just connected this to the preinstalled SkyView USB cable, but it won’t have been extremely long and would have just ended up coiled up behind the panel.  I clipped off the male end and crimped on some d-sub sockets.

I then reassembled the connector.  I really wish Dynon had just installed this sort of cable in the first place.

Here you can see that the cable is long enough to reach anywhere near the SkyView screen.  To confirm everything was working correctly, I upgraded the SkyView to 2.6 using the USB thumb drive plugged into this cable.  I’ll install an identical cable on the other SkyView screen once I order it.

While I had my electrical tools out, I went ahead and soldered some lead wires to the controls that will be installed in the control stick grips.

Before I can install the controls into the stick for good, I wanted to put a couple of coats of tung oil on the grips.