On the instrument panel, there is a need for a warning system. Kind of like the “idiot lights” on a car instrument panel. The Grand Rapids and Vertical Power can display warnings and alerts, but sometimes it’s a bit difficult to identify the actual failure or notification.

Most builders put some lights on the panel and put a label under it.

Here’s an example for a Low Voltage and Starter Engaged warning.

But I wanted something a little bit nicer.

This is the “Master Warning Panel” in a Cessna 441.  Sweet!

I found some really nice Hi-Intensity, wide angle LEDs. I then designed the circuit board that the LEDs would be mounted to.
an-sch

But the one thing I kept coming back to was how to make (what I call) the mask. The thing with the lettering. My initial plan was to run some clear transparency stock through the the laser printer. But the black wasn’t opaque enough. But if I did two layers it was. but getting the two layers to align was very difficult. But that’s the only choice I had.

Then a friend told me that the shops that made trophies had this black stock that they hit with a laser and could make clear lettering. So I started calling around and I found one that could get the material and had the laser. After some back and forth on the dimensions and lettering, I had a “version 1” of the Annunicator Panel mask.

While I was working on the circuit design, I breadboarded the circuit. Here’s what it will look like.

Now I just have to build the housing, get the circuit board etched, solder all the components, and figure out how to mount the whole thing to the instrument panel. 🙂

Now that I’ve got the mask, it’s time to start making the frame. When I first started thinking about this idea, I wasn’t sure how I would make the frame that the mask and PCB attaches to. But as usual, Malcolm had the solution… Styrene. He uses it in a lot of his models.

In case you forgot. Malcolm’s tank.

I always think of Malcolm when I watch Flight of the Phoenix (the real one, not the remake).  The only difference is James Stewart would have been flying one fast plane out of that desert if Malcolm had built it.  🙂

So I picked up a 12″x”6″x .06″ sheet of styrene and cement. I cut three 1″ wide strips. Two of the strips I cut down to the same length as the mask. These would become the top and bottom of the frame. The remaining strip I cut into nine half-inch long pieces.

I marked the position of the spacers on one of the long pieces and then glued the end spacer on.

To insure proper spacing and to keep the spacers at 90 degrees to the bottom, I used a scrap of 1×1 aluminum with a shim to get the spacing just right.

Now all the spacers are attached to the bottom.

I flipped the assembly on its back and then cemented the top on.

Finished product… kind of. I still have to create a flange for the PCB mount and the instrument panel mount. And I have to paint it black. But I’m getting there.

Once the basic frame was done, I had to add a flange to hold the mask. I used some 3/16″ styrene angle stock and created a recess to hold the mask.

Which fits in just about perfectly!

Then I reinforced the flange with a plate of .60″ sheet.

Next I created the mounting pads for the printed circuit board.

I was going to simply glue in the mask and leave it at that. But I wasn’t sure how the gap between the mask and flange was going to look. And there would be no easy way to replace the mask. So I decided to make a faceplate to cover it.

Here’s the frame with the mask and faceplate installed.

And with the PCB attached.

Then I painted the frame and faceplate flat black.

Now it’s time to start assembling the components onto the PCB.

Here are the HiFlux, 90 degree LEDs installed.

The connectors, resistors, diodes and transistors.

Finished Annunicator Panel (AKA, Master Warning Panel).

With the Fuel Pump (Amber), Pilot Door Unsafe and Parking Brake (Red) indicators illuminated.

There are a few places that need ground connections. Engine side of the firewall, cabin side of the firewall and cabin side of the canard bulkhead (front of the cabin behind the instrument panel). One traditional metal aircraft, the frame can be used. But on a composite aircraft, that’s not an option.

There are a number of pre-made ground blocks available from places like B&C, SteinAir and Aircraft Spruce. But these can be pretty pricey and most use Faston connectors. I prefer ring terminals. So I decided to make my own.

I picked up a 12″x1″x.25″ block of copper from McMaster-Carr. Drilled out a 5/16″, 3/8″ and 11 holes for 8-23 screws.Next, I countersunk the holes for the 8-32 screws and tapped them out. Then cut them into three 8″ blocks.

Then I simply screwed in the 8-32 screws.

Installed.

I’m a little worried about corrosion though. John Tvedte plated his with a tin solution. So the next time I put in an order at Mouser, I’ll probably pick up some.

I decided to remake the overhead switch panel. Originally, I had planned on 11 switches with a push button starter. But I’ve decided to move the strobe light switch to the lower panel and use a spring loaded toggle instead.

Aircraft Spruce has some headset jack housings. But they were rather pricey (~$25 each). Malcolm told me about some housings he made, so I took some wood, shaped it, covered it with fiberglass, painted and then applied some release agent.

Then I covered it about 4 layers of BID with some Triax around the edges.  Repeat four times and I’ve got $100 worth of headset jack housings.

To install, I cut four holes in the keel, located the position of the screws, then installed nutplates for mounting.

I had already mounted the EIS (Engine Information System) and the MAP (Manifold Air Pressure) Sensor. Now it’s time to start pulling wires.

I picked up some expandable braided sleeve (AKA Chinese handcuffs) from McMaster. I split out the wires that would be going to the front of the cabin, rear of the cabin and engine compartment and fed the wires through.

Connected the two DB-25 connectors to the EIS module and routed the cables into the right wiring duct.  The wires going to the front of the cabin aren’t long enough so I’ll have to splice some longer wires on before running forward in the duct.

The majority of the wires go to the engine compartment. Here’s the firewall side of the right wiring duct. I used some yellow heat shrink tubing to provide additional protection for the wires. The red, yellow and white wires are for CHT and EGT probes. The rest are for various sensors and I put those in another sleeve which runs up to the terminal strip.

I’ll have to wait before I can terminate the wires for the other sensors. I didn’t have the right size heat shrink tubing for my label maker.

Here’s the EGT and CHT connections.

I’ve already done a fair amount of work on the panel layout. So I’ve got a pretty good idea where everything is going. The other day, I finally placed the first order with Grand Rapids for the panel instrumentation. I”m going to be installing a GRT HXr with remote avionics and an Android tablet option. I’ve delayed this as long as possible because new models are constantly being released. In fact, when I started this build, the HXr wasn’t an available model.

The EFIS is not symmetrical. There are knobs and buttons on the left side. What this means is that the screen is set slightly to the left. The reason this is significant is that I want the primary information display to be centered directly in front of the pilot. So the first thing I did was to identify how far to the left of the middle of the fuselage the center of the pilot seat was. Then I measured from the center of the instrument panel to the left and placed a vertical line to indicate the enter of the pilot’s vision. I then created a second vertical line to indicate the center of the EFIS box itself.

For now, I’m still using the paper EFIS display template for positioning. I drew two lines on this also: one for the display center and one for the faceplate center.

I then put the annunicator faceplate, lower switch panel, and light dimmer, servo controller and fan control panel.

As you can see, it’s rather busy. It also looks like the lighting/servo/fan controls will have to be individually mounted since the heatsinks would prevent removing the panel to the front.

Here’s the (latest) panel plan.

Panel1

I was worried about the solid copper ground block and corrosion. But fellow builder John Tvedt put me on to some “Liquid Tin”. This is typically used to cover the copper traces on printed circuit boards.

So I picked up a bottle from my electronic parts distributor of choice… Mouser.

I cleaned up the copper, poured some of the solution in a plastic pan and dropped in the parts.

It reminds me of Tarn-X. As soon as the ground block hits the liquid, it changes color.

Before and after.

I also got some high-temp PVC sheet to use as a separator to prevent dissimilar metal corrosion when mounting metal to the titanium firewall.

The Outside Air Temperature Probe is supplied by Grand Rapids. One of the possible issues is that the OAT is used to calculate the True Air Speed (TAS). The faster you go, the higher the air temperature will appear to the probe. So locating the probe in a spot that can measure the air temperature while not being affected by the speed of the air is desirable.

One of the functions of the NACA duct is that is allows the air to slow down. So I decided to use the nose NACA duct.

Finding the center of the duct.

The material isn’t thick enough to create a recess so I had to drill through and then create a backing plate.

From the inside with the probe (covered in plastic so the adhesive doesn’t stick to it) and the back plate.

From the outside.

Finished. I’ll have to put some filler in to make look better though.