Soon, I’ll be installing the overhead fresh air plenum. I’ll need the have the lights fitted before I get to that point. I looked at Oshkosh for some good LED map/courtesy/flood lights. I found a bunch but as is the case with many things aviation, just because it goes in an airplane, you can usually add a zero to the price. What should cost $12 ends up costing $120.

$110 lights
$130 lights
$145 lights

See what I mean? But just like the door linkage…  Something I know about.

Here’s what I did. I found a light for boats. A Perko 12v light.

I bought 4 of these at a marine supply store. Now this fixture has a 12volt incandescent light inside (I’m going to have a 28v electrical system). But that didn’t matter because I just wanted it for the plastic.

I removed the bulb, mounting hardware and wires.

I purchased a dozen high intensity white and red LEDs at (of all places) superbrightleds.com.

Now I was venturing into uncharted territory. To have circuit boards manufactured would have cost me about $100. I discovered a way to make them myself. I created the layout using a free PCB (Printed Circuit Board) design program I found on the internet.

Now here’s a neat trick: If you print the layout on slick, shiny paper, it transfers to the circuit board better. Finally a use for all those clothing catalogs my wife gets in the mail.

I picked up a blank copper clad circuit board and Radio Shack.

Then I put the paper on the circuit board and using a regular clothes iron, transferred the ink to the card. The paper comes off by soaking the whole thing in water for a couple minutes and then it goes into an etching solution (purchased at Radio Shack) for 20 minutes.

I cut out the individual, circular PCB and epoxied it to the back of the light fixture. Then I drilled the holes for the LEDs, resistors and leads and started soldering.

This first one was a “proof of concept” prototype. I just wanted to make sure the design worked. So I pretty much slapped it together and installed some test points instead of wires.

I SAID it was a prototype. It’s not SUPPOSED to look pretty.

Red

White

WooHoo!

One thing I didn’t like was when I soldered the components in the solder would run all the was along the trace. On real PCBs there’s a “solder mask” that contains the solder. Then I discovered that you can create a poor-mans solder mask using glass paint from the hobby store. This is paint that you can use on glass to create a stained glass effect. After painting it on, you bake it in the oven to cure it. After that, you got a solder mask.

Here’s a “production” model.

Total cost for the for lights: About $50.

The NACA ducts that I installed nearly two years ago need to be reinforced from the inside. So a couple layers of BID around the edges of the NACAs and the fresh air duct.

Now comes the big stuff. I’m not going with the diagonal shoulder belt system that the factory sells (and is found in most cars); a lap belt and a diagonal shoulder harness. Instead, I’m going with a 4-point style with a lap belt and two shoulder harnesses that connect to a center buckle.

The problem here is that with the fast build, the factory puts in the hardpoint for a diagonal shoulder harness (this is the stuff that you don’t think about when you’re starting all of this). So I’m going to have to completely remove the B-pillar/overhead beam.

This is looking up at the roof. At the bottom-center is the top of the pilot side door opening. Top-center is the top of the co-pilot door opening. On the left side of these door openings is the overhead beam. This overhead beam (and the B-pillars which run down the side in back of the door openings) are made of carbon fiber. In order to get a hardpoint for the shoulder harnesses to mount to, I was going to have to remove this, install the hardpoint and re-install it. That’s when I made a couple discoveries. 

• The B-pillars and overhear beam are not a single unit. They are three separate pieces.
  
• Where they are tie in is not the most impressive union I’ve ever seen.
  
• The roof has a layer of carbon fiber BID… but only one layer. (Notice in the previous picture that instead of solid black, you can see some “tan” between the rear beam and the windshield.)

Here’s the joint between one of the B-pillars and the overhead beam.

And here’s a closeup. No reinforcing layups. Just some epoxy.

The first thing to do is remove the overhead beam. To do this, I scored the 2-BID layup where the beam meets the roof. Then using a putty knife, I separated the BID from the beam at one end and then literally peeled it away from the beam. Then repeat for the roof. Next I made a couple small cuts at the joints on each end, a couple whacks with a chisel and the beam came right out. 

Next I smoothed out any rough areas and sanded the entire forward roof area and lay down an (additional) layer of carbon fiber BID.

Once that cured, I decided to do an additional task. Most builders have a hard time getting the doors to fit after installing the engine. This is due to the weight of the engine causing the fuselage shape to change slightly. A few builders have installed some diagonal layups on the roof from the rear to the front to prevent the distortion. I used two plys of a fairly thick carbon fiber UNI that will help with the distortion and will add to the strength of the roof. 

Next I needed to locate where the hardpoint for the new (improved) shoulder harness will be. I did this with a plumb bob and a tape measure. The hardpoints for the diagonal shoulder harness is a piece of 2″x4″ wood. Two problems with that method for the new hardpoint. #1 is that the B-pillar is much deeper than the overhead beam (the beam is only 5/8″ deep) and #2 is the factory hardpoint uses a bolt sticking out. So I’m going to use a 3″ x 4″ x 1/2″ piece of aluminum that’s drilled and tapped. For most hardpoints, they use 2″ x 2″ x 1/8″ so mine will be much more substantial.

Here’s my hardpoint and the standard sized hardpoint.

Once the hardpoints are secured with structural epoxy, I drilled and tapped them.

Before installing the beam I glued down a small square of titanium on the ceiling where the bolt for the hardpoint would come through. Just in case a too-long bolt was used, I didn’t want it going through the skin.

I need to bond the beam in place. I want the overhead beam to become part of the of the B-Pillars to create a seamless rollcage. So I took 2 layers of leftover carbon UNI and inserted them into the ends of the B-Pillar. I then stuffed some foam under the layups to force it into contact with the inside of the B-Pillar.

Then I applied some structural epoxy to the bottom edge of the beam and pushed into position. The foam under the layups will also force it into contact with the inside of the overhead beam. I then put the beam in place with a couple bricks on top to hold in place while the epoxy setup. Then I used some more leftover carbon BID over the seam with the B-Pillars and over the beam and onto the roof.

Here you can see the duct for the fresh air in between the two engine cooling NACA ducts.

On the inside, there’s a plenum that runs from the rear up to the front. I’m going to install four eyeball vents (one for each seat) and four lights. The electrical lines for the lights will also be in the plenum. Determining the location of the vents and lights will be a little tricky since the seats aren’t in and the airplane is upside down so I’ve got to guesstimate their location.

Here’s one of the vents that I’m going to be using.

I forgot to get a picture of the plenum before cutting the holes for the lights and vents. But here’s the front of the plenum after the holes are drilled for the vents with one of the vents installed.

Here it is mounted in the plenum.

Oops. Going to need to be modified. 🙂

Before and after.

Here’s the plenum with the openings for the vents, lights and switches.

The plenum with the vent, light and switch for the left rear seat.

Closeup of the previous position.

The lights are attached with 4 6-32 screws so I had to drill holes for the screws and nutplates.

Can’t leave well enough alone. After talking with my A&P (Airframe and Powerplant mechanic) who used to work for United keeping their airplanes flying, he suggested an “all on” switch. A single switch that will turn on all the lights. Sounded like a good idea but it will require redesigning the lighting circuit board. This time, I decided to let the company that provides the design software make the board. It cost about $10 per board so I figured that I would try it.  While I was at it, I added a fourth white LED and used a single resistor for both sets of lights.

Here’s the new circuit board.

Mounted and wired.

From the inside.

Test run.

More Plenum Work

Because the air intake is on the top of the fuselage, water will be able to enter the plenum. So a drain is needed at the back of the plenum.

Then I put a bulkhead just aft of the drain so no water would pool in the plenum.

Finally, to prevent water from being forced up front and out the vents, I installed a small “half bulkhead” (a dam, if you will) between the intake and the vents up front.

I was going to add the swivel map light at the front of the plenum. This would illuminate the overhead switch panel and could be used for a map light. For some reason, I decided to check the location. Good thing I did…

Two things wrong here: 1) it’s so close to the panel that it would only be able to illuminate a fraction of the panel and 2) it will interfere with accessing the switches. So it I decided to move it to the side and a couple inches back. While it won’t light the panel like I thought, I can still use it as a map light.

Before installing, I still need to paint it.