FAB Assembly Continued

When I incorrectly oriented the FAB top during the first assembly, I drilled holes that will need to be filled with the correct orientation. Many of those holes were close to where the filter retainer angles go, so I just made a few adjustments to help them serve double-duty.

Since I had a few problem holes to fill, I made a new filter retainer that is slightly longer than the 1-inch standard.

Since I had a few problem holes to fill, I made a new filter retainer that is slightly longer than the 1-inch standard.

This wouldn’t be necessary for someone who did it right the first time.
I also made a few backing pieces to aid in hole filling.

I also made a few backing pieces to aid in hole filling.

Next I positioned the thin aluminum top for riveting to the fiberglass. I attached the thick aluminum top to the thin top with regular AN-3 washers between the two. Then I set the filter in place and clecoed the flange around the perimeter. Those washers will make up for a 1/16″ squish on the filter to help ensure a tight seal between the filter element and its respective joining surfaces.
Top in place, with washers

Top in place, with washers

With several clamp clecos in place to help be sure that nothing was going to shift, I marked and started drilling the rivet holes.
Replacing the clamps with clecos

Replacing the clamps with clecos

The length of hinge that Vans supplied for the carb heat door was made by Bandy Machining, which I thought was picture worthy, since that’s Tabitha’s old last name.
Hinge Stamp

Hinge Stamp

I cut out the shape for the carb heat door:
Carb Heat Door

Carb Heat Door

And started to prepare the steel arm
Carb heat actuating arm.

Carb heat actuating arm.

I cut the hole for the carb heat inlet, slightly smaller than the door.

I cut the hole for the carb heat inlet, slightly smaller than the door.

Here it is cleaned up a bit.

Here it is cleaned up a bit.

I attached the hinge, with the one of the pieces inverted, as instructed by Vans.
The inverted hinge half helps make the geometry of the door work better.

The inverted hinge half helps make the geometry of the door work better.

Then I drilled the rest of the perimeter holes.

Then I drilled the rest of the perimeter holes.

I altered the spacing a little to be sure that I wasn't going to hit the slot in the aluminum piece.

I altered the spacing a little to be sure that I wasn’t going to hit the slot in the aluminum piece.

The fiberglass was slightly oversized at the top, so I took it over to the belt sander and trimmed it flush.
A few seconds on the belt sander and the fiberglass matches the aluminum.

A few seconds on the belt sander and the fiberglass matches the aluminum.

After a little bit of head scratching I was able to locate the steel arm for the door. I primed it to inhibit rust a little.
I had to trim the hinge some to clear the steel piece.

I had to trim the hinge some to clear the steel piece.

One optional FAB feature is a bypass door that will allow the engine to get air even if the filter becomes clogged. I can only think of two possible scenarios that would cause this- one would be flight through snow, where somehow the snow was able to get to the filter without melting. Another would be volcanic ash or some debris like that. Both of these are very remote cases, but perhaps there is another that I don’t know about yet. In any case, I had the parts, so I thought it was prudent to install the option. I started by deburring the edge of the little trap door:
Machine Cut Part Before Debur,

Machine Cut Part Before Debur,

And After

And After

Then I located the hole and drilled it using the fly cutter on the drill press.
FAB alternate door hole

FAB alternate door hole

Posted on
Hours Logged This Session: 8.4
Total Hours: 1883.75

FAB Assembly

Today started with a few new parts arrivals. As I mentioned in the entry from a few days ago, I drilled the top oval plate for the filtered air box incorrectly. I wrote about much of today’s work back in that entry, but I’ll include pictures here.

FAB Alternate Bypass Door Parts

FAB Bypass Door Parts

The folks at Pegasus Auto Racing have an adapter that will convert the 1/8″ NPT outlet of the oil pressure sender to a 37-degree flare so that I can attach a hose to it.
Pipe thread to flare adapter

Oil Pressure Sender Adapter

In my last version of the FAB top, I cut a big hole to clear the cast lump on the bottom of the carburetor. This made a large slot that came very close to the edge of the FAB top, which was a situation that would likely lead to a crack later on. I read that some RV builders just filed off that section of the casting and didn’t have any trouble as a result.
Carburetor Casting

Carburetor Casting- Note the bump just above the upper right hole.

So that’s what I did too. I used power tools to get it close, then switched to a hand file, then finally to a scotch-brite wheel in the die grinder to polish it smooth. I was especially concerned about damaging the rest of the gasket face, so I worked very carefully. I thought it turned out pretty well!
Carbuertor Casting Bump Removed

Carbuertor Casting Bump Removed

This picture of the old FAB top shows how much material I won't have to remove out of the new FAB top.

This picture of the old FAB top shows how much material I won’t have to remove out of the new FAB top.

Even though the new hole in the top is smaller than the old one, there is still a hole for the drain spout. I cut that shape into the new top as I did the last one, by drilling the corners and cutting to connect the dots with the dremel.
The new top with the carb drain cutout, this time with the correct orientation of the thin aluminum piece.

The new top with the carb drain cutout, this time with the correct orientation of the thin aluminum piece.

Next I cut the angle piece supplied by Vans into 6 1-inch pieces. These make little tabs that hold the filter in place.
6-inch bent piece...

6-inch bent piece…

...Cut into 6 1-inch pieces.

…Cut into 6 1-inch pieces.

I spaced them as listed in the instructions and drilled for nutplates, using the nutplate jig.

I spaced them as listed in the instructions and drilled for nutplates, using the nutplate jig.

Since I have a few bad holes in the thin aluminum to piece, I’ll try and make some adjustments to the filter retainers to help fill them.

Posted on
Hours Logged This Session: 2.9
Total Hours: 1883.75

Vans FAB

I picked up where we left off last night , attaching the lower right cowl sheet metal. I took a few pictures of it all together, just because it looks so much more like an airplane.

Right Side Cowling

Right Side Cowling

Lower Left Side of Cowl

Lower Left Side of Cowl

Right Side of Cowl

Right Side of Cowl

Gap between spinner and cowl

Spinner Gap- This is the left side of the spinner, with “up” being to the left. Note that the spinner is a little bit high, since I’m hoping for some settling once the engine mounts age.

From there I reinstalled the carburetor so that I could start cutting the hole for the airbox. Note that in this series of pictures the FAB top is upside-down. This ended up being a problem later, so I would encourage you to not do the same! I started with aligning the left/right angle. I’ve flown Lycoming-powered airplanes for years, but it took building one for me to notice that the carburetor doesn’t sit on the airplane’s centerline. As others have noticed, the choice is to either keep the axis of the airbox parallel to the airplane’s axis, or to angle the airbox towards center of the nose bowl. I chose a mixture of the two, with a bit more of option 2. I marked the centerline on the lower cowl, then tried to approximate where the outer scoop would fall. To clarify, the intake includes the fiberglass FAB (Filtered Air Box), which attaches to the carburetor, and an outer fiberglass scoop, which attaches to the cowling. The FAB shakes with the engine, while the scoop shakes with the airframe. Since the front of the FAB is aft of the outer scoop by a couple of inches, positioning the front of the FAB on the centerline of the airplane will put the scoop entrance on the right side of the centerline. This is undesireable for both aerodynamic and aesthetic reasons. This was why I preferred to err to the left. To get started, I rested the FAB top on the oval top plate:
Bearhawk FAB Alignment

FAB Alignment

This picture shows the same situation from the side:
Right side

The reflections are confusing, but this is the view from the right side of the airplane, with the front on the right.

Lower Cowl

I drilled a couple of initial holes that would coincide with the front of the FAB.

I used a step drill to create large holes that would make nice round corners on the finished hole. In the end this didn’t matter very much since I enlarged the hole beyond those originals.
Vans FAB location

From those initial holes, I just started slowly working aft and enlarging the cutout.

FAB Alignment front

As you can see, the FAB top can now stick out of the cowl. It still isn’t resting on the oval plate, but I also haven’t bent the plate up to match the bend in the fiberglass part.

From there my strategy was to enlarge the hole a little bit at a time until I had at least an inch of clearance. That airbox is going to be moving around quite a bit relative to the cowl.
Bottom view looking up.

Bottom view looking up.

This picture has a couple of problems with the top oval plate. I ended up remaking this part for a couple of reasons. First, note that the carb sump has a little finger that sticks over to the left. After lots of research and hand-wringing, I decided to remove that part of the carb. I used the grinding wheel to get most of it off, then the belt sander finally the die grinder. You’d never know it was there! Also, since I was doing all of this work with the FAB top on upside down, none of my holes lined up once I flipped it back over.
The next few pictures are just to show where the FAB falls on the Bearhawk cowl.
Rough side view of the FAB location

Rough side view of the FAB location

Left side view of the Vans Filtered Air Box

Left side view of the Vans Filtered Air Box

View inside the cowl

View inside the cowl

Lycoming intake angle

This view shows the angle that I wrote about above. It’s crooked! But that’s on purpose.
The next step was to bend the FAB top to bring the front end of the assembly up closer to the cowl.

Vans FAB slope

The slope starts at 7 inches from the front.


Here is the top (it’s still upside down, which is wrong) showing the nature of the bend that I need to make.

FAB top bent

Here it is after the bend (I bent the top the wrong way, since it was upside down. It was no trouble to fix it later, but don’t copy this picture!

I think this box is much nicer than the other options available. It is a much more compact and durable design, and it uses a locally-available filter that is reusable. Another advantage is that carb heat is filtered air, which is good for we grass airport residents.

Posted on
Hours Logged This Session: 6.25
Total Hours: 1883.75

Cowling Continued Again

This evening Tabitha came out and we worked together on the cowl sheet metal. One of the challenges in trimming the leading edge of the cowl is that the edge needs to match the fiberglass nose bowl, which is hidden underneath the aluminum, and the aluminum isn’t transparent. Tabitha came up with the idea of using a piece of tape to mark the aluminum, and it worked pretty well.

Bearhawk Cowl Trimming

Tabitha’s method for marking the bottom cowl for trimming

She started by cutting out a few pieces of masking tape about 4 inches long. Then she cut some very small pieces and used to hold the larger pieces to the nose bowl, with the sticky side of the big piece facing outward. The forward side of these pieces marked where we wanted the aluminum to end. Once all of these pieces were in place, we reinstalled the metal pieces and rubbed where the tape was. Then we could carefully remove the metal piece, which took the tape with it. It takes a lot of words to describe the process, but it was really pretty straight-forward and I’m glad to have such a creative partner.
With that sorted out we were able to drill the holes in the front of the lower skins. These holes will get rivets, attaching the lower cowl to the lower nose bowl mostly permanently.
Center Punch Before Drilling

Center Punch Before Drilling

Tabitha Drills the Cowling

Tabitha Drills the Cowling

Bearhawk Cowling Clecos

All done!

Did I mention about how I was going to have to fix the hole in the side of the boot cowl? I cut the wrong shape out for the air vents. While Tabitha was at the hangar she dimpled the backing plate.
Vent Fix continued

Vent Fix continued

The next step will be to make a D shaped filler that will make the whole thing flush with the skin. I would have much rather just cut it right the first time, but as they say, experience is something that you get right after you need it.

Posted on
Hours Logged This Session: 4.5
Total Hours: 1883.75

Dynon Compass Module

I had to start by removing the carburetor this morning. This will give me plenty of room to work on the lower cowling pieces. I started preparing the sheets for the bottom. I think I’m going to start from the top and wrap them around, making the middle cut last.
I took a break from all of that to make some brackets for the Dynon compass modules. I tried to devise a system that would allow me to position the parts accurately during installation, since they are supposed to be lined up with the main box within a degree or less.

Dynon Compass modules stacked

Dynon magnetometers- one for the d180 and one for the d100.

Aluminum Rivets won't bother the magnetic field

Aluminum Rivets won’t bother the magnetic field

Dynon magnet bracket

The tall piece attaches to the rib

The bottom cowl pieces haven’t been as easy as the top pieces, but here’s the start.
Cowl Bottom PIeces

Cowl Bottom PIeces

Posted on
Hours Logged This Session: 3.9
Total Hours: 1883.75

Cowling Continued

Today I kept working on the cowling. I marked the left door for the holes that will become the quarter turn fasteners, and drilled the right door for it’s hinge. This allowed me to position the right bottom channel, and drill small holes for the quarter-turn fasteners on that side. I’m using four per side, and only on the bottom. I should add that I’m only drilling these holes as pilot holes for now. I’ll wait until the last possible moment to drill them to final size, and hopefully that will be after the boot cowl is riveted in place.

Posted on
Hours Logged This Session: 1.9
Total Hours: 1883.75

Left Cowl Door

I used the top cowl piece as a reference to position the left cowl door. I installed its hinge and left it a little bit long in the front so that I can trim it to match the fiberglass. The trailing edge has an even overlap.

Left Cowling Door

Left Cowling Door

Posted on
Hours Logged This Session: 2.8
Total Hours: 1883.75

Trimming Baffles

I woke up early this morning to try and beat the heat. I made a few more rough cuts to get the baffles clear of the cowling pieces, then positioned the nose bowl as accurately as possible. I aimed for 1/4″ clearance and 1/4″ of additional engine sag. I started the cowl work with the top piece. I used the original edge as the back, since I knew that I was going to have to trim the front to match the fiberglass piece. I drilled the cowl top to match the firewall and boot cowl, and positioned it under the fiberglass nose bowl for marking.

Engine Cowling

Trimming the Cowl Top – It’s on wrong on purpose.

I drilled a hole in a piece of plastic (an old hotel room key) and used it to make a mark on the aluminum that is parallel to the line on the fiberglass.
Custom Scribing Tool

This hand-made tool helps mark the cowl top for trimming

That worked pretty well. Here is the top piece in position.
Cowl Top in Clecos

Cowl Top in Clecos

I used another hotel room key to make a similar tool for marking the baffle tops.
Trimming Baffles

Final Baffle Trimming

I drilled the left side of the top piece to match the reinforcing channel and hinge.
Left Cowl Hinge

Left Cowl Hinge

It feels good to get back into sheet metal again!

Posted on
Hours Logged This Session: 3.5
Total Hours: 1883.75

Covering and Baffles

Tabitha came out today and resumed work on the left aileron. She finished up the tapes and applied the top coat of polybrush.

Tabitha Taping

Tabitha Taping

Tabitha Coating Tapes

Tabitha Coating Tapes

We both worked on that for a while, then I started trimming the baffles to clear the cowling pieces.

Posted on
Hours Logged This Session: 5
Total Hours: 1883.75

Initial Prop Install

Today I connected the blue LED that will become the parking brake annunciator. Since the parking brake valve is just a check valve, it could be especially troublesome to land with it in the closed position. The brakes would apply normally, but they wouldn’t release! I’m planning to make this blue light come on any time the valve arm is not in the open position. I used a 430 ohm resistor and stuck the whole assembly into one of the little aluminum casings.

Bearhawk Panel Annunciators

Annunciators- Dynon Warning, Low Voltage, and Parking Brake

It’s time to start making the cowling so that I can build the intake and exhaust systems. The first step is to put on the prop:
Hartzell Propeller

The prop fits! It sure is a hassle to install though.

This allows me to check the nose bowl positioning again.
Bearhawk Nose Bowl Position

Positioning the fiberglass nose bowl based on the spinner location

Since most of the wiring is done I put the boot cowl pieces back in place for a little while. I definitely would not have wanted to do all of that wiring work with the boot cowl on! Back when I cut the side vents in the boot cowl I did it wrong and ended up with a bad shape. Here’s my solution:

Fixing my eroneous vent hole (not a metaphor)

I’ll add one more little D-shaped filler piece and fill the crack with smurf extract. When I put the right side boot cowl on I found a bit of a clearance shortage. The side vent duct is a squeeze between the boot cowl and the electrical distribution panel. Fortunately I think it will still work just fine.
Right Side Vent

Minor clearance shortage

While I had all of that back on I also set the new windshield in place just to see how it fits. I don’t think I’m going to have to trim it at all, which is very nice.
LP Aero Plastics

Windshield Trial Fit

Posted on
Hours Logged This Session: 6
Total Hours: 1883.75

Reversing the Matco Parking Brake

Our spinner came with it’s original white paint, which matched the Husky that it came off of. I knew that we were going to have to repaint it one way or another, but we’ve both always preferred to have a polished spinner. I figured that I didn’t have anything to lose by stripping off the original paint and trying to polish the underlying aluminum. The chemical stripper that I used took the white paint right off, but the green primer didn’t respond to it. I used a fine scotch brite wheel in the die grinder to remove some of the green primer.

Hartzell Spinner

Almost naked spinner

I wrote before about my reversed parking brake control problem. These pictures show the solution. I removed the spring clip on the end of the valve arm and pulled it out. I stuck it in the other way around, thus inverting the valve’s operation. This makes so much more sense! In the picture below I left the old lines and it is even more obvious. I’m also glad to have a bit more clearance between the aluminum line and the grounding tabs.
Invertred parking brake valve

Inverted brake valve

Posted on
Hours Logged This Session: 2.9
Total Hours: 1883.75

Wiring the GNS430

Here’s the rudder. All of the taping is done and it’s ready to smooth.

Rudder ready to smooth

Rudder ready to smooth

I connected several more wires to the 430 today. It has a bunch of them, and it would have been many more if I were using a remote annunciator and indicator. The connectors on the back are divided into the three main functions of the unit- VHF Communication, VHF Navigation, and GPS. The VHF Comm connector uses standard size d-sub sockets, except for the power in. Garmin calls for slightly larger wires on the power inputs for the Comm, so they use these fancy connectors that are a bit longer and allow for the bigger wires. Each of the three connectors includes two power inputs, though I think the duplicates are more for power delivery than redundancy. It was tempting to connect one to the ebus and one to the main bus, but Garmin says that each pair should be connected to the same bus. Some folks connect the two power inputs to a single splice just forward of the connector and then run a single cable to the fuse block. I ran two separate cables all the way to the fuse block and gave each one a fuse.
GNS430 Power Wires

GNS430 Power Wires

I connected all of the wires for the GPS function of the 430, which are routed through the high-density D-sub connector with lots of holes. Most of those holes are for functions that I’m not going to need, so that job went pretty quickly. The transponder is all done except for the power feed, since I ran out of that size of wire. I’m trying to minimize my orders to Stein and B&C, but that’s easier written than done. So as of today the 430 GPS wiring is done, the VHF Comm has power only, and the VHF Nav is still empty.

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Hours Logged This Session: 5.8
Total Hours: 1883.75

Rudder Lacing and Taping

These nice weather days have provided an excellent opportunity to spend some time in the hangar. Here’s the rudder after the first coat of polybrush:

Bearhawk Rudder

Bearhawk Rudder

Rudder Rib Reinforcements

Rudder Rib Reinforcement Tape, 3/8 inch

I finished the rudder rib stitching in about an hour and a half. This is one of those skills that gets faster with experience.
I marked the areas for taping and brushed on the pre-coats of polybrush for the tapes. While that was drying I made a few more wires. Next up are the RS232 wires that connect the transponder to the 430. These cables allow the GPS to tell the transponder when we are moving so that it can automatically transfer between Standby and Mode C.
It was time to get back to the taping:
Rudder Taping in Progress

Rudder Taping in Progress

Rudder Rib Stitching Done

Rudder Rib Stitching Done

The picture above shows the pre-coat areas for the tape, the reinforcing patches around the hinges, and the chordwise tapes.
The next few pictures are documentation for the seat upholsterer. I’ll include them in case you might need them for the same purpose.
Front Seat Area

Front Seat Area

Seat Position Adjustment

Seat Position Adjustment

Outboard Seat Track

Outboard Seat Track

Inboard Seat Track

Inboard Seat Track

The Dynon sensor for manifold pressure has 1/4″ mounting holes. I didn’t want to use heavy 1/4″ bolts to mount it, since the smaller 3/16 bolts would still be very much structural overkill. Also, as I found with the shunts, 1/4″ nutplates are much more difficult to find and work with. I cut some aluminum tube bushings to reduce the hole size and adhered them to the sensor with a little bit of JB Weld
Dynon Manifold Pressure Sensor

Dynon Manifold Pressure Sensor

Dynon Manifold Pressure Sensor Back

Dynon Manifold Pressure Sensor Back

Once the epoxy cures I’ll trim it flush.

Posted on
Hours Logged This Session: 6.7
Total Hours: 1883.75

Wing Wiring

Today I finished wiring the D100. The last step was to splice together the DSAB wires, which are the wires that allow the three Dynon units to communicate with one another. I also started working on the wires that run through the wing conduit. I realized that I need to order more cable for the Dynon magnetometer. This is a 4-conductor shielded cable and with the sensor mounted in the wing tip it looks like I’ll need more than 20 feet. Richard had already run the wires for the aeroflash lights, but I wanted to be sure about which one was which. To make this job easier, I used a battery and my voltmeter.

Wire Identification

Wire Identification

I labeled two wires, then taped each one to a battery terminal. On the other end I measured for voltage until I found the corresponding wires. This system works very well as long as there isn’t any risk of a short on the measuring end. While I was working on all of that I heard an airplane flying by. Our little airport doesn’t get a lot of traffic, so it’s always worth stepping outside when someone stops by. It turned out to be a very fancy Maule!
Visiting Maule

Visiting Maule

I took several pictures of a few details, including uphostery and that sort of thing. The weather was perfect, so I started preparing the rudder for covering. This was a simple matter of drilling some drain holes on the aft edge of the horizontal ribs and wiping the structure down with the polyfiber C2210 prep solvent.
I also started wiring for the transponder. It’s a very simple process compared to the Dynon units, and especially compared to the 430, which I’ll start shortly.

Posted on
Hours Logged This Session: 7
Total Hours: 1883.75

Dynon Wiring

I started out today by drilling a hole in the firewall for the EMS wires. The thermocouple wires for the EGT and CHT sensors

are fairly large, so the hole is about 1/2″ in diameter.

EMS Wire Hole

EMS Wire Hole

I added a serial plug for the HS34, since I learned that it also needs to be able to receive firmware updates.
Dynon Serial Ports

Dynon Serial Ports

Thermocouple Leads

Those brown wires are the thermocouple leads

D-180 Wiring

The thermocouple wires were already in the connector, so the process was very simple.

I also installed the aileron balance tubes for what will hopefully be the last time. The weather is warming and it’s going to be time for covering pretty soon.

Posted on
Hours Logged This Session: 3.4
Total Hours: 1883.75

Aileron Balance and Wiring

Today I had a visit from fellow Bearhawk Builder John Rheney. It was great to have him stop by, since most of my visitors are not Bearhawk builders. We were able to talk about several of the special challenges and hard decisions in the building process. My Aircraft Spruce order from Sun-n-Fun arrived, and I got several new goodies. One is a new fuel valve to replace the Andair. The Andair is a great design for most applications, but for ours it doesn’t work very well. Since the outlet is on the bottom, the height ends up being a limiting factor. Here’s the alternative- the SPRL valve, which is available from Aircraft Spruce.

SPRL Fuel Valve Top

SPRL Fuel Valve Top

SPRL Fuel Valve

See how much shorter this one is, since the outlets and inlets are on the sides?

Tach Drive Cover

This little cap covers the tachometer drive. Since our electric EMS doesn't use a tach cable, we need to cover that hole with something.

Lycoming Tach drive

Tach drive

While I was doing all of that Tabitha was working on her window design.
Next I installed the panel annunciator for the low volt circuit. This is especially rewarding work, since now when I turn on the master a light on the panel blinks. If you don’t know what I mean, then I’d have to ask if you’ve ever made an electrical system or circuit. Hearing the battery contactor click is exciting, but blinky lights are much more visual. I found these fancy LED mounts at SNF for cheap, but I wanted to replace their unknown wires with aircraft grade tefzel wires. This has been a strict policy of mine for all wires aft of the firewall.
LED mount disassembled

LED mount disassembled

All that I’m using from this particular mount are the three silver pieces in the middle of the picture. I have a high-intensity LED that will replace this conventional one.
Low Voltage Annunciator Installed in the Panel

Low Voltage Annunciator Installed in the Panel

I’ve made provisions to duplicate all of my annunciators. This provides extra redundancy in case one fails, and also adds to the ambidexturous nature of the panel layout.
Low Voltage Annunciator Wiring

Low Voltage Annunciator Wiring

Just to recap, the function of this indicator is quite simple. When the master is on but the alternator is off, the light blinks. This is a great way to detect an alternator failure in flight, and also a great reminder to turn the master off after flight.
I pulled the lead balance tubes back out of the ailerons and checked the weight. I had originally filled them to 6 pounds each, but after further discussion with other builders I decided to remove a little bit of that lead. I drilled out enough to make the new weight 5 pounds and 3 ounces.
I ran a few more wires, including the Dynon ammeter, ground, oil temperature, all grounds, and power feeds.
Bearhawk Wiring

The wires are slowly multiplying, one wire at a time.

D180 Wiring

D180 Wiring

D100 Wiring

D100 Wiring

Posted on
Hours Logged This Session: 10.3
Total Hours: 1883.75

Installing the Alternator

In the last installment you might remember that I damaged the ebus alternator by shorting it to the airframe ground. The good news is that I was able to find a replacement for just the diode, and thus reuse the circuit board and mounting hardware that I got from Bob at aeroelectric.com. I clipped the leads off of the old diode:

Damaged Ebus Diode

Damaged Ebus Diode

Then used the soldering iron and hemostats to remove the stubs. This seems to be the most effective way to protect the integrity of the holes, and since the old chip is trash it’s no loss. I soldered the new chip in place and devised a slightly more robust mounting method:
The improved Ebus Diode mount

The improved Ebus Diode mount

Ebus Diode Mount

The silver screw will hold the white plastic piece in place, and the brass screws will handle the electrical connections.

Here it is in place:
Ebus Diode Insulator

Ebus Diode Insulator

Just to check for shorts, I turned on the master switch with the battery disconnected and applied my ammeter in series with the battery and battery lead. I got a steady .686 amps, which is about right for what the battery contactor needs to keep itself open. That’s also a good number to know- I had counted on 1 amp for my load analysis. The Z13/8 system allows me to open that contactor in the event of a primary alternator failure- in that case, the ebus can be powered by the standby alternator and the main bus is shed entirely. This low-consumption configuration keeps the current demands in line with what the SD-8 can put out.
The fuse block that I’m using for the battery bus is hollow on the back. The metal parts are recessed so that they don’t short out on the firewall, but I’d rather have something other than air between the two since the feeds are protected only by the size of the wire going to the bus.
Back of the battery bus

Back of the battery bus

I used a little bit of high temp RTV to “pot” the back, filling in the air space and providing an extra layer of insulation. This will also keep gunk from collecting in there.
I installed a powerlet style lead on the battery so that I can hook up a battery maintaning charger more easily. I used the connector that came with the charger, but I shortened the leads considerably and crimped on new rings.
I took a few minutes to clean the dust off of the trailing edge of the wing. One of the drawbacks to our hangar arrangement is that dust flies around and settles on everything. An occasional cleaning is a small price to pay for our low overhead!
I also added the rest of the alternator brackets:
Plane Power Case Mount Alternator Bracket

Plane Power Case Mount Alternator Bracket

And the alternator itself:
Plane Power Alternator

Plane Power Alternator

Everything lined up perfectly. Next I installed the aileron balance tubes in the ailerons and trimmed them just a hair so that they’ll fit.

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Hours Logged This Session: 4
Total Hours: 1883.75

Prop Governor Studs

Lately I’ve been fiddling with a Hartzell prop governnor that I got from another builder. The flange is designed so that the studs have to be just the right length, and my existing studs are too long. I spent a little while fiddling with it today before I finally decided to give up on the governor all together. This is in part because of the stud problem and in part because the splines on the governor don’t match the splines on my drive gear.

The Dynon EMS wire harness came with wires in place for every possible feature. I guess it’s easier to make them that way on a large scale. Since I know I’m not going to be using several of the inputs (fuel pressure, fuel quantity, etc) I removed those wires from the harness. I will probably be able to reuse most of them in other places, which is nice. Since I’m going to start wiring the avionics soon, I also made some wooden simulators for the Dynon boxes. I don’t have the boxes on hand yet, and the wooden pieces will make it easier for me to add the wires without making the final package too short.

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Hours Logged This Session: 3
Total Hours: 1883.75

P-leads and Wiring

I finished up the p-leads today for the Bendix mags. These mags require a special terminal, and I was able to find a used set of terminals in good shape. I used a single-conductor shielded cable, which was especially troublesome to strip and separate. The weave of the shield is very tight and it took a couple of attempts to get a good result. I added a bit of heat shrink to the empty shield right where the center conductor exits, and then another layer of heat shrink over the whole cable at that junction also. Hopefully this will be enough strain relief to keep the shield from breaking. You’ll also notice that I separated about a 4″ length, but cut the center conductor shorter. This is to allow for a cleaner installation, since the locations on the back of the mag are also staggered.

Stripped Shielded Wire

Stripped Shielded Wire

I added the outer threaded ring, then the metal piece, then the insulating piece. Then I added the little washer, bent the very ends of the conductor, and soldered the washer in place. Obviously it’s important for me to get the sequence correct here, since the other parts can’t go over the soldered end.
Mag Terminal Sequence

Mag Terminal Sequence

Bendix Mag Terminal Parts Together

Bendix Mag Terminal Parts Together

I crimped a ring terminal onto the shield, then used one of the screws on the back of the magneto to secure it. Here’s the whole thing:
Bendix Magneto P-Lead

Bendix Magneto P-Lead

The cockpit end was slightly different. I used 1/4″ fast-on tabs to attach the lead to the switch, but I also added a provision for the Dynon tachometer reading. The Dynon system is able to derive a tachometer indication by measuring the noise on the p-lead. The Dynon instructions specified the resistor value.
Dynon P-Lead takeoff

Dynon P-Lead takeoff

I crimped one end into the fast-on terminal and crimped a machined d-sub pin onto the other. This arrangement allows me to separate the wires going to the D-180, which may prove useful in future service. I used a female socket on one lead and a male pin on the other so that they are not interchangeable.
Cockpit end of p-lead

Cockpit end of p-lead

Cockpit end of p-lead

Cockpit end of p-lead

Next I connected the wire that goes from the starter switch to the starter contactor, and the wire that goes from the other terminal on the starter switch to the fuse block. This circuit works by providing 12 volts to the starter contactor terminal when it’s time to engage the starter, and that’s why it starts at the fuse block.
Starter Contactor

Starter Contactor

Starter Circuit on Fuse Block

Starter Circuit on Fuse Block

I also wired the battery contactor’s switch, the master switch. The battery contactor has a different design than the starter contactor. In the case of the battery contactor the switch lead is completing a circuit to ground. So the wire goes from the contactor to the switch, then to the ground tabs on the firewall. The contactor draws it’s current from the big terminals and thus doesn’t need a fuse.
Next I started on installing the alternator brackets. Since the bracket shares bolts with the engine halves, I will have to remove the current bolts and replace them with longer alternatives.
Lycoming Engine Bolts

These longer engine case bolts have the same grip length after adding the bracket

Shorten Bolt Threads

This bolt is a little bit long in the threaded portion. Before I cut it off, I thread on a die so that I can debur the threads more easily.

Lycoming Grade 5

The front two bolts are done. I'll have to go to the hardware store to get the back bolt. My engine builder says that grade 5 hardware is adequate here.

Since I found myself at a stopping point with the alternator bracket I went back to wiring.
Battery Terminal

Here are the battery leads, including a little boot for the positive lead.

Posted on
Hours Logged This Session: 4.4
Total Hours: 1883.75

Architecture Wiring

I sold a motorcycle and was able to buy some much-needed parts. The first is this Plane Power AL12-E160/C Alternator. This is the case mount unit since our engine doesn’t have the mounting boss. The parts look great!

Plane Power AL12-E160/C

Plane Power AL12-E160/C

Plane Power Brackets

Plane Power Brackets and Hardware

The other big part of my order was the probe package for the Dynon D180. This is an expensive package, but it comes with lots of goodies. I was surprised to see that the package included a pre-wired, color-coded 37-pin D-sub connector for the EFIS items.
Dynon EMS Probes
I’m using the Z13/8 electrical system designed by Bob Nuckolls. I started off my wiring with the leads that will make up the electrical system architecture.

Here are a few of the connections for the ebus relay.

I found one problem when I started to make the fuse links, which are very small wires connected to larger wires. Since splices are designed for the same size of wire, they wouldn’t do. Instead I used crimp-on “handshake” connectors, since they are available in different wire sizes. The whole finished product is not much bigger than a splice, and certainly as durable.
Splice Different Gauges

The small wire on the left uses a red connector, while the large wire on the right uses a blue. Clear heat shrink keeps the "handshake" connectors connected.

I have a few of the wires done now, with many more to go.
More Wiring

A few more wires

Shunt Wiring and Alternate Ebus Feed

Shunt Wiring and Alternate Ebus Feed

Posted on
Hours Logged This Session: 3.5
Total Hours: 1883.75

Battery Bus & P-Leads

Today I continued with more wiring. I finished the SD-8 ammeter wiring that I started yesterday, and made a cable for the starter:

Starter Cable

This clear double-wall heat shrink will preserve the label for a while.

I found a covered fuse block to use for the battery bus. Since it is on the engine side of the firewall I was worried about an uncovered block getting dirty. The only thing I don’t like about it is that each fuse feeds separately. To fix this I bent all of the tabs on one side:
Covered Fuse Block Modification

The top row of tabs will become the feed side.

Then I cut a piece of brass into a 1/4 inch strip and rounded the corners a little:
1/4" Brass Strip

This was from the same stock that I used to make the forest of tabs.

Brass Tab

The tab is just a little bit longer than the contacts.

I soldered the brass piece to the bent tabs, very carefully. I was able to get good melting without any of the plastic housing.
Soldered Tab

I also potted the back side of this with high-temp silicone, just to keep out contaminants and prevent shorts.

Next I started working on the P-leads for the mags. These bendix mags use a special terminal end.
Bendix Magneto P-Lead Terminal

This is the stub of the old p-lead terminal.

New kits are available to build the p-leads, but since I have these old ones I’ll just use the parts to make mine. The far right side is a soldered end that includes a small washer. I was able to melt the solder and extract the washer from the old ends. I used shielded wire and connected the shield to a ring terminal and grounded it on one of the screws on the back of the mag housing.

I’ve also been working on the wire conduit in the wing. I cut a notch to allow entry for the Dynon magnetometer cable, but that made a weak spot in the conduit tube. I cut a piece of aluminum tube for reinforcements:
Reinforcement for Plastic Conduit

Half of this tube will make a good reinforcement. I used a reciprocating saw to make the cut, but a bandsaw would have worked well too.

Reinforcement for Plastic Conduit

I roughed up the plastic and aluminum, then attached the reinforcement with JB Weld.

I added rubber grommets to each of the holes in the wing ribs, then reinstalled the conduit.

SD-8 Wiring

Today I continued with wiring the SD-8 and it’s components. I have a copy of the Z-13/8 drawing in the hangar, and I’ve been drawing lines on the diagram to note wires that are complete. First, I made a hole in the firewall for the alternator output wires.

Firewall Grommet

This grommet will fill a hole that is just big enough to get the connector through.

Firewall Hole

I chose this location in the firewall because it made for a nice short run to the alternator.

Then I ran the wires to the circuit breaker, which is part of the crowbar over voltage protection.
Circuit Breaker Wiring

The bottom circuit breaker is the 2A for the SD-8. the top is a 5A for the primary alternator's Crowbar OV protection.

Next came the wires to the switch.
Switch Wiring

The faston connectors at the back of the switch make the process easy.

Fuse links to the ammeter shunt

These wires are for the ammeter shunt. The ends include fuse links of 24-gauge wire.

The wires from the shunt go to a double pole switch that will provide a selection between the two ammeter measuring points.

Putting the Wings On & SD-8

After a year of watching, I finally found a good deal on an SD-8 standby alternator. Today Danny and I installed it on the engine. The last of the four nuts was a little bit tricky to get to, but we figured it out after a few minutes.

Lycoming Vacuum Drive

This is the spot where the vacuum pump would usually go.

I took a few pictures of how everything sits. I don’t see any clearance problems.
Bearhawk SD-8

Top view of the SD-8

SD-8 Right Side

... and From the right...

Since Don Bandy was in town and the timing was good, we decided to put the wings back on. Richard put the wings on once, but we haven’t had them on until now. A few of our local friends also came over to help, including Danny, Wade, and Kevin. I built a stand to put under the first wing to keep the fuselage from tipping over. Jim Woolf said that it wouldn’t tip over even without the stand, and he was right! That’s a bet I would have lost.
One Wing On

Wade evaluates our progress

Left Wing Extremists

Here's the left wing just before we put it on.

Since Richard already did the rigging and drilling, this installation was just a matter of lifting the wings and putting in the bolts. Even still, it takes a few folks to do it well.
On the Table

We set the wing on a padded table while we got Danny in place to put the bolts in.

Bearhawk Wing Bolts

The person at the wingtip, in this case Don, had the most important role. In the worst of circumstances we probably could have done the job with just 3- one person at the root, one at the tip, and one to put in bolts. Having more made it much easier though.

Personnel Positioning

Maybe it was Wade at the tip on this side!

Wing Strut

There's Don at the tip, while Danny and Kevin and I put the strut into place.

Tapered Bolt

I used a tapered, bullet-shaped bolt to clear the way for the airworthy version.

Wing Party

Left to right: Wade Kennedy, Kevin Ball, Tabitha Yates, Don Bandy, Bryna Riley, Chris Frye, Danny Hughes, and me.

With all of that done we went out to the Buffalo Wild Wings and ate a bunch of chicken wings. What fun!

Fiberglass on the Wingtip

The weather was nice today so I added a layer of fiberglass to the position light mount on the wingtip.

Bearhawk Wingtip Light

The position light mount has its first layer of fiberglass.

I also picked up some 1.5″ electrical conduit to use for exhaust pipes. Since they’re galvanized and welding zinc is bad for my health, I dipped the pipes into some phosphoric acid. The phosphoric acid will remove the zinc without damaging the steel base metal.
Phosphoric Acid Bath

The ziplock bag is just there to displace some acid and bring the level up higher.

Removing Zinc Plating with Phosphoric Acid

The acid has already started to dull the zinc, but it will take a few days to get back to bare steel.

I finished the second set of aluminum wedge shims for the fuel line too.
Bulkhead Fuel Fitting Shim

These aluminum wedges will eliminate a low spot in the fuel line where it passes under the front door jamb.

Cabin Heat Valve

Today I stopped by to visit my new friend Alan Waters. I asked him to weld some flanges onto my adapted cabin heat box, but instead he offered for me to come over and do it myself. This was an awesome opportunity that I didn’t want to miss! This box needed an additional hole and flange, and one of the existing flanges was too large. My plan was to cut kerfs into the flange so that I could shrink it down around a 2″ tube, but Alan suggested that we just cut the old one off with his milling machine.

Carburetor/Cabin Heat Box

Removing the old flange

The Bridgeport milling machine was like an etch-a-sketch, with one wheel to control left-right and one to control front-back.
Bridgeport milling machine

After milling

Alan was showing me how to use his lathe, so we trimmed the ends of the tube flanges.
The Lathe

We used the lathe to make the tube end square. It wasn't really necessary, but it was fun.

With the pieces ready to weld, he set me up with some practice parts and his TIG machine. I hadn’t used a TIG machine on aluminum since I became comfortable with steel welding, but it is much easier than I remember. Well, until I touched the electrode to the aluminum, then it made a mess. Alan was very patient and talked me through several practice beads.
Aluminum TIG Welding

Here is a practice bead.

Aluminum Welding Practice

The top bead isn't mine, but you can see on the far left where I touched the tungsten to the aluminum.

Another Practice Bead

Here's Another Practice Bead

With a few hours of practice, I tried welding the part. I got distracted at one point and burned a big hole in the flange.
Mouse Hole

I was doing pretty well until I burned a hole in it. Alan fixed it for me.

Ready To Install

Now it's ready to install. We used the milling machine to remove some of the material around the hole that I made.

In the end the box is just what I need, and best of all, I learned a lot from Alan. I was also able to make a quick trip to the hangar in the afternoon. The picture below shows why I’d rather not use the crimp-on terminals that I got from the welding place.
Sloppy fit welding cable

I thought that the crimp-on end left too much space around the conductor.

While I was playing with those, Tabitha did a bit more filing on the window frame areas.

Engine Controls and Heat

Today I made another hole in the firewall for the mixture, adding another hole that I’ll need to use or cover. I made some modifications to a cabin heat airbox that Jerry donated, and I’m hoping to be able to use it. That will save a day or more of trying to make one. I need to add an extra inlet to allow for the second heat muff.

Positioning the Nosebowl

I can’t make any more progress without getting the approximate position of the nosebowl pinned down. I spoke with the folks at American Propeller about the dimensions of the Whirlwind spinner, and they sent me some nice CAD pictures of two options. The short answer is that the aft edge of the spinner is pretty close to the front of the prop flange. Since the rubber baffle seal on the front of the baffle parts will allow for some adjustment, I only need to get a rough idea of where the nosebowl will fall. Step one: assemble the halves.

Bearhawk Nose Bowl

The two halves have a fairly rough fit, but I should be able to make it better with some filling and sanding.

Lycoming Prop Flange Layout

Since I don't have a spinner yet, I needed to make something to hold the nose bowl in place.

This piece of 1/4″ OSB should do nicely. I measured and drilled all 6 holes, then held it up to see how I did:
Not the Lycoming Prop Flange Layout

Hmmm... it looks like I measured to the center, but drilled to the edge of the hole.

Improved Prop Flange Layout

That's better, though perhaps a bit over-perforated.

I enlarged a couple of the holes so that I could get small c-clamps in to hold the OSB to the flange.
Simulated Spinner Backplate

The red circle is an aid for locating the nose bowl on the OSB.

Bearhawk Engine Side View

This is the location, plus or minus half an inch or so.

Limited Clearance

In this position, there isn't much (enough) room between the engine and nose bowl.

Nosebowl Alignment

This view is a handy way to align the nosebowl. From here I can compare the height of the seam to the "Lycoming" letters in the valve cover. As long as things line up the same way on both sides, I know that the nose bowl is level left-right.

With a rough idea of where the nose bowl will end up, I started working on the top for the air filter housing. I’m using the Vans Filtered Air Box (FAB) because it has several great design features. For instance, the filter element is reusable, and available from non-aviation sources. Air from the carburetor heat source is still filtered, eliminating the need to turn off the carb heat after landing at dusty/grassy places. And best of all, it eliminates the need for that expensive and troubled box from aircraft spruce that everyone else is using. I started by cutting a hole in the FAB top so to clear the bump on the bottom of the carb.
Vans FAB Top

I used the Vans template to drill these corner holes as a starting point.

The FAB Cutout

This was not enough of a hole, but it was a good starting point.

Using the Vans FAB on a Bearhawk

This was the cutout shape that it took to fit my carb. Some of the guys on the VAF site have written about removing the casting part on the right from the carb, thus strengthening the area around that cutout. I think I'll just put a doubler on the aluminum FAB top instead.

Vans Filtered Air Box Top Cutout

Here's another view from the top-ish

Governor and Carburetor

Today was a good day for staying close to the propane heater.

Snow at the airport

It was really cold at the airport today!

Hartzell Prop Governor

I got this Hartzell governor from Frank.

Hartzell Governor

I'm not sure why they designed the flange with so little clearance from the governor body.

Hartzell Governor

I didn't realize until later that the splines on this governor don't fit my engine.

Hartzell Governor

Making the circle...

Hamilton Standard Placard

The old Hamilton Standard placard made me wonder how many airplanes this governor has been on.

Hartzell and Woodward Governors

The Woodward governor is on the left, the Hartzell is on the right.

Hartzell Prop Governor Studs

The studs on the engine as of now are too long for this governor. It turns out that the drive splines are also not compatible, so I don't think I'm going to use it.

With the topic of the governor installation on hold, I turned my attention to the carburetor.
Carburetor and Throttle/Mixture Plate

I checked the plate to be sure that the bracket hole for the airflow was at least as large as the hole in the carb, and it was.

Carburetor Installed

Here's the whole thing bolted together.

Carb view from the bottom

View of the carburetor from the bottom

Lycoming 360 Intake Side View

Here's a side view of the carb installation.

With all of that done, I was ready to figure out where to route the engine controls through the firewall. I wanted to keep the throttle cable somewhat parallel to the bottom of the transponder rack, which is perpendicular to the face of the instrument panel.
Reference Marks on the Firewall

The end of the ruler points to a reference for the bottom of the panel.

Bearhawk Throttle Cable Hole

Here's the hole in the firewall for the throttle cable.

Throttle Open

The throttle is in the full open position here.

I finished installing the throttle cable, and it works smoothly. I’m at a stopping point with the mixture cable, in part because the hole on the arm is 1/4″ and the hole in the rod end is 3/16″.
I drilled the matching holes in the right rear engine baffle and the right side baffle.
Right rear baffle

The aluminum reflections make for confusing pictures!

Oil Dipstick Safety Wire

I needed to remove the oil dipstick, so I took this picture to be sure I get the safety wire correct when I reinstall it.

Dipstick Removed

With the dipstick out of the way, I was able to put in that little angle bracket just above the dipstick hole.

Left Rear Baffle Holes

I also drilled the holes on the left side. You can see that this piece is much thicker to help support the oil cooler.

Lycoming IO360 Baffle

I'll be able to trim off a little bit of the left rear piece where it overhangs the left side piece.

I wouldn’t have thought that there would be 35 pieces to the baffle kit, not counting fasteners and soft parts.

Baffles and Avionics Support

The new engine baffle piece that I ordered from Vans came in today, along with a plate for supporting the mixture and throttle cables.

New Parts

New Parts from Vans!

In the picture below you can see the difference between the new and old baffles. The old piece on top also has bends where I tried to make it line up with the right rear baffle. That whole operation was beginning to seem pretty clumsy.
Before and After Baffle

The old baffle is on top, the new one is on the bottom. The new one still needs some trimming, but not quite so much as the old one.

I’m planning to make two of each annunciator LED on the panel. The weight penalty will be very minimal, and I’ll have the benefits of redundant systems and improved visibility, regardless of which seat the PIC is in. I spaced them somewhat arbitrarily at 1 inch.
Instrument Panel Annunciators

Instrument Panel Annunciators

And the other side, for wire planning purposes:
Right Warning LEDs

Right Annunciators

I wrote in an earlier entry about wanting to create some support for the back (aircraft forward) of the Garmin racks. I re-purposed the old elevator trim push rod tubes to create a brace. I joined the two tubes together in the middle and made a template for the bend out of welding wire. I applied those bends to the new tube, yielding this:
Avionics Rack Support Tube

Avionics Rack Support Tube

I cleaned up the ends, added a crooked fish mouth to each side, and clamped the tube to the bottom of the 430’s rack. I added the sides of the boot cowl to help be sure that the instrument panel was in the right place.
Avionics Rack Support

Ready to weld

I welded both sides, cleaned off the old paint, and primed the whole thing. The first picture below is looking down:
Avionics rack support tube

Finished support tube

Avionics Support Tube

Looking across, from the left.

I ordered part number VA-149-360-PC KIT from Vans aircraft to use as a support for the throttle and mixture controls. This seemed like a good price, especially compared to spending a couple of days making one like it. The only problem is that there isn’t much room between the bracket and the firewall.
Throttle and Mixture Support

The Vans support bracket is about as long as it could be.

I’m looking forward to putting the carb on and scouting out the location for the air cleaner.
VA-149-360-PC KIT

Vans Throttle and Mixture Bracket, Side View

Tabitha also came out in the evening and worked to remove the last of the weld beads on her window removal job.

Posted on
Hours Logged This Session: 4.5
Total Hours: 1883.75

More Panel Holes

I was able to get home for a day or so amidst lots of training. I thought about how to best fix the left rear engine baffle that I cut incorrectly last month, but decided just to order a new one from Vans instead. It was only a few dollars and will save a day’s work and produce a better finished product.

I also drilled holes in the instrument panel for the crowbar over-voltage circuit breakers and the 12-volt SAE (cigarette lighter) jack. I’m only installing one jack for now, but like many other things in the panel, I’m saving room for expansion. I came up with room for another two or so. I might want to have one on the main bus and one on the battery bus, such that I could charge and/or use devices even when the electrical system is completely off.

Bearhawk Air Vent Position

I needed to position the air vent so that I could lay out the location for the 12-volt jack.

Cigarette lighter

Here's a spot for one...

12-Volt SAE Jack

Here's where I put the jack for now.

And on the other side, circuit breakers.
Circuit Breaker Layout

I'm only expecting to have two circuit breakers, but I might as well keep some panel space open in case things change in subsequent years.

Here’s a better overview picture:
Bearhawk Instrument Panel

Instrument Panel Layout

Also, I had to adjust the modified flap handle so that it would slide far enough left to be in the right position. This involved a little bit of grinding and a little bit of bending.
Flap Handle Repositioned

The flap handle is back where it should be.

I filed and sanded the filler on the mount for the position lights too.
Wingtip Lights

It's starting to look better!

Electric Cables and Polyspray

I made a few more crimps on the large conductors with the whack-a-mole crimper, but none are really any better than the first. On a more productive note, I sprayed one last round of Polyspray on the tail pieces.

Engine Baffles

The baffle kit is, well, baffling. There are lots of little parts, so I started by laying them out and picking out the ones that I needed for the first steps. The sides were easy to find, so I deburred the edges and installed them.

Lycoming 360 Side Baffles

The left side baffles and reinforcements

I trimmed the back left panel, and did it wrong. It is supposed to be on the forward side of that ear on the engine case, not behind.
Left Rear Baffle Error

The area around the engine mount is trimmed to large, since the baffle is on the wrong side of the engine case.

I picked up some 4 gauge welding cable to use for the larger conductors forward of the firewall. The crimper that I got from the welding store works fairly well, but the ends are much larger than the conductor.

Test Crimp

This crimping method leaves lots of air space in the crimp.

Installing the Starter

After seeing the amount of stress that the Garmin racks would place on the panel, I started thinking about how I can add some bracing to the back. I spent a few minutes today checking to see if that support could be as easy as a piece of aluminum angle across the two diagonal tubes, but it looks like I’ll need to come up with something else. The height isn’t quite right for anything straight across.
Meanwhile I installed the starter and started tinkering with the engine baffles.

Starter Placard

Skytec Starter 149-12LS

Stainless Firewall Shields

Today I tried a Tony Bingelis technique for making shields for firewall pass-through parts like engine controls and wires. The idea is to provide an equal level of fire protection for areas that use rubber grommets. I started by choosing a “die” from my die collection, also known as a socket set. I’ve found sockets to be handy as dies before, such as in straightening a kinked tube by forcing the socket through the middle. The outer diameter of the socket should be as large as the major diameter of the grommet, which is why it is handy to have several sizes to chose from. I used a Forstner bit to make the female half of the die in some scrap wood. That hole was about 1/4″ larger than the socket. I cut out a square of .016 stainless that was about 3 inches square, and clamped up the wood, stainless, and socket in the vice. With moderate pressure from the vice, the socket bottomed out in the wooden die, leaving a wrinkled flange area in the stainless. I used the little anvil section on the vice and light hammer taps to flatten that part out, essentially shrinking the flange. The stainless forms beautifully, and within a few minutes I had it looking like this:

Stainless Firewall Shield

Here it's ready to trim. It is much easier to do the stretching/shrinking in this footprint.

I learned a few tricks in the process of making a few of these. First, start with a 3×3 square of material, even if you are going to trim it down to a much smaller size later. This makes the forming much easier, even though there is more waste. I haven’t tried it yet, but I’m hoping that this method will also work for two-piece shields. I’ll have to make two of these to get one two-piece shield, but I haven’t been able to find a commercially available option that has all of the dimensions that I need.

Three Shields

Here are a few more samples.

I also started making the aluminum plate that will serve as a mounting pad for the position lights. My plan is to attach this aluminum piece, then build up foam and fiberglass to make it all smooth and aerodynamic. This piece will have two nutplates, which will receive the two screws that the position lights require.
Position Light Mounting Plates

Position Light Mounting Plates

Position Light Mounting Plates

Both sides, ready for nutplates

I also spent a few more minutes trying out some VHF Nav antenna ideas, but I don’t have any real progress to report.

Copper Strips, Parking Brake

In the week since I last worked, the JB weld on the ANL mount cured nicely. I filed it flush with the back of the mount and then realized that it hadn’t occurred to me to find out if JB weld was electrically conductive. It turns out that it isn’t, which I was glad to discover.

I used a 1/16″ thick copper bar stock to make the electrical connections between the electrical components on the firewall.

Copper Bar Connections

For these short distances, the copper bar is a great alternative to stranded wire.

I also mounted the parking brake valve and the hard lines to it.
Parking Brake Valve

Parking brake valve installation

I’m hoping that the loops in the top won’t be too much of a source of air bubble problems- I’m planning on filling the system from the bottom.

Current Limiter

Since the electrical output from the 60 Amp primary alternator is relatively large and relatively important, it gets a special type of over-current protection. The current limiter is sort of a heavy-duty slow-blow fuse rated at 60 Amps. The one that I’m using is a Buss brand ANL type. B&C sells a mount for it, but I thought I would make my own instead. The important requirement is that the holder be made out of an insulator, so that the mounting bolts can’t short to the firewall. I started with a stick of plastic. I used a forstner bit to drill two flat-bottomed holes for the mounting bolts, then added a 1/4″ hole to the center of each of those. This allowed me to put the bolts in, then fill the hole with JB Weld epoxy. This epoxy holds the bolt heads and keeps them from turning, and provides the insulation from the firewall. I also used the dremel to add some little cuts on the rim of the epoxy “well” just to act as a keyway in case the torque of the bolt head was enough force to break the bond loose. I added several lightening holes to the block, which are more about fun than function.

Swiss Cheese

This will be the aft side in service. I haven't cut the keyway yet in this picture.

Swiss Cheese

This will be the forward side. The wells with the 3/16\

ANL Base

Side view with the current limiter installed

Back View Again

This is another view of the aft side, before JB Weld

It probably would have made more sense to buy one, but it was a fun project.

Seats and Populating the Firewall

Today I spent time adding more stuff to the firewall. While I was doing that, Tabitha was working hard on shaping the seat foam.

I added the nutplates for the battery buss, which is going to provide power to things that will be powered even with the master switch off. I finished installing the shunt for the primary alternator.

Z13/8 Parts Layout

On the left you can see the battery buss, on the right you can see the holes for the nutplates for the primary shunt.

Here you can see the brass grounding tabs.
Grounding Forrest of Tabs

Here I've installed the firewall grounding tabs and the primary shunt.

Cabin side of the firewall

This is what all of those nutplates look like from inside of the firewall, on the right side.

New Brake Line Entry

This is the new, higher location for the brake reservoir line, which will provide better toe clearance from the brake pedals.

While I was doing that, Tabitha was making good progress on the seats.
Front Left Seat Foam

The lawn chair makes a nice holder for the front left seat foam.

Tabitha, Seat Carver

Tabitha shows off her handiwork

I also started making some pieces of aluminum to try welding on.
Duct Flange

This was piece that I wanted to try aluminum welding with. This one didn't work very well, partly because the 3/16 holes and narrow strips along the sides.

I spent more time working on a mount for the ANL current limiter, but I decided that I didn’t like the progress.

Nutplates for Firewall

I don’t have any pictures for today, but it was still a productive session. I installed the last gusset for the seatbelt tab, and installed several nutplates for the firewall-mounted electrical accessories including the battery and starter contactors.

Today George Carter stopped by to visit too. I met George at the hardware store a while back and started talking about airplanes. I’m glad he was able to stop by and see the project! He has some pilot experience and spent several years in the Air Force. He seems to be an equal opportunity aviation fan that enjoys all matters aeronautical.

Battery Box, Tail Pieces

Today I spent a little bit more time convincing myself that the tail alignment issues aren’t going to be important. I did find a minor difference between the kit and the plans when I measured the length of the tubes that hold on the horizontal stab pieces.

Span of the front stab tube

This is the dimension on the plans for the spanwise length of the tube that holds on the horizontal stabilizer halves.

Measuring the Tube

Here's the actual tube width.

The only potential complication from this tube being long might be with the possibility for interference with the welds inside of the stab tubes. The longer tubes would provide more support, and as Mark pointed out, the welds shouldn’t be a factor since the tail was installed correctly at the factory before the kit shipped.
Making the elevator trim horns line up

This is what the stab halves look like if I apply pressure to make the elevator trim horns line up. Obviously that isn't the right arrangement.

As you can read in the previous post about tail stuff, I’m not really worried about this stuff anymore. I can make everything line up except for the elevator trim horns, but they aren’t going to be moving very much or very often. Their misalignment will introduce a little bit of friction to the system, which it needs anyway. I moved on to the battery box, which was ready for assembly and installation, now that the kindergarden paint is dry. Why paint something black and black when you can paint it blue and yellow? Especially with the odyssey batteries being orange.
Bearhawk Battery Box

Here's the battery box, finally.

Battery box with PC680

The strap across the top does not get any paint.

I also made some progress on the flap handle change. I didn’t see any point in remaking the whole handle, since the arms and the hole reinforcements were the only parts to change.
Bearhawk Flap Handle Update

In the top of half of this picture you can see the new steel flap handle arm. In the foreground, you can see the flap handle that the kids who broke into the hangar decided to practice their dremel skills on.

Bearhawk Flap Handle Update

I made photocopies of the plans, then glued those copies to the steel plate to use as a template.

Bearhawk Flap Handle Update

After some careful positioning and measuring, I was able to mark the old flap handle with locations for where I should attach the new arm pieces.

Mark asked me to keep up with how much time I spent working on the flap handle, so I took lots of detailed pictures. Since those pictures are gone, I won’t be able to know an accurate elapsed time, but the time would probably vary considerably depending on tool availability. Having access to a metal-cutting bandsaw would have expedited these steps by at least an hour.

Populating the Firewall

Today I started planning to add a few more items to the firewall. I’d like to make sure that I don’t try and put two things in the same spot, and also make sure that I can have maintenance access to items that need it. Tabitha also came out for a little while and cut more foam.

ANL Current Limiter and Shunt

Here are two of the firewall participants, the main alternator's current limiter, and one of the ammeter shunts.

The current limiter is sort of like a giant fuse for the alternator’s output line.
Battery Bus Fuse Holder

I'm going to use this covered fuse holder for the battery bus, because I like the idea of keeping the fuses and associated contactors clean. None of these fuses (or any of the others) are intended to be replaceable in flight of course.

The battery bus will power items that will have power available all the time, regardless of electrical system switch position. These items will include some of the interior lights and those types of things. I also spent more time on the brake line forward of the firewall. I’ll have more pictures of that later.

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Hours Logged This Session: 3.4
Total Hours: 1883.75

Brass Grounding Tabs

Today I started making the brass grounding blocks. My orders from Stein and All Electrics came in- great fun!

New Goodies!

New Goodies! D-sub crimper, brass tabs, assorted electrical bits.

More New Goodies!

More new goodies, including some BNC crimp-on connectors, and the parts to make the Bob Nuckolls alternator diagnosis jack.

The brass terminal strips were available from Stein for $1 each, so a few minutes of soldering and a $3 piece of brass from the hobby shop saved me $50 or so from B&C.
Brass Tabs

The tabs from Stein come in strips of 10 tabs each.

Brass Stock

Here's the layout on the brass stock


I used two large brass bolts instead of one brass bolt and two little bolts as on the B&C version.

Soldered Bolts

I soldered the heads of the bolts to the interior sheet so that I wouldn't need to hold them in place for tightening.

Soldered Tabs

Since the meco torch was handy, I installed a 0 tip and used it to provide the heat for soldering. Even with the tiny tip I still kept the flame several inches from the work and hand plenty of heat.

The flux looks pretty bad in the picture above, but after some time with a toothbrush and some rubbing alcohol it cleaned up well.
I also took apart the VHF Nav antenna that I picked up in the Aeromart at Oshkosh. It was very inexpensive, and I was planning to use just the conductors. I’m still trying to figure out how to make a mount that will work well on the fin.
VHF Nav Antenna

VHF Nav Antenna Parts

I installed the brake reservior on the engine side of the firewall with one of the holes in a support tab for the firewall.
Brake Reservoir

Brake Reservoir on the Firewall

My goal is to not have any bolts holding on just the firewall, since there are so many little parts that need to be mounted to the firewall too. I did need to shorten the tabs slightly because of the somewhat short reach of the -3 clip nuts that I had. I put the paper towel between the firewall and the tab so that I could use the dremel to cut the tab without scratching the firewall.
Shortening the Tab

On the left side you can see the paper towel pad.

I debated briefly about whether or not I wanted to have the reservior on the engine side of the firewall. The benefits would be ease of servicing and reduced possibility of interior leaks. The only drawback that I can think of is that the possibility of problems in the event of an engine fire. I decided that in the event of an engine fire I’m not going to be too concerned about the status of the brake reservior! The brakes will still work once or twice without the reservoir in the system anyway. I drilled a hole in the firewall for the line to pass through, then realized that the location of the hole was going to be too close to the brake pedals. I’m concerned that there is a remote chance that the fitting might interfere with the brake pedals, so I’m going to move it up a little.

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Hours Logged This Session: 3
Total Hours: 1883.75

Battery Box Continued

As of today the fuel quantity gauges are done, and I drilled, countersunk, and primed the battery box and associated parts. Next time I’ll paint them and assemble the box so that I can add it to the firewall. Once again the pictures are missing until 8-25.

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Hours Logged This Session: 5.5
Total Hours: 1883.75

Fuel Lines, Flap Handle

I finished making the wing fuel lines today and started on the fuel quanity gauges. I used files and emory cloth to debur the holes that Wade punched into the battery box yesterday, and used the band saw to rough cut the aluminum flap handle piece to shape. I used files and emory cloth to get it deburred and shaped to the final dimensions and it is ready to go. Tabitha came out and did more window mockups.

Unfortunately my pictures for this entry and the next few are gone, thanks to some hoodlums that broke into the hangar and stole my camera. The sheriff has arrested them, but they won’t say what they did with the camera. While they were there they had some fun with the dremel and grinding wheel and cut my perfect new flap handle aluminum piece in two. Wouldn’t it have been nice for them to do that to the old superceded one instead? My pictures won’t resume until 8-25.

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Hours Logged This Session: 3.5
Total Hours: 1883.75

Aligning Tail Pieces

On a recent trip to Harbor freight I picked up another pair of adjustable height support stands to help figure out why the tail doesn’t seem to be lining up right.

I used these stands in an effort to more reliably position the tail pieces for measurement.

I leveled the fuselage left-right with a water level at the wing attach points. From there I levelled each stab half with a bubble level.
Left-Right Level

I used a bubble level to level the stab halves, carefully positioning it between rib stitches.

I also raised the tail to level the stab halves front-back and then rechecked the other measurements. I spent lots of time scratching my head, but here’s a summary on what I have so far. The stab halves seem to be built with a little bit of error in the vertical positioning of the parts. I wonder if the left and right halves were built in the same jig, such that a slight error due to gravity would be down on one half and up on the other half, thus providing the 1/8″ or so error that I see between the left and right halves. My solution is to adjust the hinge supports a little so that the elevator halves will be parallel, and just accept the error in the trim system.

Straght Trailing Edge

From this angle you can see that the trailing edges of the two stab halves are parallel.

The trim horns don’t quite line up right, so there will be a little bit of binding and friction. Since the trim system needs a little friction anyway, this will work out well. Also, the trim horn only moves slightly, so I don’t know if the binding will even be noticeable in the range of motion that it will see in service.
Trim Horn Alignment

Note the trim hole alignment as I rotate the horn.

Trim Horn Alignment

Notice that with the horns turned 90 degrees, the misalignment is still only vertical.

Trim Horn Alignment

Finally, here is a shot with 180 degrees of rotation. These pictures convince me that the trim shafts are straight but not coaxial.

In the end there might be a slight difference in height between the left and right stab halves (1/8″ or so) but both will be level with reference to the wing attach points, so I’m not really concerned.
Right Tube Verification

I verified that the removable pieces were installed correctly on the right...

Left Side Verification

... and on the left.

I spent some time getting the aluminum part of the flap handle finished. I drilled holes where the notches would go, and plan to take the piece home to cut out on my wood cutting bandsaw. I started making up the fuel lines that connect the tanks to the inboard rib. Tonight at the EAA meeting Wade brought his punch and cut out the lightening holes in the battery box.
Wade Punches

The picture is a little bit blurry, but here Wade is punching the holes at the EAA meeting.

The conduit punch had no trouble with the thin steel.

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Hours Logged This Session: 2.1
Total Hours: 1883.75

Battery Box and Avionics

Today I finished the last fuel line that I can make without putting the wings back on.

Here's a shot of the bottom of the fuselage showing the fuel lines.

While I was at the hangar I also counted the pins on the Garmin racks so that I could make a shopping list for the d-sub parts. I think if I order 50 male and 50 female pins, I’ll have enough for all of the avionics. That’s counting on using some of the pins that I already have standing by.

While at Oshkosh I purchased a Vans battery box kit for the PC680, and today I started marking the top hold-down strap for drilling lightening holes.

Here are the locations of the lightening holes, as described by the Vans directions.

Today was a short day, but small progress is still progress.

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Hours Logged This Session: 1
Total Hours: 1883.75

Test Fit Engine

Today was a busy day at the hangar. I started by drilling the holes in my new rudder pedal-cable straps. I wanted to be sure that the four straps were match-drilled, so I used a scrap piece of aluminum angle and some c-clamps to hold the straps stacked in place. After the first hole I added a cleco to keep the straps from sliding around. The aluminum angle didn’t survive very well, but it did the job.

Holding the Straps for Drilling

System for holding the straps down for drilling

End result- matched holes

The result was a set of nicely matched holes.

Now I just needed to know what kind of rudder pedal springs to shop for. I measured the distance with the rudder hooked up.
Measuring for the Rudder Springs

Measuring for the Rudder Springs

Since welding the skylight tabs was on the horizon, I used some scrap pieces of steel to weld up a jig. This is inspired by one that Eric shared, though it is slightly different. The key is that the middle leg is shorter than the other two, and that each tine is slightly bendable. The idea is that the outer two tabs will rest on the parent tube, while the tab will rest on the middle tine.
Tab Welding Fixture

Here's the crude tab welding fixture

With Oshkosh coming, I wanted to measure the length of the engine controls that I’ll need so that I can be on the lookout for some bargains. I tried taking measurements with the engine off, but it wasn’t working too well. I got some hardware store bolts to use as temporary fasteners while I wait to order the AN bolts at Oshkosh. This was all that I needed to get the engine temporarily in place, both to measure the cable runs and to inspire more progress. It was really a fairly simple job. I positioned the fuselage close to the engine on the pallet, propped the tail up so that the fuselage was close to level, and added some weight to the tail (just to be sure that it wasn’t going to nose over).
Positioning the Engine

Positioning the Engine

I used the lift to position the engine, then started sticking the bolts in. It was a strange feeling to lower the lift and let the fuselage and mount carry the weight of the engine for the first time. Of course it is strong enough to carry this weight at 6 g’s or more, but it just seems so strange at first.
Engine Installed

Engine Installed- for the first time.

My measurements were a little bit easier with the engine in place. I figure that 48″ will work for all three of the controls, depending of course on how I route them.

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Hours Logged This Session: 3.8
Total Hours: 1883.75

Cable Guard Nutplates

Today Tabitha came to help. She installed nutplates in the floorboards for the rudder cable guards while I took care of a few loose ends.

Tabitha makes nutplates

Tabitha is installing nutplates


Here are the first few.

I was recently reading through the Beartracks newsletters and came up with a few things to check on. The first was the flat plate of steel that joins the two flap cables behind the aft bulkhead.

Measuring Flap Junction

I also checked to be sure that the flap junction plate was 1/8\

In the time since Richard installed the rudder pedals, there has been a potential over-center rudder pedal problem that has come up. I needed to move the pedals forward to eliminate this problem.

Measuring for Rudder Pedals

Measuring for Rudder Pedal Placement

While I had the rudder pedals out, I was also able to turn the bottom engine mount bolts back around. It isn’t possible to install them correctly while the rudder pedals are in place. In the picture I’m tightening the top bolt.

Engine Mount Bolts

Here I'm working on the engine mount bolts.

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Hours Logged This Session: 5.8
Total Hours: 1883.75

Engine Mounts and NACA Scoops

I’ve been watching the price of the engine mount rubbers for the past few months, and the trend seems alarming. In the 2008 Vans Accessory catalog, they were $40 per lug (for a total of $160). Today Vans sells them for $125 per lug, or $500 plus shipping! Yikes! I was surprised to see the cost go up so quickly. I was looking for some way to spend less, and eventually found that Jeppesen of all places sold them. Their price was well below anything else that I could find, at $88 per lug. My only explanation for this was that their price was outdated, but who knows. I was glad to save so much money. Here’s the data from the box:

Lord J-7402-24

Lord J-7402-24 Engine Mounts

Nobody seems to know how long the bolts need to be for attaching the mounts to the engine. I don’t really understand the mystery- the mounts have a center tube that gets compressed to the washers on either side. Now that I have them on hand I can measure the length of that tube and the end washers to come up with a grip length for the bolts. Here are some pictures of my measurements, in case you find yourself wondering how long the bolts should be.

This was just the uncompressed length, not very useful.

Washer Thickness

Here's the thickness of the end washer. It's just a little bit more than .1 inch

Measuring Again

Here's another somewhat useless measurement- the uncompressed gap between the two big pieces.

Here's the uncompressed length of the pair

Rubber Engine Mount Thickness

Here's a much more useful measurement- the thickness of the assembly once it is compressed.

Thickness of Engine Ear

This is the measurement that I took of the thickness of the engine mounting ear on the engine. This one isn't especially accurate, but is pretty close.

For the purpose of ordering bolts, my measurements aren’t especially accurate, since the bolts generally come in 1/16″ increments. I figured that the compressed rubber was 2.03″ and the engine lug was .93″. This makes the required grip length for the -7 bolts 2.96, not counting for any washers (and I’ll need at least one of those at 1/16″). The AN7-34 is 2 15/16″ (2.9375″), so I ordered the 7-35 with it’s 3 1/16″ grip length. That will allow for a washer or two but will keep the bolt’s threads out of the way.

With that bit of research done, I started working on the air intakes that will go on the sides of the boot cowl. These will provide fresh air for the front seats through an eyeball wemac type of vent on the instrument panel. I got the scoops from Vans, their part SV-1 at $6.25 each.

Vans NACA Scoop

Here's one of the scoops from Vans, along with a cardboard template that I made for marking the aluminum skin.

I wanted to make an aluminum backup ring so that the plastic part would be sandwiched between two layers of aluminum. The cardboard template made that step easy.
Aluminum Backup Ring

Here are the two rings and a nice view of the back of the SV-1

I drew a few lines on the boot cowl to try and figure out where I wanted to put the vent. My primary goals were to make the centerline of the intake horizontal in level flight, and to keep the intake lower than the outlet inside, so that water would be more likely to drain out if we were flying in the rain. I’m curious to see if this works. Note from the future! This vent installation is wrong. The hole is cut to the wrong shape- the aft portion of the vent should be straight across, not rounded.
Boot Cowl Layout

Here's the mark on the boot cowl sheet for where the vent will go. I almost oriented the vent backwards! This is the right side of the airplane, with the nose facing right.

Boot Cowl Vent Intake Location

Here's a more wide-angle view of where the vent will go.

vent on flat skin

Here's the boot cowl skin flattened out and ready for cutting the hole.

Ready to dimple

Now I just need to dimple the skin, countersink the plastic, and put everything aside until I'm ready to permanently attach the intake.

See note above- this is wrong. The aft side of the hole should be a straight line. I didn’t realize this until I was looking at Patrick’s RV in November 2010.

I got to the point of dimpling the holes for the first side and had to quit for the day.

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Hours Logged This Session: 4
Total Hours: 1883.75

Seats and Engine Mount

Today Tabitha came out again to finish squeezing some more wingtip rivets. We also tested the glue on the foams to make sure that it wasn’t going to dissolve them. The glue checked out OK, so we glued one of the bottom cushion combinations. Tabitha marked it for cutting and spent some time thinking about how all of that needed to be done.

Tabitha is trying out a few different seat foam combinations and marking them to cut.

While she was doing all of that I worked on more nutplates in the boot cowl/fuselage area. Danny stopped by, and he and I installed the engine mount.

Posted on
Hours Logged This Session: 5.5
Total Hours: 1883.75

Tailwheel Spring and Wingtip

Tabitha came out today too and we made some good progress. I was at a stopping point with the tailwheel spring because I didn’t have a drill that would handle larger bits. It had a temporary bolt in place of the AN-7 that is supposed to go in there. With the new drill I was able to get the hole up to size and reinstall the tailwheel spring.

I got this new drill so that I could use larger bits. All of my others have a 3/8\

Meanwhile, Tabitha was dimpling and squeezing the rivets for the wingtip flush mount strip.

Tabitha was dimpling and squeezing.

I also spent some time getting ready to install the engine mount, now that I have the hardware.

Posted on
Hours Logged This Session: 5.1
Total Hours: 1883.75

Back from Sun-N-Fun

It’s been a while since the last building entry, but I’ve been out of town more than usual. I just got back from Sun-N-Fun with a new list of ideas and a few new parts.

One of my SNF finds was these LED position lights. If I didn’t already have the aeroflash lights, I would have probably gone with a different setup, but since I do, I wanted to find some LEDs to replace the four incandescent bulbs. I had seen these before in the Aircraft Spruce catalog, and the guy who sells them to Spruce had a booth at the show. His price was a little better, so I got a set.

Here are the LED replacements for the position lights.

I took the cover off of the nav lights and took this picture.

Inside of the Aeroflash

This is the green LED in place

And the aft-facing white

Here's the whole assembly back together again. I replaced the green lens with a clear one, and was actually able to sell the original lens and bulbs to offset the price of the new parts.

On the red side I found that the gasket wasn’t properly installed you can see what I mean at the pointy end of the strobe insulator.

Notice how the black gasket doesn't quite fit right.

The white insulator wasn't quite right either.

When I put it all back together I put the gasket on correctly and also made sure that the white insulator was correct. I wonder if it came from the factory this way.
I realized that I should probably take some documentation pictures of the engine and accessories, because I always find myself with questions when I’m away from home.

The Starter...

...and the ignition wires...

...and the starter ring gear...

...and the carburetor...

...and the carburetor data plate...

I also found a baffle kit for sale second hand. This one wasn’t related to sun-n-fun, but I hadn’t had a chance to go through the kit to make sure that it was complete.

The plans for the Vans baffle kit are on one big sheet

There's all sorts of hardware in there

To change gears again, I finally had enough lead to fill the aileron balance tube. I ran safety wire from the corner of the bench to the tube, then leaned the tube slightly down and to the right as shown in this picture.

Aileron Balance Tube

This is a 1″ tube, which is larger than the 3/4″ tube originally designed in the plans. The diameter change is to improve the aileron if I recall correctly- it doesn’t really matter, since my ailerons have a 1″ hole in them. Back with the old 3/4″ tube, builders had to fill the entire tube with lead in order to get the required 5.5 pounds. I’m glad that another builder pointed out that the 1″ tube definitely does not need to be full. Without this tip I might have not thought about that until it was full of lead. I started to wonder if this uneven weight distribution would be a problem. I asked Bob, and he said to just leave the tube at it’s full length so that it will have more attachment points, and not worry about it. I’ll probably have to drill some of the lead out to actually balance the aileron. If I leave the 1″ hole open during covering, I will still be able to get a long drill bit into the lead. I can make small covers to pop-rivet over the 1″ holes when that is done. This will also come in handy if I need to recover the aileron later.

While I had the torch out, I figured I would also weld a cap onto each of the control sticks. This will make it much easier to mount a push to talk switch on the top. In this picture I’ve cleaned the paint off in preparation for welding.

Control Stick prior to welding

I also removed the paint for the ELT bracket

I don't remember where I got the idea for this holding fixture. It is 16 gauge copper wire and alligator clips. For tacking it works well, but since the clips are soldered it might not hold if it gets too hot.

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Hours Logged This Session: 5.3
Total Hours: 1883.75