Chapter 22 - Electrical, Instruments and Avionics


I've read lots of email from Bob Nuckolls and read his web site from cover to cover. I subscribed to his mail list at and read the discussions about wiring. I bought Bob's book and his theory:
  "I prefer to assume that any given part is going to fail at some
  point in time and then adjust system architecture and 
  operating procedures so that it doesn't matter." 
                           Bob Nuckolls, 8/5/99

Go to Bob's web site and have a look at his product gaurentee. It's the opposite of what you might expect. Rather than saying that the products are good for a certain length of time, it says that they WILL fail. No telling when, so prepare thyself for that inevitable failure and make sure it doesnt spoil you're day.

I'll be putting fuse blocks in my Cozy and doing the wiring according to Bob's excellent book. When it came time, in Aug '00, to do the wiring I decided I needed as much help as I could get in this area. I placed an initial order with Aero Electric with a note to Bob asking if I'd left anything obvious out. He was good enough to call me and discuss the essential items I'd need. Since the engine which requires electrical power to run, I'm planning to implement a dual battery fault redundant electrical system per Bob's Z2 wiring diagram.

Did I say I started the wiring in August '00. Wow. Here we are in June '02 and NOW, FINALLY, I'm really starting the wiring. I downloaded the updates to Bob's book and started the learning curve.

A strategic Approach?

In the ideal world (just in case any readers actually live there) you would plan all the wiring in advance, make a complete harness on the bench, install it, then hook everything up. Of course, using this approach, you'd hook up the last wire, turn the starter, the engine would fire up first time and you'd taxi out for the first flight. Yea right! Perhaps the rocket scientists among us can do it this way, but my tiny brain simply isnt big enough to hold all that info at once and not miss something. Also, my tiny wallet isnt big enough to handle buying the avionics, and all the other various gizmo's needing electrical juice, all at once. I know things are going to change and lots of items can't be installed until you've finished the final Zolotone inside paint. Carl Denk posted the following excellent advise on the web:
Stretch a wire everywhere the harness will go and mark 
"breakouts" (where a (or many) wire branches. Measure the 
distance of all the branches (maybe by stretching more 
wire). Transfer all measurements to your bench, driving 
nails at all ends and breakouts. Make a wire list with 
numbers for all wires (will be very helpful later). Label 
all end points with the wire numbers and size wire. Stretch 
the wires where the have to go, numbering both ends and 
making more than long enough (cut, install new number when 
cutting off the old number and terminate after in place). 
Bundle wires together and temporarly wrap with tape or 
tie-rap. When pulling the wires in remove the wraps so can 
pull one wire without the entire bundle.
Chrissie, of the infamous Cozy Girrls, told me that she's making a mockup fuselage to help her plan the wiring harness. Hmmm. Sounds a bit anal to me. Then again, anything that involves a lot of up front thought prior to taking some kind of satisfying physical action, is alien to me. My approach to the wiring task was more evolutionary than strategic. After getting my head around the Nuckolls schematic for a two battery, internally regulated alternator system I simply dived in, started installing stuff and wiring things up.

Master panel, Fuel Gauges & Gear Switch

I originally planned to get Wayne Lanza's premade panels for these items. The master panel isn't needed because I'll be using fuses. Eventually I designed my own annunciator panel and switch layout.

Map Light

I installed wiring for a map light before adding the shoulder support in Chapter 8. Much, much later, I ripped this wire out because it was in the wrong place.

Building the Intercom

When ordering my antenna parts from RST I went momentarily crazy and also ordered their intercom / audio panel / marker beacon receiver kit. Perf boards, face plate, case, some bags of components and instruction manuals. Hmmm. This may be beyond me! RST tell me they get a secretary with no electronics experience to build one of each kit. I wonder if she'd build mine for me. I'll take a hiatus from fibreglass soon and find out if I'm capable of constructing a complex electronic device.
I took a trip down to Radio Shack. Came back with the RST recommended tools list. Spent 4 hours sorting through components and installing some diodes and resistors. I've never done any electronics assembly before. This is kinda fun, but there must be 100's of tiny components to recognise and install. I'm not very confident of my soldering skills, but I'm getting better.

Over a couple of weeks I built my audio panel / intercom unit. My first few solder joints were pretty rough, but I got the hang of it and, by the time I finished the unit I was able to do a reasonable job. What worried me was that the first few connections are just as important as the last few! It took me about 20 hours to build the unit. I built a little panel for my headset plugs, hooked it up and was truely amazed to find that it worked just fine. Char & I sat in the living room and conversed via intercom for a few minutes. The next day I connected it up again. All I could hear on the intercom was a loud buzz. Hmmm. What's that burning smell? That smoke coming out of the unit doesn't seem right. I quickly pulled the plug, but the damage was done. My fancy new intercom panel was fried!

When I saw that smoke I pretty much wrote off my electronics experiment. But, the RST instruction manual says you can send the unit back for "calibration". Hmmm. I wonder how far their definition of calibration extends? I built the marker beacon unit in one evening (a easy job after the experience of building the audio panel), then packed the two units up with a explanitory letter and sent them back "for calibration".

Two weeks later I got the following email...

The units are calibrated, repaired, and ready for return.

The TBA-810 on the 564 was destroyed when the solder lug attached to the
rear chassis came loose and swung up and touched the 810 output.  I put
extra shrink sleeving over the lug and installed it tight.  I also put the
47 ohm resistor in R102 on the 522.  These were warranty repairs that we did
at no charge.

However, U101 (LM3900) on the marker receiver was installed backwards, and
the 100K AGC control and the 1K RF level control were reversed.  There were
roughly half a dozen solder bridges between the 564 and the 522 and about a
dozen missed or cold joints on the two.  We spent an extra hour and a half
finding these problems and charged you half an hour of shop labor.

Together with the $59 cal fee, $25 for half an hour of labor, and $6 for
shipping, the total came to $90.  

Now THAT is what I call service! Truely amazing!

I end up with a professionally checked and calibrated audio panel / marker beacon / intercom with lots of superb features for MUCH less than I would have paid for an off the shelf unit with half the features. And I learned how to build electronic components into the bargin. I'll be getting other electronic items (like maybe my radios) from these guys - that is if they'll still sell me stuff! Now - if only I had a finished airplane to install these gadgets in! [Note: See "testing the intercom" below before getting one of these.]

Planning the panel

I used the poor man's panel planner system to layout the various gauges. There's no way I can plan the complete panel since I don't know what equipment I'll be installing. I decided to get started on this anyway and plan the locations of the probable items like the basic T aand the radio stack. I looked at the DigiFly from Wayne Lanza (see links). The Rocky Mountain unit is nice, but its not cheap, and I assumulate information much better graphically than I do from text. One consideration here is that I'll be installing lots of engine sensors. I don't want to fill the panel with hard gauges if I can do it with an electronic system that also gives me GPS, moving map and atitude instruments. I'll still have the more critical gauges in physical form. e.g. tach, oil pressure, oil temp, coolant temp, coolant pressure. Fuel gauges (over and above the sight gauges) will probably be the neat little unit from Wayne Lanza. Later I saw, and fell in love with, the EFIS-ONE from Blue Mountain. The owner, Greg Richter is not only a fellow Cozy builder (now flyer), but he's also riding in front of a 13B rotary. Having said all this, I WANT his EFIS system because of its features. It may be a while before I get one, but get one I will. I printed out the layout for the EFIS-1 Screen and used the link on Blue Mountain's installation page to try different layouts which allowed for the huge EFIS display screen.

When it came time to start the wiring I still didn't have all my panel components, or even decisions, so I used a kind of "suck it and see" approach to wire routing and panel planning. This is typical of the way I approach a lot of things, especially large complex tasks. Rather than try to figure out every little detail in advance, I tend to dive in and get started. As I go along I try things out. I make small advances in the overall objective. Sometimes I make mistakes and have to go back and correct something, sometimes not, but one way or another, the big picture gradually evolves out of the murk. I find this much easier than trying to force a complete plan when there are issues still to be resolved.

I was amazed to reading one post on the Aeroelectric list from a guy who's planning his Lancair wiring. He had thought out and documented every wire size, fuse value, component placement and wire route. Every bulb and switch had its location, function and control figured out. When I got to the end of the post I realized that this guy hadn't actually built ANYTHING yet. This was his planning, before starting the whole airplane project. Wow. That's a hell of a lot of detail for someone who hasnt even mixed any epoxy. Personally this approach just couldnt work for me. Perhaps my mind can't hold enough information at one time. A little of the ADD perhaps. I find it better to ignore details until I have to deal with them. I can't see how anyone could possibly consider all the practical considerations in advance and actually get it right. Ah well, that's just me. I wanted a "standard" panel, so I laid out the basic 6 flight instruments in their standard configuration right in the middle of the left side of the panel. Next I installed the ignition and battery master switchs on the left side. It makes sense to group things depending on their usage and function, so the left lower side will be my "ignition" area. The aux battery switch and the alternator breaker will go in this area too. Switches will fit nicely along the top center. I wired the lights first, so I installed a group of three switches for nav, strobe and landing lights.

I just gotta have one of those EFIS/One things, so I'd better plan for it now. The display on an EFIS/One is roughly 11.3 * 8.4 inches which is a lot of real estate on a Cozy panel. I don't want this screen directly in front of me (at least not to start with), so it either goes in the middle with the radios off to the right, or it goes on the right side with the radio stack in the middle. Then again, I might use the circular MicroAir radio. I decided to assign space for the EFIS in the middle of the panel and put the radios to the right of it. I drew lines on the panel in pencil, and cut a hole for intercom. I'll put engine instruments in the EFIS space where I can see them during early testing. This way they'll be physically replaced by the EFIS later.

Instruments - The basic T

Around July 2000 it finaly came time to start thinking about instruments and gauges. I'm not keen on everything being electricity driven, and I don't expect to be able to afford a full EFIS anytime soon, so I'll be getting vacuum (steam) powered atitude instruments from Howard Francis (480-820-0405). He sent me a very nice reconditioned DG and an ASI on approval. Howard is the guy Nat recommends in the newsletter. The ASI had pre drawn arcs for Cozy MKIV and TAS scale calibrated in MPH only. After some consideration and advice from other builders on the maillist, I decided to return the ASI in favor of a KTs calibrated gauge. It had pre drawn arcs, but I'll be able to stick on new ones or have the arcs redrawn once I know the speeds for my airplane. The DG is a keeper. Over the next two years I gradually accumulated a full set, all from Howard. It took so long because Howard is very particular about what he sells. I wasn't in a rush.

Once the last of my basic six gauges arrived in June 02, I drilled holes in the panel and fitted them. I dremelled away the shape of each instrument from the back of the panel to get the bezels flush with the front. The screws just go the front skin of the panel, but everything seems fairly secure. Some of the instruments are threaded and some need a special type of nutplate on the back. Howard sent me a supply, but you can get the special instrument screws and nutplates from Wicks. Now I have the first six gauges in I'm anxious to plan the rest. I'm tempted to leave a space for the EFIS, but on second thoughts I'll probably just put in whatever I get and revise the whole thing later on.


I got some yellow tubing from Wicks that's supposed to be for vacuum systems. It seems too soft so I asked Nat about it, and he recommended tygon tubing from the hardware store. Home Depot had a bunch of sizes at very low cost. I used the fittings from Wicks, and plumbed everything in tygon. My EAA tech inspector commented that it would be nice to have a water trap in the static line. He suggested a T and a vertical drain with a release valve of some sort.

Headset Plugs

I don't think you're supposed to spend a whole day installing the front headset jacks. I did. After glassing the front armrests in place I remembered that I'd planned to put the headset jacks just in front of the seatback by the pilots left (and passenger's right) elbow. This seems like a good place because the wires will be out of the way, and the headsets can go in the baggage area out of the way (and the sun) when parked. So - how do I get the jacks in, now I've glassed the armrests in place. Damn. I should have installed the jacks from the underneath first. After a bit of thinking, I realized that approach wouldn't let me change the jacks or get at the wires if they came loose. I eventually (it took a while) came up with a plan. (see note below - it wasn't much of a plan). I cut four aluminum rectangles about 2 inches by 1.5 inch. In two I drilled holes the right size for the jacks. These will be on the top. In the other two I drilled 7/8 holes big enough to pass the whole jack assembly. These will go at the bottom. Next I drilled pilot holes for sheet metal screws in the bottom pieces and larger holes in the top pieces. Then I cut away the glass to expose foam where the jacks will go, floxed the bottom pieces in place and glassed over them. The jacks, with long pre-labelled wires attached, can be lowered through the holes. The top pieces will hold the jacks in place. Cool - I have a good solution. Now - why did it take all day? I've got a nasty feeling there are going to be many more days like this in this chapter. I haven't even done the rear headset plugs yet.

A couple of days later I was looking proudly at my headset jacks, and thought - "What about the microphone?" Pretty basic huh! I'd made holes for one jack on each side, but I needed two. Is it that long since I've flown? This kind of basic error worries me. If, after flying for 35 years, I can't remember that I need a plug for the headset AND a plug for the microphone, what chance do I have of setting up an electronic ignition system? Hmmm. It's HOT here in July. Maybe I was just having a bad day. Embarrased, I drilled a second hole in each armrest and made new aluminum cover plates. No one will ever know.

Later I ripped out all the wiring and replaced it with the proper shielded stuff.

Engine instruments

While at Sun & Fun '01 I came across Ralph Krongold and his I-K 2000 Flight / Engine monitor. The system displays up to 22 colored bar graphs simultaneously, plus gives 6 digital readings. I liked the unit, but what particularly impressed me was that Ralph was prepared to listen when I said I needed it to work with a Mazda rotary engine. Not only did he listen, but he knew enough to ask intelligent questions and followed through by quizzing Jim Sower, visiting Tracy Crook and picking his brain for what should be monitored on a 13B. A couple of weeks later Ralph happened to be in South Florida and stopped by to visit my project and discuss my requirements in more detail. You just don't get service like that from most companies these days. At Sun & Fun I asked Vision Micro if their unit could be used with a Mazda. They said no, and turned to the next customer. In any case I like the IK unit better because it displays much more information graphically. Sure, the Vision Micro display has a certain "cool factor", but in practical terms it dedicates a lot of IP real estate to a couple of analog dials which I'd prefer to have as physical instruments anyway. I sent Ralph away with an order.

I later recinded that order in favor of the EFIS-ONE from Blue Mountain, which I can't afford yet :(
Ralph was good enough to refund my deposit. :)

Wingtip lights and Strobes

I've had a problem with paying $700 for a pair of lights ever since I ordered the plans and started looking through the prices of the parts. While at Sun & Fun '01 I spotted a build it yourself strobe kit from Great Plains Aircraft for $29. I bought two. The first one took me about an hour to assemble. It worked first time and seems VERY bright. The second one took an hour an a half. An hour for my eyes to return to normal after testing the first one, and half an hour to assemble the kit.

I must have invested many hours in the issue of wingtip lights both in experiments and planning. Once I had strobes I looked around in auto parts stores for suitable lenses, backplates and covers. I never found anything that looked good. Eventually I came across the CCI lights (see my links page. After continued correspondence with Art, I decided that I'd get these neat looking lights. While waiting for them, I thought about it some more. The CCI lights are designed for the top of the winglet. They'll stick out and be easily damaged in the standard position. Hmmm. Putting them on top of the winglet gets them out of the way, but presents two problems. - I'd have to blank off the inboard side to avoid being distracted by the strobes, but most important, I decided that the lights wouldnt be visible from below. In the end, frustrated by the unavailability of the CCI lights, I ordered an Aeroflash kit from Wicks.

Once I had the Aeroflash lights I cut pieces of blue foam to match the baseplate and microed them to the wingtips. When the micro cured I sanded the foam with a flat board until it almost dissappeared at the back. Next I glassed the foam with 2 ply BID running the glass about 3/4 inch onto the winglet. Now. How do I attach the backplate? I cut holes for the nav bulb fitting and the wires, inserted a couple of pieces of al sheet behind the glass and floxed them in place. Using the baseplate for a pattern I drilled the aluminum for sheet metal screws. To finish off the light fittings I added micro around the edge and curved it to a "pleasing shape". After painting I'll fit the lights with some RTV to seal the join between the baseplate to the winglet. My lights will be fairly conventional, but they look "right" and, most important, the issue is finally delt with.

Wiring the wings

I didnt get the installation wiring from Aeroflash because the plugs wouldnt fit through my wings anyway. (Wrong - they would have fit). In June '02 I began the learning curve in earnest and started ordering electrical stuff. I wasn't sure if I needed shielded wire for the strobes. The circuit diagram that came from Aeroflash didnt help, so I called them. Yes, they recommend 3 core 18 guage shielded wire. I found some from Atlantic Aircraft supply and ordered 40 feet. Next came the connectors in the wing roots. I joined the aeroelectric mail list and asked Bob Knockolls. 'Lectric Bob' as he's known said to wire it straight through and leave a big coil of wire in the wing root until final installation of the wings, then run the wires through the fuselage. He suggested that I cut and splice the wires if ever I remove the wings later. Makes sense except for logistics. I want to get all the wiring done before taking the plane down to the airport and incurring hanger rent. The next best alternative suggested by Bob was Matenlock connectors, so I ordered two of these for six cables. I forgot the shield ground, so now I'll have to splice this around the connectors. At this point I had to stop the wing wiring because the wings were on, and I couldnt get at the other end. Once the aileron controls are installed with the new rod-ends I'll take off the wings and carry on with this wiring.

Wiring the Headrest

I'd added a map light wire when I made the headrest. Now I decided that I wanted the map lights mounted just behind the headrests, so I ripped this wire out and started again. It's strange how the jobs at this stage self multiply. I decided that I should probably install all the wiring in the headrest at one time. Hmmm. What am I going to put in the headrest? Speakers? I'd bought a couple of 3 inch 25 watt speakers for the intercom and possible music. The headrest, just behind the pilot's left ear and passenger right ear seemed like a good spot. I've noticed that there are very few places to put anything. As I assemble my bits and pieces I'm finding it increasingly difficult to find vacant spots for them. Anyway, I decided to recess the speakers in the headrest, so I cut out holes for them, floxed and glassed all the edges, then added a couple of ply BID reinforcement around the area. Next, I wanted a dome light in the center. I got a small red auto "clearance light" as a temporary measure and cut a small hole for it. I may replace it with something better later, but it'll do for now. This light will be wired to my essential bus in case of electrical failure.

Finally I'm going to get a goose neck map light for either side. That's a total of five items needing two wires each, just in the headrest. Wow! Next question - Which wire to use? I referred to Bob's book to help remind me of the electrical formula I learned more than thirty years ago, and havent used since. Amps = Volts / Ohms. OK. My handy little multimeter says the resistance of the dome light bulb is 11 ohms. Running on approx 13 volts this is going to draw about 1.2 amps. 22 AWG wire is good up to 5 amps. The goose neck lights are not going to be 4 times more draw, so they get 22 also. The speakers carry very little power, so its 22 for them also. I need 10 22 gauge wires. I've never done this stuff before, but I guess it makes sense to make harness of all wires needed, then run it all at once. How long should the wires be? I havent even located the main bus and aux bus fuse blocks yet. Rather than wait for this, I measured from the side of the fuselage in front of the panel down the center console and up to the headrest. I added a foot for good measure, then cut ten lengths. I printed out some wire numbers and names, and used Bob's shrink wrapped label trick to label each end of the wires. I cheated here by putting both labels on at the same end, heat shrinking one of each, then sliding all the other labels down the wires to the other end. The trick would have worked well if three of the labels hadnt come off. Never mind, I traced the wires with the multimeter and put them back on. In a couple of hours I had a nice looking harness, taped every 12 inches of so with masking tape just to hold it together.

Much later I found some LED map lights in AutoZone for $9 each. I bought a blue on and a red one and installed these behind the headrests. They put out enough of a beam that they light up the panel just enough. The goose neck fitting ended up in the middle.

Installing the Fuseblocks

I've been reading my Aeroelectric Connection book. I have to say it's a tough read. Not because it's complicated or badly written - it isnt. It's an excellent book if you want to learn everything there is to know about aviation electrical systems. Bob pours out everything he knows about the subject. He tells us the entire history of each component and its technology, and why different approaches had problems. Eventually he gets to the stuff I need to know, but seperating the essential information from the interesting background is a chore.

I asked Bob for a "shopping list" of typicial items I'd need for wiring a canard pusher with a dual battery installation. I started to pick at the list. I gleaned from "the bible" that fuseblocks are the way to go, so I ordered four. A 20 fuse Main buss, a 10 fuse essential buss and two 6 fuse battery busses. I also got a couple of 24 tab ground blocks, one for the panel and one for the firewall. At a local automotive store (AutoZone) I found a set of fuses that has an LED on each fuse. The LED glows when the fuse is blown.

There's suprisingly little room in the Cozy IV to fit something 11 inches * 4 inces (main and essential bus together). I'd prefer to be able to see and reach the fuse blocks during flight. I know you shouldn't be messing with fuses in flight, and its advisable to find the problem, not just replace the fuse - but changing a fuse in my Piper Cherookee did help get me home once. Also the FAA say that the pilot should be able to reach any fuses which are "essential to flight". Bob's whole philosophy dictates that no fuse or system will ever be "essential to flight", but I still want the fuses where I can get at them, if only so I can see the fancy LED when one blows.

So - where to mount the fuseblocks? After sitting in the pilot seat and searching around for a good spot, I finally went to Brian Deford's web site and saw that he'd mounted his under the passenger armrest. The heavy cable comes down the conduit and goes straight to the fuseblock. Excellent idea, except that my armrest is glassed in already. I set to with the dremel and cut out a panel about 12 inches by six inches starting at the horizontal joint where the armrest starts to head back in to the fuselage side. I'll refit the panel as a door hinged at the bottom. I chopped the electrical duct back to about 2 inches from the seatback and reshaped the area as it transitions into the floor to make it flatter. Next I had to move the rudder conduit which I had installed a couple of years ago so that it came out of the same hole as the electrical conduit. I cut away the flox, remounted it right under the map pocket and drilled a small hole through the lower panel for it to exit about 2 inches above the hole for the electrical stuff. This happens to give the rudder cable a better angle onto the pedals. Of course I had to remove my carefully swaged cable end, but I need to do this anyway to install the proper springs needed for the hidden bellhorn. I've done a lot of this "retro-fitting" as the plane has gradually come together. With hindsight I could have saved a bit of trouble by doing everything right the first time, but then I think the extra research would have made my overall progress slower - and there will always be mistakes or rethinks. For example - cutting the armrest and moving the rudder cable took me all of an hour. PLanning this stuff in advance and getting it exactly right would have taken a lot more time. There is just too much to know and implement in perfect order with no backing up. My advice to new builders is to plow on with the plans procedures, then come back and modify things as needed.

I noticed that Brian mounted his fuseblocks on a piece of plywood. I preferred to have them as tight into the fuse wall as possible so my door will fit nicely and cover the fuses. I used four pieces of thin aluminum sheet to act as anchors for sheet metal screws and embedded the aluminum pieces in a 3 ply BID repair of the area. I figure I dont need a very strong mounting because the fuseblocks arn't going anywhere anyway. They'll be held in place by all the wires.

I hinged the door to the fuse area, but later, when I added the seats I found that the door couldn't be opened more than an inch or two before it hit the seat. I wanted the fuses to be accessible, so I removed the hinge and installed a inch wide strip of cured glass along the bottom. I covered this with a scrap piece of leather to match the armrests. The door slots into place with the lower inch inside this strip. A snap catch holds the top in place. Access to the fuese is easy - you just pull the snap and lift the door out. Taped on the back of the door is an idiots guide to whic fuse goes where and what size it should be.

Wiring the wings

It came time to do the final wiring on the wings and put them away. I set the left wing on the bench and pushed the antenna and strobe wires through the hole. I got about half way and hit a blockage. After half-hour of poking with 3/8 tubing and blowing from both ends (alternately) with 100PSI air, I got all the insect nests and rolled up leaves out of the tubes and was able to push the wires through. Other builders could save this problem by plugging all the holes early on. Now I came to the question of what size wire to use for the nav lights and strobes. I measured the resistance of the bulbs as 10 ohms. OK, Ohms = Volts / Amps. At 14v this is 1.4 amps for each bulb. According to Bob Nuckolls you have to wire everything in the same circuit with the same wire. e.g. if all the nav lights left and right are fed from one fuse, then you need the same wires all the way. OK, total load is 5.6 amps. Add a little for losses in the wire and you're up to 7amps which is the max for 20AWG, so it's 18AWG wires for these guys. Now - my next question is that I can't see any reason I'd want nav lights off and position lights on or vice versa, so why dont I splice the wires up at the fittings?

I asked Bob and he said to run the individual wires down to the switch. He didnt say why. Ah well. Just this one time I'll do what I'm told without an explanation. I got my fancy new crimper from B&C and set to work. I labeled the wires with little labels under the shrink wrap at the wing roots. I decided that the butt splices near the nav lights are going to be buried in the wing conduit and, hopefully, will never see the light of day again. So, I added some shrink wrap over the crimped splices and squirted RTV in both ends just before shrinking. When I built the winglets I couldnt see dragging a long loop of wire around until I was ready to wire everything, so I'd cut off the antenna wires about a foot from the winglet. Now I used connectors and a crimper from B&C (Aeroelectric connection) to make the joins and potted these as well. The result was a nice set of potted joins which, I hope, will be good for many years. Next I gently pulled all the wires from the root and fed the joins into the conduit. When the nav lights mated with the winglet I added more RTV between the surfaces and screwed the lights down with self tapping screws into the aluminum backplate I'd installed earlier. Now it was time to fit the lenses and test the lights. I installed the red lens on the port side (after double checking) and went inside for the green lens for the starboard (Char's) side. When I came back to the patio I tripped and did one of those comedy juggling acts with it. I dropped it, caught it again, threw it up in the air, bounced it on my elbow, then finally caught it on the way down (almost) with my foot. It hit the concreate and smashed. No more green lens. The next day I called Cheri at Wicks, told her my sad story and ordered a replacement.

Wiring the strakes

I tested the power draw of each Nav light and calculated the wire size I'd need. I got some three core shielded 18 awg for the strobes. OK, so how do you know how long the wires have to be? My solution was a simple practical one. I ran a piece of 20 awg wire from where the switches are going to be, along the wire conduit to the back, through the spar and out of the hole. I cut the wire, then pulled it back through, labeled both ends, and crimped the pin for the connector plug at the wing root. This would be the nav light. I ran another wire of the same length for the position light. There were seperate wires coming out of the light fixture, so It seemed natural to run a wire to each. I probably should have joined them at the light fixture since they'll be switched by the same switch anyway. I made up wire numbers as I went along - e.g. "L109 Nav Red" was the red power lead on port side nav light. I printed labels in a 7 point font and shrinked wrapped them to the wires. Once all the wires were ready I twisted them into a harness and used a coat hanger to pull the wiring harnesses through the holes in the spar.

Next came the antenae wires. I ran a test wire from the panel all the way to one wing root to get the length. Here I hit on an issue the archives and the mail list didnt seem to have an answer for - where do all the wires go? For example, I have three antena wires and two power wires (nav & posn lights) that need to go from the wing root, through the spar, then down the electrical conduit. How do you get from inside the spar to the electrical conduit? I decided that a hole in the bottom of the spar was needed. I drilled it forward of the spar cap (Duh!) and away from the landing gear reinforecements. While I was at it, I drilled another hole in the top of the spar just right of center to avoid the internal bulhead and forward of the spar cap. This would allow the wires from the upper firewall area to decend to either the center console, or the side conduits. I dug out foam between the surfaces around the holes and floxed, then 2 BID taped the holes for reinforcement. Finally I drilled into the electrical conduit on each side where it goes through the "hell-hole".

Wiring the EFI Computer

I have the EC2 from Tracy Crook upgraded for turbo. I had Tracy make the harness for me, or rather remake my attempt. When I measured for wire lengths I'd planned to send the wire down the side conduit and up to the panel. Later I installed the EC2 controller on my throttle quadrant, so the best way to run the wires was down the center on top of the heat duct. The only problem with this was that I now had about 7 feet too much wire, and I didnt want to make a hole big enough for Tracy's nicely installed plug. My solution was to mark all the wires, cut them near the plug, run the wires through the holes, then butt splice them 7 feet shorter. The big plug on the back of the EC2 sticks out quite a bit, and only just fit behind the bulkhead I made to seal off the area above the spar. It would be better if that plug came out the side.

Wiring the Firewall

I'm doing Bob's dual battery, single alternator system drawing Z11A, but with a OV crowbar protected internally regulated Mazda alternator. I downloaded the free version of TurboCad 2D (It also comes on Bob Nuckolls CD), imported Bob's DWG files and began laying out my wiring. First I planned the forward side of the firewall above the spar. There are a lot of components you can hide in this area. I got a Panasonic 17ah rg battery, and will get another identical one when I'm almost ready to fly. Using the battery I made fiberglass battery holders on each side per plans. The EC2 EFI computer can go in the middle. While in France visiting with Jean-Patrick I'd seen his electrical layout. Rather than a fat wire to connect the battery to the battery contactor, he'd used some 1/2 inch brass busbar stock and covered it with large shrink wrap tubing. I liked the look of this setup, and Jean Patrick gave me a length of the shrink wrap to bring back. So, I drilled holes for the battery contactor above the battery, with the terminals in line so a three inch vertical strip of the brass busbar strip I got from AeroElectric would join the two termnals. I drilled for the starter contactor above and to the right so I could use another brass strip in a kind of staircase approach. The battery busses fit nicely outboard of the contactors.

Attaching the various items to the firewall was interesting. In some cases, like the ground bus, you want to drill through the firewall. In other cases you just need some way to screw something to it. My solution was nutplates like the ones we use for rudder and aileron attachment. Lots of nutplates. It goes something like this... Drill a hole partially through the firewall big enough to take the threaded part of the nutplate body. Fill the hole with flox. Put a touch of grease in the nut plate hole. Insert the nut plate, then use 2 BID tape over the top. After cure cut the glass from the screw hole with a knife. Bingo. One embedded nutplate. this is how the firewall ended up

Fat wires

I ordered some #2 wire. Wow! this stuff is serious. I don't think I need any in the plane, except, perhaps, for the starter. But the starter contactor is fed by #4 wire, so whats the point? If the starter doesnt get enough juice, I'll give it #2 wire, otherwise this stuff stays on my shelf. I know now why 'lectric Bob recommends those little rubber booties for the fat wires - it's to hide the mess you made of the insulation while soldering the terminal with a blow torch! I only screwed up one before I learned to heat the ring and let the heat flow down to the wire.

Wires and more wires

I did my wiring using my typical ADD methodology. Add a few wires here, add a few wires there. There's no way I could build a harness in advance and install it in one go. There's just too much to deal with all at once. At this point I don't even have my engine instruments or radios. As with the panel planning, the wiring just evolved. I pretty much followed Bob's drawing 11A. I used masking tape to hold the wires in a bundle, then pushed additional wires into the tape loop as the harness evolved.

Once I'd attached my first fat wire for the ground, and wired the alternate feed switch, I realized that I should have power on the main bus with the feed switch on. Cool. Its time for my Cozy to come to life. Let's see, now. What have I connected up so far? The taxi light and the intercom. OK. I sat in the pilot seat, selected alternate feed and, with much anticipation, turn on the taxi light. Nothing. Hmmm. OK. Debugging time. I got out my fancy new digital multimeter, set it for 12vDC, put one pin on the ground bus under the panel and one pin on the main bus. Yep. I have power. Now I checked the taxi light switch. Maybe I've wired it wrong (there are only three terminals - how far wrong could I be?). Yep. I have power at the switch. OK. It's gotta be the light fixture. It's been in the nose for three years and suffered wet sanding many times. Maybe it got wet. I removed the ballast cover plate, removed the weights I had in there, removed the fiberglass bulkhead I'd fitted over the light, then removed the light fitting. Did I have power at the fitting? I tested from the ground bus to the fitting. Yep. 12vdc. OK, gotta be the bulb. I removed the bulb. It looked ok. Hmmm. What about the ground? Was there continuity between the ground bus and the ground on the fitting. Nope. Ahha! Must be the connector on the ground wire. Perhaps it got wet. It was one of my very first crimps, maybe it didnt take. I snipped off the ground connector and replaced it. Nope. Still no ground. OK, lets trace the wire back. Maybe theres a break in the wire. I carefully worked my way back along the wire ties pulling on the wire to identify it at each section. When I got to the panel the wire disappeared into a serious bundle. I sneaked along the bundle pulling the wire a little at each section. Along the back of the panel we went, all the way to the other side, down to the ground bus. Just as I got to the ground bus the wire came free of the bundle. I pulled on it... and up came the free unconnected end. Damn! I'd run the wire over to the bus before the bus was there. I'd been planning to connect it later. Undaunted, I decided now was later, crimped a connector on the wire and hooked it up to the bus.

At this point I recalled an incident from my childhood. You probably don't want to hear about my childhood, but here goes...

I was about 13 years old. My older brother, Michael, was 19 and heavy into auto rally (mini-cooper s, the original version, not the BMW knock off). He'd blown his engine in a rally and was rebuilding it in our garage. I watched him for three long days as he took out the motor, stripped it, cleaned and rebuilt every part, installed new bearings and reassembled it. Eventually he lowered the motor back into the car, hooked it all up and, lastly about mid afternoon on a Saturday, reconnected the battery. At this point he cleaned and put away all the tools, shut the bonnet (England, remember) and closed the garage door. "Arn't you going to start it?", I asked. "It'll run", he said, and proceeded to go in the house, take a bath (this was England in the 60's) and put on clean clothes. Mike sat down, had dinner then arranged to meet his girlfriend for the evening. When it came time to leave for his date, he calmly walked out of the house, got in the car..... and drove away like he was on another rally. I remember hearing the tires screech from the wheel spin as he pulled away from the junction about half a mile away. Now thats confidence in you're workmanship. I was impressed! But then, I was easily impressed at 13.

I went in the house for a drink and to cool off. I was tempted to have a shower and get changed to go out, but I wasnt planning to go anywhere, and I had plenty more wires to connect. After a while I came out, sat in the pilot seat, and thinking of Mike and his engine, selected the alternate feed and clicked on the taxi light.... You guessed it. NOTHING!

I removed the light fitting again, and tested for power and ground. Yep. I fiddled with the bulb, and on it came. Loose fitting. OK, I have a spare fitting. I'll put it on later.

Testing the intercom

Once the intercom and headset jacks were all wired up it came time to test the intercom which had been so kindly repaired by RST and had lived in the back bedroom drawer it's shipping box for over a year.

I got my headsets, plugged them in and turned on the power. Nothing. I tested the power into the intercom. Nope. Ah! The intercom is powered from the essential bus. I thought the essential bus would have power from this setup, but maybe not. I'll have to check the diode wiring and the schematic. (Note - I'd wired the alternate feed wrong. I moved it to the essential bus later). In the meantime I moved the connector to the main bus, and saw a small blue flash as I connected it. Definately some draw there, but I wouldnt expect that much. The LEDs on the intercom weren't on, but I could hear a crackle in the headset. I adjusted the squelch. There was no on/off click, but I could definately hear something happening in the headset. As I turned up the volume (which seemed to spin 360 without a stop) I could almost hear myself speaking into the mike. It was then that I detected slight smell of burning. I saw a tiny wisp of smoke coming out of the back of the intercom. Maybe it's just warming up I thought, ever so hopefully. I switched it off and removed it from the panel.

I decided to take a look inside and see what was up with the volume and squelch pots. I removed the cover and saw that the volume knob was broken off at the tip, and the squlch knob seemed worn. Maybe I turned it too hard. No problem. I can easily get replacements from RST. The tip of the volume control was broken off in the pot. I wanted to test the intercom one more time, so I decided to remove the broken piece. I built this thing, I should be able to repair it - right?

I removed the nuts on all the switches, removed the cover plate, undid the bolt holding the mini control panel and swung it into the light. OK, all I have to do is unsolder one leg of the pot and bend it a little and I'll be able to push the broken piece of plastic out. Using my desoldering braid I removed the leg from the board. The plan worked. I resoldered the leg, screwed the control board back in, lined up all the switches and reinstalled the cover plate. Now I could adjust the pots with a small screwdriver. I decided to try one more test before sending the unit back to RST for another "calibration". (See earlier paragraph about original my assembly problems). I plugged the unit into its connectors, and hit the alt feed switch again. Again I got the crackling. Again I got the burning smell and the wisp of smoke. I turned if off, quickly removed the cover and used my nose to find the smoker. A small resistor was the wrong color (black) and smelled different to the others. I composed another begging letter for Jim Weir and sent the intercom off to RST (fix department).

About 4 weeks later the intercom came back. Unopened. RST have moved since they printed the audio panel manuals. I called, got the right address and sent it off again. About 6 weeks later I called and spoke to Jim. They'd had some extreme weather problems and were a bit backed up. No problem, I said. It's not like I'll be grounded without it. My unit would be done soon. About 6 weeks later I called again. Apparantly the audio panels are (were ??) repaired off site by a sub-contractor. After a week or so I received a call from Gail, Jim's wife, who was most embarrased about all the delay and inconveinience. Gail told me that the problem should have been identified during the initial repair, and that this repair would be at no charge. Can't beat that.

A week later my intercom came back fixed with a zero bill. The bad news was that the package also contained a nice letter telling me that the internal wiring harness REALLY needed to be unsoldered and replaced to get the intercom up to RST standards. Reading between, and along, the lines the letter politely told me that, while it worked today, I'd built it so goddamn badly that they really didnt want to gaurentee that it would work tomorrow.

Hmmm. Perhaps my experiment in electronics wasn't such a good idea. I learned a lot building the intercom, and my second one would probably be a lot better, but it may be that I don't have the aptitude for such fine work. My advice to anyone considering building an electronics kit would be to evaluate you're skills. If you have the skills (or can learn them), aptitude and time then go for it. On balance I might have been better off buying a prebuilt unit. Replacing the wiring sounds much harder than installing it in the first place. My plan now is to install it the way it is. If it works - great. If/when it fails I'll throw it in the can and buy a prebuilt unit.

Chatting over the CEW

What's CEW? Read on. I double checked the polarity of the wiring, then plugged the RST audio panel into its three plugs. Next I got out my headset and an old damaged headset, plugged them into the pilot and co-pilot sockets and turned on the master. Hmmm. I heard something, but it wasnt good. Crackling and Electronic Whining (CEW) is what I'd call it. I messed with the volume and squelch but all this did was make the CEW louder, softer or silent. I could sorta here my voice over the CEW, so I called Char out and got her on the other headset. We could hear each other - just. The voice was intermittent and mostly drowned out by CEW. I was beginning to think that perhaps this was the end of my experiment in electronics and began "flipping through the memory pages" in my head looking at the prices of audio panels. On a whim I climbed in the back to test the rear sockets. At least I'd know if they were wired up. I plugged into the right rear and got the same CEW. I guess that's good. Finally I went to plug into the left rear, but couldn't find the sockets. The retaining plates had been removed to do the upholstery and the plugs had fallen down inside the fixed part of the armrest. I removed the removable armrest and fished around inside to find the wires. I found the wires and pulled them out. Char was still standing by the plane with the headset on. I saw her expression change. It looked like a good expression. Hmmm. I plugged into the left rear sockets and heard .... nothing. Total silence. The CEW was gone. "I think I found the problem, I said to Char over the intercom. She jumped, then replied. "Ooooh Good" or something like that. It didnt matter what she said. What mattered was that it was clear. I mean REALLY clear. As in "Are we Clear? Yes. Crystal!
Bingo. The left rear sockets had been resting on the torque tube. My audio panel is working just fine, so it's on to connect my new ICOM A200 radio.

More Minor Mistakes

One evening Char asked why there were so many connectors laying around on the patio. I explained that these were the ones I'd screwed up while crimping. My technique is to crimp them, then try quite hard to pull them off. If they come off, then I strip the wire again and add another one. Maybe one in ten comes off. Occasionally I forget to put the shrink wrapped label on the wire before crimping the terminal on. I noticed I'd made this mistake on the intercom power lead so I snipped the connector off, got distracted and put another connector on. I'd forgotten the wire label again. Ah well, connectors are cheap.


A long time ago I got a wiring diagram from Alex Strong which shows how to make a control board for the elevator trim using radio shack relays to switch the current direction. I'd made up a double unit to control the landing brake and trim. I fished this out of the pile of stuff on my electric's shelf planning to mount it and wire it up. The problem here was that I lost the wiring diagram years ago and I didnt know what the ten wires were for, and I hadnt labelled them. I remembered that red and green were power and ground, so I hooked these up and experimented with my multimeter until I had the functionality I needed. Connect this wire to power and this wire is +12v. Connect power to this wire and the current reverses. Great. The relays seemed to work perfectly. I installed a plastic connector and found a spot for it on the left fuselage wall behind the panel. I mounted it on some rubber baffle material to protect it from vibration. SOmehow I also need to protect it from getting wet if water comes in the NACA air duct just above it. Later I mounted the relay board in a plastic project box from radio shack, sealed the edges with RTV and mounted the box just by the static vent port.

Playing with LEDs

While I was experimenting with the relays I forgot to turn off the master switch. Next morning my battery was drained. Around this time there was a discussion on the Aeroelectric mail list about LEDs, and I downloaded Bobs PDF on how to connect these neat little gizmos. It boils down to the fact that you can buy LEDs already set up for 12V, or you can buy just about any LED and connect a resistor in series with it. The voltage / current requirements of the LED are fairly standard and the value of the resistor doesn't seem to matter much provided that it's between 400 and 1K ohms. I decided to make myself a temporary "master on" warning light and went down to Radio shack to see what they had. The choice of LED's is limited if you want them 12v ready, but they have all manner of neat little LEDs in raw form. They have blue ones, blinking ones, red / green alternating ones, big fat ones, tiny ones....

I got a bit carried away and bought a whole selection, including a kind of "grab bag" with 20 assorted LEDs and a couple of packets of resistors. The total cost was about $9. Good value for the hours of fun I had. That evening I set up a blinking red LED as a temporary master on warning light. It sticks up above the panel so I can see it from the kitchen. I also installed red and green LED's for the landing brake. I discarded Jack's nice engraved nose gear panel and set up the gear and landing brake switches and LED sets in a neat little "landing" panel right below the manual gear retract. I'm trying to organize the panel in functional groupings as I go along.

One nice thing about building an airplane is that you get to play with cool stuff and implement your own ideas in between the more serious building stuff. After playing with all the colored LEDs for a while I had one of those ideas. I'd been wondering Where to put an annunciator panel and how to label it. I'd been thinking that it should go somewhere in the top center of the panel, and that I'd have lights with labels under them. I put the instrument panel cover in place to see how much of the top of the panel it covered up. Hmmm. Quite a lot. I've already drawn an 11 * 8 square on the panel to reserve space for my EFIS/One, so there isnt a lot of room above this, and I'd like to put some small switches in the small space that remains. Hmmm. The instrument panel cover wastes about 3/4 inches of space. I've made it nice and curved and plan to cover it with leather. It'll look nice, but I don't have anywhere to put my pretty LEDs. The best place for them is at the top, in my line of sight. Then inspiration came to me. Suddenly I had the whole picture in my mind of how this was going to be done. This doesnt happen often, so I dived in and did it while the image was still there. I cut a 5 inch hole about 1/2 wide right out of the front of the curved panel cover. In this hole I mounted a piece of plexiglass. I found some cured 2 BID, cut dividers with scissors and stuck them inside the curve with flox. While this cured I used my computer to create a white on black label. I printed this on acetate sheet, cut it out and stuck it on the plexiglass window. I'll revise it as the panel evolves and may eventually get it screen printed, but this gives me an idea how everything is going to look when its done. Next I used a small radio shack breadboard to mount a row of ten 20 ma LEDs, each with its own 470 ohm resistor. I pretty much choose the colors at random. Some yellow ones, some green ones, some blinking red ones and a blue one. I'll figure out what to warn myself about later.

I ran a common ground and mounted everything except the LEDs on the back of the board. I drilled ten holes in the panel just the right size for the LEDs and mounted the board up against the back of the panel with the LEDs sticking through the holes. After a little fiddling with the font size and placement I got my labels lined up so that each LED lit up one label, and the dividers stopped the light crossing over to the next label along. The panel looks cool (my opinion) and I still have room for my switches below it. Next I got a few of the 3000 MCD red LEDs and mounted these in the panel cover too. These should give me enough red light to read the panel at night. OK, I went a little crazy with LED's. Actually I'm not done yet. I have about ten LEDs left. Gotta put them somewhere!

When I came to fit the voice annunciator (see below) I found that it was triggered by grounding, so I had to dissassemble (read chop up) my light annunciator panel and redo it with a common live. I did a much better job the second time around and ended up with the leds and resistors flush with the back of the panel.

Once I had the voice system hooked up I added wires to my LED panel so they could share the grounding and would come on at the same time as the voice to give me both visual and audio warning of a problem. I powered the voice system up and the LED's came on and stayed on. All of them. Hmmmm. I sent an email to Rick Lewis. He replied:

Ok here is whats happening.  The eight lines coming from the annunicator 
are at a voltage level of 5 volts.  This is done internally using eight 
pull up resistors.  Your led is at 12 volts, thats a 7 volt differance.  
In other words the led thinks its negative lead is already at ground 
because of the internal pull up resisters.  You have a positive voltage 
on one side of the led and a less positive of the other.
       This can still work but you'll have to use PNP transistors as 
switches.  This will isolate the led from the internal voltage in the 
I told him this was great, and as soon as I find out what a PNP transistor is I'll be home free. :)

Taking pity on his electronically challenged customer, Rick worked on the problem and came up with this:

your LEDs are on all the time because your supply voltage is 12 volts, 
lets reduce it.  I am sending your another module that contains a voltage 
regulator.  It's output is only 5 volts and this will be hooked to the 
LEDs instead of the 12 volt line your using now.  This will also require 
you to change all the resistors to a different value.  

Aggggghhhhhhhhh! Did I mention that the resitors and LEDs are potted in micro?
I ripped my LED panel apart and rebuilt it for the third time. I'm getting pretty good at this stuff now. The new LED panel was installed and floxed in place in a few hours. This time I used 600mcd directional LEDs which should light up my panel better. Rick charged me $2.00 for the parts and $3.85 for the shipping and ziltch for his expertise. Can't beat service like that.

While I was replacing the eight LEDs for the voice system I added three more LEDs to balance the panel out width wise. I haven't decided what to use these for yet, but I gotta use them for something cause I used two flashing reds and a real pretty blue one. Later I decided that the blue one could be for the air conditioning switch.

Voice Annunciator

First another off-topic story. Soon after I first met Charmaine I was driving and was about to miss a highway turn off. With some difficulty I was able to get around a couple of vehicles and get "close" to the exit ramp, but I hadnt fully allowed for my high speed. During the event Char shouted something. Committed now, I took out a bit of the verge, generated some dust, dodged around a couple of trucks, then sucessfully got to the ramp. Afterwards, while we were waiting for regular heartbeats to return, I asked what she had shouted. It had been something like "John. Watch out, there's a grass verge coming up fast". I suggested that, in future, she use a short meaningful warning like "GRASS" to communicate the problem quickly and clearly. In the years following my suggestion Charmaine has introduced a number of short, meaningful and helpful warnings into our travels. Shouted words such as "TREE" and "TRUCK" come to mind. So, despite the comments of some of my "manly" friends, I'd reaally like to install a voice annunciator with a few choice words from Charmaine to get my attention ...such as "John! gear... Gear...JOHN...GEAR".

...or for a REALLY drastic situation, perhaps I could get my EX-wife to record the message! That would surely get my attention.
Then, on the other hand....I have a bit of Tinnitus, and unfortunately my ex just happens to speak in the frequency range I don't hear.

Seriously, I felt that, apart from being "cool", a voice warning system would be a good safety feature. I might miss a flashing light, and a "horn" would annoy me too much, but a voice in my ear at the right time would probably get my attention.

I looked at the bare sound chips but decided that, while it sounded interesting, I didnt need another learning curve of PIC programming and eproms. I contacted Richard Lewis who demoed a voice annunciator at a Cozy dinner. His phone number is in the Cozy newsletter. Keep trying. He seems to travel a lot. After some discussion about features and possible options, Rick sent me a box full of stuff with the promise that, if I didn't like it, I could return it. I like it. Within 30 minutes of receiving the unit in the mail I was recording my own messages. It holds 8 messages of about 16 seconds each. Each message is triggered by grounding it's wire. If you hold down a button while grounding the wire, then the built in mike picks up whatever you say. The voice is very high quality digital and clear. No sign of compression loss whatsoever. The message keeps repeating until the condition goes away. If you want it to say once only, then you need a little module from Rick. I got one for my "System is up and running" message. There's a system defeat option which shuts the whole thing up for 5 minutes. If more than one message is called, they speak and repeat in turn.

As an added bonus the system can also be used to train you're pet parrot to speak. Rick says you can record what you want the parrot to say and leave the system running when you go out for the day. When you get back the parrot will either be fluent, or dead. Unfortunately this doesn't seem to work on cats or Golden retrievers.

I'm very impressed with the voice system. It's good value and it works as advertised. Rick is ready to help with wiring and control questions. He was good enough to supply pre calibrated low voltage, oil pressure and temperature modules with senders, so my job was made much easier. I decided on the following eight messages:

  • 1. "System is up and running" - Triggered when power goes to the transponder encoder. Why? Because I have a bad habit of forgetting to turn the transponder on before take-off. I've heard the old "please recycle" message from ATC too many times. This way I'll be expecting the "system up" voice message, and it's absence will remind me to turn on the transponder. Circuitous I know, but it'll work for me.
  • 2. Gear up on throttle back - I'll also have a flashing LED for this.
  • 3. Canopy open on throttle up - I'll also have a flashing LED for this.
  • 4. Low oil pressure
  • 5. High oil temp
  • 6. High coolant temp
  • 7. Low battery voltage
  • 8. High engine temperature (EGT) Another message for low fuel would be nice, but fuel isnt something I tend to forget about. How's that for famous last words.

    Later I revised my list of warnings:

  • 1. Low fuel pressure
  • 2. High coolant temp
  • 3. Gear up on throttle back
  • 4. Canopy open on throttle up
  • 5. High engine temperature (EGT)
  • 6. High oil temp
  • 7. Low oil pressure
  • 8. Low battery voltage

    I put the CHT and Battery voltage senders in the back near the batterys.

    Plane Speaking

    I'd tested the annunciator (or is it an enunciator?) on the coffee table in the living room, and got Char to record all the messages. Finally I installed it into the plane, hooked it up to the intercom and installed the speakers in the shoulder rest. I probably won't have an ADF, but I will have an AUX (music) so I hooked the voice warnings into the ADF feed for the RST audio panel. I flipped the switch to speaker and grounded one of the message terminals. Nothing. I checked all the wiring and tried switching to the AUX feed. Finally I thought to fiddle with the live connector for the voice panel....

    The plane spoke. It said, quite loudly, and somewhat to my suprise, "John. The main bus battery voltage is low!". "Well, yes. I guess it is," I replied, "you see I've been trying out electrical stuff and haven't charged the batteries for a few weeks", I explained, walking over to get the battery charger. We had quite a few good conversations once the ice was broken, but I won't bore you by repeating them.

    I hooked up various sensors, and the plane's vocabulary increased. If I push the throttle the full with the canopy open it said "John. Close the canopy", and if I reduced throttle to idle with the gear up it would say, "John. Lower the gear."

    After a few hours the conversations got a bit limited and the damn plane just wouldn't shut up. "John, The oil pressure's low", it would complain. "Well right, yes. I'm sure it is", I'd say, "This is probably because, in case you hadn't noticed, you're engine's not bolted on right now". to which it would reply, "John. Close the canopy". "I would, but it's over on the hot tub", I'd say".

    I decided it was high time I installed the STFU button. Now the plane and I are getting on much better. It speaks. I hit the STFU button. It shuts the f... up.

    Before we move on, let me mention another saga that occured during the above wiring, just to make a point. It doesn't seem to matter what I do, or how much care I take, nothing ever works first time. Not never. Take the STFU feature, for example. This is a very simple issue. You ground a wire momentarily, and it stops bugging you for 5 minutes.

    I got a mini push button switch from Radio Shack and soldered the connections to my orange STFU wire, and ground. While the plane was busy explaining about the low oil pressure and low buss voltage I hit the button. It started again. "John"...I hit the button..."John"... I hit the button again..."John"... you know the feeling. Some of us had wives like this.

    I disconnected the orange wire and grounded it. She STFU. Hmmm. Maybe the ground wire isn't connected properly. It was. Maybe the switch is faulty. I tried another one. (They come in packs of 4). She still wouldn't STFU. I tested the push button with my multimeter. It was a short, until I pressed it. I looked on the back of the packet and saw the note: "Normally Closed". Why would anyone design a push button that OPENS the contacts when you push it? Damn. I found another switch with a momentary (normally open) position and connected it up. Now everything works fine. Is it just me, or does everyone go through this? Are there builders out there who just hook stuff up once, test it and move on? If stuff ALWAYS works first time for you, let me know. If it's just me I'd really like to know.

    Voltage Display

    I ordered a Vector Portable 12-Volt LCD Voltage Meter Part # VEC008 from Autobarn. It costs $13.95, is backlit and gives high, medium and low voltage lights. The only problem is that the lights are wired in what I consider the wrong way. When the battery is good they all come on. As it deteriorates they go off one by one. I want a light if voltage is low, a different light if it's high and no light if its ok. So, diverting from the stuff I HAVE to do for a few hours, I took the gizmo apart. I mean REALLY apart. I desoldered the LEDs, installed wires instead and added my own LEDs so I can have them in my annunciator panel. I removed the cigarette lighter connection and hard wired the LCD display. I cross connected the low + terminal to the High and medium + terminals and now the lights go on and off depending on voltage. Don't ask me why. I found this by trial and error. It works. I'm happy.

    Panel Lighting

    When I made my panel I used a sheet of acrylic as a backing board for my walnut veneer. I cut the holes for the instruments with a chamfer so that I could light the champhers with LED's embedded between the acrylic and the original glass panel. I experimented with red 3000 MCD LEDs from radio shack, but they were too large and didnt put out enough light. When Vance Atkinson's fuel sight gauge lighting upgrade arrived I knew I had my solution. The tiny LED's he provides must be at least 5000 MCD. They're a blue / white light which, I'm told, is better than red. Apparantly red lighting tends to make all the "red lines" on you're gauges disappear, which is probably not a good thing. I spoke with Vance and he kindly agreed to provide the part number for the bare LED so I could get some for my panel.

    I couldnt locate the part number Vance gave me, so I ended up with a couple of red LEDs under the curve of IP cover, one either side. They're dimmed by the B&C dimmer unit.


    A fellow builder advertised an ACK30 encoder on the Canard Forum, so I picked it up for half the price of a new unit. Budgets were fairly tight, so I bid on a Narco AT50A transponder on Ebay and got it for small change compared with the price new. It came with a tray, but no connector. Eventually I got an upgrade kit from Narco. Expensive, and it contained the wrong BNC connector, but at least I could move on. A few days later Narco answered my initial email and told me the main connector could be had for $9. Damn. I've decided I don't like Narco. I wrote them a letter.
    Recently I had the need to contact Narco customer support to 
    obtain an edge connector for a used AT50A transponder. I 
    emailed customer support asking where the connector could be 
    obtained. 24 hours later I had not received a 
    reply, so I called the support line. I got a tape 
    saying they'd call me back. Frustrating.
    A few hours later they DID call me back. I asked about the 
    connector and was told it came in an installation kit for $81. 
    This seemed expensive, but the lady mentioned that the kit 
    included everything I'd need to set up the tray, including 
    instructions and pinout information. I ordered the kit. The 
    next day I received a response to my original email query 
    signed simply "Narco". I am beginning to understand why 
    you're support reps wish to remain annonymous. This email 
    provided the part number of the connector and price of $9. 
    A few days later my "installation kit" arrived. It contained 
    the connector and contacts. The plastic bag also contained a 
    few screws and cork pads plus two BNC connectors of the 
    same type. Both the WRONG type. No instructions, additional 
    information or pinout info. I later find I can buy the edge 
    connector and contacts from Molex suppliers at much less than 
    the $9 price offered by Narco. 
    I am in the process of choosing all the avionics for the 
    panel of my homebuilt Cozy IV. As you can probably tell from 
    the above, my first impressions of Narco are extremly poor. 
    John Slade
    Cozy IV
    A matter of hours later I received a reply:
    Dear Mr. Slade
    I apologize for the miscommunication on the edge connector.  
    We are more than willing to credit your account for the 
    cost of the installation kit and you keep the kit.  
    The technician that answered your e-mail was specifically 
    addressing your situation.  Generally we sell the kit 
    because that is what most people want.  
    If you need the pinout information quickly, I can have 
    it e-mailed to you today.  Also, as far as we know, the 
    Molex connectors are a custom order for us and are 
    not carried by Molex suppliers.
    Bob Chajkowsky
    Operations Manager
    Narco Avionics
    20 minutes later I got an email with the pinout information, and the next day Narco Customer Support Engineer, Brian Freedman called to explain the problem with the BNC connectors. It turns out that the BNC for the tray has a coax pigtail of a specific spec for transponders. This normally comes with the tray and is a seperate kit. He's going to send me the part number via email. The BNCs in the other kit were for the connector between the pigtail and the antenna. Fair enough. It all makes sense now. Brian also (very curtiously) explained that normally they deal with distributors, who deal with dealers, who deal with the A&Ps doing the installations. Obviously (my words) they can't give direct support to every no-brain homebuilder who doesnt know the first thing about installing avionics... i.e. people like me :)

    Bottom line was that I pushed Narco a bit hard on this one, and they reponded very quickly, politely and effectively without pushing back. I'm impressed with their service, but having said that, it wouldnt be fair to expect ongoing direct service on every little detail of my avionics installation. Its time I got to know a local avionics firm.

    I thought the issue was closed. An hour later I got the following from Narco:

    Our sales department informs me that the credit for the installation kit
    will be issued today. I am sending you, at no charge per Bob Chajkowsky, the
    tray coax and all of the hardware necessary to attach it to your bare tray
    along with the installation manual for the AT155. The manual should help you
    determine the parts you will need to complete the installation and how they
    are assembled. The AT155 uses the same tray as the AT50A. If you have any
    other needs or questions feel free to e-mail or call.
        Brian Freedman
    Wow! These guys are really going the extra mile. A few days later the correct BNC connector and arrived followed closely by a credit for the amount I'd spent on the kit. I'm impressed.


    The encoder came with pin-out info which covered it's connection to my AT50A, but I didnt have the pin info for power and ground to the transponder. Bob Nuckolls seems to have a pinout list for just about every piece of avionic equipment ever made. He had what I needed. I wired the encoder up to the transponder and added power, dimmer and ground feeds.

    The next job was mounting. I made a radio stack cage from 1/2 * 3/4 aluminum angle from the hardware store and riveted it to F22 and the panel. I riveted the encoder to the bottom of the cage.

    The final part of the transpoder install is the antenna which I got from Bob's Nuckoll's product list. Finding a home for it wasnt easy. It wants a 6 inch ground plane horizontal to flight path. Try finding 6 inches of flat horizontal surface on an almost finished Cozy without having the antenna poke through the floor and as close as possible to the transponder. The fiberglass plenum for my AC unit won. I mounted the antenna into the top of the plenum.

    Transponder Testing

    In Dec '03 Al had a local guy coming into the hangar to test his transponder, so I got him to listen to mine too. Nothing. Even when connected directly to the antenna. Nothing at all. I sent it back to Narco on their web site rebuild offer, and had a very pleasant experience. A few days later I got a call from a technician at Narco. I have this image of a wizended 65 year old guy with horn rim glasses who repairs the "older" systems because that's what he grew up on. He likes nothing better to take these things apart and then explain to the owners how he can fix them. He told me the transponder worked, but wrongly. i.e. I should have been getting a reading - it would just be a wrong reading, so I need to check my antenna wiring. We talked about football (UK style) and rugby and he said he could fix my transponder, upgrade it with all the current mods and yellow tag it for a few hundred $. Excellent. A week later it came back, looking exactly the same, but now with a pretty yellow tag. Now all I need to do is check the antenna wiring for closed circuit, then reinstall the transponder and get it tested again. I highly recommend Narco's upgrade & repair service.


    I got my panel mount compass from recreational mobility and mounted it at the top left side of my panel. It worked fine... until I turned the cabin heat (AC) blower on, then it turned left 30 degrees. The blower wires went within a couple of inches of the compass. Hmmm. Arrive too hot/cold, or get lost to stay cool/warm. I don't think so. I was busy ripping out the wires to reroute them when I noticed a few other wires which might also be a problem. Sure enough the taxi light and landing lights put the compass off 30 degrees or more. I ripped out these wires too. The nav light wires also go that way. I hooked up the nav lights with an "extension cord" because the wings were stored hanging from the patio roof. Sure enough, I got a 20 degree turn when the lights went on. I rerouted these wires too.

    Throttle Cables and Broken Arms = Rethinking the panel

    Follow my logic here....
    I'd set my mind on an EFIS ONE from Blue Mountain, but the throttle cable and a broken arm got in the way. Excuse me? First the throttle cable. You see, I'd installed the control panel for my EC2 fuel injection/ignition computer in the armrest complete with walnut veneer backing, just behind the throttle quadrant. When I came to install the throttle cable I found that it passed a bit too close to the back of the EC2 board for comfort. So I needed to find a new home for the EC2 panel. This is where the broken arm comes into it. I learned that Tracy Crook broke his arm, so while he was incapacitated he designed and built a graphic engine monitor (EM2) system to work with the EC2. It sounds perfect. Makes EC2 setup simpler and contains all the engine monitoring systems I'll need. Perfect. I sent him a deposit. The EM2 is 6.25 * 3 inch, and ideally the switches for the ec2 should be close by. The way to do this would be in a radio rack in the panel. No problem. I have one of those. It's almost full, already, with the intercom and the transponder. There's room for one radio, but I was wondering where I could put the other one. Now I need two racks. The taped 11 * 8 square on the panel had to give. No more EFIS. ALso, Tracy's gizmo will do all the engine things the EFIS does. I already have a full set of guages, so I'd be buying the EFIS just for it's very nice GPS, Topo and weather capabilities. The other item that swayed me was that I want to do some IFR training in the Cozy, so I'd like to have two standard localizer / glide slope heads. They need room on the panel too. By the time I've mounted the heads, the EM2, the EC2 panel and the radios I'm not going to have very much panel space left. Certainly not 11 * 8. More like 6 * 5. I liked the setup Benoit had in France, with his Garmin portable GPS mounted from the passenger side of the fuselage.

    Which radios? I searched around on EBAY and called some avionics shops. I spoke to Gary at Dunkirk Avionics in NY and got a bit of an education. Turns out that what I need is King KX155 Nav/Comm with a KI 209 Indicator. The second indicator can be a KI 208 (no GS). Gary repeated what I've heard from other sources ... stay away from Narco.

    I used the panel planner link from, ironically, Blue Moutain's installation page, and tried a couple of approaches to laying out the remaining stuff. If I have VOR localizer and glide slope indicators, I'd like them in front of me, just to the right of the main six steam gauges. On the other hand, the long term main navigation aid is certain to be a panel mount GPS of some sort, and that ought to be in the middle, so I think the VOR heads will have to go over to the right side near the radio stack. I measured the panel a couple of times and tried paper cutouts in various places. If I put the EC2 control panel just above the center vertical, I have about 5.5 inches centered above it. Putting the short EC2 panel at the bottom means that the central radio stack will clear Wilhelmson the manual gear rod. I'll have to move the defrost hose an inch or so, but I think it'll all fit. The space would be perfect for a Garmin 530. I checked the prices - ouch. I decided to look for something else. Sun and Fun is coming up next week. I'll take a good look at what's available, what I can afford, and what I can get used. My panel continues to evolve based on three criteria - what I can afford, what will fit, and what I want - in that order.

    Avionics Decisions

    Avionics is a complex world of high prices. I discovered
    a web site by a Cozy builder that helped me a lot. Another big help was the Southeast Aerospace site which has the specs and pictures of just about every avionics product available. So far I have an AT50A transponder, my RST audio panel and an ICOM A200 com. So I'm short a com, a nav/LOC/GS, a GPS and a second VOR capability. I'd also like to have DME. The future seems to be the GPS/COM,so if I get a relatively inexpensive one like the GNC-300XL I can replace it later with the GNS-430 or 530. I already have a stand alone com. I don't want to end up with 3 coms, so I'm considering the KNS-80 with a KI-206 CDI to give me the nav, DME and glide slope.

    Thinking it through once again I came to a new conclusion. We don't need no stinking avionics. Seriously, why spend good money on old stuff. What I realy want is a Garmin GNS-430, but I don't need it yet - which is good because I cant afford it yet. What I need to begin with is good engine situation awareness. Tracy's EM2 wasn't available, so I had to install a bunch of round gauges temporarily. Since I don't have any avionics theres lots of room for these gauges. Isnt it nice how things work out?

    I reinstalled the piece of panel I'd cut for the center stack and cut holes in it for four 2 inch gauges. These will be oil pres, oil temp, water temp, fuel pres. I installed the fuel guages below the right hand stack. I'll also need boost and egt. These will go in 2 inch holes to the right of the center stack. Later I can extend these holes for CDI's. Once my engine is tested and running consistently Tracy's EM2 will probably be available. I'll install it using the same senders, and remove the round gauges. This will make space for my Garmin 430 which, perhaps, I'll be able to afford by then. This plan actually makes sense. To me.

    A visit from the Pope and radio problems

    Bulent (the Pope) Alieve dropped by the hangar with a friend who wanted to try out a Cozy for size. While they were there we tried the com radio I'd installed. I'd heard approach ok with no antenna when I was at the house, but I hadn't been able to hear anything on it since I installed the wings. That should have been a clue. The radio and intercom seemed to be working OK, but when we listened to a transmission on a handheld it was almost totally masked by a loud squeal. I couldn't hear his transmissions at all. After they left I tugged on the antenna wire where it enters the tray and it come out. Hmmm. I disassembled the connector, resoldered the wire and tried again. When I tried to transmit the radio just went off and stayed off. It was late, so I went home hoping I'd blown a fuse rather than my brand new ICOM 200.

    Next morning the hangar gremlins had been at work, and the radio came on as though there had never been a problem - it must have some self protection circuitry built into it. Before transmitting again I thought to test the antenna for a short. Sure enough there was a dead short across the antenna. I removed the connector, but the incoming wires still showed a short. The antenna wire has two joins, one at the wing root, and one behind the nav light. I KNOW I tested for shorts when I finished off the wing, so the suspect would be the wing root. Unfortunately I'd have to remove the recently installed wing to get at the connector. Damn. I'd taped the joins, RTV'd the wing bolt covers and everything. Ah well. I removed the bolt hole covers and undid all the bolts, again. I had the wing supported on saw horses and foam, and was inching the bolts out of the holes little by little, trying to keep it balanced. When the bolts finally came clear the wing started to fall off the foam supports and I was stuck. Luckily Joe the electrician was working in the hangar, so I called for help and he supported the winglet while I repositioned the supports. With the wing off I undid the connector and tested for a short in the fuselage side. Yep. While I was at it I tested the wing side. There was a short there too. I removed and carefully replaced both connectors and the shorts went away. I must have been having a bad day when I installed them. I think the problem was that the wires wern't pushed far enough into the connectors, and the two wires had been crimped together. Lessons leared... put the connector inside the end of the spar so it's accessible through the bolt hole cover. This way you don't have to take the damn wing off. Also, test the connectors for shorts after they're installed.

    I reconnected everything, put the wing back on, reinstalled the radio and intercom and listened. Some guy was clearing the pattern and was kind enough to tranmit his intentions. I heard him clear as a bell. Cool. I went to transmit for a radio check, but nothing happened. My transmit button seems a little loose, and the radio isnt indicating a transmission. Ah well. Maybe the hangar gremlins will fix that for me tonight.

    Believe it or not, they did. Next day the radio came on just fine and I was able to monitor the advisory frequency. The tx light came on when I transmitted, but I got no response to my radio check calls. Maybe the brick and metal of the hangar was masking the transmission. I'll roll her out onto the ramp one day and find out.

    Rev 1 panel complete

    After seeing that Tracy's EC2 was predominatly digital I decided to stick with my analog gauges for rev 1 of the panel. I find I can scan analog gauges quickly and keep my head outside where it should be. I can also see trends on the analog that I wont spot on a digital readout. I have to read digital output and think about what I'm reading. I have voice and LED warnings on critical items. So, the center of the panel is cut out for 6.25 but filled with 2 inch engine gauges. Once I'm a bit more comfortable with the engine I'll replace these with an engine monitor and a GPS/COM.

    I was left with a blank spot in the panel which is eventually where my CDI will go. I picked up an old VOA-5 indicator on Ebay for $15. Apparantly these CDIs are doorstops because they can only talk to Narco 12A's which are obsolete. I installed the VOA-5 head in the panel anyway. This fills up the blank, gets the panel ready for the Narco 122D that's probably going in there, and it's the first test for passengers. If they ask, "Where's the NAV unit to power that CDI?" I'll know they're on the ball. In fact, if they ask "How the hell are we going to navigate?" I'll be even more impressed. Then I'll get out my handheld GPS and let them work it.

    The last item on the panel is labelling. I've come down to the Brother 1500-pc label maker as the best way to do this.

    [Later Notes: I filled the panel with round gauges. The coolant pressure gauge went beserk and I'm a bit untrusting of some of the others, in particular the Westach 4-way gauge. The oil pressure gauge DID help me spot a fluctuation that turned out to be just air in the system, but after only 4 hours of flying I've ordered the EM2 from Tracy. In particular, I need the fuel flow info and the ability to tune the EC2 graphically. I should be able to wire the "out of range" light to the voice system so Char will say "John. Check the engine" when something gets out of limits. Of all the electrical gadgets installed in the plane, the one I like best is the voice system. It spoke to me yesterday during decent. Excellent! Steve Brooks has the Wilhemson automatic gear extension system, but he managed to cheat it by doing his final approach at greater than it's extension speed. It was trying to extend when he landed leading to some damage. A voice in your ear is an nice inexpensive way to handle gear and other warnings. The Narco transponder still doesn't work. The ICOM A200 radio is excellent. The RST intercom is working fine. I got a Garmin 196 GPS which gives me all the nav info I need. I may get an EFIS later, but for now, I like having the conventional flight instruments.]

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