Electrical
Our electrical scheme will follow Bob's AeroElectric scheme Z-12 more or less. We aim to have dual alternators due to the fact that this will be an all electric plane. I'm one of those that thinks vacuum systems suck (I know... old joke).
At first I was a little daunted at the prospect of wiring our plane, but one wire at a time is what Mike said, and sure enough, he's right. Eventually, it all comes together and hopefully it doesn't smoke the hangar out when I flip the switch. I've been cheating though by turning things on as I'm going along just to make sure!
I've been getting most of my stuff from Stein Bruch at SteinAir. His prices are excellent, and stuff always arrives promptly. I even got a free T-Shirt once. It was a big order though.
I made an Excel sheet to calculate wire sizes based on equations and charts in the AeroElectric book. I'll post it here, but be aware that I'm not an Electrical Engineer, so if you use it and spot a problem, be sure to let me know!
Basically, the inputs are along the top in the yellow boxes. Everything else is calculated based on the Wire Data Table. At the bottom are the results by wire size. I only plotted the voltage drop requirement size, because plotting the other sizes would cause problems thanks to extrapolating data.
I have this on my PDA, so down the hangar I can plug in the numbers and save it off. Then when I get home, I can print it off and add it to my electrical system folder.
Click the image for the Excel tool.
Reading the AeroElectric Connection, the fuseblock idea made sense to me, so this is the direction I've been heading. The only circuit breakers will be for the alternators. You can see here the main bus top, essential bus lower left and the battery bus lower right. This whole ensemble swings down for access once it's all together. I haven't even got half of it wired yet, it's taking me forever!
Here's the battery and starter contactors. Not wired them as of yet. I need to make the diodes still.
Here's a gratuitous shot of the switches and some of the wiring. Lot's of temporary tie wraps to help keep it where I want it. Otherwise, this would be a mess of spaghetti!
This shows the installation of the ELT, Strobe PSU and the A/P servo. The A/P servo cable had to be cut in order to thread it through my fuselage. I also took the liberty of shortening it some. I spliced it all together, heatshrinked it and put some insulation tape on it. The tape I used is the type used in the auto industry on harnesses. It's pretty good stuff, and will last a LONG time (I got it off Mike... Thanks Mike!). I ran conduit under the left and right floorboards for the noisy strobe cables to try to keep it away from the rest of the electrical system and antenna cables.
A close up of the strobe wiring. The shields are connected to one of the mounting bolts for ground. The ground for the actual PSU runs all the way forward to the ground block on the firewall/panel.
A close up the ELT. I put a rib in there because after mounting the holder to the floor, it felt a little too flimsy. The rib helped quite a lot. I don't want this thing going off every time I land due to bouncing around on a flexing belly skin!
Here's the regulator from B&C. I need to get another standby one too, which I'll mount in the same place, but on the other side of the rib. That way, the regulators will form a nice rib sandwich!
The doubler plate for the transponder antenna. Mike's friend Russ was in town, and he helped me rivet this. Russ is building a Rocket.
The transponder antenna. It's just hanging there for now.
Most recently, I've been working on the flap system. I got the whole lot in OK, and also mounted some bulb holders underneath the cross bar that supports the seat backs for interior baggage area illumination. I'll try to get a shot of it next time I'm at the hangar.
Here is the connector for the flap positioning system. I'm getting to like the Molex connectors. They lock together positively, and you can get them in many different configurations. Here, it also serves the purpose of connecting the interior lamp wiring (the blue wire coming up).
The flap positioning system has four wires to connect. No need for relays either, which is great for our Infinity stick grip mini toggle switches. There are four wires to connect... +ve, ground, extend and retract. I'm now working on the stick grip wiring, so I can finish the flap stuff off.
Here you can see the beginning of the stick grip wiring. I made some support channels for each strip. They turned out OK. Unfortunately, it's not so easy to get terminal strips with enough terminals for the Infinity grips, there are so many functions. I am able to combine a lot of grounds, but not all of them, since I'm running governors from Matronics for the trim system, and the flap position system from van's. These have a funky set up as far as grounds, so need to adhere to the circuit diagrams supplied!
Here I figured out which wires were which for the aileron trim. I had terminals on the right hand side, and then remembered I needed to link in the passenger side grip too! Duh! So, I ended up cutting these off and re-crimping with another wire in there for the cross link.
Et voila! Here it is in better shape. the lower blue yellow green wires are for the elevator trim. The governors are mounted under the seat floor, with a small hole in each floor to adjust the speed. There's a heck of a lot of wiring going on here.
Here's the co-pilot side, showing the aileron trim. The cool thing about the Matronics governors is that if a trim is activated by either pilot or co-pilot, it locks the other guy out, so a short circuit cannot occur. Sweet.
So, I spent 9 hours bent over this thing today doing the stick grip wiring, and my back is killing me. It still isn't finished, and it doesn't seem like I've done very much really. If you look hard at the pilot side seat surface, there's a little hole between the left centre rib that forms the tunnel, and the next rib to the left. This is where the governor is located. Easy adjust, without having to take anything apart. I'll stick a label on this panel so I remember which way to turn the potentiometer.
5/2/2004 6 hours
I managed to get 6 hours in at the hangar today, did 3 hours this morning, went to a birthday party, and then came back for more back breaking punishment. Last week, I couldn't touch my toes at all. This week, I can almost put my hands flat on the floor I've done so much bending down over this thing! It still isn't done either! It's seems like there are a killion wires coming out of these sticks!
Here I have all the wiring done for the pilot side lower terminal strip. I also finished the upper strip today, but forgot to take a picture. Getting this all completed also help with.....
The picture I forgot....
Getting the flaps going! So, these are all the wires going into the flap system (except the blue one for baggage compartment illumination). The flaps now work from the pilot side. I need to finish the wiring for the panel flap switch, and also the co-pilot stick. Next time I'm at the hangar, I'll probably figure out the co-pilot stick itself. I need to find a good way to connect it, so it's easily removed. Some passengers may want to sit and read a book. You never know, and it'd be nice to have it out of the way occasionally.
I need to get a good picture of the stick grips, so I can describe the functions. We have.... Trim on the cooley hat, both elevator and aileron, thumb operated flaps right of the cooley hat, auto pilot disconnect on the left of the cooley hat. Lower down, the trigger is used for push to talk, there's a thumb operated on off switch for landing light or whatever else takes my fancy as my moods change (still not sure what to do with this one), and a pinky operated starter button with a lockout switch on the panel. We need a starter button on the stick, coz we're doing the taildragger, and it's nice to have the stick in your hand when you start her up.
5/3/2004 2 hours
I finally took a photo of the baggage illumination. It's pretty bright. The small hangar lights were actually on in this shot. I turned all the flourescents off. I have two lights the same up front illuminating the foot wells. They're basically automotive dome lamp bulbs with a bayonet fitting (so they never come loose). Simple and effective.
Maybe I should've taken this one with the lamps off! Still, you can just about see what's going on. I'm going to stick some reflective aluminium under there too.
Now that at least one of the sticks is fully wired, I decided to take a break from it and get the flap positioning system set up. This was really screwy too. I followed the directions to the letter, and for some reason the positions stops all worked when the flaps were on their way up instead of down! Everything went the right way according to whichever way you pushed the switch, it just seemed to be sensing wrong. I talked to Mike, and he had the same problem. I ended up reversing both the motor power wires AND the switch wires! Now it works perfectly, and I'm quite pleased with the result. Hit the switch once and it stops at the next flap angle. Perfect.
I finally assembled this stuff permanently, and safety-wired it. In this picture, I haven't tightened the nut yet... The safety wire can be seen sticking out near the flap control arm. This is the first thing I've had to safety wire with the safety wire pliers! In the past, I've safety wired stuff with regular pliers. So slow! I wish I'd had some of these pliers back then!
One of the Infinity stick grips. Excellent quality, with nice tactile switches. A lot of fun to assemble to the stick though! You have to juggle A LOT of wires and switches until you can get both halves together!
5/4/2004 2 hours
Didn't take any pictures today, so I'll post some later. Today I worked on making the second tier terminal strip for the co-pilot side. Once I'd done this, I mounted the grip to the passenger stick. I still haven't figured a good way to connect the wires so it's removable. I know a high density 15 pin plug will fit inside the stick, but it would be hard to keep the connectors together since it won't fit in the stick tube without cutting off the screw tabs.. Trouble is, when inserting the stick, you have a tendency to twist it in, so a fixed plug won't work. I ran the control stick ground wires too
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5/5/2004 0 hours
Yep, no hours. Basically, I went to the hangar, and Mike was there. I was chatting with him for a bit, and then we got Cameron to bring some beers. So, basically about three hours went by with us just hangar flying. Enjoyed the time down there though. Better than the pub in some respects! Since it was Cinco de Mayo, Cam bought Corona, and some limes! None of us are even form Mexico! Cameron is from Texas though... Close enough.
5/7/2004 1 hour
Tonight, I wired the flap switch on the panel, and hooked the wires to the co-pilot terminal strips. So, it's all working now from the panel and the pilot stick. The co-pilot stick will be working when it's connected. Why do we need all these switches on the sticks when even the person stowed in the baggage compartment could reach the switch on the panel?!! Don't ask. Initially, I thought it'd be cool, but now I'm thinking it's too much work! I also ran the PTT switches to the avionics stack.
Well, the rest of the evening was spent helping Mike put some wings on another RV-7. Good experience for me, since I'll be doing that on mine sometime. Who knows when.
5/13/2004 2 hours
Yesterday, I ordered the standby regulator from B&C. Man, this stuff is adding up. $268! Wow. Then, there's an installation kit too for another $228! Ouch! I didn't bother ordering the installation kit for fear of the wife... I did order a dimmer though too!
Tonight, I got to the hangar and started the Co-Pilot stick. I found a perfect solution (or near perfect) for the connection. I need to connect 16 wires, but three are grounds, and can be linked together making a requirement for a 14 pin plug. I managed to find a 13 pin DIN plug! The outside has a grounding shell, so effectively making it a 14 pin! Perfect! So, I started soldering. Now this took forever! All the little solder cups were so close together. Anyways, the end result turned out pretty good.
Unfortunately, in my excitement, I forgot to snap a picture of the connector on the cable before sticking it in the stick. I'm sure you can imagine it... It's like an audio/video connector. Not sure why 13 pins would be necessary, but it worked for me. Here's a shot of it in the stick base. I'll be leaving it sticking out a bit on the base and the stick, then when the stick is connected, it'll push up into the stick itself due to flex in the wires. Stick, stick, stick... I used this word a lot in this paragraph didn't I?!
5/14/2004 3.5 hours
I got a good amount of time in on the plane tonight, and had a quick beer with Mike afterwards. I spent tonight doing the stick grip side of the connector and completing the wiring in the floor.
Here's the male connector side. These are the pins you're supposed to solder wires to! Since they're so dense, it was pretty much impossible to do. Last night, me and Mike were chatting about how to do it, and beating around ideas, and it turned out that female D-Sub crimp pins fit on these pins perfectly!
So, here are some D-Subs crimped to the wires and heatshrink going on....
And all connected. The clear heatshrink you see there was then slid over these connectors to make sure they all stayed together. Turned out great!
The fully assembled connector.... I put heatshrink over the strain relief too, to make sure it wasn't going anywhere.
Here's a shot of it all snug inside the tube. I need to put a removable clip in the tube to stop the connector sliding into the tube when you connect it. Getting the length here was critical, because the wires in the tube will only compress so far, and you need to be able to see it to connect the female side. In this picture, the connector is about flush with the end of the stick.
I finally got the stick wiring done on this side, although, it's as yet untested! All these connections, I'm bound to have done something wrong somewhere! I have been double checking everything with the multimeter as I've been going along though. Hopefully, it'll all be good! So, if you REALLY LIKE wiring, I'd definitely recommend getting yourself a couple of these stick grips! A multitude of functions, and very nice, but an awful lot of work!
5/16/2004 5 hours
Today, I started wiring the back up engine gauges. The primary gauges are part of the Blue Mountain EFIS 1. I decided to daisy chain the power and ground leads here to keep it simple. Both ends of the daisy chain are connected to the main bus or the ground bus accordingly, so if a wire breaks, all the gauges downstream/upstream won't go out. If you're wondering about the red/black wires going forward from each gauge, I stuffed them through the mounting holes temporarily to get 'em out of the way!
Here's a shot of the grounding block on the firewall. Starting to fill up. Do I really think I'll be needing all those tabs?
Starting to get some wires going to the fuse panel here too. You can see here where I mounted the main bus/e-bus diode. The fuse panel acts like a heatsink. I've tried running this to see how hot it gets. I put heatsink compound between it and the panel. Doesn't really get hot when mounted, but it did when free floating.
Just a shot between the panel and sub-panel showing what's going on.... I'm trying to keep it tidy while I'm doing this. I should take a picture of Cameron's wiring!
7/18/2004 8 hours
Today, I wired in a few more gauges, including the ammeter, manifold pressure, and both fuel gauges. I also fitted the secondary alternator regulator, and wired it. I mounted the relay for the pitot heat under the pilot seat. Steve came by too and helped out with the wiring a little. Good to have some conversation and company! Nobody else was there today. I got him to bring an electric drill since I forgot mine, and needed to cut some holes real slow!
I also spent a lot of time debating a centre console. I would've posted pictures, but my camera battery ran out. I'll take some pics of the mock up I made out of cardboard. I hope to put the throttle in the console, along with the fuel selector.
Another shot between the panel and sub panel... A little more wire....
Here is the secondary alternator regulator. I made a "rib sandwich" between the two regulators by mounting them back to back. At the bottom right, you can just see where I put the shunt for the Van's ammeter.
The other side of the "rib sandwich". This shows where I mounted the manifold pressure sender. Again, a Van's item, and a back up to the E1.
7/25/2004 5.5 hours
Today I did some more wiring. Wiring, wiring, wiring... When will it ever end? I bet even you're getting bored with it! Today I wired the elevator and aileron trim servo supply and ground wires from the buses. The aileron will be off the main, and elevator off the essential bus. Since aileron is just acting by spring loading the stick, it's easily overcome if necessary. Elevator though is another story. I also wired the pitot heat, master contactor and tidied up a few loose ends here and there.
Here is the pitot heat relay. An automotive relay is very easy to mount, thanks to the mounting lug with a hole for an AN3 bolt.
Here is my label for the aileron trim speed governor adjustment. It's under the seat. Elevator is on the other side, under passenger seat.
8/1/04 3 Hours
After returning from Oshkosh this morning, I got away with slipping down the hangar for a bit! Lucky me! I wired in the supply cables from the battery to the buses, and messed around some with the turn coordinator. Photos to follow coz I forgot the camera at the hangar. Duh!
I fitted the diodes to the contactors....
Here's a shot showing a bit of the power cables going to the busses...
8/8/04 9 Hours
After getting the panel back together, I decided it would be a great idea to start wiring the stack. Hmmm... Where exactly do I start with this mess?!!! I bought the stack used from TBE. This was the first time they had any Apollo stuff, and they were amazed by the demand for it. Unfortunately, the tray didn't make it with the SL-30, and they gave me an applicable discount to buy a tray. So, I tracked one down form a company in Ohio. I think they were having a sell everything we have sale, because they asked if I wanted them to prewire a bunch of trays for my stack. I declined, and they sent this huge bundle anyways! It looks like a good starting point, so I'm going to try to use what I can from it. Basically, the plugs are all crimped, cables marked and long enough to practically reach anywhere in the plane. All I have to do is figure it out!
I started with the Com portion of the stack. So, here I have Com 1 wired to the audio panel, and I've started to wire Com 2. This was about as far as I got before I had to call it a day. It was a pretty late night. Looks like I have A LOT of wires going to ground on the audio panel, and only one measly little crimp pin to go to. So, I guess I end up making a fancy splice with loads of wires coming together before going to the pin with one 18AWG wire.
8/10/04 3.5 Hours
After work, I stopped by to carry on wiring. Truth be known, I was darting around the plane a bit. I didn't have my camera with me this evening, so Pictures to follow...
Anyways, I finished up wiring Com 2 (GX60) to the audio panel. That's the Com interconnects done now. I moved on to the Com ancillary stuff like the Pilot & Passenger headset jacks. I located them in the floor just in the back corners behind the seats. When I take a photo, all will become clear.
I also messed about a bit with a gas strut for the glovebox. It seems to work pretty well, but I'm not sure whether to use it yet. Again, a picture will help.
Our DJM throttle quadrant arrived today. Looks good. I might have to modify the throttle handle though to make it like the centre mounted versions. I had the flat one, because it'll work on the centre console, and they had them for FADEC already, with throttle and prop levers.
8/10/04 3 Hours
I managed to get to the hangar again this evening, and finished up the wiring to the pilot headset jacks. Lucky I double checked, because I had the mic jack wires switched! So, I fixed that, and all was good. I ran more wires to the audio panel. It's just one wire after another these days! Here's a powered up radio!
8/17/04 2 Hours
Tonight's hangar visit was a little shorter. I ran the mic wire from the the copilot side to the audio panel, and also attempted to solder on the transponder antenna connector to the cable. Well, this thing is a fantastic heat sink, as my soldering iron couldn't muster it. So, I need to get the pencil torch on the case. Unfortunately, no matches at the hangar, so I ended up leaving to finish off later.
My order came from Mouser tonight too. I got the 78pin D-Sub for the annunciator. 78 pins! I know it doesn't use all of 'em, but looks like at least half of them will be utilised. I'm NOT looking forward to wiring that!
I stopped by the hangar last night too, but I spent the evening cleaning up the mess and vacuuming a little.
8/28/04 9 Hours
I did a lot of wiring today, as can be seen by the size increase in some of the cable runs. Steady progress is about the best way to describe the wiring task. Sometimes though, I have to get away from it and do something else.
Anyways, today's tasks were to wire in some more of the stack, and start to integrate it into the EFIS1. So, I started with the SL-30 radio. This is a relatively simple affair with the RS232 digital link, only three wires and you have it all! So, now I can control the OBS from the E1, and also select and change frequencies for the radio. I was surprised that it wouldn't automatically tune the VOR though. Maybe there was a deliberate reason this wasn't done, or maybe it's not even possible? I'll ask on the BMA discussion board.
Also, now the E1 has the ability to use both serial and analogue inputs, so I'll get to use my Apollo ACU that I'd already cut a hole in the panel for before I found out that I may not really need it.... Doh! Anyways, to make the most of it, I decided to hook up the thing anyways, and use it to switch between external sources to the E1, even though now E1 can do this by itself. I received the Mouser order for the 78pin plug, but when I tried to wire it up, the crimp pins I had were too big for the plug! I guess that's coz it's high density, and not a regular D-Sub. So, I ordered some HDP-22 pins.
So here's a shot of more wiring... You can see the transponder is also in here all connected. I wired it to the E1 too.
Once this was all wired in, testing it out proved a disappointment. For some reason, the xpdr wouldn't show an altitude. On the xpdr, there's a D4 grey code input, and the E1 doesn't have that as an output. I wondered if this was a problem, but later research showed that not to be the case. It's more likely that my E1 doesn't output enough voltage to show a signal to the xpdr for the specific grey code channels, which could be down to one of the following reasons... 1. My battery was quite low by the time I checked this out, and thus the voltage to the xpdr from the E1 wasn't quite high enough, or 2. The E1 needs the amplifier card that some of the earlier models didn't have. I'm hoping to go down the hangar soon and check it out now I know what to look for, and resolve the issue as necessary.
While I was at this end, I did the A/P disconnect and the AOA flaps down wire. So, that's the 'Encoder' plug on the E1 done. Only another bazillion wires left to run! Here's the E1 end of the routing....
8/29/04 3 Hours
I went to the hangar today and finished up what I could of the stack wiring. Apart from the ACU, it's complete. All the wires running to the back of the stack are now complete. All that I need to do now are connect them to the ACU, and then the ACU to the EFIS 1. Then, I think it's pretty much done. I still have some other wires to run for some of the lighting switches, and I need to do the antenna cables for the stack. I also need to connect all the ground wires for the stack, but I'm going to leave them until the last minute in case I need to add something else. I also added wiring for a music input. Maybe a satellite radio will be in the works one day!
For the xpdr issue, I checked the output voltages for the grey code, and all measured 3.32v or 0v. So, 3.5v is what's needed, and 3.32v doesn't cut it. I'll call BMA tomorrow and get them to send me an amplifier card. Then we should be good. See my EFIS page for details on this issue.
I finished up the wiring to the ACU from the radio stack, and also to the E1. That's about it now for the stack.
The EFIS end... The ACU outputs go into Analogue 1. There are eight required, CDI L/R, Nav pass/fail, GS Up/Dn and GS pass/fail. For some reason, the E1 doesn't utilise the To/From outputs. I need to read a bit more about this to find out why.
The other thing I did tonight was to tie in all the Grounds for the stack. Then I started testing it. No antennae still. I need the connectors. Anyways, the radio checked out great, and I could send/receive transmissions loud and clear to/from the handheld in the hangar, The AOA voice annunciation worked perfectly, the intercom works great and even more amazing was that there was no smoke! This audio panel has a six place intercom. Perfect for an RV! Maybe I should hook up an exterior set of plugs for ground grew to plug in to!
The one loose ground wire is for the Marker Beacon antenna.
