Panel wiring, circuits, breakers, switches, etc.

[Helmetfire]

I'm starting this thread because I am starting a electrical panel relocation/new instrument panel project on my '54 Supercub, and will have a bunch of stupid questions for you all in the near future. Any help is greatly appreciated! Of course I am working under the supervision of my IA, but I like to consult with the pros here to be armed with the appropriate info when needed. The big chunk of this work will be included in a field approval (hopefully), and our PMI will be visiting tomorrow, so my IA and I will get a chance to talk with him about the approval.

The panel I'm taking out was installed some time ago, is homemade from army surplus tank armor, and over the years has accumulated too many instruments and holes. I'm taking out the vacuum system, moving the electrical panel from the wing root to the lower panel, nixing the stock speaker, installing an Atlee underseat battery mod, and installing a B&C 40A Alt in place of the existing 20A Gen...these are the brunt of the project. The new panel will be a blank from Atlee made from .050.

The picture is what the panel looked like up until a few days ago. The layout will be basically the same with the radio and xpdr moved up and together to make room for the switches on the lower left, and CB's on the lower right. Planning on keeping all but the vacuum instruments with the posssible exception of the VSI...I like the VSI and use it alot but this one has the worst fading, reads about 200FPM low, and I could always have the VS on as one of the functions of the map display on my 396. I will try to move the Mixture, Primer and Cabin Vent controls back close to their original locations keeping the primer close to the start switch as some here have suggested. My GPS has since been moved just to the right of the compass but I'm thinking about buying a small panel mounted compass and sticking it somewhere on the panel, then moving the GPS front and center betweeen the V brace, then hardwiring a cord with a CB that turns on with the radio master.

Old Electrical panel: quite a birds nest behind there, sorry forgot to take a picture of the back...

As far as the wiring goes, my goal is to reduce complexity anywhere possible. I want to incorporate circuit breaker switches where possible to eliminate unnecessary CB's and wiring. Using all new Tyco switches and breakers to keep all the dimensions consistent behind the panel. Heres some general questions I have:

1. I haven't received the B&C 40A Alt yet, what size switches/breakers will I need with that setup? Is the overvoltage control incoporated into the LR3 regulator that comes with the package?

2. Having trouble figuring out what size Switch breaker to order for the LANDING/TAXI LIGHTS. Mine are tied together somewhere in the wing and both turn on with one switch. Presently they are protected by a 30A CB, but I think that might be a little high. I calulate two 30W / 12.8V bulbs will draw roughly 11-12 Amps, but my computation could be wrong.

3. Take a look at my rough wiring diagram and let me know if this would be an appropriate way to wire the system. I'm still a little fuzzy on the symbology especially in the master switch area (DPST switch), the two solenoids by the battery, and where the regulator ties into the system. My main concern is the items located on the 12V bus, is this close to how it should look? Hopefully its clear enough to read. (look familiar Steve?) To clarify the items a bit starting from the to of the 12V bus:
Field CB 5A
Ammeter
Aux pwr CB 5A
Ldg Lights CB Switch 20A?
Nav lights 5A?
Strobe 5A?
Cabin lights 5A? (Grimes instrument map lights left and right)

Avionics bus:
Com 5A
XPDR 3A
Encoder 2A
T/B 5A
GPS 5A


Starter 5A

thanks for any help!

Aaron

 

[Aviator]

Your diagram is very hard to read and interpret. Suggest you start with one of the basic diagrams posted here, understand it, then work up to whatever you want to add, change or remove.

 

[Dave Prizio]

Airplane Wiring

I think your wiring of the master and starter relays could use a redo. Here is a drawing of a generic airplane electrical system that I made to show possible ammeter shunt locations, but the wiring of the master switch and relays is of interest to you.

 

[kevin]

If you look at 43.13, there is a table that shows what size circuit breaker to use with your amps. It also has a graph that shows what size wire to use given the length of the run and the amperage draw.

 

[Darrel Starr]

Helmetfire, I have a wiring diagram for our Super Cub that I drew on AutoCad. It has wire gauge and other info on it. I have paper copies (15 x 43 inches) that shows the whole airplane's electrical system including the 40 amp B&C alternator, avionics, landing & pulse lights, strobes, EI gauges, etc. You and anyone else are welcome to have a free copy -- just send your name and mailing address to me and I will mail you one. darrelstarr@aol.com
This diagram was drawn on AutoCad2002. So if you have the capability to download and read .DWG files. I will email the file to you.

 

[qsmx440]

I'm starting this thread because I am starting a electrical panel relocation/new instrument panel project on my '54 Supercub, and will have a bunch of stupid questions for you all in the near future. Any help is greatly appreciated! Of course I am working under the supervision of my IA, but I like to consult with the pros here to be armed with the appropriate info when needed. The big chunk of this work will be included in a field approval (hopefully), and our PMI will be visiting tomorrow, so my IA and I will get a chance to talk with him about the approval.

The panel I'm taking out was installed some time ago, is homemade from army surplus tank armor, and over the years has accumulated too many instruments and holes. I'm taking out the vacuum system, moving the electrical panel from the wing root to the lower panel, nixing the stock speaker, installing an Atlee underseat battery mod, and installing a B&C 40A Alt in place of the existing 20A Gen...these are the brunt of the project. The new panel will be a blank from Atlee made from .050.

The picture is what the panel looked like up until a few days ago. The layout will be basically the same with the radio and xpdr moved up and together to make room for the switches on the lower left, and CB's on the lower right. Planning on keeping all but the vacuum instruments with the posssible exception of the VSI...I like the VSI and use it alot but this one has the worst fading, reads about 200FPM low, and I could always have the VS on as one of the functions of the map display on my 396. I will try to move the Mixture, Primer and Cabin Vent controls back close to their original locations keeping the primer close to the start switch as some here have suggested. My GPS has since been moved just to the right of the compass but I'm thinking about buying a small panel mounted compass and sticking it somewhere on the panel, then moving the GPS front and center betweeen the V brace, then hardwiring a cord with a CB that turns on with the radio master.

Old Electrical panel: quite a birds nest behind there, sorry forgot to take a picture of the back...

As far as the wiring goes, my goal is to reduce complexity anywhere possible. I want to incorporate circuit breaker switches where possible to eliminate unnecessary CB's and wiring. Using all new Tyco switches and breakers to keep all the dimensions consistent behind the panel. Heres some general questions I have:

1. I haven't received the B&C 40A Alt yet, what size switches/breakers will I need with that setup? Is the overvoltage control incoporated into the LR3 regulator that comes with the package?

2. Having trouble figuring out what size Switch breaker to order for the LANDING/TAXI LIGHTS. Mine are tied together somewhere in the wing and both turn on with one switch. Presently they are protected by a 30A CB, but I think that might be a little high. I calulate two 30W / 12.8V bulbs will draw roughly 11-12 Amps, but my computation could be wrong.

3. Take a look at my rough wiring diagram and let me know if this would be an appropriate way to wire the system. I'm still a little fuzzy on the symbology especially in the master switch area (DPST switch), the two solenoids by the battery, and where the regulator ties into the system. My main concern is the items located on the 12V bus, is this close to how it should look? Hopefully its clear enough to read. (look familiar Steve?) To clarify the items a bit starting from the to of the 12V bus:
Field CB 5A
Ammeter
Aux pwr CB 5A
Ldg Lights CB Switch 20A?
Nav lights 5A?
Strobe 5A?
Cabin lights 5A? (Grimes instrument map lights left and right)

Avionics bus:
Com 5A
XPDR 3A
Encoder 2A
T/B 5A
GPS 5A


Starter 5A

thanks for any help!

Aaron

Maybe (very possibly so take with a grain of salt) I am missing something but a quick look at your diagram I see what I think are a couple of mistakes. Your top connection to the field goes from the 12v buss to the field, through the field winding, through the contactor, through the ammeter and then back to the 12 v buss. That is not a complete circuit from positive to negative or correct location for the ammeter. The drawing is difficult to see on my laptop but the charging circuit looks messed up. In addition I would want my ammeter to show current flowing into the battery and current going out of the battery but not including the starter current. Maybe aircraft systems are different as to ammeter location. I may be confused as to what "5" on the diagram actually is. I am thinking field winding and if so that diagram appears wrong. What is the wire from the overvoltage detect up to an arrow? Does it connect to anything? The reason I'm hedging my comments, the numbers and such make it look like you copied some professional diagram so is it copied correctly? Can you give the originaal reference?
Edit: I have to run so can't look anymore at this but except in another dimension that battery connection will not run anything since the first place it goes is through a small coil. One good thing the moment the battery is connected, irregardless of any switch positions the master and starter relays will engage permenently running the battery dead in short order helping to eliminate the potential for fire caused by the lack of correctness in the rest of the circuitry! Path: Ground -- battery minus -- thru battery -- battery plus -- thru master relay -- through starter relay -- back at ground. A permanent complete circuit! Sorry, couldn't resist. Better get some help.

I have got to leave but the diagram keeps drawing me back! The possibilities of interactions are so cool! After engaging the two relays by connecting the battery, pushing the "starter button" should disengage the starter relay as the other items on the 12 volt buss bleed what little voltage (probably about 6 volts if the relays are similar sized) is left running the relay. Talk about giving a mechanic fits!!!

 

[mvivion]

Instead of panel mounting the compass, order a SIRS compass from Aircraft Spruce, and mount it high in the windshield. That will free up more panel space yet, AND present a functional compass. It's pretty hard to get a compass to swing in a panel mount. Can be done, but.....

The SIRS compasses are great and they come with adhesive to stick to the windshield....done.

MTV

 

[Helmetfire]

Helmetfire, I have a wiring diagram for our Super Cub that I drew on AutoCad. It has wire gauge and other info on it. I have paper copies (15 x 43 inches) that shows the whole airplane's electrical system including the 40 amp B&C alternator, avionics, landing & pulse lights, strobes, EI gauges, etc. You and anyone else are welcome to have a free copy -- just send your name and mailing address to me and I will mail you one. darrelstarr@aol.com
This diagram was drawn on AutoCad2002. So if you have the capability to download and read .DWG files. I will email the file to you.

Thanks Darrel, just sent you an email!!! I've seen your panel pics it turned out VERY nice!!

...it look like you copied some professional diagram so is it copied correctly? Can you give the originaal reference?
Edit: I have to run so can't look anymore at this but except in another dimension that battery connection will not run anything since the first place it goes is through a small coil. One good thing the moment the battery is connected, irregardless of any switch positions the master and starter relays will engage permenently running the battery dead in short order helping to eliminate the potential for fire caused by the lack of correctness in the rest of the circuitry! Path: Ground -- battery minus -- thru battery -- battery plus -- thru master relay -- through starter relay -- back at ground. A permanent complete circuit! Sorry, couldn't resist. Better get some help.

I have got to leave but the diagram keeps drawing me back! The possibilities of interactions are so cool! After engaging the two relays by connecting the battery, pushing the "starter button" should disengage the starter relay as the other items on the 12 volt buss bleed what little voltage (probably about 6 volts if the relays are similar sized) is left running the relay. Talk about giving a mechanic fits!!!

Glad I could provide some entertainment for you!! Lol. Maybe just disregard the wiring diagram for now as obviously I need a little more help in that area. I tried to copy a diagram that somebody here sent me but I tried to modify it a bit to suit my plan, you can see the result I know how to wire it, just don't know how to draw it... My main concern was the circuit breakers and breaker switches and figuring out what amp ratings to use.

Instead of panel mounting the compass, order a SIRS compass from Aircraft Spruce, and mount it high in the windshield. That will free up more panel space yet, AND present a functional compass. It's pretty hard to get a compass to swing in a panel mount. Can be done, but.....

The SIRS compasses are great and they come with adhesive to stick to the windshield....done.

MTV

Didnt know about that option but I like it...I'll look into it, thanks

The FAA guy stopped by today to look over my project and gave me some good advice on how to word the FA, what to include and what NOT to include. The only problem I have right now is figuring out where I'm going to put everything, so the drawing I send them is accurate...I can see making a plan, then later realizing that something won't fit where I wanted to put it...doh!

 

[sjohnson]

I'm having trouble reading your schematic, but it looks like a key difference between the one you started with and the one here: the original used two 30 amp fuses and no master solenoid. Here, you're using a master solenoid. I suspect this is the source of some of the preceding comments regarding the master, and you may want to look over a different schematic to get some guidance in that area.

 

[Helmetfire]

....it looks like a key difference between the one you started with and the one here: the original used two 30 amp fuses and no master solenoid. Here, you're using a master solenoid. I suspect this is the source of some of the preceding comments regarding the master, and you may want to look over a different schematic to get some guidance in that area.

Yes, the fuses and the DPST master switch are what I was trying to incorporate, albeit unsuccessfully. I got screwed up when I tried to connect the dots between the Alt, master switch and solenoids...back to the drawing board.

On a different note, the T/B that was previously installed turned out to be a 28V instrument...the word "Beechcraft" on the face should've clued me in :roll: Now I have to find out what to put in its spot, or just ditch all gyros and stay a little further away from the scud

 

[Darrel Starr]

Order a SIRS compass and mount it in the baggage compartment -- the best spot for something you will never use.

 

[sjohnson]

..., or just ditch all gyros and stay a little further away from the scud

I kept the T&B because it was used in the original military configuration, but I almost never use it. I turn it on at night just as a backup. It's also a pain to physically support it - the thin panel is not strong enough and I had to clamp the rear of it to a fuselage member. A quality GPS might be more useful, use less power and weigh less.

Edit: Transponders require that the compass be a minimum distance away, about 18" or so (check your docs). This implies that a panel mounted compass must be on the opposite side of the panel from the transponder. My panel mounted compass moves 10 deg. or so just by moving the stick around, and the stick has been degaussed. I use the compass about as much as I use the T&B - never.

 

[Darrel Starr]

I first had a 40 amp CB on my 40 amp B&C Alternator. But then I talked to the folks at B&C who told me that under certain conditions the alternator could put out 45 amps +. They recommended a 50 amp CB so that is what I now have.

Also remember that the size of the CB is set (see AC 43.13) to protect the wire, not the device. So, if you are wiring two 100 watt landing/taxi bulbs each with their own 10 or 12 gauge wire and run them both into one CB, you can use a 20 amp CB since the max current will be(2X100watts)/14 volts = 14.3 amps. Why? because the max CB allowed is 30 amp (12 gauge) or 40 amp (10 gauge) so use whe smallest CB you need under the max allowed -- 20 amp in this case.

 

[Steve Pierce]

I just went through all of this myself. I used schematics from Piper, B&C, Electronics International, AC43.13 etc. I used the chart Daryl posted for CB sizes and it coincided mostly with what Piper did. I also got rid of redundancy by using circuit breaker switches where possible. Takes a lot of fore thought to figure out how to get everything in there with no interference. I use Clyde Smith's instrument panels with a 2024-T3 doubler behind. Piper used a doubler on their gyro panels. Piper did not use a master relay on this 1971 Super Cub and after some research and pondering I did not install one. They also changed from a single double throw switch to two single switches for the landing light. I debated on this and ended up using a single switch to turn both the landing and taxi light on simultaneously since I am using HID lights and the current draw is very little. I have way too much time in laying all this out so I will scan and post what I came up with to try and save someone else the time. Of course thy are all different but a lot of things are the same.

 

[qsmx440]

Helmetfire I thought I might comment on your comment that you don't know how to draw it but do know how to wire it. I understand that. There is a neat way to look at drawing a schematic that works pretty good. I was trained in the classic schematics used in radio work and the first time I saw one of those "Haynes" or "Clymer" manual types I resisted it but have since reconsidered especially for simple electrical work. I would suggest this as a way to organize your thoughts. This is just an example of a schematic type:



Notice that the "flow" of the circuits proceeds from top to bottom and each circuit exists on it's own simplifying thought and maybe later making troubleshooting easier. Also notice how I mistakenly powered the starter relay off the battery "hot" buss instead of the "switched"side. Hope this helps.

 

[Helmetfire]

This isn't working. My paint file doesn't show up

QUOTE]

Darnit, and I'm a visual learner :lol:

 

[qsmx440]

Recheck my post I got it to work.

 

[Helmetfire]

Also notice how I mistakenly powered the starter relay off the battery "hot" buss instead of the "switched"side. Hope this helps.

So in this diagram, you would be able to climb in the airplane, hit the start switch, and the starter motor would turn over until the battery ran out of juice?? The simplicity is good...building blocks ;-)

 

[qsmx440]

So in this diagram, you would be able to climb in the airplane, hit the start switch, and the starter motor would turn over until the battery ran out of juice?? The simplicity is good...building blocks ;-)

Yep. That pretty much sums it up! You get the added benefit of maybe hanging around the propeller while your friend asks "whats this button do?"

When I was drawing that it took 45 minutes of me fighting with my lack of knowledge about "Paint". I must not have been paying much attention to what I was drawing.
You were able to follow the circuit.:roll:

Here is 1.1:

 

[qsmx440]

Helmetfire I have put together a schematic trying to clarify your #3 question in your first post. This will need to be reviewed by Steve, Mike and others that actually understand the system but I went to B&C's site and found their schematic for a VFR basic system. I broke out the Master switch, alternator and starter parts and redrew them in what I hope is a clearer schematic of those parts.
Caveat: I am not an aircraft mechanic. The representation is just my attempt at making things clearer to a non electronics person. My attempt may (probably does) contain errors and should be reviewed by those in the business and does not represent an actual way to wire an aircraft. done.

B&C's VFR schematic:
http://www.bandc.biz/pdfs/001510VFRSingleALT.pdf

My attempt at re arranging it as to the pertinent parts. Note: many extraneous parts were ommited for clarity like protection diodes across relay coils:


I don't really like how they grounded master relay through the dash board switch. I would prefer a seperate + switch near the battery. The grounding switch on the dash means in a crash should the wire be smashed on it's way to the dash it would turn the power "on" even with the switch off. Not good!
I don't understand the need for the second switch on the master DPST switch if they are mechanically tied together. Why not just a separate field switch on the dash? Is this any help? Is it even right? Steve, Mike , others?

 

[Aviator]

Re: qsmx440 Dwg.: Looks good schematically, neat and tidy too, but I would NOT want to feed the starter from the bus. Neither the the master relay, nor the bus, nor its wiring can handle the starter load. I'd take the starter solenoid feed right off the battery (connected on top of the battery terminal of the master relay)

Here's a simple layout without and with a master relay.

​

 

[qsmx440]

Re: qsmx440 Dwg.: Looks good schematically, neat and tidy too, but I would NOT want to feed the starter from the bus. Neither the the master relay, nor the bus, nor its wiring can handle the starter load. I'd take the starter solenoid feed right off the battery (connected on top of the battery terminal of the master relay)

Here's a simple layout without and with a master relay.

View attachment 10143
​

Yes! I agree. I don't know why they did that but that's the way B&C showed it. I just drew it as I saw it except for the ammeter which would have to read >200 amps the way I drew it I figure. The only reason I think B&C ran the starter off the switched buss is to save the weight of two large wires going forward. In order to be safe the starter relay would have to be located right next to the battery and probably not be included in the ammeter circuit. Again I would think, just like the master relay the starter button should supply +12v to engage the starter relay with a fuse right next to the battery. In a crash the fuse would blow rendering the circuit dead. Otherwise crushing the "high ground" wire going to the switch would cause a spark, close the start relay and allow power on the starter wire going to the engine compartment. In other words the second diagram looks like a fire or explosion hazard the way the master switch relay is energized. Is that considered "normal" for aircraft?

 

[Aviator]

... the starter button should supply +12v to engage the starter relay... the second diagram looks like a fire or explosion hazard the way the master switch relay is energized. Is that considered "normal" for aircraft?

Yes, it's best if the starter button closes the starter solenoid coil circuit on the (fused) +12VDC side of the coil, to prevent starter engagement when the master is OFF. Here, you'll have an unfused high amp wire going to the starter but only on the ground (presumably) and only for a few seconds.

The master relay is a different ball of wax. For starters (pun), its amp rating is usually much less than what a starter draws, so it shouldn't never be between the battery and the starter solenoid. As for the rest, here's a previous post on the pros and cons of supplying ground (rather than +12VDC) with the master switch to energize the master relay.
http://www.supercub.org/forum/showthread.php?44218-Master-Solenoid-connection&highlight=solenoid #11

“fire or explosion hazard the way the master switch relay is energized. Is that considered "normal" for aircraft?”

Sorry, I can't follow your reasoning... The master switch and relay schematic on my 2nd diag. is the same as on yours, except for a fuse - not shown for simplicity - between the relay coil +12VDC terminal and the battery terminal. In both cases the relay is energized when the master switch closes the circuit to ground.

 

[qsmx440]

Yes, it's best if the starter button closes the starter solenoid coil circuit on the (fused) +12VDC side of the coil, to prevent starter engagement when the master is OFF. Here, you'll have an unfused high amp wire going to the starter but only on the ground (presumably) and only for a few seconds.

The master relay is a different ball of wax. For starters (pun), its amp rating is usually much less than what a starter draws, so it shouldn't never be between the battery and the starter solenoid. As for the rest, here's a previous post on the pros and cons of supplying ground (rather than +12VDC) with the master switch to energize the master relay.
http://www.supercub.org/forum/showthread.php?44218-Master-Solenoid-connection&highlight=solenoid #11

“fire or explosion hazard the way the master switch relay is energized. Is that considered "normal" for aircraft?”

Sorry, I can't follow your reasoning... The master switch and relay schematic on my 2nd diag. is the same as on yours, except for a fuse - not shown for simplicity - between the relay coil +12VDC terminal and the battery terminal. In both cases the relay is energized when the master switch closes the circuit to ground.

Yes the same as B&C but in my notes I commented (I think) that if I was wiring it that way the master switch would be located next to the battery but that I didn't like that circuit at all. The logic: If you want the power shut down for sure you turn the master switch off. You don't want it coming back on again during the crash and bending of metal. So in B&C's world and your second diagram the relay coil return to ground is a wire going up to the switch on the dash where the Master switch completes the ground. Open the switch and the relay relaxes and all power is shut down, just before you crash. During the crash as metal folds around you, the gas tank bursts open and then as things collapse that "ground return" wire gets crushed (making a connection to ground). What does the relay do? Yep applies power to all the 12v circuits all over the aircraft! If instead you "break" the 12 volt side of the relay coil power and switch that, as the wires get crushed the relay coil fuse (hopefully master relay and relay coil fuse is right next to the battery) blows and no power is applied to the 12v bus. Make sense?

 

[Aviator]

The logic... Make sense?

Not disputing your logic: Like I said, it's a tradeoff. Maybe Steve Pierce's (and others) solution is best: Battery under the pilot's seat with a c/b accessible in flight – with or without a master relay.
http://www.supercub.org/forum/showthread.php?41160-Looking-for-Piper-drawing-15500-Electrical/page2 #45

 

[Helmetfire]

Here is a panel layout that I am working on...tell me what you think! It shows all the electrical circuits that I plan on using. I forgot to add a 12V Aux power plug on this panel, not sure where I'd put it yet anyways. Carb and Cabin heat are both located on the side panel right now, still debating wether to leave them or move them to the instrument panel...I don't want it to get too cluttered, plus thats more cables to buy and more sheetmetal patches and paint.

Just got my Atlee underseat batt box today, if anybody has any pics of that setup to include the cable routing that would be appreciated.

Edit: Forgot Mag switches too, maybe put those high and right above the start switch so its an easy move to flick the right mag on after start...

 

[mike mcs repair]

Here is a panel layout that I am working on...tell me what you think!...

• mixture needs to be on other side of panel, carb heat should be in that location, so you can smoothly turn carb heat off in a go-around after throttle hits full stop in one motion.
• starter button more to the left so finger/thumb can be pressing start button, while the ball of your hand can be feeding in prime into engine as needed to keep it running while starting a cold engine..(watch out for the panel mount tab there and tubes..)
• the T&B there will prolly require you to cut out the upright support if it is still there..(was it you that showed the pic with it already removed??)
• all breakers do NOT need to be switch breakers, especially since you have an avionics master, they can just be Push pull then, since radios have there own on off switches...( all those center breakers should just be normal or push pull)
• aux plug accessible, but under dash so you don't have to look at ugly adaptor junk...

 

[Helmetfire]

• mixture needs to be on other side of panel, carb heat should be in that location, so you can smoothly turn carb heat off in a go-around after throttle hits full stop in one motion.
• starter button more to the left so finger/thumb can be pressing start button, while the ball of your hand can be feeding in prime into engine as needed to keep it running while starting a cold engine..(watch out for the panel mount tab there and tubes..)
• the T&B there will prolly require you to cut out the upright support if it is still there..(was it you that showed the pic with it already removed??)
• all breakers do NOT need to be switch breakers, especially since you have an avionics master, they can just be Push pull then, since radios have there own on off switches...( all those center breakers should just be normal or push pull)
• aux plug accessible, but under dash so you don't have to look at ugly adaptor junk...

-Carb heat will stay on the side panel I think, I usually turn it off just prior to landing anyway
-Fixed starter button...of course these are approximate locations but should be out of the way of tubes or mounting tabs as shown.
-UPright support channel is already MIA, hopefully nobody notices...
-labeled c/b's more clearly
-good idea on Aux plug...ugly...

 

[sjohnson]

I don't know if cabin air vents are located in the same spot on all Cubs, but on mine its in the center, and your cabin air control location would result in an awkward routing around the radios and bend in the coax. You might consider putting it in the area under the ammeter.

If you were to put your carb air control in place of your cabin air control, then the coax would run alongside the radios and all your engine controls (except mags) would be in one general area.

Do you have an intercom?

Will your radios clear the angled tubing behind the panel?

 

[Helmetfire]

I don't know if cabin air vents are located in the same spot on all Cubs, but on mine its in the center, and your cabin air control location would result in an awkward routing around the radios and bend in the coax. You might consider putting it in the area under the ammeter.

If you were to put your carb air control in place of your cabin air control, then the coax would run alongside the radios and all your engine controls (except mags) would be in one general area.

Do you have an intercom?

Will your radios clear the angled tubing behind the panel?

-Putting the cabin air on the right side means a bend in the cable to the left to get out the top center of the firewall, then an extreme bend to the right almost 180 degrees to get back into the vent control box. At least thats how its setup now, wouldn't surprise me if this isn't the way its supposed to be routed. Also, I want to avoid putting anything on the lower right side of the panel because when I get into the plane, my right foot sometimes hits the panel right in that area and wish to avoid bending/breaking anything that might be mounted there.

-I don't want the carb heat cable anywhere near the mixture control to avoid potential problems. The radios don't really extend too far back so getting the control cables around them shouldn't be to difficult. And yes, they will clear the tubing no problem.

-The intercom is integral to the Garmin SL40 com radio I have. Still getting used to it, but seems to work fine...although doors off summer flying might prove to be annoying with the back seat mic getting additional wind noise. If I need to add an intercom later I can either put it above the radio, or mount it on the wing root panel where I just yanked out the speaker.

All good points to keep me thinking, and for now, this is just a plan...trying my best to think of any problems before they happen, but I'm sure we all know how well that works out sometimes ;-)