Piper vs. Cessna Ground Plug

Hello there,
I am currently looking into what type of ground power receptacle to put into the aircraft that I am building. The main two options are a Cessna-type three terminal plug and a Piper-type one terminal cylindrical plug.
Are there any pros-cons to each of them?
Is any one of them more/less prevalent in your average GA airport? I think this would be my deciding factor but I have only had to jump an airplane *once* and the FBO there had both plug types (it was a big jet center).

Thanks for the help guys!
~Miguel

I used the Piper

plug --- much easier to install ----- however, I do carry my own jumper cables with the correct female end.

We operate two FBOs. The small Lektro tugs we have for moving small airplanes have the Cessna style plugs. We have to install an adapter if the aircraft has a Piper style plug.

3-prong

There is no such thing as a Cessna plug. There is the Piper plug, and there is the 3-prong plug used universally by practically ALL OTHERS.

The 3-prong plug is far more common to find when you end up at some far away airport needing a jump. That's why I installed one in mine.

Neither

I know that there's always the potential to need one, but given the amazing lifespan of Odyssey batteries, I decided to not to install one at all. If I had a Cessna or Piper with the antiquated batteries they use, I'd definitely install one, but not sure that I'll miss having one in my RV. Even if I leave the master switch on there's nothing draining the battery.

I also installed the Piper Plug on the baggage wall on my RV-10. I found this plug is about half the price of the other 3-prong one. I then bought a long set of heavy gauge jumper cables and cut them in half and then installed the Piper Plug on the other end. This made for a very nice cable to carry in the airplane.


Ray Doerr
RV-10 N519RV (40250)
907 on the Hobbs

You should always consider the fact that taking off with a dead battery (thats the reason you needed a jump I assume) is risky business. Most of us depend on electrics to run our GPS, radios, ignitions, fuel pumps etc.. If your struggling alternator happens to give up shortly after you take off, you will quickly be left with no power.

alpinelakespilot2000 said:

I know that there's always the potential to need one, but given the amazing lifespan of Odyssey batteries, I decided to not to install one at all. If I had a Cessna or Piper with the antiquated batteries they use, I'd definitely install one, but not sure that I'll miss having one in my RV.

Click to expand...

You might miss it the first time that you do end up needing it and don't have it.

True, Odyssey batteries do have better longevity than the antiquated batteries in the certifieds. But they still do age, and they do weaken in cold temps, and they do self-discharge if they sit for a while, and of course they do discharge if you leave a load on. S*** happens.

alpinelakespilot2000 said:

Even if I leave the master switch on there's nothing draining the battery.

Click to expand...

Not true, unless you're using an exotic solid state master contactor. The standard master contactor draws about 0.7A by itself, which will take just a few hours to drain an Odyssey battery down to where it will no longer crank. Even if there are no other loads turned on.

rdoerr01 said:

I also installed the Piper Plug ... I then bought a long set of heavy gauge jumper cables and cut them in half and then installed the Piper Plug on the other end. This made for a very nice cable to carry in the airplane.

Click to expand...

Good idea. If you do install a Piper plug, or any other non-standard plug, I would strongly suggest carrying suitable jumper cables or some sort of adapter in the plane. Don't count on some FBO having one.

Consider though that if you count the adapter, then with it the Piper plug may end up being the heavier and more expensive option compared to just a standard 3-prong with no adapter needed.

P.S. I've flown Pipers for many years, and I like them very much. But I wasn't so pleased with Piper the first time I ended up needing a jump at an airport away from home. Many helpful folks around happy to lend a battery cart... with a 3-prong plug. Hard-learned experience.

Ground power

I fly for a living and have many times used GPU's.
I decided to install a universal plug uring my building of my -8, see link.

http://www.vansairforce.com/community/showthread.php?t=91258&highlight=Ground+power

CAUTION: If you install either plug using a common technique currently published on the WEB:



If you utilize the bottom diagram to connect a "Piper" style ground power receptacle, the Ground Power Contactor will remain energized even after ground power is disconnected until either the battery is dead due to current drawn by the Ground Power Contactor relay coil (about 1A) or the 2A GND PWR circuit breaker is pulled even if the master power switch is turned off. The battery itself will keep the contactor energized even after ground power is removed unless the circuit breaker is pulled. The ONLY way to de-energize the relay is to pull the circuit breaker once the ground power receptacle has been utilized, before or after flight! If you do install a two-conductor (or "Piper" style) ground power receptacle per this diagram, at least add a switch in line with the circuit breaker (or use a switch/breaker) and keep it turned OFF when not using ground power.

If you utilized the universal mil-spec three-conductor ("Cessna" or "Military" style) receptacle in the first diagram, the Ground Power Contactor will be de-energized any time ground power is not present at the third pin of the receptacle.

I used the three-conductor ground power receptacle.

My 1955 Cessna 180 has one of the three-conductor plugs, and I've never used it. I've owned the plane since 1986 and have about 1,400 hours in it, mostly cross-country.

It would be high on my list of things to remove to save a bit of weight, complexity and room under the cowl.

If the battery is reasonably accessible, consider that jumper cables or a battery charger might also be available at airports.

Dave

I knew I saw this!!!

Here is a really cool alternative to any expensive plugs. Good for charging, but not cranking. I would not want to get airborne on a really dead battery anyway.

http://www.eaavideo.org/video.aspx?v=1009394733001


CC

David Paule said:

My 1955 Cessna 180 has one of the three-conductor plugs, and I've never used it. I've owned the plane since 1986 and have about 1,400 hours in it, mostly cross-country.

It would be high on my list of things to remove to save a bit of weight, complexity and room under the cowl.

If the battery is reasonably accessible, consider that jumper cables or a battery charger might also be available at airports.

Dave

Click to expand...

I installed the ground power plug for two main reasons:

1) While building I've already used it for many hours of avionics/electrical systems testing and configuration using one of these:



2) I live in Minnesota, and even with quarter-turn fasteners attaching the cowl, the battery is not that accessible. I want to be able to quickly jump the aircraft to get the airplane started to get it somewhere warm to get the battery charged, if needed.

Somehow, living in Minnesota programs the brain to think about prioritizing the ability jump-start vehicles before frostbite sets in, even if in reality I won't use it much after I start flying

Sparky said:

Somehow, living in Minnesota programs the brain to think about prioritizing the ability jump-start vehicles before frostbite sets in, even if in reality I won't use it much after I start flying

Click to expand...

Bingo! Even though I lived in Texas when I built my -8, I remembered all too well jump starting airplanes that weren't set up for it when I lived (or visited) up north. And the truth is, I travel all over the country, at all times of the year, and getting stuck someplace cold is no fun. But the most important reason was cited above - easily putting external power on the airplane for working on glass panels and avionics. I put the Piper-style plug on because it was simpler - I carry my custom jumper cable on extended trips when it might be needed.

Now on our -3, I simply didn't want the weight of the jack - I did, however, put in a low-amperage external power jack to power the ship for avionics set-up and testings. It can also easily be used to charge the battery, which is buried in the baggage area.

Bottom line - whatever you choose, do it because it makes sense for your situation, not because someone else chose it for their situation.

Paul

Reference post #10

I'm not sure I see the necessity of the groung power plug relay. My Bonanza does not have one. Please enlighten me.

Thanks,

flyinga said:

I'm not sure I see the necessity of the groung power plug relay. My Bonanza does not have one. Please enlighten me.

Click to expand...

For one thing, the ground power relay acts to protect your electrical system from overvoltage of the ground power supply. If the ground power supply is inadvertently set to 28VDC instead of 14VDC, the OVM-14 OV module will "crowbar" (short out) the ground power relay coil causing the ground power circuit breaker to open, preventing the ground power relay from energizing, thus preventing the 28VDC getting applied to your electrical system.

It will also protects against reverse polarity.

ground plug

I have a ground plug For Sale, as I had it in my RV6A build kit and decided not to install it as I'm handy to everything where I fly.
If your interested let me know and I can email you back with the make etc..it's the round type all new and as well I have some other items that I didn't use all new as well.
[email protected]
Kind Regards

QUOTE=mmarmol;743202]Hello there,
I am currently looking into what type of ground power receptacle to put into the aircraft that I am building. The main two options are a Cessna-type three terminal plug and a Piper-type one terminal cylindrical plug.
Are there any pros-cons to each of them?
Is any one of them more/less prevalent in your average GA airport? I think this would be my deciding factor but I have only had to jump an airplane *once* and the FBO there had both plug types (it was a big jet center).

Thanks for the help guys!
~Miguel[/QUOTE]

Thanks!

Man you guys are awesome
Looks like the answer is to install the Cessna/Military style plug on the airplane for maximum compatibility with whatever random GPU I might need to plug into in the future. And that is a great point about it being helpful to troubleshoot/test the aircraft's electrical system. Also, thanks for the wiring diagram!

Have a good one,

~Miguel

EAA video - DANGER!

comfortcat said:

Here is a really cool alternative to any expensive plugs. Good for charging, but not cranking. I would not want to get airborne on a really dead battery anyway.

http://www.eaavideo.org/video.aspx?v=1009394733001

Click to expand...

Wow. I just watched this video. What it suggests is a VERY BAD IDEA!

Using an uncommon non-standard connector system (Piper plug, etc.) as we've been discussing, is one thing. The worst penalty for that is just inconvenience. No biggie. But what this video is suggesting is to use what IS a standard connector system for something entirely different, household 110V A/C, that is dangerously incompatible with 12V DC aircraft electrical systems.

Even with the male and female ends reversed, that is asking for trouble. Only a matter of time before someone with a gender-changer accidentally plugs the airplane into a wall socket, or even more easily, accidentally plugs an A/C appliance into the airplane. In either case, likely resulting in damage and possibly fire. Or worse, when someone accidentally plugs the male half of the cord into a wall socket and gets electrocuted at 110V by touching the exposed battery clamps at the other end of the cord...

And to continue... As the video shows, the guy attached battery clamps to the other end of the cord, thereby creating what looks very much like jumper cables. Hopefully even the casual observer realizes that it would be a very bad idea to try to jump-start using this contraption, putting hundreds of Amps through an extension cord designed to carry about 15 Amps. It would almost certainly catch fire. But perhaps less obvious, it would still be a very bad idea to even charge a dead battery with this thing. At the start of charging a very low battery, it may very well accept currents in the neighborhood of 50 to 100 Amps. Not quite as bad as running the starter, but still a major overload of this very unfortunate extension cord, and again, flirting with the prospect of fire.

So, if I really have to say it... folks, please don't do what this video suggests.