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P mag problem

RV7ator said:
Some of you sharp eyed ones might notice that Sonny (LostPilot28) and I live in Boise. He's diagonally opposite me on the other side of town, which is just as well since he's confessed to enjoying wire tracing.;)

John Siebold
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Hey John, when you say "progressive switching", are you using the 2-10 DPDT switches (ie. one 2-position switch for each Pmag)? I don't recall your setup when I last saw your airplane.

Regarding chasing wires...I'll help anytime! I don't know why I like doing it, but I do. I managed to get all of my switches & busses (battery, main, endurance, and ground) wired up in 2 days. All I have left to do is the comm, which looks pretty simple. I'll save the transponder for when I get my EFIS's...but I'm anticipating being done with wiring in about a week. :)
 
Z 13/8 Rev N Aero Electric Drawing

I don't see how Revision N wiring of the PMag allows for testing of it's internal generator. It's either on or off.
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My understanding is that you test the P-Mag's onboard generator by leaving the switch to the P-Mag on (ungrounded) and by switching off the Main Bus with the Master. If you've got most stuff on your E-Bus and have the Alt Feed on, then you won't have to deal with avionics resetting.

If you don't like that idea, I suspect adding a panel breaker for the P-Mag feed would make the most sense.

My plan is to wire it like Rev N and shutoff the Master, but leave the E-Bus alt feed on, whenever I want to test the P-Mag's generator. I imagine I'll do it for every flight but haven't decided that for sure.

Contrary to Rev N, I believe I'll be wiring the E-Mag feed off the E-Bus rather than the Battery Bus. I also intend to use shielded wire for each p-lead in the event I ever switch to mags.

I'm shipping my E-Mag & P-Mag to Brad tomorrow for the update/fix on the sensor mount. They'll then send it to Superior in Coppell. I'm scheduled to build my engine November 10-12. Yay :D

George
 
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P-mags, control them both with just two switches.

Sonny, I wanted to have just two switches also, make them as ergonomically similar to generations of planes from the past, yet follow E-mags wiring approach.

With a pair of (expensive) 2-50 switches you can do it if you want. I have put further info here. It works well for me.
 
2-10s they are, Sonny. Toggle down, grounded/powerless; toggle centered, ungrounded/powerless; toggle up, ungrounded/ship's power. I prefer this because I can force the p-mags into internal power mode by shutting off ship's power. This allows turning off the master so the aircraft can fly with no drain on the battery. You must turn off the master using E-mags scheme, and you may not want to do that. I prefer the selectability.

Twice I've had alternator failures when 3 and 4 hours away from home. (How is it machines can detect the most inconvenient time to fail?) The master contactor eats considerable power itself before anything else gets juice, so it's nice to be able to shut 'er down to conserve battery life. The P-mags happily drone on, and leave me free to on-off the master occasionally to observe the engine monitor, use the radio, etc., without bouncing the p-mags in and out of self-power.

Which brings me to a minor thread steal. I abandoned Nuckolls E-buss concept with the current ride. It makes little sense when everything, with trivial exception, has an on-off switch. The P-mag advent pushed me in this direction. Now, I have a main buss off the contactor, and a battery buss feeding P-mags, a low drain (a nice, legible, black and white!) GPS, back up fuel pump, and clock. No e-buss block, no diode, no switch. The e-buss concept would only additionally serve to isolate a runaway alternator; a field switch, over voltage protection, and B-lead fuse/breaker covers that instance.

Truth be told, I enjoy wiring also (but not tracing problems!). It's clean work and every termination is in itself a minor accomplishment.

John Siebold
 
RE:Shut down

Steve Sampson said:
Sonny, I wanted to have just two switches also, make them as ergonomically similar to generations of planes from the past, yet follow E-mags wiring approach.

With a pair of (expensive) 2-50 switches you can do it if you want. I have put further info here. It works well for me.
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Steve

I like your set up. One ? What is your shut down procedure at the end of a flight.

Frank @ 1L8 ...RV7A... NFY................
 
Thanks to everyone for their replies. The more knowledge I gain, the more confident I get with my switchology. So far, I think I'm still on track to use the 2-10's.

fstringham7a said:
Steve

I like your set up. One ? What is your shut down procedure at the end of a flight.

Frank @ 1L8 ...RV7A... NFY................
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If I'm looking at his wiring diagram correctly, he'll have to hold the 2-50 switch in the spring loaded position on both PMags (after shutting off the Master) to kill the engine. Or he could use his mixture.
 
FWIW, I use the standard "light aircraft" shutdown procedure.

Avionics off, pull the mixture, P-mags off, master off.
 
fstringham7a said:
Steve

I like your set up. One ? What is your shut down procedure at the end of a flight.

Frank @ 1L8 ...RV7A... NFY................
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Frank, Thanks! Shut down is just like you would in a 152 or similar.

Throttle back.
Pulll the mixture.
Turn the p-leads off.
Turn the master off which takes power off the P-mags.

Then from time to time I test the P-mags low running. Then I do:
Throttle back to 1000rpm.
Lean it out if I am not already.
Turn say the left p-lead off. (So we are going to test the self generation on the RH mag.)
Lift the RH mag switch so the power is removed. Remember you have to hold it up against the spring.
As slow as you can, throttle back and try to note where it quits. Its around 700rpm but its very hard to know because it fades away very gently.
Let the engine stop.
P-leads off. Master off

Now you need to remember you have some fuel in the manifold because the lights went out, so I normally only do this when I will be starting again shortly.

Personally, I cant think why anyone would do it any other way. I can do everything I need to, and its ergonomically the same as the past. Its also almost exactly E-mags wiring dia. with the two switches combined into one.
 
Just wanted to follow up and let everyone know that I spoke with Brad at Emagair today. I was pleasantly surprised that he didn't condemn my wiring setup. He did say that Emagair suggests you wire up your Pmags as per their instructions, but he said that it's because they only test their product in that one configuration. Very smart of them to say so...there are so many different ways to do the same thing, but they can't test them all.

Brad said that there's no reason that using the 2-10 switches shouldn't work, and that they did release a firmware fix long ago that addressed the problem of wiring them as per the Aerolectric Connection (Rev L). But, because they don't test it that way, he stopped short of giving me the thumbs up. Fair enough.
 
lostpilot28 said:
...Brad said that there's no reason that using the 2-10 switches shouldn't work, and that they did release a firmware fix long ago that addressed the problem of wiring them as per the Aerolectric Connection (Rev L). But, because they don't test it that way, he stopped short of giving me the thumbs up. Fair enough.
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Sonny,

Did you get the email I sent you?
 
E-Mag Overtemp

During the early stages of break-in, my oil temps were high due to using the Van's oil cooler baffle during the summer. Additionally, the E-mag/P-mag blast tubes were quite short. One July day with OAT in the high 80s, I flew about 18 miles, parked a few minutes then failed the run-up on the E-mag. Since my engine runs quite well on one mag only, I have no idea if the mag failed airborne or from heat soaking. I was unable to restart that mag even after full cool-down and they sent a new unit. A couple weeks later, I cruised about 12 miles in formation with a J-3 at 60kt on a hot day...bad for cooling. The mag failed again, but this time I was able to clear a fouled plug with leaning after an overnight rest.

Good engine cooling and blast tubes that practically touch the base of the mags are critical to keeping the E-mag and P-mag happy. I removed the oil cooler baffle, now using it only during Maine's cold winters and extended the tubes. There has not been a bit of ignition trouble in a year and 160 hours. I recently had a prop strike, which necessitated an engine teardown inspection. I will be breaking the engine in all over again, but this time in fall temperatures, hopefully with no ignition issues.

The guys at E-mag have been super and I would not fly behind any other type of ignition.
 
sparks again

Taking out the E/P mag and installing Unison mags has been an interesting event. But the new latest, no SB's, Slick mags started right up and seem to run great.

The simplicity of the wiring scheme for traditional mags is awesome. I also removed the cooling blast tubes, don't need them anymore.

Now all I need is for the weather to clear and I will be able to fly, it snowed yesterday.

E/P mag failures lost me almost one whole month of flying this last summer.

As soon as I can I will send in the E/P mag for the final blessing from Emagair then they will be for sale with all the latest upgrades and tranferable warranties.

Mike Ice
 
Mike,

Do not remove those blast tubes. Regular magnetos have temperature limits that are not to different from P-Mags. The coils do not like heat and most certified airplanes have blast tubes also.

Martin Sutter
building and flying RV's since 1988
 
mag blast tubes

Martin and Vic,

I looked at several Cessna's this past week and none of them had blast tubes for the mags.

Are RV's that different that they require blast tubes?

Does Van's suggest Blast tubes for regular Mags?

Mike ice
 
Mike Ice said:
Martin and Vic,

I looked at several Cessna's this past week and none of them had blast tubes for the mags.

Are RV's that different that they require blast tubes?
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How tightly are Cessna's cowled? Van has gone to great lengths to craft a cowling that fits tightly to the engine, and to come up with a design that requires the minimum amount of cooling air. As a result, you will often read reports from builders saying that they must climb at over 100 mph to keep the engine temperatures in an acceptable range. I've never heard a single engine Cessna that needed to climb at over 100 mph for cooling reasons.

I don't know whether blast tubes are "required" on mags on RVs or not. But, I wouldn't use the Cessna experience as a guide unless you are prepared to push a lot more air through the engine, and accept the performance penalty that goes with that.
 
Can Cessnas even climb at more than 100 MPH?

Just a joke there. My time climbing in 150's and 172's were not at over 100 mph.

I have had a few year's experience with one P-Mag and one bendix on my -6A. )O-360 Hartzell CS. I have had no problems with it. I just keep tabs on software updates and have Brad update the unit when a new one comes out. I just completed my annual, and received the P-Mag back from Brad yesterday. He did the magnet update as well as a software update. I understand that a few of you have had some problems, and I am sorry for that. Keep in mind that this is nothing new. No matter what you put on your plane, you may have problems of some sort or other. The P-Mag is a solid design, and will get even better over time. I have never had a glitch with mine. Just works great. Took it up for a check out after the annual was completed earlier today, and everything worked fine. I am going to install another P-Mag as soon as I can wrangle the money out of mama.

Brad has been great at P-Mag. They really support their product, much farther than most other companies would go. If we ran for the hills everytime a new supplier with a great idea had a problem, we would have nothing to purchase in the experimental market, except old designed grossly overpriced. STC'd products. Heck, in that case, we might just as well just fly the Cessnas. Just my opinion. Roger
 
Pmags gone

Good point Kevin.

It hardly ever gets hot enough here in Alaska to pose that problem of needing more cooling but...

Last winter a friend covered up most of the air inlets on his 7 but it was -20, yep twenty degrees below zero.

I still have the holes in the rear baffle wall and will keep a check on the mags. I already know I will have to add some sort of an air **** in front of the #1 cylinder and a cover on the oil cooler. Both the #1 cylinder head temp and the oil temp are low.

Oh well, I am getting to where I don't fly much in the winter anymore so it really doesn't matter anymore.

Good point Roger, Most Cessnas I owned could climb at over 100 mph but not very fast.

I really liked the E/P mags. They just seemed to fragile and complicated for my use. If I lost one of them in Barrow or Shishmareff I would be screwed but with the Unison most mechanics will have a fix.

I will have an E & a P mag for sale real soon. I will send them both back to Emagair for all available updates before I sell them.

Once again I have nothing bad to say about Emagair, they just did not work for me.


Mike Ice
 
oops, made an error on previous post

I meant to type some sort of air dam in front of the #1 cylinder and hit an extra n.

Mike
 
Answer to the mystery P Mag problem

I finally have the Mags back from Emagair and the solution to all my problems with the P-Mag was finally discovered.

This message was sent to me by Brad and I believe it was the problem all along.

"The shaft was pushed in on 1019, (yellow LED alert) may have happened during the return shipping. If it was that way when you had it, you would have seen the same thing (Yellow LED) and it would not work at all. When position was corrected, it worked fine on the bench. We went ahead and replaced the circuit board anyway to make certain there wasn?t something else on causing a problem. We did the service bulletin on both so they are current."

I never even realized that you could get a yellow light on the LED indicator. I checked it after I installed it and timed the mag. It looked sort of green to me, how green, yellow is a combination of green and red. It certainly wasn't red so I thought it was green.

Oh well, My loss is your gain.

The Mags are back and are now for sale. I have over $2,300 in costs for the mags, auto harness, plug adapters drive gear, plugs and maybe $400 in shipping costs. Expensive lesson but time to move on.

Brad suggested that a fair price might be to knock 20% off the total.

What do you think? Any offers?

Mike Ice
 
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