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P-mags, E-mags, EI discussion

jbDC9

jbDC9

Well Known Member
Electronic ignition failure? Just out of curiosity, can you share with the rest of the class which EI system you're using? Hope it's not dual Pmags...
 
MarkC said:
Hi,

I didn't at the time. Being a very low time pilot the last thing I wanted to do in the minute or so the engine kept running was to switch anything off! In hindsight that would probably have been a good thing to try because if it was one of the EI's it may have got me home without having to land.

We live and learn (live being the operative word).

Mark
Click to expand...
Good to know for all of us, but I can assure you I would not have started swtiching things off either! lol Mark, I admire your coolness under fire.

I've had 3 engine outs in ultralights. Sounds dramatic, but they were in Nebraska.The whole state is a landing strip, except for cows, deer, & fences. lol

Well Done Mark. You get the VAF Airmanship Award of the Month.



Larry
 
Brilliant Aviating.

Mark,
After seeing the pics and recovering from the shock of the thought of facing a forced landing it terrain like that, I have to congratulate you on your airmanship and skill.

I would never suggest that you change anything that you did.

So not to comment on anything you did, but simply because the incident has got me thinking, can anyone explain if it is possible that an engine might NOT run with the mags in BOTH position, but run in eitther the LEFT or RIGHT position.
If so, then this would be a reason to cycle the Mag switches.

So, all you electical whizes?

Pete
 
fodrv7 said:
Mark,
After seeing the pics and recovering from the shock of the thought of facing a forced landing it terrain like that, I have to congratulate you on your airmanship and skill.

I would never suggest that you change anything that you did.

So not to comment on anything you did, but simply because the incident has got me thinking, can anyone explain if it is possible that an engine might NOT run with the mags in BOTH position, but run in eitther the LEFT or RIGHT position.
If so, then this would be a reason to cycle the Mag switches.

So, all you electical whizes?

Pete
Click to expand...

Hi Pete,

Thanks! the important thing is that I'm here to talk about it. The end justifies them means as far as keeping alive is concerned :)

On your question about mags. The only way I know of that could cause something like this with both mags on is if one of them got way too advanced somehow, that way the fuel/air mixture would burn on the first mag firing way too early, and the second mag firing would have little effect because the fuel/air mixture would be burnt already. Switching off the bad one would solve the problem in this case. Unfortunately as I mentioned earlier; being a low time pilot switching ANYTHING off at that moment was not at the forefront of my mind :-O

Cheers,

Mark
 
P-Mags

David-aviator said:
How come you guys are running with dual P-mags?

When I was messing around with Lycoming, it was one electronic device and one old fashioned impulse coupled magneto, seemed like a good idea then. The difference in timing in cruise didn't seem to matter one bit, the engine ran great.
Click to expand...

I'm running on duel P-Mags because I think they're awesome! If you've ever flown behind them you'll know what I mean. They are smooth as silk and enable a lower fuel burn than regular mags. Starting is first time every time and they check out great.

Just wanted to be clear here: even if it is the P-Mags that prove to be the culprit for my emergency (which we don't know for sure yet, they are currently on way their back to the factory) I will STILL run with them when I get them back. Overall I'm very happy with them and the guys over at P-Mag (Brad and Tom) are just about the best guys in the business to work with. If the mags are at fault, then I'm to blame really: I should have cycled the switches as that would have kept me in the air. Hindsight is always interesting.

Thanks to everyone for their support.

Mark
 
MarkC said:
I'm running on duel P-Mags because I think they're awesome! If you've ever flown behind them you'll know what I mean. They are smooth as silk and enable a lower fuel burn than regular mags. Starting is first time every time and they check out great.
Click to expand...
Regarding how smooth they are...an RV-7 pilot with dual P-mags told me that he cruises at 2500 RPM on a regular basis, which I thought was kinda high RPM. I asked why and he said that down around 2300 RPM he feels a stumble. I'm just passing on what I heard, names remaining nameless and all...

Two local SoCal RV pilots have had to send their P-mags back multiple times.

I'm sure EMagAir will get it together, but the product is not free from bugs YET. I'm not trying to slam the product, because honestly I want to use one if and when my mag dies...I would just like to see the reliability approach 100% across the board.

Mark, don't rule anything out until you're positive. I'm glad everything worked out. You did a heck of a job!
 
I have a P mag and an Emag

.

As this has now become public I will relate that exactly the same symptoms happened to me...All of a sudden for no reason, CHTS and oil temp went sky high, or at least I think they did...Was a engine monitor issue? Don't know for sure but after I exited the runway the engine quit and was almost impossible to restart..Sounds like something happened.

During the incident (over the mountains about to enter IMC thankyou very much!) I ran full rich, what I should have done is shut down one of the ignitions to see if it was associated with a particular system but I didn't.

I must confess I was running premium autofuel. I sent my E/Pmags back to Emgair and they did not find anything on the test stand.

I am a little concerned about the "blow in the tube" timing method and I wonder if that possibly went back to its factory setting?

This is all speculation but there is no obvious reason for the fuel to be the issue...I was running it for a few hours before the incident. I have now been running 100LL while I complete my IFR training and so far all has been well.

Now this is all conjecture on my part. It may not be the E/Pmags at all but this is another data point. I thought I was the only one, now there are two we know of....Somehow we have to get to the bottom of this, could still be coincidence of course..

If you think its a detonation issue it seems getting the motor borescoped is highly recommended as recommended by Mahlon Russell. Mine fortunately came back just fine.

Be careful out there

Frank
 
David-aviator said:
How come you guys are running with dual P-mags?

When I was messing around with Lycoming, it was one electronic device and one old fashioned impulse coupled magneto, seemed like a good idea then. The difference in timing in cruise didn't seem to matter one bit, the engine ran great.
Click to expand...
David,

P-Mags are different than what you are used to. They revert to being self powered, if they loose aircraft power. Thus no need to back them up with a traditional mag. Which is why the "old school" guys run one EI and one mag. Check their web site: http://www.emagair.com

Dan,

The stumble you mentioned has been resolved. Turns out that if they are installed as originally spec'ed in the manual, the power wires are undersized. I seem to recall them being 20 AWG. Brad & Tom now recommend 18 AWG for the power leads. This and the latest software upgrade should fix any remaining issues.

As for what caused Marc's problem. Only time will tell, and Marc, I hope.
 
Frank Ive been watching the posts and I too am baffled. High CHT's and oil without a change in EGT suggest engine intake(not airbox) ingestion. Which is silly since you pulled the cowl and there was nothing there.
If there were some change in timing, you certaily would have seen an EGT change and likely a big one.
When you say the mixture didnt change anything, did you mean to say the a change in mixture did not produce desirable results? Or it did nothing and produced no results one way or the other?
Fuel pressure does not equate to fuel flow. But a reduction in flow would have no impact on Oil temp rising. The rise in oil temp is the odd ball out here.

OK Enough babbling. I have said a lot and added nothing. Great.
And good on ya for finding that pavement and hitting it.
Best
 
szicree said:
Excuse my ignorance, but what would one expect to see in CHT with a carb ice event?
Click to expand...

Not sure, but it wouldn't of mattered, my engine is injected.

Mark
 
frankh said:
.

As this has now become public I will relate that exactly the same symptoms happened to me...All of a sudden for no reason, CHTS and oil temp went sky high, or at least I think they did...Was a engine monitor issue? Don't know for sure but after I exited the runway the engine quit and was almost impossible to restart..Sounds like something happened.

During the incident (over the mountains about to enter IMC thankyou very much!) I ran full rich, what I should have done is shut down one of the ignitions to see if it was associated with a particular system but I didn't.

I must confess I was running premium autofuel. I sent my E/Pmags back to Emgair and they did not find anything on the test stand.

I am a little concerned about the "blow in the tube" timing method and I wonder if that possibly went back to its factory setting?

This is all speculation but there is no obvious reason for the fuel to be the issue...I was running it for a few hours before the incident. I have now been running 100LL while I complete my IFR training and so far all has been well.

Now this is all conjecture on my part. It may not be the E/Pmags at all but this is another data point. I thought I was the only one, now there are two we know of....Somehow we have to get to the bottom of this, could still be coincidence of course..

If you think its a detonation issue it seems getting the motor borescoped is highly recommended as recommended by Mahlon Russell. Mine fortunately came back just fine.

Be careful out there

Frank
Click to expand...

Thanks for the insight Frank. When did this happen to you? Recently? What engine do you have? Injected? Or Carb?

Mark
 
Fuel injected

Its a Mattituck Io360 parrallel valve.

When it happened to me the full rich did not bring the CHT's down...I honestly can't remember what happened to the EGTs but I THINK they went high also.

As I was in cruise I pulled back the manifold pressure to reduce the power as much as posible...i was barely flying at the end...on an ILS in actual IMC..lovely.

The high oil temp (redline) is explained during preignition (and presumably to a lesser extent detonation)...In other words the cylinders are so hot that the cylinder gasess force their way past the rings as the cylinder is still traveling UP the bore...The hot exhaust gasses then heat the oil directly.

NOT a happy situation for the engine to be sure, hence the strong recommendation to get the engine borescoped

Frank
 
Can't be icing

When it happened to me it was a very warm day and I was not up high. Besides the CHT's were close to redline, and it was burning a LOT of fuel like 14 or 15GPH before I pulled it back..In ither words it was running extremly rich and there is no way to explain the redline oil temp either.

It had to be either whacko instrumentation (hopeful) or detonation/preignition which points to timing (or low octane fuel) all other things being equal.

This is where I got after some research, not climing to be an expert.

Frank
 
frankh said:
.

As this has now become public I will relate that exactly the same symptoms happened to me...All of a sudden for no reason, CHTS and oil temp went sky high, or at least I think they did...Was a engine monitor issue? Don't know for sure but after I exited the runway the engine quit and was almost impossible to restart..Sounds like something happened.

During the incident (over the mountains about to enter IMC thankyou very much!) I ran full rich, what I should have done is shut down one of the ignitions to see if it was associated with a particular system but I didn't.

I must confess I was running premium autofuel. I sent my E/Pmags back to Emgair and they did not find anything on the test stand.

I am a little concerned about the "blow in the tube" timing method and I wonder if that possibly went back to its factory setting?

This is all speculation but there is no obvious reason for the fuel to be the issue...I was running it for a few hours before the incident. I have now been running 100LL while I complete my IFR training and so far all has been well.

Now this is all conjecture on my part. It may not be the E/Pmags at all but this is another data point. I thought I was the only one, now there are two we know of....Somehow we have to get to the bottom of this, could still be coincidence of course..

If you think its a detonation issue it seems getting the motor borescoped is highly recommended as recommended by Mahlon Russell. Mine fortunately came back just fine.

Be careful out there

Frank
Click to expand...

Unbelievable Frank! Can't help but think about all those discussions you and I had about auto gas!

You guys aren't going to have any piece of mind until you tear those motors down and do a full inspection. ( And install a pair of bullet-proof Slick Mags)The rod bearings could be compromised, or the rods themselves. Boroscopes won't address that. Detonation is nothing to fool with.
 
Autogas

Well thats where its gets unclear.

From what peterson Aviation told me they did not see ANY difference between the detonation margins between 100LL and 89.5 motor fuel...Note NOT 92 octane, but 89.5. The FAA made them brew special low octane gas to prove there were no detonation issues in certified engines...Thats how they get to sell the STC's. So I'm not convinced at all the fuel was the issue...

In other words if it was preignition/detonation I'm not convinced 100LL would have prevented it...Which I bet aligns with Mark's experience.

Because this all cost me about a month of delay in my IFR training I simply decided that for now autofuel is not a priority. Running autogas is a change and that deserves some careful test flights in the local area in good weather...Not throwing it in the tanks and then blasting off into IMC.

So its IMC first, autoful sometime later but I will retard the ignitions to the same as what a mag gives before I do.

As to tearing the engine down..believe me the the thought had occured. mahlon advised that as my event was short and there were no signs of cylinder damage AND the power setting was very low it was unlikely the bottom end is damaged...Oil pressure is still good. At the next oil change I'll get an analysis done (about 100 hours) and if there are abnormal readings its "Off with its heads?

So to speak!

Frank
 
David-aviator said:
How come you guys are running with dual P-mags?

When I was messing around with Lycoming, it was one electronic device and one old fashioned impulse coupled magneto, seemed like a good idea then. The difference in timing in cruise didn't seem to matter one bit, the engine ran great.
Click to expand...

That's what I have now. Bendix impulse coupled mag on left side and Lightspeed Plasma II on right side. The mag is just along for the ride in cruise power as the spark has already been advanced by the elec. I can turn off the mag completely with no change to engine operation. At low idle, the mag seems to help. Probably due to getting the flame front moving across those giant pistons with two sources of spark.

MIGHTY fine job handling the situation. Welcome to the RV glider club! Been there done that too.
 
lcnmrv8r said:
First, Congratulations on a well executed off field/ emergency.

Second, could this be a possible induction/ice issue. I realize that you have an injected engine and I am not sure of your exact setup, I am also aware that most injected aircraft don't have a provision for intake heat, I am also aware that injected engines are commonly referred to as "unable to have icing issues", however, there is still a venturi effect at the throttle body and I have seen ice form at the throat of injected race car engines before. If conditions are perfect, it's possible.
Hopefully I won't get blasted for this post but thought I'd put my two cents in. Maybe it's worth something maybe not. Bottom line- Good job and good luck figuring out what went wrong.
Click to expand...

Anything is possible I guess, but in Arizona with no visible moisture in the air and a temperature of +1C (I noticed the OAT when we were coming down). Not sure that is viable but to be honest I'm not an expert on icing so I'm thankful for all and any ideas now.

Mark
 
Are you going to get the motor borescoped?

It would seem a highly prudent measure, even if there is some damage a prudent strip will be a lot better than the potential alternative.

if you think about it, something very bad happened, it may have caused no damage at all but there is no way this is a simple icing incident.

It could possibly be instrumentation if you have an all in one EMS type system, but then aLL of your data would go haywire.

Please do keep us informed.

Frank
 
Remebering what you saw.

This post is a really good brainstorming session and hopefully someone will suggest something that leads to an answer.
As suggested timing does seem to be a likely possibility.

What would be really good would be to have all the data from the flight, such as you can download from some EFIS Systems.

One bit of data that would really help is a read out of Ignition Advance.
Lightspeed make such a system.
http://www.lsecorp.com/Products/IgnitionIIPlus.htm at bottom of the page.

I don't know if it would fit the ignition system in this case, but I do have it in VH-WHZ and will endevour to check the Timing in the event of similar engine problems.
Hope I never do and hope I remember to check if I do.


Pete.

lightspeedadvanceqb7.jpg
 
fodrv7 said:
One bit of data that would really help is a read out of Ignition Advance.
Click to expand...
But, given that the readout of ignition advance comes from the EI, if the EI somehow gets confused and starts firing early it seems likely that the display of advance would also be wrong. So, if the engine is running rough, but the EI claims to be firing at the right time, it could by lying to you.
 
Kahuna said:
Frank Ive been watching the posts and I too am baffled. High CHT's and oil without a change in EGT suggest engine intake(not airbox) ingestion. Which is silly since you pulled the cowl and there was nothing there.
If there were some change in timing, you certaily would have seen an EGT change and likely a big one.
When you say the mixture didnt change anything, did you mean to say the a change in mixture did not produce desirable results? Or it did nothing and produced no results one way or the other?
Fuel pressure does not equate to fuel flow. But a reduction in flow would have no impact on Oil temp rising. The rise in oil temp is the odd ball out here.

OK Enough babbling. I have said a lot and added nothing. Great.
And good on ya for finding that pavement and hitting it.
Best
Click to expand...

There IS something here and it is worth discussing.

The phenomenon of high CHT and oil temp occurring out of a stable cruise configuration is very wierd. Something is changing from that stable condition and the engine is in trouble very quickly.

A change in mixture caused by a change of inflight temperature will lean or enrich the flow but the only indication I ever notice was a slight rumble if it was caused by flying into colder air - mixture too lean. If the intake is blocked by ice, the same thing will happen. I had a total loss of power once on 9500' due to ice and it all happened very gradually. This will not cause excessively high cylinder temperatures or high oil temperature. It may cause detonation, but not the high temperatures these guys saw if the timing is at 24 degrees or even 30 with an electronic system. With ice, the engine simply dies for lack of air, the exhaust gets cold which in turn removes a source of heat to get rid of the ice which causes the engine to get quiet and cool quicker yet.

But what would happen if the timing advanced to 50 degrees? The internal temperature of the cylinder would go up dramatically because of the increased pressure due to late opening of the exhaust valve. This in turn would cause blow by the rings heating the oil and as the CHT went up, this too would increase oil temperature more yet.

The symptoms would seem to indicate the issue is timing.....it is difficult to imagine a set of conditions that could produce high CHT and oil temp - and loss of power - other than timing. (Or all 4 exhaust valves not opening? Not likely. That would mean a total cam failure which would not fix itself. Mark's engine fixed itself after shut down.)

This is just an opinion - if the ignition system has a penchant for fixing itself after power down and power up, an opinion may be all there is. The evidence would indicate the problem is within the ignition system and if that is true, it is most likely timing.
 
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Kevin Horton said:
But, given that the readout of ignition advance comes from the EI, if the EI somehow gets confused and starts firing early it seems likely that the display of advance would also be wrong. So, if the engine is running rough, but the EI claims to be firing at the right time, it could by lying to you.
Click to expand...

Wouldn't it depend where the actual failure was in the EI.
If it was because the EI was actually outputing an excessively advance spark, then surely that would show up on the display.

And if the cause was that the EI then having one EI and one Mag would seem to offer redundancy.

I was advised that there is no great advantage in having two EIs and so I have one EI and one Mag.
Pete.
 
Another thought

I do agree with David that excessively advanced timing might cause both high CHTs and High Oil Temp.
But what would cause both EIs to incorrectly advance the spark at the same time.

Poor cooling? High OAT? Low OAT? High Altitude????



Pete.

Where is Walter?
 
Pete, would it be necessary for both to go haywire? I'd think just one EI over-advancing could cause this kind of trouble...

The worst that can happen in this particular scenario is if both P-Mags check out OK on the bench... how do you go about figuring out what caused this w/o "repeating the experiment"
 
yes it only takes

one of the ignitions to advanve to cause detonation/preignition.

Frank
 
Nobody's addressed leaning. Was anybody running lean of peak when this happened? Just a thought.....
 
Scott,

Can you explain to me why guys continue to run these highly experimental and problematic devices on your engines? Why add any additional risk to this already risky sport? When you combine emags, composite sumps and auto gas, your incremental risks approach those of spaceflight.

Interesting to note that both you and Frank kept your emag stories private until just recently......making me wonder how many other issues haven't been reported.
 
Nope...Full rich

Yukon said:
Nobody's addressed leaning. Was anybody running lean of peak when this happened? Just a thought.....
Click to expand...

I wish I had shut a mag down to confirm it was or the other or neither but I didn't.

Frank
 
Of Course not

Radomir said:
Pete, would it be necessary for both to go haywire? I'd think just one EI over-advancing could cause this kind of trouble...

The worst that can happen in this particular scenario is if both P-Mags check out OK on the bench... how do you go about figuring out what caused this w/o "repeating the experiment"
Click to expand...

Fuzzy thinking on my part.

Of course, one ignition system over advanced will cause premature ignition. (For a minute there I almost typed ejaculation.)
Pete.
 
Highly experimental?

Yukon said:
Scott,

Can you explain to me why guys continue to run these highly experimental and problematic devices on your engines? Why add any additional risk to this already risky sport? When you combine emags, composite sumps and auto gas, your incremental risks approach those of spaceflight.

Interesting to note that both you and Frank kept your emag stories private until just recently......making me wonder how many other issues haven't been reported.
Click to expand...

I think the answer here is that we clearly did not think they were "Highly experimental" and to be honest we don't have enough data yet to say if they are or not..I mean how many have they sold so far and what is the failure rate?

What I think would be useful is to keep gathering the evidence, clearly we now have one rough running engine that was clearly due to an E/Pmag, but that is the only concrete evidence so far.

The other two failures are conjecture. Now of course anything that cause you to worry, particularly when it can destroy a 25000 dollar engine (or much worse) may well make you go the tried and trusted route of a couple of mags.

But (purely personally) I don't think we are there yet.

Frank
 
frankh said:
I think the answer here is that we clearly did not think they were "Highly experimental" and to be honest we don't have enough data yet to say if they are or not..I mean how many have they sold so far and what is the failure rate?

What I think would be useful is to keep gathering the evidence, clearly we now have one rough running engine that was clearly due to an E/Pmag, but that is the only concrete evidence so far.

The other two failures are conjecture. Now of course anything that cause you to worry, particularly when it can destroy a 25000 dollar engine (or much worse) may well make you go the tried and trusted route of a couple of mags.

But (purely personally) I don't think we are there yet.

Frank
Click to expand...

Thanks Frank for your quick reply, and it makes alot of sense from the aspect of your initial problem. Now thanks to the timely honesty of two forum members you now have more "data". That's three failures, in three months,
across a fairly small user community.

Everybody has got their own comfort level with risk, and after reading your Subaru experiences in Kitplane, I must assume your threshhold is quite high.
I've had 5 engine failures in 34 years of flying. They are absolutely no fun, very risky, and I am doing everything in my power to make my RV-9 airframe/engine combination as reliable as possible. Once your airplane lets you down, you NEVER fully trust it again.
 
Up until now I was planning on two pmags, but I think it's gonna be Lightspeed and Slick for me.

I think the emag website is very telling here. The site gives a long laundry list of all the desired attributes of an aircraft ignition system along with all the shortcomings of current offerings. When you look at it objectively, it's clear that to engineer such a device is quite a challenge, maybe too much of a challenge after all. I mean, look how long we've been using mags.
 
Well Yukon, frankh answered it for me. I DID NOT think it was "highly experimental" at that time. Still don't really.
 
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Scott DellAngelo said:
The odds of losing both are slim (the reason I still run them), but again if I pull one it will be for something totally different (standard mag or other) so that I don't have all my eggs in one basket as I said in the previous post.
Click to expand...

This is the part that concerns me. It's true that losing both is unlikely, but what if one failing (by over-advancing the timing) has the ability to toast my engine, rendering the other ignition worthless? This seems like a failure mode that is outside the normal considerations.
 
That's three failures, in three months, across a fairly small user community.
Click to expand...
I must have mis-counted. I only read one failure, diagnosed and fixed by the manufacturer. Two cases of conjecture.

I emailed Emag a few days ago to ask about how to re-time them and found out they are now at firmware revision 21 or 22. About 4 revisions past the one that I have. I sent mine back for another free update before putting them into service. I'm sure they'd send out a service bulletin if there were any safety-of-flight changes, but those that have had the P/E-mags for a while might want to update.
 
Does anybody know what all those revisions are? If the product has required 21 changes since introduction, perhaps it was rushed to market. I know these kind of growing pains are common with cutting edge tech, but a buggy Ipod can't get you killed.
 
Excellent post, Scott. Your rationale makes good sense. However, and I think you'll agree, your thought process is HIGHLY dependent on information sharing from your peers.......

There is something about this sport (I think it's called MALE EGO) that limits the amount of honesty we employ regarding our aviation endevours. I certainly haven't told you guys all of my foibles, and probably never will.....!

The certified world has SDR's (Service Difficult Reports) filled out by fairly disinterested parties (A&P's) and distributed to the maintenance community, via the FAA and equipment manufacturers. When a part keeps failing, the Feds issue an AD, and the problem gets fixed. Sometimes things get fixed without an AD, via Service Letters, but in all cases the process starts with information sharing.

I just had a very illuminating conversation with Brad at Emag, and he very honestly portrayed the state of developement of the E/Pmag. 400 units in the field, only a handful of problems, I should say, SHARED PROBLEMS.
Appears to me to be lots of promise with these unit, due to the hotter spark and variable timing.

Something he said though, that really set off alarm bells though, is the variable ignition is controlled and initiation by a map table of RPM and MP.
That means that if gas of marginal octane is used, through mixing of car gas with 100LL, jet fuel contamination, or off-spec auto fuel, the software map will run your advance right up to 39 degrees, with no detonation monitoring whatsoever, whenever the power is reduced to cruise.

Variable ignition timing is real cool, but without automated detonation/preignition sensing like a car has, seems like a very risky proposition to me. Careful monitoring of CHT/EGT would help, but a single pilot in the cockpit can only do so many tasks with reliability.

Lets keep working together to get a handle on the risk factors we face.
Lot's of room for improvement.
 
Variable ignition timing is real cool, but without automated detonation/preignition sensing like a car has, seems like a very risky proposition to me.
Click to expand...
This is true of all the electronic ignitions. I don't think any have detonation/preignition detection.

Also, you can disable or reduce the ignition advance in the E/P-mag if you want. Just don't hook up the MAP tube, or alter the amount of advance via the serial port and their EICAD software.
 
Yukon said:
Excellent post, Scott. Your rationale makes good sense. However, and I think you'll agree, your thought process is HIGHLY dependent on information sharing from your peers.......

There is something about this sport (I think it's called MALE EGO) that limits the amount of honesty we employ regarding our aviation endevours. I certainly haven't told you guys all of my foibles, and probably never will.....!

The certified world has SDR's (Service Difficult Reports) filled out by fairly disinterested parties (A&P's) and distributed to the maintenance community, via the FAA and equipment manufacturers. When a part keeps failing, the Feds issue an AD, and the problem gets fixed. Sometimes things get fixed without an AD, via Service Letters, but in all cases the process starts with information sharing.

I just had a very illuminating conversation with Brad at Emag, and he very honestly portrayed the state of developement of the E/Pmag. 400 units in the field, only a handful of problems, I should say, SHARED PROBLEMS.
Appears to me to be lots of promise with these unit, due to the hotter spark and variable timing.

Something he said though, that really set off alarm bells though, is the variable ignition is controlled and initiation by a map table of RPM and MP.
That means that if gas of marginal octane is used, through mixing of car gas with 100LL, jet fuel contamination, or off-spec auto fuel, the software map will run your advance right up to 39 degrees, with no detonation monitoring whatsoever, whenever the power is reduced to cruise.

Variable ignition timing is real cool, but without automated detonation/preignition sensing like a car has, seems like a very risky proposition to me. Careful monitoring of CHT/EGT would help, but a single pilot in the cockpit can only do so many tasks with reliability.

Lets keep working together to get a handle on the risk factors we face.
Lot's of room for improvement.
Click to expand...
I'm glad to see this discussion, and I think it is still guarded. I'm sure their is more to come. I sent my e-mag p-mag back after 6 weeks of frustration and fear of destroying my $21,000 engine or worse. I only had to pull one cylinder off a new engine because of bad timing. I hope it doesn't take someone getting killed to get this problem resolved one way or another.
 
Davepar said:
This is true of all the electronic ignitions. I don't think any have detonation/preignition detection.

Also, you can disable or reduce the ignition advance in the E/P-mag if you want. Just don't hook up the MAP tube, or alter the amount of advance via the serial port and their EICAD software.
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I understand that, Dave, but that doesn't make it right. 39 degree advance,
initiated by an unsophisticated mechanism such as an RPM / MP map without
some kind of automated CHT/EGT limits alerting is very problematic. Seem like
it would be a simple addition to the software to light a BIG RED LIGHT on the panel when the CHT goes past 450. Not foolproof, but alot more doable than
detonation sensing.
 
It is almost impossible to get detonation burning 100LL, running below 23 inches MAP (75% power) with anything under 9.0 to compression ratios, even with 39 degrees total timing. Now if you have 10 to 1 and burn auto fuel, you better reprogram max advance to a lower value as this could cause problems.

Software run amok problems could cause almost anything to happen including severely retarded timing which will raise both EGT and CHTs to alarming values.

We have offered knock sensing capability on our EM series EMSs for years but implementation on all engines involves considerable testing on sensor placement and validation to ensure that false triggering due to engine mechanical noise does not happen. In practice, on mechanically noisy engines like Lycomings, this capability is rarely used.

Advance/ retard curves should be tailored to each specific engine combination through extensive testing and should also take into account the lowest fuel octane used.

All digital control devices go through software changes and upgrades as field experience dictates. It does not necessarily mean there were problems with the original code. Of course it also does not mean there wasn't!

All the traditional aircraft type EIs use cumbersome interfaces or none. SDS panel mount programmers give you a real time display of total timing and you can reprogram any part of the curves in flight should you desire. This opens up the possibility of proper flight testing and obtaining maximum performance at any power setting within just a few minutes for your engine/ prop combo.
 
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Davepar said:
This is true of all the electronic ignitions. I don't think any have detonation/preignition detection.

Also, you can disable or reduce the ignition advance in the E/P-mag if you want. Just don't hook up the MAP tube, or alter the amount of advance via the serial port and their EICAD software.
Click to expand...

Right on. When you sign up to get the advantages of these (or any) electronic ignitions that is part of the deal. I could never see a knock sensor working on one of these noisy engines. One of the really nice things about the e/p-mag is this ability to change the advance. It takes far longer for me to get the top cowl off (doesn't take long) than it is to change that if I want to. As Davepar says if you don't hook up the MAP then it will run fixed timing, but then again what would be the point? Also you can wire a switch to jumper to pins on the ignition and change between 2 different advances while flying if you so choose.

Edit: And Mark if you are reading this, as I am sure you will, please let us know what you find to have been the problem.

Scott
 
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rv6ejguy said:
It is almost impossible to get detonation burning 100LL, running below 23 inches MAP (75% power) with anything under 9.0 to compression ratios, even with 39 degrees total timing. Now if you have 10 to 1 and burn auto fuel, you better reprogram max advance to a lower value as this could cause problems.

Software run amok problems could cause almost anything to happen including severely retarded timing which will raise both EGT and CHTs to alarming values.

We have offered knock sensing capability on our EM series EMSs for years but implementation on all engines involves considerable testing on sensor placement and validation to ensure that false triggering due to engine mechanical noise does not happen. In practice, on mechanically noisy engines like Lycomings, this capability is rarely used.

Advance/ retard curves should be tailored to each specific engine combination through extensive testing and should also take into account the lowest fuel octane used.

All digital control devices go through software changes and upgrades as field experience dictates. It does not necessarily mean there were problems with the original code. Of course it also does not mean there wasn't!

All the traditional aircraft type EIs use cumbersome interfaces or none. SDS panel mount programmers give you a real time display of total timing and you can reprogram any part of the curves in flight should you desire. This opens up the possibility of proper flight testing and obtaining maximum performance at any power setting within just a few minutes for your engine/ prop combo.
Click to expand...


Ok Ross, if I stipulate to the fact that it is impossible to detonate 100LL below 23 inches, will you agree to this?

Reasons for catastrophic detonation with EI

1) software code problems
2) MP sensor malfunction
3) RPM sensor malfunction
4) MP wiring fault
5) RPM wiring fault
6) numerous EI potential hardware faults
7) car gas / 100LL mix
8) contaminated 100LL
9) purposeful use of car gas on a hot day with 39 deg advance (Frank)
 
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