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.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
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..
tobinbasford said:
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
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.
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...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.
David,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.
szicree said:Excuse my ignorance, but what would one expect to see in CHT with a carb ice event?
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
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
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.
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.
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.fodrv7 said:One bit of data that would really help is a read out of Ignition Advance.
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
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.
Yukon said:Nobody's addressed leaning. Was anybody running lean of peak when this happened? Just a thought.....
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"
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.
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
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.
I must have mis-counted. I only read one failure, diagnosed and fixed by the manufacturer. Two cases of conjecture.That's three failures, in three months, across a fairly small user community.
This is true of all the electronic ignitions. I don't think any have detonation/preignition detection.Variable ignition timing is real cool, but without automated detonation/preignition sensing like a car has, seems like a very risky proposition to me.
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.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.
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.
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.
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.