P-mags, E-mags, EI discussion

[rv6ejguy]

Yep. You pretty much covered 'em all there. Those old magnetos look pretty good now.

Many people get transfixed on advanced timing causing serious engine damage but don't realize what seriously retarded timing can do also, especially on engines running at high power settings continuously. If the timing was retarded to 0 or 5 BTDC instead of say 25, I'd guess EGTs might increase 200-300F with the CHTs also increasing 100+ degrees. Meltdown is only a few minutes away. Of course in this case, you feel a massive power loss as well whereas with overly advanced timing, say 40 BTDC you might not notice.

Several of our customers have preferred to hedge their bets and retain one mag. Not a bad idea as ours is alternator/ battery dependent.

 

[frankh]

Not quite

9) purposeful use of car gas on a hot day with 39 deg advance (Frank)[/QUOTE]

The weather was not hot and the cylinder head temps running a cool 350F. The advance was limited to 34 deg and I data from Petersen that 89.5 octane had the SAME detonation margins as 100LL.....This really surprised me.

So yes while the decision to use 92OCTane fuel was purposeful it was not done without some research. Further more it ran perfectly well for several hours that way before throwing a wobbly. It laso did it in cruise where the MP was at about 24"...Of course it may have done it at 30" but I never saw it.

Frank

 

[frankh]

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

Don't think this quite true...I think the E/Pmag will always start at zero degrees with or without MP tube. I also THINK that if you disconnect the MP tube the max advance will be limited to 26 DEG...I.e it won't vary with MP of cirse but it will with RPM?...Not sure about that.

A better was would be to use the EICAD function

Frank

 

[rv6ejguy]

I've been building/ tuning/ dynoing engines for over 25 years. My experience does not support the contention that 92 RON pump gas has anywhere near the detonation limits of 100LL. I ran 100/130 and 100LL in many, many race and street turbo engines over the years and I can state without reservation that you can run WAY more MAP and or total timing on 100LL. I've run engines up to 64 inches with 10 to 1 CR and 35 degrees total timing on 100LL. No way that can be done on 92 RON.

I think if 92 RON was capable of this feat, a similar formulation with suitable vapor pressure as avgas would be in use today. While it may indeed work fine on naturally aspirated aero engines, I think would lead to many broken turbocharged ones.

I'm wondering what altitude and ambient temps you were at and if vapor lock could have been an issue?

 

[szicree]

Many people get transfixed on advanced timing causing serious engine damage but don't realize what seriously retarded timing can do also, especially on engines running at high power settings continuously. If the timing was retarded to 0 or 5 BTDC instead of say 25, I'd guess EGTs might increase 200-300F with the CHTs also increasing 100+ degrees. Meltdown is only a few minutes away. Of course in this case, you feel a massive power loss as well whereas with overly advanced timing, say 40 BTDC you might not notice.

Several of our customers have preferred to hedge their bets and retain one mag. Not a bad idea as ours is alternator/ battery dependent.

Wouldn't this only be a concern if both units malfunctioned?

Also, Does anybody know how the MP/RPM sensor would respond in a case of ice/obstruction?

 

[frankh]

I've been building/ tuning/ dynoing engines for over 25 years. My experience does not support the contention that 92 RON pump gas has anywhere near the detonation limits of 100LL. I ran 100/130 and 100LL in many, many race and street turbo engines over the years and I can state without reservation that you can run WAY more MAP and or total timing on 100LL. I've run engines up to 64 inches with 10 to 1 CR and 35 degrees total timing on 100LL. No way that can be done on 92 RON.

I think if 92 RON was capable of this feat, a similar formulation with suitable vapor pressure as avgas would be in use today. While it may indeed work fine on naturally aspirated aero engines, I think would lead to many broken turbocharged ones.

I'm wondering what altitude and ambient temps you were at and if vapor lock could have been an issue?

That would be more in line with what I would have expected.

I hoope VL was not the issue as I developed the fuel system specifically for a high vapour pressure fuel. I.e I have an electric pump in each wingroot with no mechanical pump...Each pump has a pressure relief valve that circulates back to the tank. This was the system I ran (albeit a low pressure system) for my Zodiac which ran perfect, excluding engine valve guide issues.. for 400 hours on auto fuel.

This airplane was only at 3k when it threw the wobbly and both punpings systems were running at the time and showing healthy fuel pressure.

So VL is not and issue here I think.

Frank

 

[Captain Avgas]

Many faults can be publically unreported.

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.

Yes it is interesting (and beneficial) that some people are now stepping forward.

I know of two parties who have returned their ignitions to Emagair for good after experiencing continuous problems that robbed confidence (and they received a full and prompt refund I should add). They told me this privately but neither has ever gone public.

It is a little considered fact of the experimental market that when a builder opts to purchase low volume experimental devices he often becomes captive to the supplier in a technological sense.

If something goes wrong with your P-Mag, your BM EFIS, your Trio Autopilot etc etc then you have only ONE place to go to get it serviced or fixed. Logic says that if you publicly bag that company you cannot expect them to be anything but hostile towards you. They may service you but it will be begrudgingly (that's human nature). So when builders do have problems and suddenly realise that they're locked into a long term relationship they often conclude it's best not to vent their concerns publicly.

This attitude can be reinforced by the fact that most people are defensive about their choices (no-one wants to admit they made a mistake) or simply because they feel protective about the vendor (he's a nice guy).

However the end result of all this is that a lot of faults in "experimental" devices are never reported in the public domain.

I sent an email to the VansAirforce Forum on 1/15/07 "P-MAG Revisited" asking for an update on P-Mag experiences.....one guy honestly reported that his Emag was a "lemon" and had been replaced with a Pmag. None of the guys currently reporting problems stepped forward. This is the thread if anyone is interested: http://www.vansairforce.com/community/showthread.php?t=14291

Final analysis....a lot of serious faults in experimental products go publicly unreported. I no longer expect disgruntled purchasers to confess all in public. Likewise, a lack of adverse reports does not mean all is well.

Conclusion: It's the experimental market....but it doesn't pay to be too experimental.

I really like the concept of the PMags (and I believe one day they'll probably be a great product) but I've decided to drop them from my list because I can't afford to be a beta tester with my type of flying ops.

Incidentally to those who said they didn't know that the PMags were "experimental"......you're joking....please tell me you're joking ?

 

[RV7Guy]

Don't speculate

Come on folks, there are not enough facts to know if it was the Pmags or not. They are one possibility and that is why they were sent in for investigation. I'm confident that if Brad and Tom find a problem they will not hesitate for a moment to let "us" know.

There are many of these in service building hundreds of trouble free hours including mine with 190 hours.

It is certainly not necessary to "break the glass" on this issue. Like anything there will be issues crop up. Look at the early Dynon 10's, the Superior sumps and the many failures of the Facet pumps out of the box. None have been abandon. Do a search on Blue Mountain and stand back. Look at the multitude of issues with Subaru's. They are still there and still being purchased.

For a new concept I believe that Emagair has had less problems that one would normally expect. More importantly is how the company handles problems that come up.

In summary, lets wait and see what is learned before we judge.

 

[fodrv7]

Old Pilots and redundancy.

For a new concept I believe that Emagair has had less problems that one would normally expect.

Darwin,
Do you mean less problems than one would expect for an 'Experimental' system or a 'Certified? System or any system?

One of the cause of confusion (and reason for talking at cross-purposes) with this topic is the lack of "Oxford Dictionary" (Webster for some) definition of 'Experimental'; as it relates to aircraft.

We all know what certified means and that it cost so much to do the certification, that the price is loaded to recover the R & D costs. Which is not unreasonable.

But what does 'Experimental' mean in relation to RVs?
Does it mean we are "experimenting". I don't think that is our intent. Definitely not mine.

Surely, it just means that no one has certified it. (Certificated if you are a Yankee)

But if 'Experimental' means that you are flying off the 'Certification' hours' for a manufacturers system, the failure of which will result in a forced landing, then surely, surely, this non-certified system should be backed up by a system that has already had the 'Certification hours' flown off.

Now let's not get sarcastic and say,
?It is called a Magneto, Willard!?
Because Magnetos were "Experimental" once, as anyone who has owned a Vintage Car knows. Vintage Car means pre-1930 over here.

Magnetos are NOT inherently more reliable than other ignitions systems. It's just that there has been 100 years of development to refine their reliability.

And that is why, you would be wise, to have one on your aircraft whilst you are involved in the "Certification" process for a manufacturer; a manufacturer with a brilliant concept, but without the finances to ?Certify? it?. Sorry, certificate.
Pete.

 

[Scott DellAngelo]

Incidentally to those who said they didn't know that the PMags were "experimental"......you're joking....please tell me you're joking ?

That all depends on your definition of experimental. Personally with hundreds in the field I would not call them "highly experimental". The airplane itself is EXPERIMENTAL let's not forget.

Scott

 

[RV7Guy]

Certified or not

Darwin,
Do you mean less problems than one would expect for an 'Experimental' system or a 'Certified? System or any system?

And that is why, you would be wise, to have one on your aircraft whilst you are involved in the "Certification" process for a manufacturer; a manufacturer with a brilliant concept, but without the finances to ?Certify? it?. Sorry, certificate.
Pete.

We are already doing this with virtually every product we put on our plane with the "Experimental" tag. Do you really believe our Dynons, Trutrak AP, Trutrak T&B and other stuff went through the same process that a certified piece of equipment. I don't think so. We are putting the hours on this equipment for the manufacturer whether we like it or not.

What we get in return is an extreme value with equipment, in many cases, that is far superior in performance and features than it's high priced certified brother.

If you have concerns, stay with a certified plane.

 

[AZtailwind]

Let them have their fun, they're just jealous of our planes that go twice as fast, burn one third of the gas and cost one third of the price to build

You are absolutely right Mark, and Yes I am (But soon to be out of the cans and into an RV)?
What a Great job of flying!

 

[fodrv7]

Absolutely Agree.

We are already doing this with virtually every product we put on our plane with the "Experimental" tag. Do you really believe our Dynons, Trutrak AP, Trutrak T&B and other stuff went through the same process that a certified piece of equipment. I don't think so. We are putting the hours on this equipment for the manufacturer whether we like it or not.

What we get in return is an extreme value with equipment, in many cases, that is far superior in performance and features than it's high priced certified brother.

If you have concerns, stay with a certified plane.

Darwin, I absolutely agree with what you say.

But, we are not discussing failure of some non-essential system in this post. This is not about Autopilots or EFIS.
The point I was making is that the consequences of failure of some systems are so significant that they are duplicated. Ignition systems are one.

In the case of the ignition system, one EI gives nearly all the advantages of a pair, so why would you NOT have one 'Experimental' for it's advantages and one 'Certified' for known reliability.

Of course; ?We are already doing this with virtually every product??..? as you say. But a little prudence as to whether to replace BOTH components of a REDUNDANT system with ?Experimental? might be in order.

Pete.

 

[JonJay]

Great Job

Way to handle a potentially very bad situation. Has the FAA hassled you at all? Did you fill out a NOA form?

 

[rv8builder]

RV-7 Engine problem

What ignition system (manufacturer) are you using in your RV-7 that apparently gave you the problem?

Thanks in advance,
Dale
12 working days until retirement!

 

[brianwallis]

Title

That all depends on your definition of experimental. Personally with hundreds in the field I would not call them "highly experimental". The airplane itself is EXPERIMENTAL let's not forget.

Scott

I personally believe that it is time for a change of nomenclature. The experimental "label" should be used for airplanes and systems that are truly experimental. I hope in the future, the RV series and a few other proven designs would achieve the rank of "custom". I dont know if Van truly knows it or not but he and a few other people working for him (Doug too) have elevated the RV not only to a special place but fueled a giant leap in technology for the little guys. I know Paul Dye would agree with me on the point that many things we take for granite came from the space program.... and now SO many things we have in the "experimental market" are the outreach of the famous economics professor Adam Smith. The silent hand of competition has wiggled it's fingers and hO BOY.... here come the products that are not weighed down with the certification processes.... According to the law of averages... yes, some equipment will fail and for unknown reasons... but Aircraft builders tend to be an educated bunch and know what they are doing on the most part. I feel bad for the folks who experience these failures but through everyone's efforts... we adapt and overcome for everyone's benefit.
my .02

Best
Brian

 

[rodbower]

engine mystery

Reading the reply's to the engine quitting on the RV7 brought to mind some recent problems with an RV8 and a RV10. I would like to share what I have been told by both the owners and Ken Tunnell of Lycon Engine Rebuilders.

The Rv8 using a new lycoming 180 hp engine was quitting without any apparent reason. The owner has his plane based at Camarillo and I spoke with him about the problem. He said the problem was never resolved to his satisfaction and had Ken Tunnel replace the engine. He has had no prblems since.. A friend of mine bought the same engine from Ken and has had no problems. He is flying it in an RV4 .. Ken took the engine apart and found that the valve guides were out of spec and the problem went away. Evidently, when the engine reached operating temp a valve would stick open( I think intake) and cause the existing fuel charge in the system to ignite.. Food for thought

The RV10 with an overhauled bottom end and new lycoming cylinders quit suddenly. (the time was flowen off). Landed in a goat pasture and had to be fenced off to keep the goats from jumping on the wings.. THe airplane just quit and once on the ground (pasture) started up and ran fine. Goats ran fine too. It was taken apart and trucked to Visalia where I hang out.

The man that overhauled the engine (IO 540 with dual electronic ignitions) came up from L.A. and could not duplicate the problem..

The cylinders were removed and valve clearance problems were found. Ken also found that the rebuilder had ground off the hard surfacing on the rockers to come up with the proper push rod lenght..

Airplane is now in service without problems..

Food for thought

Rod Bower
RV8 Fastback

 

[Ron Lee]

Possible Dual P-Mag Problems

I know another RV pilot who has dual P-Mags and used the blow in the tube method to time. I observed the LEDs and apparently the initial timing was fine but soon thereafter one or both seemed to lose their timing. Turning the prop and checking seemed to do it. Turning the power off then on may have also "corrupted" the timing. Other observations suggested that the timing changed to perhaps 50 degrees BTC (If I recall this correctly). Also note that "loss of timing" may not be accurate. The LED lights were not giving the expected color whatever that means.

I am not a P-mag expert so take all of my comments as suspect. I also have no desire to impune the credibility of the P-mag product or the manufacturer but IF there is a safety of life issue here I would rather toss this info out and let P-Mag owners discuss it, identify possible solutions etc.

 

[N941WR]

I know another RV pilot who has dual P-Mags and used the blow in the tube method to time. I observed the LEDs and apparently the initial timing was fine but soon thereafter one or both seemed to lose their timing. Turning the prop and checking seemed to do it. Turning the power off then on may have also "corrupted" the timing. Other observations suggested that the timing changed to perhaps 50 degrees BTC (If I recall this correctly). Also note that "loss of timing" may not be accurate. The LED lights were not giving the expected color whatever that means.

I am not a P-mag expert so take all of my comments as suspect. I also have no desire to impune the credibility of the P-mag product or the manufacturer but IF there is a safety of life issue here I would rather toss this info out and let P-Mag owners discuss it, identify possible solutions etc.

Ron,

I'm sure this is possible but you never really know.

The way you time the P-Mags is:
1. Turn off power to both mags
2. Turn prop to TDC on Cyl. #1
3. Put the P-mags in ground service mode. (This powers the ECU but does not allow the plugs to fire.)
4. Blow in vacuum advance tube.
5. Take them out of ground service mode.
6. Go fly.

I suppose it is possible for the issue to be software related but it is much more likely that either the things were miss wired or there was a hardware failure, IF it is an ignition problem.

Remember, the cause of Mark's power failure has not been determined.

 

[Ron Lee]

Dual P-mags

Bill, the owner has flown with dual P-mags before and loves them. I am assuming that he knows how to time them. I watched him do it and it appears that he does it correctly. But the engine would not start recently. I queried him about spark plug wires and he was adamant that they were fine since he has flown with this system before.

I am just adding a possible data point for others to evaluate. As is typical with events like this information is incomplete.

However, the owner here may next use a typical mag timing process instead of the blow tube. He is a smart guy and feels that may help. Apparently with the blow tube there can be two "native" positions and perhaps something causes something in that area to lose the correct one. This is just my best recollection of a system that I do not have. Owners of dual P-mags can determine if it is of any value.

 

[smokyray]

All the eggs...

Mark,
First, nice job on the FO landing on the highway! I agree, I think your problem was ignition. I don't much about the P-Mags, but I have a Rose EI and Slick Mag on my both my RV4 and HR2. More than once having 2 different types of ignitions has paid dividends when one or the other had issues.

Redundancy is your friend.

My 2 cents..

Rob Ray

 

[Ironflight]

Redundancy is your friend.

Rob Ray

....and un-like redundancy is your BEST friend!

Paul

 

[Ron Lee]

Redundancy

SmokyRay and Ironflight...I assume that you are saying the same thing in that having different failure modes (one EI and one conventional mag) is a good thing.

BTW, I have one Lightspeed EI and one slick mag. Basically for the reasons you provided.

 

[Martin Sutter]

The back up issue is debatable in terms of not having two of the same units. After all the conventional standard is two magnetos. When using two electronic ignitions it makes sense to have one and a magneto to avoid the power supply as the common denominator as a point of failure. In the case of P-Mags wich both produce their own power there is no greater possibility of both failing concurrently than is the case with two magnetos. While one P-Mag failing by advancing it's timing would obviously raise havoc with engine operation, turning it off will restore engine power once the other P-Mag is allowed to fire the plugs at normal timing. Random timing advance is a failure mode we are not used to with magnetos, they usually either quit or misfire while the remaining one still does a good job keeping the engine going. The problem with excessive advance as a failure mode is that it lights off the charge before the correctly working second unit can do it's work. Having two different electronic ignitions systems would buy littel in terms of redundancy, especially since all others are dependent on outside power sources. By the way, I am not suggesting that excessive advance was a fact in the case of the Arizona engine failure but only responding to the theory of this being the case advanced previously in this thread.

Martin Sutter
flying and building RV's since 1988

 

[flyeyes]

(snip) Random timing advance is a failure mode we are not used to with magnetos, they usually either quit or misfire while the remaining one still does a good job keeping the engine going. (snip)
Martin Sutter
flying and building RV's since 1988

Martin, I would have agreed with this statement up until last fall.

We also have a Cirrus SR22, and experienced a mag failure in October which advanced the timing on the right mag, effectively trashing the engine. TCM's analytical lab traced the failure to inadequate venting of the mag, which caused a buildup of nitric acid which led to brittleness of the plastic timing gear. The gear shed teeth which allowed the timing to advance.

The airplane made it to an airport without a problem, but on disassembly of the 700 TTSN motor all six cylinders, the crank, and even the case were sufficiently damgaed to require replacement. Fortunately TCM honored the warranty and covered repairs, although as far as I can tell the only original parts remaining on the motor are the accessories, data plate, and oil sump.

As a student pilot (when Jimmy Carter was president) I was taught to never touch the mag switches in flight. Now I consider it a primary troubleshooting step, and actually do mag checks in cruise occasionally to look for early signs of "weak" plugs or other issues.

 

[Paul Thomas]

Students pilots are now taught that checking the mags is one of the things to do in an engine failure, or at list I was.
I believe it's a checklist item for engines failure on the newer Cessna's, but I don't have a PIM handy.

 

[airguy]

When I got my PPL almost 10 years ago in a C-172, my instructor emphasized to check the mags to make sure the switch was in the "both" position on engine failure - nothing else. Checking L/R/Both was never mentioned.

 

[gmcjetpilot]

Shot gun blast thread but fun

When I got my PPL almost 10 years ago in a C-172, my instructor emphasized to check the mags to make sure the switch was in the "both" position on engine failure - nothing else. Checking L/R/Both was never mentioned.

I was taught to switch the mag switch to single source and later as a CFI taught students to switch mags, left and right and than back to both. Pretty standard practice. I blew a piston in a Piper T-hawk and went thru the drill knowing it would not do it, but did it anyway. I landed on grass with partial power. I know it was drilled into my head. It makes sense does it not?


As far as this thread I think its interesting and and like a shot gun blast , evident by the 10 pages in a few days. It morphed (nothing wrong with that) to P-mags, EI bashing, Auto fuel, emergency procedures and lots of speculation and non-sequiturs. Here is my opinion:

EI if very reliable and unlikely to cause detonation. Chance of random advance out of the blue has not been shown in this case or in past cases. Rumors of engine damage is pure theory, and I'd ask you to prove it with facts.

Yes timing advance can cause PRE-IGNITION which can lead to DETONATION. However there are many other things that can cause these things besides timing going crazy.


Lightspeed: You might find that a CRAZY timing advance from not possible to extremely unlikely. LS has "hard wired" advanced not software I believe. Also LS timing indication should show actual timing advance. With that said anything can happen, murphy's law.

Dual EI is unlikely to both fail, so turn the bad one off makes sense.

P-mag? I know little about them but waht I read, but I do know Lightspeed is not running "Code". It has hard wired advance curves that are very conservative.

Yes electronics can fail or wires come disconnected but radical timing changes not likely. I doubt that you will have failure of both EI regardless of brand simultaneously.

I agree plane old MAGs work but they are not immune from failure or causing rough running or loss of power (see mag switch flick back and forth procedure).

Probably a MAG plus EI set up is a good way to go, with two totally different concepts as was pointed out. However dual EI does give a 1% to 2% more fuel economy over the 3%-4% from a single EI installation. The real gains are from flying at high altitudes/low power or low power where the advance takes over. Down low the gain is much smaller. If all you do is local flying at higher power than EI advantage is less. Still EI is smoother and can start easier. Magneto's are magnetos old mechanical design but works. The farm tractor technology has advantages.

Auto fuel? No thanks, 100's of auto fuel incidents and accidents (direct or indirect cause) in both experimental and certified planes with STC's for auto fuel is way more scary than some speculation on EI.​

With all that said to each his own and yes its experimental.

 

[Davepar]

In the case of the ignition system, one EI gives nearly all the advantages of a pair, so why would you NOT have one 'Experimental' for it's advantages and one 'Certified' for known reliability.

That's why two tires on my car are rubber and two are made of stone. High performance and reliability.

I'll admit I've jumped in with both feet using two P-mags. I didn't want to deal with an old, bulky, heavy, clunky magneto. Maybe that was a mistake, but so far I haven't heard any reasonable situation where the magneto would help out. In the original case of the P-mag supposedly firing early, the same thing would happen with mag + P-mag. Maybe 50% less likely, but the mag wouldn't prevent it.

Apparently with the blow tube there can be two "native" positions and perhaps something causes something in that area to lose the correct one.

This is where I think the constructive discussion wanders right into pure conjecture. Unless this came from Emag, I wouldn't believe it. It makes no sense to have two native positions. As far as I can tell from my limited messing around with my P-mags, setting the timing moves the index. And it stays there.

I'd rather stick with first-hand accounts. Hopefully anybody that has any sort of issue with their ignition is contacting the manufacturer as well.

 

[David-aviator]

HIGH EGT & OIL TEMP - NO POWER

The thread has drifted so far off the map it's become meaningless.

The original symptoms - High EGT/Oil Temp and No Power - are still out there begging for some answers.

Ok, so there's something special about flying with these devices. It is especially sacred after writing a check for 2 of them. But the reality is they don't have much of a track record as records go. There aren't millions of them in use, perhaps a couple thousand of the most popular. Compared to magnetoes and auto engine ECU's, they've hardly been born.

The toughfest decsion going with an auto ECU had to do with accepting just one of them. But here too, reality plays into the equation. There are millions of them in use and yes, they do fail, but when's the last time you saw an auto on the side of the road with a failed ECU? Sure there have been a few, but the statistical reliability of these units is incredible. Not so with recently invented aircraft EI systems. There simply is not the base of units in use to establish their reliability. One experimental EI is just fine, but back it up with something that has been around for a while.

 

[Yukon]

The trouble is Dave, first hand accounts are hard to come by. Most people won't talk about their setbacks, especially when it involves equipment choices, and maybe insurance payouts. The only reason Mark is talking is because he pulled off a flawless, no damage off-field landing, AND air retrieval. Had things gone differently, he probably wouldn't have shared, nor would the others.

Wasn't too many years ago car tires required inner tubes, because the reliability of tubeless tires wasn't up to par. Radial tires used to blow up all the time, not so much anymore. ( YOU brought up the tire analogy!)

Plenty of indication here that Emags are suspect. If you want to sign on as an un-paid test pilot, more power to you. Grab the bull by the horns. Only 400 units in the air, anxiously awaiting your first hand accounts!

By the way, nobody has been really clear why they put these things on anyway????? 5%, 10%, 30% more power......economy.......what's the draw???

Haven't heard anybody yet say 2 mags let them down.

 

[Captain Avgas]

The trouble is Dave, first hand accounts are hard to come by. Most people won't talk about their setbacks, especially when it involves equipment choices, and maybe insurance payouts. The only reason Mark is talking is because he pulled off a flawless, no damage off-field landing, AND air retrieval. Had things gone differently, he probably wouldn't have shared, nor would the others.

There are many reasons why early adopters of truly "experimental" devices might be disinclined to step forward publicly and talk about faults.

One of those reasons centres around the fact that too much bad press might cause the relevant company to go broke...thus leaving device owners with no possible means of support for their expensive doodads. Most of these experimental start-up companies are very small and financially very brittle.

High EGTs, high oil temps, low power.....it certainly smells of a timing problem.....I suspect many people would be very interested in a progress report on this matter.

 

[Ted Johns]

Haven't heard anybody yet say 2 mags let them down.

Umm, except for Post #106, in this thread!
"We also have a Cirrus SR22, and experienced a mag failure in October
which advanced the timing on the right mag, effectively trashing the
engine."

There's four basic failure modes for ignition; no spark, too retarded, too advanced, and scatter mode (random timing).

I've personally seen three out of the four. I've seen the spring partially fracture on a set of points, it makes a "fun" semi-random spark generator. I've seen advance weights stick (auto, obviously), and everyone has seen point based systems fail to spark at all.

With the reading of post #106 I've now been made aware that point based ignitions can fail in all four modes.

Now, anything a point based system can do, an electronic system can do. I'm sure E.I.'s can fail in the four basic modes.

If my engine starts running like s**t whilst high above the ground, I'm going to check the gas, and try each ignition individually. This is what I was taught from my CFI, and what I've learned from 40 years of wrenching on engines.

And if that doesn't work, I'm going to pray I have half the flying skills that Mark exhibited!


Ted Johns
RV7 plans preview

 

[gmcjetpilot]

Stuff happens, but fortunately rarely

Umm, except for Post #106, in this thread!
"We also have a Cirrus SR22, and experienced a mag failure in October
which advanced the timing on the right mag, effectively trashing the
engine."

There's four basic failure modes for ignition; no spark, too retarded, too advanced, and scatter mode (random timing).Ted Johns
RV7 plans preview

I would like to read the accident incident report on the Cirrus SR22 mag failure. If you are below 75% power its kind of hard to trash the engine. With takeoff power, yea, bad news.

As far as ignition failure I guess that covers it, but more specifically, I have seen weak spark and cross-fire (spark jumps to wrong spark effectively changing timing of that cylinder). Also plug failure can can cause pre-ignition and detonation, independent of the ignition.

There have been dual mag failures. The one I am thinking of is with a two-in-one type magneto. How they certified that I am not sure. I guess the statistical chance of failure is low but not impossible.

 

[David-aviator]

And if that doesn't work, I'm going to pray I have half the flying skills that Mark exhibited!


Ted Johns
RV7 plans preview

And luck.

Mark did a fine job landing on that road, but the fact that it was there was pure luck. By his own admission, the flight was not planned along a road but over some mighty rough terrain.

Skill is important this business, after that it's luck. He had both going that day.

 

[USCANAM]

I'm glad on several accounts!!

Mark
Glad that your experience was not harmful to you and your plane. You showed a lot of talent for a low time pilot. Here in Lower New England you would have never found a major road with cars spaced several miles apart!!
When electronic mags first started to appear for certified engines in the early 90's, I was very interested especially since they claimed you could either get 10% more power, or 10% better fuel economy, and since at the time I was flying my Mooney on Trans-Atlantic flights (12 total) it seemed like a good item to have on the plane. But certification dragged on, and I ferried others people's planes over instead, and the mags on the plane were working just fine.
Now, lately when I was researching an engine for my RV 9, I finally decided that in the long run it was far easier to go with the old Slicks, rather than have to be concerned about backup power if I went with to E mags etc. etc.
What I did do was select an IO-360 to make up for the loss of power by using the Slicks.
Having read this thread I'm glad I kept with the KISS principle!!
Once again Mark...Good Job
Jack
RV9A N99552

 

[turbo]

god may have been on board

mark, glad everything turned out all right. my "gump" checklist for engine emergency is "GAS". it stands for [ gas air spark ] also if you want to put a P on the end you get GASP. sounds like someone may have said a Prayer for you. was there a passenger with you? good luck. turbo 3,000+ hobbs hrs on o-360-a1a snew, rv6-a since jan 2000.

 

[flyeyes]

I would like to read the accident incident report on the Cirrus SR22 mag failure. If you are below 75% power its kind of hard to trash the engine. With takeoff power, yea, bad news.

Snip

That was my thinking as well, before this incident. The two ATPs flying the airplane at the time have a lot of experience with continental recips, but mostly turbo variants. They were in level cruise at 8000' an about 65% power when the #4 CHT very quickly (both noticed it turn red on the MFD) indicating 500+ degrees from the normal cruise indication in the low 300s. They richened the mixture and reduced power, but it stayed pegged. They assumed it was probably a probe failure, which isn't all that uncommon on the Avidyne system. They didn't really notice the engine was rough for several more minutes, and at that time they were already descending to land.

They landed without incident, but the airplane was smoking badly in the pattern, and the oil was full of metal. Only the #4 cylinder looked bad on a quick borescope, but TCM replaced all six, and even the case after disassembly.

I think it's true that you can't hurt the engine under 65% power with the mixture, but seriously advanced timing is a whole different animal.

 

[Captain Avgas]

It's been well over 2 weeks since this incident took place so I would imagine that Mark would now have a fairly good idea of exactly what transpired to cause his engine to quit.

Perhaps he could advise us and end the speculation.

 

[MarkC]

It's been well over 2 weeks since this incident took place so I would imagine that Mark would now have a fairly good idea of exactly what transpired to cause his engine to quit.

Perhaps he could advise us and end the speculation.

Hi Folks,

So here is what I know thus far: I got a call from Brad at e-mag earlier this week and he said that after running my mags on their test engine for about 20 minutes and cycling between left and right mags; their engine did indeed start to run rough on one of them. It was not however the exact same symptoms I saw, more just like spluttering and running really rough. Also this could only be identified by switching to, and running on just that one mag, with both mags switched on Brad said he couldn?t tell there was anything wrong. The guys at emag have been really good about the whole thing; they sent me out a brand new mag overnight and kept the one that failed for further investigation. I put the mags back on my engine and they are running well. So, there are there ?facts? that I know for sure, now for some speculation, these are just my personal thoughts, no facts to back them up. I believe what happened is this: the version of the P-Mags that I have, include the quick-time feature built in to them (blowing in the tube in a special sequence to time the mags, it makes it VERY easy to do without having to mess with the mechanical method, and this is the way I had done it the first time), I think that when the mag failed it actually slipped away from the ?quick-time? setting and back to the mechanical setting. I assume this because it would make sense in 2 ways: one is because this would explain why when the mag was on my engine it showed symptoms that the timing went VERY advanced (high CHT?s, High oil temp etc.). When the mag failed on the test engine over at emag, the symptoms they described could very easily be the timing going retarded (coughing and spluttering, running rough, and the fact that this couldn?t be identified until the other mag was switched off). To add to this I have spoken to another gentleman who believes he has had the exact same thing happen to him; luckily his occurrence was while he was on the ground doing a run up. So that?s it, that is all I know, Brad over at emag has promised me that when they find out for sure exactly what went wrong he will let me know, and I will of course let you folks know.

My suggestion from all this (just a suggestion as I?m not qualified or trained to give advice in this area): when you install your mags, use the mechanical timing method until they figure out exactly what went wrong and fix it in an update, and if you have them installed now and you used the quick-time feature, then change it or at least remember to cycle between the 2 in the event of an abnormality while flying. The mechanical method is the way I installed my mags this time, and I?m confident going forward that these EI?s will perform well just as they did for the 95 or so hours up until my little problem. I have no problem flying behind them at all.

Thanks for all the kind comments and support you folks have given over the past couple of weeks. I plan on trying to get to the Cable RV Fly-in over in California next week if the weather permits, so maybe I?ll meet some of you there?

Safe flying to all of you.

Mark ? RV-7 ? N234C
Flying again (98 hours)

 

[dan]

Thanks for all the kind comments and support you folks have given over the past couple of weeks. I plan on trying to get to the Cable RV Fly-in over in California next week if the weather permits, so maybe I?ll meet some of you there?

Mark,

Thanks for the honest report. EMagAir has their work cut out for them, but hopefully they can nip all these issues in the bud over time. Hope to see you at the Cable Rendezvous...fly safe!

 

[Scott DellAngelo]

My comment to everyone with them is just time them mechanically. It is not that big of a deal. Having a reference off of "true" allows for a chance of failure if that reference ever becomes bad for any reason what-so-ever. The piece of mind to eliminate that problem (no matter how slight) is worth the extra 15 minutes when installed in my opinion. I personally had mechanically installed mine anyways after they were out to get the firmware upgrade which included that feature.

Scott
#90598 - N598SD Flying - ~90 hours

 

[frankh]

Just a minute

Your forgetting my incidence Mark. I can't put it down directly to the E/Pmags (because I had swapped to autofuel) but the symptoms were exactly the same...It also ran perfectly well for several hours before the incident on autofuel.

I think that makes 2 definates and one highly probable.

Incidently, did you get that motor borescoped?...If you think you had a detonation issue then there is at leats one engine rebuilder that would highly recommend you do so.

Cheers!

Frank

 

[fodrv7]

Advance or Retarded.

Mark,
If the suspect Mag inadvertently advanced the ignition, as was initially suspected, then if the BOTH position was selected, then the ignition would in fact take place early, with the second mag firing after the fuel was already burning.

If, on the other hand, the suspect Mag was retarded then there would be no effect unless the Mag switch was not on BOTH but on L or R, which was being the suspect Mag. With the good Mag NOT selected ON the ignition would indeed take place late.

Is there any possibility that the suspect Mag only was selected. ON.

Pete.

 

[MarkC]

Mark,
If the suspect Mag inadvertently advanced the ignition, as was initially suspected, then if the BOTH position was selected, then the ignition would in fact take place early, with the second mag firing after the fuel was already burning.

If, on the other hand, the suspect Mag was retarded then there would be no effect unless the Mag switch was not on BOTH but on L or R, which was being the suspect Mag. With the good Mag NOT selected ON the ignition would indeed take place late.

Is there any possibility that the suspect Mag only was selected. ON.

Pete.

Pete,

I think maybe I didn't spell it out well enough: I believe the mag went ADVANCED when it failed on my engine, so as you point out above; this effect would still be apparent if BOTH were on (fuel being burnt early). The same mag on the test engine at emag had the symptoms of going retarded, and therefore only showed when just that mag was on, not when BOTH was selected.

Cheers,

Mark

 

[MarkC]

Your forgetting my incidence Mark. I can't put it down directly to the E/Pmags (because I had swapped to autofuel) but the symptoms were exactly the same...It also ran perfectly well for several hours before the incident on autofuel.

I think that makes 2 definates and one highly probable.

Incidently, did you get that motor borescoped?...If you think you had a detonation issue then there is at leats one engine rebuilder that would highly recommend you do so.

Cheers!

Frank

Hi Frank,

There have been a few occurrences with different symptoms by the sound of things. Hopefully now they have a mag that they have seen fail they will be able to figure out exactly what is going on.

There was no detonation (I'm pretty familiar what "pinging" sounds like from my race engine experience). I was more concerned with glazing the cylinders and losing compression/burning oil. I've done everything I was advised to do by both the engine manufacturer and the builder, I now have 5 hours on the engine since the upset and all seems to be ok.

I'll let you know if anything changes.

Thanks,

Mark

 

[frankh]

yes but

I would be surprised if you could actually hear pinging with such a noisy airplane and engine.

Well if your oil temp and CHTS went sky high that (at least I was told) is pretty indicative of detonation. Detonation shows up as piston damage pretty clearly.

I mean if you think about it, if the charge is exploding way before TDC and the piston blowby is directly heating the oil in the crankcase, then something pretty catastrophic is happening...Piston damage would seem highly likely in this scenario.

I am surprised you would be getting different advice....Can you explain?

Frank

 

[MarkC]

I would be surprised if you could actually hear pinging with such a noisy airplane and engine.

Well if your oil temp and CHTS went sky high that (at least I was told) is pretty indicative of detonation. Detonation shows up as piston damage pretty clearly.

I mean if you think about it, if the charge is exploding way before TDC and the piston blow-by is directly heating the oil in the crankcase, then something pretty catastrophic is happening...Piston damage would seem highly likely in this scenario.

I am surprised you would be getting different advice....Can you explain?

Frank

Frank,

Your surprise surprises me Try running about 90 degrees lean of peak over 8k feet, even with just mags at the regular 25 degrees BTDC, that is what pinging sounds like, you'll know it once you hear it. Pinging happens at the onset of detonation. If you've ever heard actual detonation you'll know exactly what it sounds like. Detonation is a function of more than just advanced timing, it has to have the right fuel/air mixture, intake temperature, compression etc. The timing can be so far advanced that the flame front moves slowly and causes blow-by instead of a massive explosion as the compression stroke has not yet completed far enough for all of the factors above to come in to play so it's more of a "whisp" than a "boom".

Advice? I took advice from the head of development and testing at ECI, and also a guy who has a lot of experience building, running and racing these types of engines for over 30 years. Add to that the two race cars in my garage that I personally have rebuilt the engines of several times, and (for me at least) that's enough. When you're used to dealing with engines blowing 21 psi of boost in to a 10:1 compression environment you get to know detonation VERY well and the aftermath thereof.

Hope that this explanation helps?

Thanks,

Mark

 

[szicree]

If I'm understanding this correctly, you sent the suspect unit back and now it's got a whole new failure mode? I know these things run great when they work, but still ...?

 

[frankh]

Frank,

Your surprise surprises me Try running about 90 degrees lean of peak over 8k feet, even with just mags at the regular 25 degrees BTDC, that is what pinging sounds like, you'll know it once you hear it. Pinging happens at the onset of detonation. If you've ever heard actual detonation you'll know exactly what it sounds like. Detonation is a function of more than just advanced timing, it has to have the right fuel/air mixture, intake temperature, compression etc. The timing can be so far advanced that the flame front moves slowly and causes blow-by instead of a massive explosion as the compression stroke has not yet completed far enough for all of the factors above to come in to play so it's more of a "whisp" than a "boom".

Advice? I took advice from the head of development and testing at ECI, and also a guy who has a lot of experience building, running and racing these types of engines for over 30 years. Add to that the two race cars in my garage that I personally have rebuilt the engines of several times, and (for me at least) that's enough. When you're used to dealing with engines blowing 21 psi of boost in to a 10:1 compression environment you get to know detonation VERY well and the aftermath thereof.

Hope that this explanation helps?

Thanks,

Mark

Well I'm certainly not looking for an argument here, just that we have both been given opposite advice for the same symptoms and while I do not have your experience of detonation there seems to be a few things that don't add up in my mind.

When my engine was borescoped it was found to be in perfect order so the outcome may well be fine in each case.

Can't say I have experienced the scenario you describe when running LOP, as I run roughly 100F LOP all the time and don't get any signs of pinging.

I understand how you can get blowby, by which I assume you mean the charge blows out of the exhaust valves rather than pushing the piston down?...This in theory would raise the EGT's but how does that explain the high CHT's you experienced?

Secondly, I thought you said you had redline (or at least high) oil temperature?

From my Google searching on "pre-ignition" The explanation I got was that charge was lit (or lit itself) while the piston was on its way up the bore, thus putting a great deal of stress on the piston and big end bearings because the piston was trying to compress a rapidly expanding charge. The resulting pressure forced this red hot charge past the rings and heated the oil directly in the sump, presumably with quite a bit of crankase venting going on too.

With all these nasty happenings going on it was suggested that the engine could well be damaged and the borescope would reveal the tell tale signs of pitted pistons etc.

As I said I'm just trying to learn here for mine and the collective benefit of the group.

Frank