E-mag / P-mag

[szicree]

Chuck,

I see your point. However, with a 2 p-mag setup, the 'Lectric Bob deal has
2 fuses, and 3 switches, with the third switch only being cycled during maintenance. Wouldn't the other way have 2 switches and two breakers, witht the breakers being cycled every flight? It also occurs to me that the extra switch in Bob's design could simply be a fuse that is left out except during maintenance.

Steve Zicree
RV4 Wiring

 

[gmcjetpilot]

Pete I get it?

I think you're slightly missing the point. With a p-mag 2 switches are required, that do 2 different jobs. Also the "p-lead" does not do exactly what it does on a regular mag, it just stops the p-mag producing sparks, the electronics are still working. So agree that a "mag" check is required to ensure that both ignition systems are functioning properly.

However, a p-mag has its own generator that powers it most of the time. Ship's power is required for starting, but not much thereafter. So if the engine starts we know that ship's power is getting to at least one p-mag, if the run up is good we know that both are operating from ship's power or their own generators, but we don't know if the generators are working. Another 2 switches are required, on the power feed to both p-mags, to interrupt ship's power to check.

Bob Nuckolls doesn't really like circuit breakers, preferring fuses, so he has tried to come up with a system with the minimum number of switches (to remove potential failure points). Seems that for this application a pair of switched breakers might just be the best answer?

I would hesitate to wire the airplane so that it could not be hand-propped (or so that the timing was difficult to check at the annual) - hand propping has got me out of an awkward situation on more than one occasion.

Pete

Yes Pete I get it, thanks. You can and should turn off the L & R "Mags" during "run-up" to test the ignitions independently. I was just asking a question.

I also get you want to check the self-power function. I agree that this would not need to be done routinely. However with the three-position switch you could do this or a CB that you could pull and a two-position switch.

However Bob is not anti-circuit breakers; but he just likes the auto fuse blocks. He defends the CB very much in it's use for a critical over voltage function with his "Crow bars". CB's of high quality are fine. The CB type you can pull would be acceptable for occasional use as a switch. CB's are fine and used in every certified GA plane, Boeing 777, B-2 Bombers and F117 stealth fighters, so I think our RV's are OK with them.

Having a simple ON/OFF switch is all that is needed for each P-mag. For those occasion you want to check the self power function you pull the CB. I AM NOT a fan of three position switches.

As far as hand propping, not a fan either but you will need electrical power to get the P-mag going as you say for start. G

 

[Davepar]

...I AM NOT a fan of three position switches...

I'm curious. What's wrong with 3 position switches? I'm planning on making use of them for a few things (off/taxi light/taxi+land light, off/nav lights/strobe+nav lights, etc.). Seems like a good way to reduce the number of switches (and thus confusion) on the panel.

Dave

 

[Highflight]

Just an update on lead times. They are currently at 5 months. I ordered my P-mags mid-July and they won't be shipped until next month.

That doesn't seem to be the case, Dave, at least not as of this morning.

I called this morning and ordered two P-Mags and was told that there are about 30 or so left available in this current run that should all be delivered in December.
I'm told I'll have mine in about a month which is a LOT sooner than I'm going to expect my Mattituck engine to be ready considering I'm not intending to order IT until around Christmas (12 to 14 week lead time for the engine).

I think what happened is that they do "runs" and you ordered yours as part of the current run that I'm getting in on the tail of so we'll both get ours at the same time.

Maybe I'll hang the P-Mags from my Christmas tree for a bit...

 

[Davepar]

Ah, that makes sense. Once those 30 extra are gone, It'll probably be a while before the next run is ready.

 

[casper]

P-Mag

I ordered my E-Mag and P-Mag 6/22/05. I'm still waiting
Doyle Reed RV7A

 

[tacchi88]

Lasar

There seems to be some misinformation about LASAR. To begin with it doesn't care about plug gap. More is better. As for seeing them on sale on e bay, indicated little about its reliability. the number of LASAR units are considerable compared to E mag, and all due respect to the E mag, they are indeed, an excellent alternative to plain old magnetos.
LASAR is managed ignition timing, unlike plain electronic, in that it alters timing constantly as the engine requires. In additon, it's timing map is specific to Lycoming engines.
How do I know, I sold my Arrow with more that 800 hrs of LASAR, and it's still going strong. My RV10 will be LASAR equiped, and to make sure prices don't get any higher, I've already purchased it. I do like the built in redundence feature, so I'm stuck with AV plug, but then again, those 800hrs, and the additional one the new owner (near 1000) has, will negate cost of plugs. BTW, I did try Mogas(though not recommended due to FAA regs for cert, AC, eichh), the difference is short of astounding.

 

[RV7Guy]

Emag/Pmag

When I ordered mine I was aware of the delay. Mine were ready ahead of schedule. I asked them if there was someone on the list that needed them sooner and deferred my order a couple of months. Took delivery two months later.

My neighbor just ordered and was told December. I have found Brad to be great to work with and most importantly, honest!!!!

I'm two weeks from starting my engine. I'll keep everyone posted.

Darwin N. Barrie
Chandler AZ

 

[chuck]

There seems to be some misinformation about LASAR. To begin with it doesn't care about plug gap. More is better. As for seeing them on sale on e bay, indicated little about its reliability. the number of LASAR units are considerable compared to E mag, and all due respect to the E mag, they are indeed, an excellent alternative to plain old magnetos.

I think LASAR does care about the plug gap when it's battery has failed and it is no longer and EI but is a "tried and true magneto". IF you widen the gap AND you have a electrical problem your engine could have reduced power output (or none). In all of the literature I've read about LASAR I haven't (yet?) seen them recommend widening plug gaps. Is there a reference from the manufacturer you could point to? I also haven't heard of recommendations of autoplugs on a LASAR system.

One of the great things about a PMAG is that you put two in the mag pads (no other boxes), you save about 3 lbs, you get EI, and you don't need an spare alternator/dual battery system.

LASAR is managed ignition timing, unlike plain electronic, in that it alters timing constantly as the engine requires.

PMag/EMag does this as well when provided with a MP line. This is considered their 'standard' mode of operation. The LASAR has the same inputs plus an optional CHT.

In additon, it's timing map is specific to Lycoming engines.

This indeed could make the LASAR produce more power than an EMAG especially if CHT feedback is used (not available on EMags). I wonder if this is why LASAR's (anecdotaly) run hot since they could dial in more advance and use CHT as a limiter at high RPM's.

Running a standard gap plug might negate the gain though. The proof would be in a power test that nobody seems interested in. EMag has been particularly coy on this.

Chuck

 

[tacchi88]

More LASAR

I've never read about the plug gap in their literature either, but from the service end of it, more gap is just a tad better than standars gap. The plain magneto doesn't mind wider gap once it is running, but starts are a problem due to anemic spark. In 27 years in aviation (A&P/IA), battery failures and charging failure are few and far between, with aircraft that are properly maintained. Assuming that the owner/operator has a least an "airworthy " battery, even if there is a charging failure, the battery is still operating LASAR. It's low amperage draw, will outlast most fuel tanks and kidneys.
The E mag is a fine accomplishment, but in no way is it managed timing with a map specifically for the engine specified. It is step altered. Many after market automotive ignitions work this way. It is an excellent step over a fixed timing magneto, but in no way as effective as managed timing.
As to the running higher CHTs, this is an unfortunate statement made by Unison and misconstrued. They say that higher temp will be seen since combustion is complete, rather than having a portion of fuel going out the pipe, which in turn cool EGTs and CHTs, but forgot to mention that nowhere do these temps come close to harm ingthe engine. Poor choice on their part. During my ownership I rarely saw more that 350 on CHT and high of 375, far from the 500 limit. Before LASAR, it woiuld operate between 290 to 325. Too little heat is as bad as too much heat.
LASAR is also effective in helping to prevent shock cooling. In long fast power off descents, EGTs rarely drop more that 100 to 150 deg, rather than nearly stone cold, as a magneto would do.
Everyone has a choice to make. In my opinion, as stated previously, if there was no LASAR and E-mag was there, it would be a no brainer over a crappy 110 year old magneto. Electronic spark and timing change. I simply think that LASAR is a cut higher. 800+ personal hrs, and now nearly topping 1000 with the new owner, the fuel savings alone (20%), higher altitude climbs, and the rest of improvements, is hard to ignore.
This forum is great. lots of points of views, information, ideas and education.

 

[DB1033]

To time (and hand prop) the system you need the power on and the PLead grounded! I worked around it and got it timed but had some interesting words...

You should still be able to hand prop your engine if you're using B.Nuckoll's 2 switch setup. When the switches are in the "ON" position, the battery power is supplied to the Pmag and the "stop producing sparks" wire is un-grounded. The only thing you would use the 3rd switch (B.Nuckoll's diagram Z-33) for is to time the mags.

As for the hand propping issue, I can't imagine what circumstance would have me hand propping a plane with an electronic ignition (even if it is a p-mag).

A situation could arise where the battery has insufficient charge remaining to turn the starter but is still able to power the EmagPmag. in the FAQ section of the the Emagair website they mention that they are able to get them to produce sparks on the bench using a 9-volt battery.

I guess you could wire in a little 9-volt battery terminal in your panel and keep an extra battery in your flightbag for those times when the A/C battery is completely flat.....hmmm??

 

[Davepar]

...The only thing you would use the 3rd switch (B.Nuckoll's diagram Z-33) for is to time the mags...

On the later Emag/Pmag models, the timing advance can be controlled by turning the power on before or after ungrounding the mag lead. Bob's diagrams seem to be AWOL at the moment, but if I remember right that 3rd switch would be needed to use this feature.

Personally, I'm planning on keeping it simple/flexible. A bat switch for each Pmag power and a key switch for the mag ground wires and starter.

Dave

 

[Alex D]

Once you go Emag you don't go back!

I have been using my P-mag/e-mag since February 05. I have not had any problems starting the engine at all. I have noticed a consistent 1/2 a gallon less fuel burn per hour, specially during long trips. I have 120 trouble free hours on them. I can't wait until they come out with the 6 cylinder ones, so I could use them in the RV-10.
Alex D

 

[aadamson]

Just be careful

I have been using my P-mag/e-mag since February 05. I have not had any problems starting the engine at all. I have noticed a consistent 1/2 a gallon less fuel burn per hour, specially during long trips. I have 120 trouble free hours on them. I can't wait until they come out with the 6 cylinder ones, so I could use them in the RV-10.
Alex D

That .5 gal, and I'll assume you meant gph? Is mighty small when compared to a 180/200 hp 4 cyl that uses 8-10 gph. That's around 5% and while some of that is coming from the EI, I'd suspect some is coming from engine break in, DA changes as we get warmer and most likely your flying habits. For a good EI setup, I'd expect more like 10-12% fuel savings (based upon what the guys running the CDI base dual systems are seeing).

BTW, at $3.00 a gal, that's only $1.50/flight hour savings... It's gonna take a good bit (probably half TBO) to pay for them ...

Don't worry, I'm a huge fan of the new EI. My concern is that I'll be flying lots of cross country and getting to "who knows where" and having a problem, then having to figure out how to get home cuz I can't fly the airplane.... I think for now, I'll take good ole mags - at least all the A&P's in "who knows where" can help me sort out the problem.

 

[Davepar]

My calendar shows 13 months between Feb '05 and Mar '06. It would be tough to put on 120 hours in 2 months, except for maybe Dan.

 

[aadamson]

what i get

My calendar shows 13 months between Feb '05 and Mar '06. It would be tough to put on 120 hours in 2 months, except for maybe Dan.

Well, I deserve that after breathing acetone and epoxy fumes most of the day...

yep, you are right... hmm, I still would have expected better... Ah, well, I do hope the technology matures and gets better, its certainly better than Mags, just not as easy to have serviced.

Makes ya wonder, tho, doesn't it.... If the EI is doing it's job, it also made better power, so perhaps that math needs to be less about fuel savings only and more about TAS vs fuel savings. If you got 5-7kts better speed *and* .5 gal better fuel, then the math starts to work....

Course, did I say I've been breathing acetone and epoxy all day too

 

[rwtrwtau]

Splitting hairs?

That .5 gal, and I'll assume you meant gph? Is mighty small when compared to a 180/200 hp 4 cyl that uses 8-10 gph. That's around 5% and while some of that is coming from the EI, I'd suspect some is coming from engine break in, DA changes as we get warmer and most likely your flying habits. For a good EI setup, I'd expect more like 10-12% fuel savings (based upon what the guys running the CDI base dual systems are seeing).

The difference between 5% and 10% is only another .5 gal anyway. Aren't we splitting hairs?

BTW, at $3.00 a gal, that's only $1.50/flight hour savings... It's gonna take a good bit (probably half TBO) to pay for them ...

Even at $3 hr it will take a while to pay for them, however...

• One Emag and one Pmag on a new engine costs around $600 more than two Slick Mags (Not all that much and a lot less than LSE)

• You get to run auto plugs, cheaper and easier to replace if needed

• Slick Mags are virtually a throwaway item at overhaul. The Emags are not well known in this area but I would expect them to be better

• More HP

• The engine virtually runs on one as well as on two = more redundancy

• Pmag is the only experimental ignition on the market that is not dependant on electrical power. Similar certified units cost a lot more

• Emag will not destroy your starter like LSE (admittedly mags do not have this issue)

I suggest that there are other reasons that builders are installing electronic igitions other than pure economy. None of them stack up that well if that is the measurement you have in mind. I agree servicing would be easier on the mag.

Richard

 

[Davepar]

Well, I deserve that after breathing acetone and epoxy fumes most of the day...

Ah yes, the joys of a plastic plane builder.

I'll actually be diving into the epoxy this weekend to work on the cowl a bit. I'm sure 2 + 2 = 5 soon enough.

Dave

 

[RVbySDI]

That .5 gal, and I'll assume you meant gph? Is mighty small when compared to a 180/200 hp 4 cyl that uses 8-10 gph. That's around 5% and while some of that is coming from the EI, I'd suspect some is coming from engine break in, DA changes as we get warmer and most likely your flying habits. For a good EI setup, I'd expect more like 10-12% fuel savings (based upon what the guys running the CDI base dual systems are seeing).

BTW, at $3.00 a gal, that's only $1.50/flight hour savings... It's gonna take a good bit (probably half TBO) to pay for them ...

It is interesting to me that we so often judge whether something new is benefitial based upon how much it cost in $$$. If we discuss this issue in terms of engine power output efficiencies, amount of fuel the engine burns (regardless of what that fuel cost), longevity, simplicity, ease of installation/maintenance instead, would you still be second guessing yourself on whether you would use 100+ yo mechanical magnetos or new Electronic Ignition (EI) technology? I see this technology as a no-brainer in most all of those terms. Afterall, if it were not "better" to use EI on internal combustion (IC) engines, why are all of those Indy 500 racers, NASCAR engine experts, open ocean boat racers, in fact, all the ad nauseum users of IC engines that want ultimate performance using EI rather than the "reliable" magneto to power their engines? Why in the world can a cheap tin can car sold by, hmmmm, well, EVERY CAR MANUFACTURER IN THE WORLD, use them? Why aviation IC engines are thought of as "different" from any other type of IC engine is beyond me! An "airplane" engine burns fuel and needs something to ignite that fuel as efficiently as possible in order to produce the most power possible out of that burning and subsequent explosion. How is that different than any other IC engine performance goal?

With relation to your statement about how long it would take to pay for P Mags, the true problem with the cost is the initial out lay of $$$ to purchase the equipment. Price should not be our primary determining factor for whether we should purchase these products or not.

Why does an EI system on any land based IC engine cost a quarter the price of anything with the label "aviation" on it? Ok, that is a rhetorical question, so please don't drill me with facts on FAA certification, economies of scale, supply & demand, development costs or (heaven forbid) the all important "safety" of the product issue. I am aware of all of those issues as they relate to costs in our aviation world. However, I do contend that if I have the production capability to keep up with demand without substantially adding to my costs, I would make just as much money (read that as profit) on sales of my "widget" if I sell 1000 @ $500 rather than 500 @ $1000. The key is, as long as I can meet production, I am going to make just as much money selling twice as many "widgets" at half the price. What is wrong with that? I make the same amount of money, customers do not have to spend as much on my "widget" just because it has "aviation" printed on it, I keep workers employeed, suppliers supplying, shippers shipping, etc. etc. A win/win scenario.

Don't worry, I'm a huge fan of the new EI. My concern is that I'll be flying lots of cross country and getting to "who knows where" and having a problem, then having to figure out how to get home cuz I can't fly the airplane.... I think for now, I'll take good ole mags - at least all the A&P's in "who knows where" can help me sort out the problem.

This sounds like you are expecting something to fail. I don't get into my car and expect it to fail on me. Just because we have this issue of "safety" in the back of our minds because a dead engine means we can't just pull over on the side of the road when flying shouldn't keep us from using the most efficient means of powering our flight. Your statement sounds like it has that typical "If it aint broke, don't fix it" philosophy tainted with the "fear of safety" issue thrown in for good measure to both scare yourself and anyone who hears your conversation on the issue. True I am sure EI have failed in the past and will fail in the future on airplane engines but I, for one, don't want to live my life in fear of the "what if's" of the world. I don't want to die, I have no intentions of building my airplane in a way that will kill me, I believe that manufacturers will produce their "widgets" to minimize the threat of it failing on my health. As with price, I don't want to make decisions on what I use on my airplane to be dictated by fear either.

Ok, lambast me if you will. Those are my .02.

 

[jimrobinette]

Off topic maybe, I would be cautious of saying that NASCAR is looking for "ultimate performance", as they are still using carbs on their engines, as opposed to something much more performance oriented and "better" like fuel injection!! When Toyota decided to join the good 'ol boys down south, they had to develop an engine with a carb on it specifically for NASCAR as they didn't build carb'd engines anymore anywhere in the world!!! And I am sure it isn't a money issue with these teams. Everyone has their reasons for doing whatever it is, and as you say, it isn't always money.

....Afterall, if it were not "better" to use EI on internal combustion (IC) engines, why are all of those Indy 500 racers, NASCAR engine experts, open ocean boat racers, in fact, all the ad nauseum users of IC engines that want ultimate performance using EI rather than the "reliable" magneto to power their engines? ....

 

[N941WR]

Off topic maybe, I would be cautious of saying that NASCAR is looking for "ultimate performance", as they are still using carbs on their engines, as opposed to something much more performance oriented and "better" like fuel injection!! When Toyota decided to join the good 'ol boys down south, they had to develop an engine with a carb on it specifically for NASCAR as they didn't build carb'd engines anymore anywhere in the world!!! And I am sure it isn't a money issue with these teams. Everyone has their reasons for doing whatever it is, and as you say, it isn't always money.

Very true but NASCAR is using EI on their cars. Just spoke to a friend who is a body hanger for Hindricks Motor Sports to verify. Seeing how these guys build's the cars is something else. My budy came by today to borrow some things for the Corbra he is building and is always taking my tool catalogs to work with him. Kind of funny.

 

[smokyray]

Plug for Jeff Rose/Electroair...

Guys;

Here is a positive plug for my Jeff Rose EI: 1500 hours on my RV4 for the last 10 years so far with outstanding service.
Of note:
1 GPH reduction in FF.
Better starting, smoother engine overall.
No RPM drop on the mag check for the EI.
Squeaky clean plugs, I use automotive Denso L-14U's/Accel automotive plug wires.
Better reliability over the single mag over time.
Cost less than a new Bendix Mag (at the time).

Just do it...

Jeff has sold the business to a guy in MI, can still be found at www.electroair.net.

Bottom Line, I like it! And it's not 30's technology...

Rob Ray

 

[BruceMe]

Guys;
Here is a positive plug for my Jeff Rose EI [snipped]
Rob Ray

I have a Rose system sitting in a box that I'm affraid to install. Complexity and weight have hindered me on it. But reading your endorsement (1gph better efficiency helped a lot) may have just changed my mind on the matter.

-Bruce

 

[Jconard]

Off topic maybe, I would be cautious of saying that NASCAR is looking for "ultimate performance", as they are still using carbs on their engines, as opposed to something much more performance oriented and "better" like fuel injection!!

For max HP in a non turbo charged car, Fuel injection WILL NOT increase HP compared to a properly tuned carb. It can sometimes improve transitional response, and improve longevity by reducing over-rich periods which are necessary in carbed race applications.

Years ago, the Formula Atlantic series went to fuel injection, by mandate, and away from side draught webers. They were actually slightly less powerful, but the engines lasted a bit longer. The longevity of the engines was the selling point to series participants. Personally, I found that to be silly considering that competitive teams went through engines every race weekend or every other weekend.

Formula Car and Race engine tuning has numerous requirements which have nothing to do with airplanes. The main one, is that a driver needs good throttle response and must be able to modulate the power, in an airplane, for all intents and purposes, there is no need for throttle response. I know I will get flamed here, but a slight hesitation in an airplane would be cosidered a deal killer in a race car. This is where the advantage in variable mapped fuel and ignition systems pay off in auto applications, and are where the "technological advances" pay off. Since those same requirements do not obtain in an airplane it is also why fixed timing, carbed aircraft engines perform as well, and often better, than complex systems in power/fuel/weight performance. Add electronic ignition, which can operate well at altitude, and there is NO performance advantage, in an airplane, to the use of "technological advances".

Many people simply have an emotional response, based on the belief that mapped ignition and fuel systems MUST be better than carbs. But, measured by the variables necesary to aircraft use (power/fuel), these "advances" do not advance performance...they only add complexity, and satisfy the emotional need to feel advanced.

At similar speeds, it appears that carbs and fuel injection vary about .5 gph. They are both improved about the same by electronic ignition.

But, even at 1.0 GPH difference, with a Fadec costing as little $4,000, and even with fuel at up to $4/gal, it would take 1,000 hours to make up the difference. But, along the way, one fuel pump replcement $375 vs $35, and one servo rebuild $1,500 vs $200 carb rebuild, and you are out into the future again.

I guess, in the end "advanced" to me would mean a combination of better performance in terms of power/fuel use, decrease parts and systems complexity, and decreased cost.

I understand that values will vary from person to person, but I hope to build a light and simple (hence mathmatically reliable) airplane for minimum cost. My O-320 C/S SB RV-7 with Autopilot will likely cost less than most people's instrument panel.

But the way, the definition of technology is: "the practical application of knowledge especially in a particular area"

Used as a term of art it means that for a given mission, a new devise in not a technological advance unless it advances the performance of the mission. The preference of simplicity (principle of elegance) when added means that technological advance in a particular area should only add necessary complexity, and improve performance enough to justify added complexity.

Probably a rant...Definitely a rant...but every time I see the concept of "technological advance" discussed, I just cannot resist.

 

[Mel]

HERE HERE! Well said.

 

[Mike S]

To add one more thing to Jconards very well written post--------the driving force behind the modern electronic fuel injection we are all familiar with in our cars, is--------------SMOG laws.

The main advantage of the FI is that sensors talk to a computer, and it can adjust for any weirdness going on in the engine, a carb doesn't.

Mike

 

[RV7Factory]

The main advantage of the FI is that sensors talk to a computer, and it can adjust for any weirdness going on in the engine...

Or in the case of FADEC, weirdness in the cockpit.

 

[Captain Avgas]

True, but.....

For max HP in a non turbo charged car, Fuel injection WILL NOT increase HP compared to a properly tuned carb. It can sometimes improve transitional response, and improve longevity by reducing over-rich periods which are necessary in carbed race applications.

True, but FI will allow you to run Lean of Peak and that's where the best Brake Specific Fuel Consumption is to be found. With a carbie the door's pretty much closed.

 

[BOBM]

Not True

---True, but FI will allow you to run Lean of Peak and that's where the best Brake Specific Fuel Consumption is to be found. With a carbie the door's pretty much closed.---

I beg to disagree. If FI were necessary for LOP, then how did Lindberg get to Paris, the P-38 boys fly 1350 miles to get Yamamato, Bill Odum fly the Waikiki Beech Bonanza from Honolulu to Teterboro in 1947, or Max Conrad set all those distance records in little Indians in the 50' & early 60's? Millions of flights had been made LOP over the history of aviation before the term LOP was even invented. They called it "long range cruise" 'cause they had never heard of EGT---& they all had CARBS.

 

[Walter Atkinson]

It comes to mind that with all of the new EI systems out there that someone would ask these guys what their ICP curves look like as the timing map is changed. So far, I am unaware of any of them who have that data--which is critical data where longevity and safety are concerned.

Personally, I would not put ANY ignition system on an airplane without first having seen that data.

YMMV.

Walter

 

[gmcjetpilot]

Electronic Ignition is Dangerous? may be

someone would ask these guys what their ICP curves look like as the timing map is changed. So far, I am unaware of any of them who have that data- Personally, I would not put ANY ignition system on an airplane without first having seen that data. Walter

Good, point. You probably are right they don't have the ICP data. Have you done any test on EI? EI makers don't publish their MAP timing curves because they're proprietary I guess.

I asked questions of at least three EI manufactures and read all their literature. From service it's ironic the only certified EI, LASAR, seems to give operational issues for pilots with the highest CHT's.

In general timing remains fixed at 25 degrees until the power is 75% or less. Than the max advance for all of them is around or approx 40-42 degrees. The Lightspeed Plasma system has a cockpit timing adv display option, so it's not a secret. Any one know what E-mag, LS plasma or other timing curves are?

It would be wounderful to get data like ICP you have available with your test cell. Any chance you'll do testing with differnt small 320/360 Lycs and EI?

WHY is advanced timing is goodness? My understanding is at low power and lean mixtures the flame front slows down. If the ignition stays retarded it's too late. Rich mixtures burn fast so retarded timing is best, but too much advance at high power can cause pre ignition and detonation. Both can cause serious damage as we know.

Walter you are implying there's some danger with timing advance? I agree, but my understanding is like LOP, if the power is low than T-adv is safe within reason. Obviously if timing is totally wacky it can cause backfire, power loss and engine damage. Is 42 degrees max adv not modest? Walter, RV6ejguy, Bob, Jconard what you-all think?

"I know I'll get flamed here, but a slight hesitation in an airplane would be considered a deal killer in a race car. This is where the advantage in variable mapped fuel and ignition systems pay off in auto applications, and are where the "technological advances" pay off <snip> electronic ignition, which can operate well at altitude, there is NO performance advantage. Many people simply have an emotional response, based on the belief that EI / FI MUST be better than mag/carbs."

You're right on, but "Better" needs context. My O-360-A1A, I enjoy a simple fuel system and very good performance. The FI vs. Carb issue is complicated with things like carb ice, aerobatics and possible LOP operations, but my carb is not prone to ice (vfr), I do all the acro I want and I'll give the LOP thing a try.

However with EI, I don't buy the NO performance advantage comment. I plan a dual EI plasma system. With 4-5% or better efficency, smoother operation it's a valid replacement to the venerable magneto. (Data from cafe foundation org report on EI). However all you fly is local down low, the EI advantage is smaller. If you climb to 10,500 ft and cruise mostly, than EI shines. So I partially agree. If you are starting from scratch than at least one EI seems reasonable. If you already have two good magnetos, than staying with them might make more economic sense.

(corrected) I beg to disagree. If FI were necessary for LOP, then how did Lindberg get to Paris, the P-38 boys fly 1350 miles to get Yamamato........ Max Conrad set all those distance records in little Indians in the 50' & early 60's?

Bob you are right, but I would point out not all Carb engines are the same. A big low compression radial is not the same as a small Lyc. Engines are engines, true, but when one jug of a BIG rotating mass engine stumbles a little it's not as noticeable. Also there is less crank rotation till the next one fires. On a little 4 banger when one starts to stumble (uneven power pulse) it gets unpleasant waiting 90 degree crank rotation for another shot.[/U]

 

[Captain Avgas]

Bob you are right, but I would point out not all Carb engines are the same. A big low compression radial is not the same as a small Lyc. Engines are engines, true, but when one jug of a BIG rotating mass engine stumbles a little it's not as noticeable. Also there is less crank rotation till the next one fires. On a little 4 banger when one starts to stumble (uneven power pulse) it gets unpleasant waiting 90 degree crank rotation for another shot.[/U]

George, you attributed a quote to me that I did not make. The Lindberg, P-38 comments were made by BOBM. My argument was that for all practical purposes one probably needs FI to run LOP. Because this is a Vans forum I didn't think I needed to specify that I was referring to Lyclones. As you have rightly pointed out our good friend BOBM is referring to radials. I haven't seen too many radials in RVs lately.

 

[gmcjetpilot]

Oops never mind

George, you attributed a quote to me that I did not make.

Sorry, my mistake, corrected. I concur LOP and FI go together better than Carb's, although as BOBM points out it can be done, which is also a true and fair statement. My point to BOBM was we have to be very spacific when talking about LOP, engine and installation. However BOBM has me encouraged with his LOP success he has with his O320 RV. I think the issue is or where this thread is going related to EI in general and E-mags spacifically:

IS TIMING ADVANCE AND LOP OPERATIONS OK, SAFE?
(since most LOP has been done on engines with fixed timing. Is there a place we can get into trouble?)

 

[Jconard]

George:


The quote you used was edited by you to mean something different than I said. I guess that is what the "<snip>" meant.

The full accurate quote :

"Since those same requirements do not obtain in an airplane it is also why fixed timing, carbed aircraft engines perform as well, and often better, than complex systems in power/fuel/weight performance. Add electronic ignition, which can operate well at altitude, and there is NO performance advantage, in an airplane, to the use of "technological advances".


As you can see, I am comparing aircraft systems to modern mapped engine management systems, and suggest that most of the performance gains promissed by automotive style systems can be gained by EI, meaning that there is no advantage to "advances" by comparision to a carb and EI, or simple FI and EI.

I always like reading your posts, but please do not quote me for propositions I do not make...

The point I was making was an argument for simplicity, and for evaluating the value of complexity based solely on aircraft measurements, which I propose should include power/fuel only, with an overiding bias towaard simple, reliable systems.

 

[gmcjetpilot]

Woo my, simple miss understanding

George:

The quote you used was edited by you to mean something different than I said. I guess that is what the "<snip>" meant.

The full accurate quote :

"Since those same requirements do not obtain in an airplane it is also why fixed timing, carbed aircraft engines perform as well, and often better, than complex systems in power/fuel/weight performance. Add electronic ignition, which can operate well at altitude, and there is NO performance advantage, in an airplane, to the use of "technological advances".

As you can see, I am comparing aircraft systems to modern mapped engine management systems, and suggest that most of the performance gains promised by automotive style systems can be gained by EI, meaning that there is no advantage to "advances" by comparison to a carb and EI, or simple FI and EI.

Wooo no need to get snippy about my <snip>. pun intended. No, I am sorry it was not clear to me and the full paragraph does not help; What does "technological advances" and "modern mapped engine management systems" mean.

Is the E/P-mag not technologically advanced or MAP controlled? This thread was about E/P-mag, and yes I clearly missed your point. To be fair you did start your post talking about NASCAR and Formula Atlantic series car racing, so I should have known. Doho! My fault.

To be honest the paragraph you quote, "there is NO performance advantages", I don't completely agree with, but I guess we can agree to disagree. I do agree the traditional mechanical systems independant of electricity offer an overall advantage but not necessarily raw absolute performance.

Ok so "technological advances" means........ only cars? Sorry I am still confused since I was thinking any EI (e.g., E-mag) is technologically advanced, at least over a magneto which goes back 100 plus years. Also we where not really talking about fuel injection, EFI or FADEC, which got me a little side tracked. However I like a lively discussion and found your EFI management system comments interesting.

Also the term "modern MAP'ed engines" also means an EFI automobile system. I got it. I agree 100 percent with that. However that term might include also aircraft spacific FADEC systems, which turns the Lycoming into a modern MAP'ed engine. Certainly it has performance advantages, but I like to keep it simple. From what you are saying we agree and think the advantage is nil for FADEC. You say no advantage. I don't agree totally, but I like to keep things simple, separate and independant. I know the FADEC guys are smart, but I like the idea of critical systems physically separate and with total system independents. Hard to beat 100% mechanical fuel metering (Carb/Mechanical FI) and self powered magnetos. You can talk about dual batteries and alternators all day, but you can't beat no electricity required. To keep it a little on target, that is the P-mags claim to fame.

Anyway sorry I miss read your quote and that you think I changed the meaning somehow. That's my fault since I did not know what you meant.

Thanks for making it clear. Sounds like you are of the same opinion, EI for a Lyc (E-mag, LS, electro air, LASER) is goodness and DOES have performance advantages. I prefer to keep it to ignitions. If I'm still confused than I guess we agree to disagree, because in my opinion EI does give Perf advantages that also makes overall design goal and economic sense as well.

 

[zav6a]

Ei Map

Jeff Rose publishes their advance and manifold pressure curves and has provision for cockpit readout as well so no secret there.

What appears to be undocumented are ICP curves for various advance/mixture combinations - particularly lean and advanced. Sounds like most of Walters work was done at 25 degrees fixed. The Cafe Foundation EI work clearly indicates advantages of running more advance at low loads and lean mixtures (presumably putting the peak ICP at a more optimal point of crank rotation) so I am not quite as concerned as Walter about running advance without the test stand research. Particularly at load loads. It would be nice to have the data though.

I'm sure GAMI has this sort of info as it integral to how PRISM is to work. Throwing that out there as a challenge for someone connected with that project to lift their skirt.

With the advent of cockpit readouts and cockpit control of timing we can do some really cool things with the old Lycomings. Just need a little more data to stay out of trouble. A mini occilliscope with a pressure versus time trace for each cylinder would be the ticket. Imagine the debate we would get into with that kind of data floating around!

 

[gmcjetpilot]

Good stuff

Jeff Rose publishes their advance and manifold pressure curves and has provision for cockpit readout as well so no secret there.

Thanks do you have a link to Jeff Roses timing curve or copy?

It's interesting the GAMI PRISM system. Did not know. Here's a quote from John Deakin on PRISM in a Avweb article:


There is a most elegant and UNIVERSAL solution to this whole mess, and it's
called PRISM. That stands for "Pressure Reactive Intelligent Spark
Management," and it's running, right now. It looks directly at the combustion
event, and alters the timing of the spark to optimize it.

I wish I owned stock in GAMI, because if they can get this system past FAA
certification, I absolutely believe it will revolutionize the gasoline-powered,
spark-fired, internal combustion engine, whether it's in your lawnmower,
your car, your airplane, or an R-2800 radial.

Snake oil? Pie in the sky? NO. I've SEEN it run. I've run it myself. It works.
More about it in a future column, we're talking about fuels, here.


WOW! John Deakin sounds excited. How does it work. They mention CDI ignition, and that is not new. They also mention Automatic detection/prevention of detonation! hummmm How do you do that? Is there combustion pressure sensors! WOW! That sounds expensive.



Here is the link to above full text and a link to GAMI's PRISM brochure:
http://www.avweb.com/news/columns/182149-1.html
http://www.gami.com/prism.html

May be Walter, another disinterested third party like John Deakin, can tell us how it, PRISM, works. Sounds like from the text it's a CDI ignition. I wounder how they're going to "revolutionize" all gas combustion engines including my lawn mower? YEA! that's the ticket, I want electronic ignition on my lawn mower. Darn I pay someone to do it. Shoot.

I wounder what GAMI will charge for this electronic ignition? I suspect if they get it certified the Bonanza driving Doctors will pay a pretty penny. May be Walter can give us a scoop on how it works. With LASAR, E-mag, Plasma, Electroair and Aerospark, this would make the 6th EI system to choose from, if they ever market it. Cool. To be honest if they are going to charge GAMI prices the experimental market will not bite. I am like you zav6a, I am not concerned about modest timing advance at lower power, but I could be wrong. May be Walter has some insight to our folly.

 

[zav6a]

Curves

George

Jeff Rose (Electroair) curves are a down a page or two on this link.

http://www.electroair.net/technical.html

There is a dial on the unit to set maximum advance with RPM. Not cockpit contolled.

I understand that PRISM does in fact involve pressure sensors (integral to the spark plugs, there is no other easy access to the combustion chamber). A computer watches the pressure and where the peak pressure is occuring and adjusts the timing one way or another to optimize the combustion event relative to crank angularity, and retards it in the event that detonation is occuring.

It would be neat, particularly to adjust for varying fuel (spelled auto) but we have a tendency to reject computers doing the work for us. Witness manual mixture adjustment when auto-compsenation is surely within our capabilities. Probably not a lot more to gain from an economy standpoint relative to a timing optimized, high energy EI spark but could prevent some of those turbocharged Bonanzas with ham fisted pilots from melting down!

Closer to the post, any info from anyone on spark duration on some of the EI sytems? I know Electroair has relatively long duration, I think something like 20 degrees of crank rotation at typical plug gaps. This is good for hard to ignite mixtures at either end of the lean/rich spectrum. I have experience with CDI systems that have very high energy but a short duration. Where is E-Mag/P-Mag on this spec?

 

[zav6a]

Ei

By the way, I looked under the hood of my 5 hp Briggs and Stratton lawn mower and it already has electronic ignition!

 

[gmcjetpilot]

ahaaa yes

Thanks for the electroair info. interesting and very logical.

Here are the plug type pressure sensors you might be talking about (bottom right).
http://www.tfxengine.com/SensorsOverall.html
They all look like automotive style over the top electrode.

On a related note Textron Lyc is not making cylinders with 14 mm threads for auto type plugs. http://www.lightspeedengineering.com/News/News.htm

Pressure sensors look expensive for a Briggs and Stratton,

PS: True CDI ignition duration is shorter than inductive ignition sparks like the electroair or E/P-mag. However the Lightspeed CDI Plasma III is a multi spark discharge, and I believe it has comparable duration to electoair. The E/P-mag I don't know about simply because of the size of their coils, which no doubt make a slight compromise to performance for their smaller physical size. The real benefit to CDI of course is the ability to fire at very high RPM's. Induction ignitions die at high RPM's because they don't have time to "recharge". We run low RPM equivalent to less than 5,500 RPM (2,700 x 2 wasted spark fires twice as often); that's in the upper usable range for induction ignition. Much above 6,000 RPM induction ignitions starts to lose performance, where a CDI can handle extremely high RPMs, therefore it's better suited for high revving engines. The Plasma II and III are the only CDI ignitions on the market I know of. The Plasma III is a multi spark discharge unit, which overcomes the shorter duration spark. The reason for the price jump on multi spark discharge is the large capacitor's, which are not cheap.

Spark intensity is NOT an issue with any of these EI units, which all make a magneto spark look like a match compared to a gas acetylene torch.

 

[Walter Atkinson]

George:

We do have a lot of data on timing changes and ICP effects. It is rather impressive how a very small advance can have very negative effects when ROP--even at 75% power.

ROP mixtures burn fastest at about 40dF ROP and are slower at full rich by a significant degree, the timing needs to be changed ROP as well. Advancing from the mag timing is seldom the answer at high powers, ROP. I have that data from real-time running Lycoming engines on this.

I would have to dig out the data on the average high power LOP advance that is common to hold the thetaPP of 16 dATDC. I have it and can dig it out later. Here's the question. How does the timing map know whether you are ROP or LOP? It makes a world of difference.

PRISM works by using pressure sensors to measure the ICP and ThetaPP in real time, then adjusts the timing on the fly for whatever combination of MP/RPM and mixture is being used. There is no map. It is real-time, measured data on the salient issue. Nothing has to be calculated or assumed. It samples 50,000 times per second. As of now, the pressure sensors are mounted in the spark plugs. Later, we expect a major cylinder maker to provide cylinders with special bosses for the pressure transducers. It is elegant, has a fail-safe system that is three layers and turns into a smart mag if everything fails. We have tried to force a Lycoming TIO-540J2BD to detonate and in about five years have failed miserably in the attempt as long as PRISM is active. It will not allow the engine to detonate. Period.

Walter

 

[jim]

Prism

Hi Walter,

So, how much do you think PRISM will cost, and is it going to be available for 4 cyl lycomings and / or clones? When will it be in production? Any necessary mods to the engines using it?

Thanks,

 

[zav6a]

Rop Ei

I wonder if my experience of smoother operation LOP is in part due to bad thetaPP ROP due to (over)advance on the EI at low load.

Guess I had better order the cockpit timing control module.

Or, I'll be happy to beta test a PRISM.

Duane Zavadil
IO-320 6A

 

[Walter Atkinson]

Duane:

**I wonder if my experience of smoother operation LOP is in part due to bad thetaPP ROP due to (over)advance on the EI at low load.**


I have no idea without putting instrumentation on it, but it's not an unlikely scenario.

Walter

 

[dserratt]

Whats the talk about Mags

First of all I would like to point out that the term proven technology doesn?t mean much today as technology advancements are made on yesterdays proven technology. For instance generators were proven technology for decades yet I don?t see anyone arguing that alternators are unnecessary new fangled contraptions fuel injection further complicated aircraft engines yet they seem to have improved on the carburetor as the alternator did on the generator.
So let?s talk about the reliable Magneto versus the unproven electronic ignition.
The magneto operates by passing a coil through a magnetic field which causes current to flow through the points and in to the coil causing a separate magnetic field when the points open the magnetic field in the ignition coil collapses causing a spark to jump the gap in the spark plug. Since the spark is weak the gap has to be small .018. Also new points operate at a certain performance level but continuously degrade as they operate until they either fail or are replaced. so who wouldnt want the put magnetos on a new car? The only reasons i can think of are the maintenance, hard starting, poor fuel economy, reliability and cost.
Now lets talk about multi spark systems, these systems compensate for the low energy sparks ability to reliability ignite the fuel air mixture and only operate at low RPM?s usually about 1000 or 1500. These systems used to be popular in race applications because the more fuel and air you can burn the more power you make but this rich mixture is also harder to ignite this concept isn?t used so much anymore as high energy and more precise ignitions work better.
Now lets talk about the long duration spark, this seems at first glance to be fairly sound concept but if we look deeper we can see it?s not and here?s why.
We will take an O-360 which is a common engine it has a stroke of 4.35 inches so for one full of the crank that is 8.7 inches for the full up and down stroke. So if we take say 2250 RPM?s for instance we multiply 8.7 * 2250 we get 19575 ipm or / 60 seconds we get 326.25 ips. Also if we take 2250 RPM?s times 360deg we get 81000 deg per minute or / 60 sec we get 13500 deg per second /1000 will give us deg per mili sec = 13.5, so we can see even at relatively low RPM?s a few 1,000ths of a second can throw your timing off but I keep hearing that a few millisecond spark duration would be really good so lets do the math 13500 deg per second / 1000 gives us 13.5 deg per millisecond so that?s 40.5 deg of spark duration. So now we have to ask how consistent is our spark timing and after the low energy spark starts how long does it take for the fuel to begin to ignite and how long does it take to finish burning because if it is still burning after the effective power stroke it?s wasted energy.
Now lets look at electronic ignition which produces a high energy spark which uses a larger gap and causes the fuel air to ignite more precisely and burn more completely also compensating for engine speed and load to control ignition timing making more useable power and using less fuel because of a more efficient use of the combustion process
Now lets look at reliability, these systems are used on tens of millions of cars and trucks and tens of thousands of military vehicles.
These are only my opinions based on years of experience with E/I and years of experience with engines using points and magneto configurations.

 

[David-aviator]

Well, I deserve that after breathing acetone and epoxy fumes most of the day...

Adam, be careful of what you breath.

I built 2 plastic airplanes and my thyroid gland went ape.

It became so enlarged it had to be removed over a concern of cancer, of which there was none. Been on levoxyl ever since, about 8 years now. Three doctors did not know what caused it. I believe it was epoxy fumes, as another builder in California said it happened to him also, same symptoms, same conclusion.

dd

Enjoying his thread very much. EMAG/PMAG is an education for sure. Flew with Jeff Russell's system for several years and it worked fine but did bust a starter ring once when it misfired on start, probably caused by a voltage drop when the starter was engaged. If starter was engaged and then ignition turned on, it did not happen again. That system had a map that simply varied timing with MP.

 

[Steve Sampson]

e-mag / p-mag wiring diag

Anyone know where I can find e-mag's suggested wiring diagram. I had a good poke around their web site but could not find it. I am sure it was there in the past.

Thanks.

 

[N941WR]

Steve,

The AeroElectric book has a great diagram on how to wire them up.

Only one question, the book spec's 20 AWG wire and the Pmag guide calls for 18 AWG. Dummy me wired it with 20 and now I'm wondering if I should pull it all out use 18.

Anyone out there have a suggestion?

 

[MCA]

Steve,

The AeroElectric book has a great diagram on how to wire them up.

Only one question, the book spec's 20 AWG wire and the Pmag guide calls for 18 AWG. Dummy me wired it with 20 and now I'm wondering if I should pull it all out use 18.

Anyone out there have a suggestion?

I talked with Brad at e-mag the other day. He said they used to spec 20 and now spec 18 gauge wire. Bob must have based his diagram off the older manual.

Marc

 

[RV7AV8R]

Advance sellection on P-mag

The p-mag affers a choice for max advance of 34 degrees and I think the other choice is 39 degrees. I am using 34 now and wonder if anyone has experience with using the higher advance option? I have an 0-360.
John Adams