This was well known in the industry 20 years ago. Electromotive never really fixed the problem with frequent crank sensor failures. Does anyone know if Electroair is using something different now?
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Van's Air Force
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P-Mag, Electro-Air, or EFII
- Thread starter RV8Squaz
- Start date
This was well known in the industry 20 years ago. Electromotive never really fixed the problem with frequent crank sensor failures. Does anyone know if Electroair is using something different now?
FasGlas
Well Known Member
The problem was not the sensor but the wire at the sensor potting. If they weren't stable the wire would vibrate until it broke internally. These were very early units. They did change to the heftier 1/2" sensor but, in the case with any wire left loose to vibrate, they would be susceptible to internal breakage. I have heard of the very early sensors failing but I've never seen either one fail. I used one for 10 years without a problem, still have it. I did just have an EGT probe fail for that exact reason, internal wires broke at the potting.
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I was a single mag, single Pmag flyer, until a fateful VFR flight this March.
About 30 miles from my home field I looked down to see my fuel gauges bouncing from full to empty, quite odd. A quick scan showed >16v on my voltmeter! Holy cow, alternator-off. Volts go to 11.5. Hmmm, I thought scratching my head. Guess I'll turn all the loads off and see if anything changes. So I killed everything electrical, turned the Alt back on (probably not the best idea in retrospect), and it went right back to >16v. Off again. 11.5v again. I thought at this point I better call approach and tell them I won't be talking anymore or squawking as I flew around/under the class C to my uncontrolled field. The second I keyed the mic all I heard was static and the volts dropped to <8v.
I made an uneventful landing (with both ignitions) and taxid in to the hanger. Bad auto voltage regulator was the problem, replaced it with an OV protected one (B&C). Battery had blown it's top and a 35v rated capacitor in my tach had blown, so I'm guessing the volts were north of that.
What would have happened with a full distributed electronic ignition? I know you'd hopefully have had OV protection that worked, but just like anything those fail too.
I now fly dual Pmags.
Jon
About 30 miles from my home field I looked down to see my fuel gauges bouncing from full to empty, quite odd. A quick scan showed >16v on my voltmeter! Holy cow, alternator-off. Volts go to 11.5. Hmmm, I thought scratching my head. Guess I'll turn all the loads off and see if anything changes. So I killed everything electrical, turned the Alt back on (probably not the best idea in retrospect), and it went right back to >16v. Off again. 11.5v again. I thought at this point I better call approach and tell them I won't be talking anymore or squawking as I flew around/under the class C to my uncontrolled field. The second I keyed the mic all I heard was static and the volts dropped to <8v.
I made an uneventful landing (with both ignitions) and taxid in to the hanger. Bad auto voltage regulator was the problem, replaced it with an OV protected one (B&C). Battery had blown it's top and a 35v rated capacitor in my tach had blown, so I'm guessing the volts were north of that.
What would have happened with a full distributed electronic ignition? I know you'd hopefully have had OV protection that worked, but just like anything those fail too.
I now fly dual Pmags.
Jon
Tomcat RV4
Well Known Member
My RV4 /subaru starts the second I touch key. I am super impressed with SDS, ROSS, as I am glad I had done enough research to make this decision !
rmartingt
Well Known Member
Those can fail, but so can regular mags (or anything else). The question is, which is less likely to fail? Plus, if you're running an electrically-dependent engine, you should make sure that a single failure like that can't take down the entire system. A backup alternator or isolated standby battery would meet that.
We can sit here all day long and cherry-pick scenarios where our chosen system would continue to function while certain other ones wouldn't. But doing so is false comfort, especially if you are ignoring the weaknesses in your own favorite system.
Toobuilder
Well Known Member
The example you cite is one of an inadequate aircraft electrical system design, not the failing of any particular ignition system. My Taylorcraft has no generator or battery, but the days of aircraft electrical systems being "optional" are long gone.
Yes, blowing the top off a battery is probably going to take the airplane down if that is your only source of power for the ignition, but how often does that really happen if the electrical system is properly designed? And forget the ignition aspect for a moment- blowing the top on a battery in an airplane is a serious safety event in itself. Should we be worried about batteries now?
As our airplanes become more complex, we need to pay attention to the entire thing as a system, rather than a collection of parts plugged in here and there. Make sure you understand the requirements, and then design a system that satisfies those requirements.
GalinHdz
Well Known Member
RV8Squaz
Well Known Member
Scott,
Thank you! Your posts had everything to with me getting off my duff and putting a timing light on it. I'm hoping I will have the same results you did and get the temps back down to where they've been for the last nine years/1100 hours.
The thing that made my situation particularly confusing was that I was breaking in a freshly overhauled engine (I had a cracked case and put four new cylinders on). So at first I watched my temps come down and then, I'm guessing, at the 10-20 hour point the temps came up like yours. I've been seeing 425 in the climb and 390-400 in cruise even at very rich settings. I'm looking forward to seeing my old temps.
I looked at the different options and like you, I decided to stick with the LSE Plasma. I had a nice conversation with Klaus and I decided it was going to be the quickest, least expensive, least complicated way to get back in the air.
Thanks to all of you for your input!
Very good. Your circumstance is particularly difficult with the new cylinders. Just don't stop looking at them. Those high temps certainly included detonation at each takeoff and high power condition (cylinder break-in). There is no "fixing" the lasting effects of hard detonation. I know for a fact that my cylinders are "feeling the burn" from our event and I'm going to be on the lookout for deeper damage.
I don't know that we can ever relax after having run around with 43 deg advance.
Raymo
Well Known Member
Pros and Cons
I plan initially to use a Slick mag on the left and Pmag on the right, as many have done. Then add the second Pmag down the road, which most say does not have as much bang for the buck.
I am now considering a left side SDS CPI to gain more options for variable timing, vs the second Pmag.
Anyone else running this setup? Seems like it would protect against a full electrical system failure.
I plan initially to use a Slick mag on the left and Pmag on the right, as many have done. Then add the second Pmag down the road, which most say does not have as much bang for the buck.
I am now considering a left side SDS CPI to gain more options for variable timing, vs the second Pmag.
Anyone else running this setup? Seems like it would protect against a full electrical system failure.
Toobuilder
Well Known Member
If you are going to run a mixture of ignitions, I'd suggest you keep the Slick and add the CPI. The single EI advance curve is different than a dual EI curve, and I think that having a Pmag in the mix is really going to complicate matters. At least the Slick will be locked out and you can work around that easily with the CPI programming.
Micheal;
I don't see a problem with Ray's CPI-Pmag proposal.
The Pmag has an established timing and manifold pressure curve, that has been mapped and posted here on the forum. It is a known 'quantity' and better than a fixed mag 'in my experience'.
I have one Pmag and one Bendix mag on my RV-8 and my T-18.
I would consider it to be an upgrade (worth doing!) to add a CPI or a home brew + Mega Jolt in place of the magneto.
I don't see a problem with Ray's CPI-Pmag proposal.
The Pmag has an established timing and manifold pressure curve, that has been mapped and posted here on the forum. It is a known 'quantity' and better than a fixed mag 'in my experience'.
I have one Pmag and one Bendix mag on my RV-8 and my T-18.
I would consider it to be an upgrade (worth doing!) to add a CPI or a home brew + Mega Jolt in place of the magneto.
Toobuilder
Well Known Member
As long as the entirety of the P-mag curve is less aggressive than the desired curve, then yes, the CPI can be used to fine tune the system. You can always add advance to a dual system, but its tough to take it out. At the very minimum I'd want to make sure the jumper is in on the P-mag, forcing the lower curve. I'd also look at setting the advance on the CPI to retard a few degrees at takeoff power. Even though I think the P-mag delivers timing near the data plate value at high MP and RPM, setting the CPI to lag behind a few degrees will drive the total effective timing later, giving more detonation margin without any real detriment to power.
I think that the PMag is a very capable alternative to a magneto, and I would totally run one alongside a more programmable (Pmags are somewhat programmable) ignition. Or run two at the same time, which is what I do now. It's such a beautiful thing to set timing on them, they both get set at simultaneously! It's pretty neat.
RV8Squaz
Well Known Member
**** IGNITION UPDATE ****
Per my earlier post, I had decided to stick with the LSE Plasma III and so far, I'm glad I did. I had two very nice conversations with Klaus. I sent the unit via Priority Mail and he turned it in less than 24 hours. I should get it back by Saturday. Pretty darn good service.
The module had a blown capacitor. In addition to the repair he updated the box to allow it to perform at lower voltages and more efficiently with less current draw. My unit was over 10 years old with 1100+ hours. He did the job for $275; a bargain when you compare it to the other options I was looking at!
I borescoped the engine and was relieved to find out I didn't have any damage. It looked like what a 50 hour engine should look like. I was a bit concerned since I was breaking in my engine and purposefully flying it at high power settings, full throttle/RPM to cruise and then 75% power, keeping power in during descents. I think the thing that saved my bacon is that I maintained very rich settings during the break in and due to having a good engine monitor (VM1000C), I was able to notice high temps immediately and take quick action to cool the engine.
I used a ViVidia AbleScope VA-400 previously mentioned in another thread. I am very satisfied with the results. Here's a pic I took of my #1 cylinder:
Thanks again to Scott Card for first posting his findings. I sent you a PM. And thanks to all for your comments about the different ignition systems. I'll let you know the final results once I get it flying again. I'm hoping to see a significant drop in my temps.
Per my earlier post, I had decided to stick with the LSE Plasma III and so far, I'm glad I did. I had two very nice conversations with Klaus. I sent the unit via Priority Mail and he turned it in less than 24 hours. I should get it back by Saturday. Pretty darn good service.
The module had a blown capacitor. In addition to the repair he updated the box to allow it to perform at lower voltages and more efficiently with less current draw. My unit was over 10 years old with 1100+ hours. He did the job for $275; a bargain when you compare it to the other options I was looking at!
I borescoped the engine and was relieved to find out I didn't have any damage. It looked like what a 50 hour engine should look like. I was a bit concerned since I was breaking in my engine and purposefully flying it at high power settings, full throttle/RPM to cruise and then 75% power, keeping power in during descents. I think the thing that saved my bacon is that I maintained very rich settings during the break in and due to having a good engine monitor (VM1000C), I was able to notice high temps immediately and take quick action to cool the engine.
I used a ViVidia AbleScope VA-400 previously mentioned in another thread. I am very satisfied with the results. Here's a pic I took of my #1 cylinder:
Thanks again to Scott Card for first posting his findings. I sent you a PM. And thanks to all for your comments about the different ignition systems. I'll let you know the final results once I get it flying again. I'm hoping to see a significant drop in my temps.
