Oscar Avalle Posted October 11, 2014 Report Posted October 11, 2014 Ryoder posted this but somehow it got lost: Anyone have experience with an electroair ignition in a O360? I really like the concept of a modern ignition system and the lack of 500 hour inspections, wearable parts etc but the smoothness and efficiency are my biggest draws to the system. I hope that the system will allow me to fly even more economically than I do now when at 1800 RPM in super economy cruise. Yeah I know people hate it when I fly my Mooney that way. I want to keep doing it and get even better performance and economy. How about installation? Is it a big job or relatively straightforward like a mag replacement? Quote
Oscar Avalle Posted October 11, 2014 Author Report Posted October 11, 2014 I don't have an electroair installed but I did install several years ago a LASAR ignition system on my O-360 of my M20C. I have flown it for more than 10 years. and I like it. Pros: The plane starts without a problem It works like a car ignition. You turn the key and the engine starts. Reliability and back up: It is very reassuring to have a triple back up (two magnetos and LASAR). Fuel efficiency: Marginal Power: at higher altitude (>5000 feet) the engine runs smoother. Cons: CHT: The system advance the timing of the ignition. That translates into higher CHTs which in my Mooney are already on the high side.... I don't know if the electroair works on the same basis, but I at least you get a fast review of a similar system. 1 Quote
philiplane Posted October 12, 2014 Report Posted October 12, 2014 I have a copy of an engine emissions test report that NASA performed for the EPA in 1976.(report TM X-73500) They studied a 160 HP Lycoming engine extensively to see what effects humidity, air temperature, fuel mixture, and ignition timing had on emissions. A by product of the study was a 206 page volume of fuel consumption and horsepower statistics. While the focus was on emissions, they gathered extensive data on BSFC and HP under a wide range of conditions. Interestingly, while there are performance losses when timing is retarded from spec, there are little or no gains when advancing the timing beyond spec. They basically confirmed that 25 BTDC was ideal for that engine. Advancing the timing to 30 BTDC had virtually no benefit. Retarding the timing to 20 degrees cut HP from 157, down to 148. Advancing it to 30 degrees only raised it from 156, to 157. The main thing to take from this, is that keeping ignition timing precisely at the specification is more important that most people realize. That means maintaining the ignition system with a focus on the timing event inside the magneto, and from the magneto to the engine. Internal timing is important to achieve the dwell time needed for coil saturation and optimum spark output. Optimum spark is both high voltage and long duration. External timing puts the spark to the plug at the correct moment. Most mechanics do not understand the difference in these two events. It's poor maintenance that causes poor performance, not necessarily the fact that the magnetos have a fixed timing event or are 1930's tractor technology. I suspect that the majority of magneto-equipped engines with more than 500 hours on them have incorrect timing. Even when the external timing is set correctly, the internal timing can be off several degrees, resulting in loss of performance. Combine this with poor quality spark plugs like Champion massive electrode plugs, and you can be losing 10-15 HP. Add in carburetor heat leaks, poor cylinder baffling, and fuel system discrepancies, and you create a real dog. Controlling the engine fuel mixture and timing with a closed-loop electronic control system is the way to achieve the best performance. We're probably farther from that goal than ever, since the Aerosance FADEC seems to have gone nowhere since 1998. This system uses two different timing curves and adds them based on conditions. An RPM curve, with a max of 26.5 degrees at 2700 RPM.. And a vacuum curve, with a maximum of 18.5 degrees at 16" MP. They are added together, but there are no conditions under which you could get all 45 degrees of advance. Under typical conditions you may get 28 total. You would have to be at 16"MP and 2700 RPM to get all available advance. It drops off steeply after that. If you apply the EIS timing curve to a typical Lycoming performance cruise power setting of 24" MP and 2400 RPM, you get ZERO vacuum advance, and only 24 degrees BTDC because you have yet to hit 2500 RPM, where the RPM advance curve equals the OEM timing setting of 25 BTDC. To get any benefit from the vacuum advance curve, you have to be below 75 percent power. It appears that settings of 55 to 65 percent power will allow total advance to equal or exceed the OEM setting of 25 BTDC. At 22"MP and 2300 RPM, you get 23 BTDC rpm advance plus 4.5D for a total of 27.5 BTDC timing. If you go to 23/2300, you get 24+2.25 for 26.25 BTDC total timing. Some Comamche 250/260 pilots use 22"MP/2100 RPM cruise setting, giving 22 degrees RPM + 4.5 vacuum advance for 26.5 total timing. And don't forget as currently configured, this system gives ZERO vacuum advance above 24"MP. So it is useless on a turbo. The highest amount of advance will occur under high RPM and low MP conditions. For example, at 10,000 feet you might have 20" MP and 2500 RPM. Under these conditions you will get 34 BTDC total timing. This is where you should see the maximum benefit. Low MP high RPM cruise flight above 8000 feet. The least amount of advance, sometimes LESS than OEM, will occur during high MP conditions such as takeoff and climb. This is according to the Electroair charts: http://www.aircraftspruce.com/catalog/eppages/electroair.php It will be interesting to see how Electroair fares compared to the LASAR system that failed in the market place. Maintenance was part of that, because parts were ridiculously expensive and sometimes unobtainable. Buried in the Electroair STC Instructions for Continued Airworthiness: Every 1000 hours or 5 years, replace the ignition harness. It can't be deferred because as an STC ICA it is an Airworthiness Limitation. Any idea what that will cost? They could set the price at $1000 and you could choose to buy it, or ground the plane. This system uses two different timing curves and adds them based on conditions. An RPM curve, with a max of 26.5 degrees at 2700 RPM.. And a vacuum curve, with a maximum of 18.5 degrees at 16" MP. They are added together, but there are no conditions under which you could get all 45 degrees of advance. Under typical conditions you may get 28 total. You would have to be at 16"MP and 2700 RPM to get all available advance. It drops off steeply after that. If you apply the EIS timing curve to a typical Lycoming performance cruise power setting of 24" MP and 2400 RPM, you get ZERO vacuum advance, and only 24 degrees BTDC because you have yet to hit 2500 RPM, where the RPM advance curve equals the OEM timing setting of 25 BTDC. To get any benefit from the vacuum advance curve, you have to be below 75 percent power. It appears that settings of 55 to 65 percent power will allow total advance to equal or exceed the OEM setting of 25 BTDC. At 22"MP and 2300 RPM, you get 23 BTDC rpm advance plus 4.5D for a total of 27.5 BTDC timing. If you go to 23/2300, you get 24+2.25 for 26.25 BTDC total timing. Some Comamche 250/260 pilots use 22"MP/2100 RPM cruise setting, giving 22 degrees RPM + 4.5 vacuum advance for 26.5 total timing. That's a whopping 1.5 degrees advance, which NASA says gives you a .0064% HP increase. If you go over square, you lose the vacuum advance and are back to 24 BTDC, so you LOSE a degree of timing. Oversquare settings like 24/2300 and 23/2200 are known to produce good performance, long top cylinder life, and lower vibration. Using them essentially cancels the vacuum portion of the EIS timing advance, and with good reason but without thinking this all the way through. As cylinder BMEP rises under high MP and lower RPM combinations, the chance of detonation increases. The simplest way to avoid this is to retard timing under those specific conditions, or to find the happy medium under all conditions. That happy medium is the OEM advance setting. But this system appears to retard the timing below the OEM setting in many cases, unnecessarily. This might be beneficial to high compression or turbo engines that need more detonation margin or want the ability to operate on lower octane fuel. But typical Lycomings only need 91 octane and so the detonation margin with 100LL is huge. And don't forget as currently configured, this system gives ZERO vacuum advance above 24"MP. So it is useless on a turbo. The highest amount of advance will occur under high RPM and low MP conditions. For example, at 10,000 feet you might have 20" MP and 2500 RPM. Under these conditions you will get 34 BTDC total timing. This is where you should see the maximum benefit. Low MP high RPM cruise flight above 8000 feet. The least amount of advance, sometimes LESS than OEM, will occur during high MP conditions such as takeoff and climb. This is according to the Electroair charts: http://www.aircraftspruce.com/catalog/eppages/electroair.php The numbers I have seen posted don't appear to be any better than book performance numbers for a new plane. It appears that most of these retrofits are on 30-50 year old planes that were driven by upcoming repairs or dissatisfaction with constantly throwing money at old problems. So we may simply be seeing "performance improvements" that would come from stock new replacement parts, installed by competent mechanics. For example, I flew a completely stock B model Twin Comanche for years that would true at 170 KTAS at 9000 feet on 15.4 GPH. No speed mods whatsoever, and actually had poor paint and some other drag inducing items costing a few knots I'm certain. But good engine maintenance made it efficient in spite of the aerodynamic challenges. I'll wait to see how this evolves before jumping in. A better timing curve is needed IMHO. At the moment I see no benefit for the substantial outlay on my twin, or for my customers. NOTE: In the EA info pages is a note about cylinder Peak Pressure occurring at 11 degrees ATDC. I'm not sure if this is an error or intentional, but all data I have seen indicates optimum PP occurs in a band from 14 to 18 degrees ATDC and it is linked to ignition timing. If PP occurs too soon the engine will be prone to detonation. If too late, it runs hot and loses power. Since converting several engines back to Bendix magnetos with Tempest fine wire plugs, I have had zero lead fouling issues in the lower plugs on O-235, O-320, and O-360 Lycomings that formerly had miserable fouling issues. And with no operational changes. This was after directing the pilots to use Lycoming's recommended shut down procedure. Which is 1000-1100 RPM for one minute, leaned, and then pull the mixture to cut off. That helped a lot but the whole problem was in the crappy Champion spark plugs and Slick magnetos all along. I'm sure the EI will be an improvement in the same manner, but with less maintenance. So if you don't have the $$$ for EI, follow the Lycoming shut down procedure, ditch your Champion plugs, and pay close attention to your magneto's maintenance requirements. So to recap, the best benefits of the EI system are found above 10,000 feet at high rpm (higher than most pilots normally use, such as 2500-2700 rpm), and low manifold pressure. Sort of like trying to coast in first gear... 2 Quote
Piloto Posted October 12, 2014 Report Posted October 12, 2014 Electronic ignition systems on cars has made significant improvements on efficiency and maintenance. But I have yet to see a car doing 20 mpg at 170 mph like my M20J does. Unlike car engines that operate at a wide range of RPM aircraft engines operate at a constant speed in a very narrow range of RPM. There is no practical advantage in changing the ignition timing. You are better off getting a set of fine wire plugs that will last you over 300,000 miles and maybe a set of Gami injectors. In fact the Porsche Mooney employed dual electronic ignition and was never as efficient as the Lycoming engine. José Quote
N201MKTurbo Posted October 12, 2014 Report Posted October 12, 2014 I wish they had the dual mag replacement STC'd. I'd buy it tomorrow. 1 Quote
ryoder Posted October 12, 2014 Report Posted October 12, 2014 Philip where did you get your timing curve info? I'd like to see the timing values as a column in the cruise perf table to see if there is any advance on any of the POH recommended power settings. Very helpful info. I want a true fadec engine some day and I get it that the electroair might not be that at this point in time. I'll probably end up with overhauled mags and fine wires and call it a day. Quote
philiplane Posted October 12, 2014 Report Posted October 12, 2014 The timing curve link is in the post, it is direct from the manufacturer. Quote
carusoam Posted October 12, 2014 Report Posted October 12, 2014 There is extensive discussion for the M20J timing. 20 and 25 dBTDC are available to some, not all. You can find some interesting details of real Mooney experience. Byron is one of the key authors on the topic. Best regards, -a- Quote
Andy95W Posted October 18, 2014 Report Posted October 18, 2014 The October issue of The Aviation Consumer has a review of the Electroair system. They had almost nothing bad to say of the system, and owners they spoke with were very happy with it. They estimated it would pay for itself in about 700 hours. The only negative they mentioned is that it wasn't as effective at lower altitudes. At a Mooney's normal cruise altitude of 7-10k, and above, it is supposed to save about 1.5 gph. Imagine what it would do coupled with a PowerFlow exhaust. Now I just need to convince the wife of the benefit... Quote
ryoder Posted October 19, 2014 Report Posted October 19, 2014 I guess I should subscribe to aviation consumer. Quote
Oscar Avalle Posted October 21, 2014 Author Report Posted October 21, 2014 On 10/18/2014 at 10:39 PM, N1395W said: The October issue of The Aviation Consumer has a review of the Electroair system. They had almost nothing bad to say of the system, and owners they spoke with were very happy with it. They estimated it would pay for itself in about 700 hours. The only negative they mentioned is that it wasn't as effective at lower altitudes. At a Mooney's normal cruise altitude of 7-10k, and above, it is supposed to save about 1.5 gph. Imagine what it would do coupled with a PowerFlow exhaust. Now I just need to convince the wife of the benefit... I will try the combination in November with the LASAR ignition and report back... Quote
aviatoreb Posted October 21, 2014 Report Posted October 21, 2014 Whatever happened to gami prism? Quote
chrisk Posted October 23, 2014 Report Posted October 23, 2014 I flew a "F" model with the ElectroAir ignition this weekend. I can't say much about the performance, but the electronic ignition was noticeable on the run up. Switching to the electronic system alone had no RPM drop, but it would give a brief back fire when switched. The right mag would produce a normal drop. My friend tells me it will let the engine run as low as 300 RPM and it is easier to start. I wish I could give a better report, but I didn't get to fly the plane much before it had a mechanical with the prop (not ignition related, but engine overhaul related). Quote
ryoder Posted October 23, 2014 Report Posted October 23, 2014 Thanks for the info on the runup. I like the sound of a zero mag drop. Quote
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