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And the e-mags single plug firing is still better than 2 conventional mags firing 2 plugs? It's too bad they cost what they do. They would never pay for themselves verses conventional mags. |
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This system is the most tested electronic ignition in the industry. I suspect the ignition curve is proprietary, and that the previously illustrated curve is out of date (it was published with the initial announcement, before development was complete). It will run for hours on just your battery, and a back up battery is being developed. I run dual SIM's on my RV6 with IO360, CS prop, and Gami's. Starts better, runs smoother, and LOP at cruise is as smooth as reducing the throttle. |
BTW, I think Surefly having a COVID sale. 15% off, last I checked. April2020
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The initial inflammation and subsequent flame spread requires time. For illustration, let's ignore spark rise time and the relatively slow growth of the initial flame kernel, the zero to 10% mass fraction burned period in the textbooks. Start at the 10% burned point and consider only the travel speed of the subsequent flame front, somewhere around 25 m/sec (i.e. 985 inches per sec), for an engine like the parallel valve Lycoming. Bore is 5.25", with the plugs roughly 3.5", maybe 4" apart. 2700 RPM is 0.00006 seconds per degree of rotation, thus a 13 degree difference in timing (i.e 38 BTDC for the EI and 25 for the mag) means the mag would lag 0.00078 seconds behind the EI. 985" x 0.00078 seconds = 0.7683". The EI's 13 degree head start moved the flame front less than an inch across the chamber...not yet to the other plug. So goes theory; an experiment is required to prove or disprove. Fly a fixed pitch RV with magneto and EI at some altitude which significantly advances the EI. Ground the magneto. Is there an RPM drop? If so, the magneto was contributing to the combustion process. Reports welcome. |
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Mag/mag, mag/EI, and EI/EI combinations all spark simultaneously at high power. At high power, if one is too far advanced, one or more cylinders may tip into detonation. If one is grossly retarded, the engine may not make rated power. All the advanced timing stuff happens at low power. |
It's Getting Clearer
Thanks everyone for this discussion. I read every post I encounter about electronic ignition closely. The EI, magneto, spark advance, MP relationship makes sense to me now.
I love some VAF. :D |
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The nomenclature used had me confused. They should call their system "Advanced Retarded Timing". OK, maybe not..:D |
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If it is said that the system is providing "advanced timing" with lower power, one would read that to mean it advances the timing, when apparently it's doing exactly the opposite of that. |
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