mike.smith wrote:The point is simply that everything has a failure mode. Nothing is perfect. There are tradeoffs for everything. Just because something can fail does not automatically make it a liability. For anything mechanical, having a backup is the wisest choice of all.
This is very true! The point I was after is that if it can be improved, then it must be. To illustrate: many moons ago I was training a student in a Challenger with a 503 Rotax. Those engines, especially the ignition systems, are not known for failure ... at least not both at once. Yet it happened to me and my student. It seems that the glue Rotax was using on the stator coils to hold the small end plates on would sometimes fail over time with exposure to heat. One of the coil plates came loose, got caught in the flywheel and came around like a knife blade and took out all the wiring for both ignitions. Was a dead stick slip into a muddy field landing. Researching this event I only found one other case of it happening. Is that acceptable? Perhaps the reason the issue wasn't more wide spread was that after the first failure Rotax stepped up and addressed the problem by changing the glue and manufacturing process.
lutorm wrote:If one wants a dual ignition, the Aerovee magnetrons seem quite good as the stupid-simple, self-contained, system.
They are a great idea but they do fail. I've seen it happen. The other concern is that we see builder's using splicers to put better plug leads on them in an effort to quiet the noise. After all they are designed for mowers and can be a bit noisy in the electrical system. Adding splicers is not something I would do as it still leaves part of the old wire, adds two more failure points to each HT lead for a total of eight, combines wires of different core & resistance, and has more places where moisture and dirt can enter.
lutorm wrote:It would be quite easy to replace the fixed-time secondary ignition with an aftermarket electronic ignition system. The only hardware needed would be to replace the trigger magnet with a toothed trigger wheel since you can keep the existing coils.
The toothed trigger of even a lobed cam lode is a good idea. Many auto distributors use such a set up.
lutorm wrote:On the other hand, a Sonex isn't really a traveling machine, so I'm not sure it's worth the complexity.
I know a couple of folks that use the Sonex for traveling. Not so much for commuting but there have been a lot of miles put under Sonex wings! To me it wouldn't matter whether I'm a mile or a thousand miles from a landing strip ... I want as much reliability as I can get.
rizzz wrote:I have a Bendix D2000 dual magneto directly driven from the crankshaft on the back of my VW:
This discussion wasn't aimed at the Aerovee but at other ignitions and options as described here.
Primarily I was curious as to the thoughts of others as to whether they would fly behind a single plug ignition system and if so, what would it look like. We have a vast number of different engines being used from the AeroVee, Revmaster, Hummel, Corvair, Viking, Jabiru, etc and these all have different ignition systems and some are very different.
If you were designing a modern ignition system for your engine what might be the approach you would use? Would you use coil on plug technology? An approach like Electroair or SDS systems? Or are you of the old magneto tried and true approach?
Again this is not about making the current offerings from any company look inadequate but rather trying to see what builders would like to see coming along in the near future.
Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
Signature Finish 2200 Paint Job
166.7 hours / Status - Flying
Member # 109 - Florida Sonex Association
https://www.youtube.com/watch?v=1VP7UYEqQ-g