Well Udo, I’m not sure about @Steve6443 ride… but my guess is that it has got no magnetos, but runs a dual electronic ignition system, fully battery dependent.
In the homebuilt uncertified world, we like to… experiment 
Around my place, there’s barely a magneto equipped homebuilt left…
A quick recap of combustion engine ignition systems, as available today to non-certifieds:
These systems can be combined, and yes, the fully digital ones do require a solid electrical architecture.
UdoR wrote:
Aren’t there magnetos to keep the engine running?
Some aircraft have an “electronic ignition”, like what you have in your auto. These devices require a source of electrical power. When that stops, so does the engine.
boscomantico wrote:
And never [magnetos] in any Rotax-powered aircraft.
But at least in certified carburetted Rotax engines the electronic ignition modules are self-powered by generators, so for the point of view of redundancy it could just as well have been magnetos.
My aircraft is not certified, is powered by a Rotax 912iS engine – ie fuel injected, twin ECU for control. Means highly efficient, there is no red lever as you climb, the aircraft leans itself. At 2000 ft MSL at Eco settings, I am burning 17 liters per hour, at 10000 feet I‘m burning 13 – no red knob anywhere to be seen – and all on Super 95 Octane.
However the engine NEEDS electrical power to run hence the system has a main and a backup battery. The aircraft only has a single alternator charging both so with a failed backup battery, I am down to a single point of failure which could stop the engine – if the alternator failed, then (eventually) I would have no engine power. The question is – how good is my alternator, how good is my main battery?
Can you tell that at a glance from within the cockpit? Yes, for that moment in time. But you can’t say what will happen in the next moment or two, hence I decided to return and land. Perhaps the certified 912iS is different but my aircraft isn’t. And my wallet thanks me for that 
Dan wrote:
good old magneto(s), self powered, don’t need any power from any battery (example, the good old J3 Piper Cub, hand prop, and off you go)
And there´s not only one self contained magneto there´s as you say two of them, and the airplane can fly on a single one (not dispatch (legally!).
Each type of aircraft category comes with its pluses and minuses!
But at least in certified carburetted Rotax engines the electronic ignition modules are self-powered by generators, so for the point of view of redundancy it could just as well have been magnetos.
Must be the same for non-certified carburetted Rotaxes.
Indeed many variations between electrical installations of aircraft. The certified Bristell (carburetted 912 version) has two alternators, a battery and a back-up battery. The latter is only meant to power some of the avionics and glareshield though. And then the AI back-up instrument has its own back-up battery..
Most Rotaxes (those not of the “i” variant) use CDI. It’s not a magneto, but works without battery. It’s what’s found in many small high revving engines. Simple and reliable.
Certified Rotaxes usually have two (or even 3) generators. Two are built into the original generator in the “i” versions (separate windings and regulators) supplying separate ECUs, while a completely separate generator (auto variant) are mounted running of the prop shaft.
Even for the non certified iS, both generators and the battery have to be dead before the engine quits. I guess it’s up to the aircraft manufacturer to decide if the third/second additional generator shall be installed.
What’s best. An additional generator, or additional battery? A non solvable conundrum it seems An extra battery is definitely much easier than incorporating an additional generator.
Yeager wrote:
Each type of aircraft category comes with its pluses and minuses!
Absolutely, but frankly I don’t see any advantage of traditional magnetos vs self powered eletronic ignition . As long as the engine would make 800+ RPM the sparks would fire. Nothing else needed.
LeSving wrote:
What’s best. An additional generator, or additional battery? A non solvable conundrum it seems An extra battery is definitely much easier than incorporating an additional generator.
Best architecture is the one which in case of a component failure would assure uninterrupted engine operation and at the same time would’n require any action from the pilot.
There’s a thing or two about failure modes that’s important too I would say.
