FAA Approves Electronic Ignition - Possible Avfuel Solution?

[n86121]

Other than FADEC being simpler, and electronic ignition being easier to start,
I can't imagine there is any noticeable gain in efficiency, miles per gallon, or power speed.

Unless I am missing something,
automobiles gain their 'efficiency' by handling constantly CHANGING power requirements more precisely.

I remember from my Princeton aersopace design course, a car on a level highway at constant highway speed needs on order of 20 HP (or less) to overcome all friction, internal and external: air, internal friction, wheels deforming, etc.

Thats why cars are all looking the same. They all ready the same market studies for what the market wants, and they are all engineering the same few variables to optimize drag and friction. They also become lighter to require less HP to accelerate fast, but super acceleration is more for marketing than regular use.

That is also why a tiny car engine that can provide efficient cruise at low power, with high efficiency, and also have massive turbos and other add-ons that adjust changing fuel, air, timing; such as for ACCELERATING the mass of the vehicle, or improved performance, etc.

My son's 350HP sports car still gets 30+ miles per gallon, when turbo's not accelerating it. But hard acceleration and it drinks fuel. Physics.

Our airplane engines operate more like an industrial powerplant: Many hours at mostly steady state, within a very narrow band of RPM and mostly constant power at a given altitude.

There are only three variables: How much fuel, how much air, and when to ignite it?

There are also other clever things one can do to improve volumetric efficiency: Intake systems with less drag. Larger valves to breathe easier, etc.

I had a Lotus in the 70's that had a 45mm carb on EACH cylinder, a flow through exhaust, and 4 LARGE valves per cylinder. I recall the exhaust vales were huge. It got 250HP out of a normally aspirated 4 cylinder engine, sounded like you were at Le Mans, and was a rocket, AND got great mileage when you weren't flooring it.

At a steady state, I BELIEVE our aircraft engines are pretty much optimal for fuel, air, timing, and exhaust. They may not operate very well outside of that, but we don't operate them out there for long anyway.

So I dont understand where the gains can come from?

[mshac]

Surefly, the company I linked to in an earlier post, makes no claims of increases in efficiency or power associated with their product. From their website:

What are the advantages of a SIM configured for fixed timing over a magneto?
The SIM is a solid-state ignition module with the benefit of improved reliability and zero maintenance (no rebuilds & no overhauls) over the lifetime of the SIM. Another benefit is improved starting.

[wslade2]

Advantage electronic ignition: no points. Anyone that ever had an old car that uses points, remember that Achilles heel…

On my first car, with points, they would fail at most inopportune time. Usually away from home and tools with some other life event needing to be critically completed.

We fly behind them with great faith and trust. The advent of electronic ignition in automobiles moved things up to a much greater level of reliability.

[mshac]

Originally Posted by wslade2

We fly behind them with great faith and trust.

That's why we have two. Because we don't really have that much faith or trust in them!