Andrew Gideon writes:

Well, if "old" Diesels made sense for GA use, you'd a thunk there would
be lots by now. There don't seem to be.

My understanding is that this has, until recently, been a weight issue.

Note that over the last ~30 years, cars too have come under intense
scrutiny over weight, and where to (and not to...) save. It includes
things such as making the brake cylinder{s} from aluminum vice steel,
reducing the capacity of the automatic transmission case/sump to use less
ATF, etc. and many smaller gains. All those ounces add up.

There are significant advantages to engines that run closed-loop, and
FADEC control systems add others. Yes, it's best to have zero single
points of failure in any design, be it a Bonanza or a highway bridge,
[or flywheels] but that's not always possible.

This appears to me to be another strawman. Sure, zero SPOF is not always
possible. But how does that impact the goal of minimizing the SPOF?
Your later comments about granite cumulus would appear to be of the same
sort. Hyperbole, perhaps?

Call them what you want. Zero SPOF is almost never possible. The question
is, what do you gain, and how do you mitigate the new risk? That twin
with the dead battery is a good example; it was bad engineering to depend
on the one main battery for the FADEC's, but with an added gel-cell for
them alone, that flaw is 99% gone. [You need some automagic battery test
as part of startup.]


(The alternative, by the way, is where GA is now -- 1950's technology
holds forth; outside of the avionics, and it run on 1960-design
alternators.)

This might also be explained by the size of the market. Also, don't
ignore the "pause" imposed by the liability issue. Now that small GA is
"moving again" we are seeing innovation.

You think it's moving? I'll let others speak their mind {Jay, Donnie
etc.}, but from outside, it looks to me like it's reaching stall
speed. GA {in the US} faces large fuel cost increases, an aging fleet,
airport losses to developers, and an overall grim economy. And, sooner
than you think, I bet leaded gas will vanish. Then what?

Does AOPA etc. try to estimate the # of GA hours flown per year?
I can see two ways to swag same: ATC data and total gallons of 100
Octane sold. Both have flaws but it might be interesting to see a
10-20 year trend.

And I'm not one to discount the coffin corner of low volumes plus
regulatory overhead. But what I observe is not a pause but a fergett-it
by new vendors coming from such. YMMV.

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