Cobalt wrote:
aviation engines are reasonably efficient at cruise
But only if you know how to use all the knobs in the cockpit, first of all the red one.
This is something which greatly evolved in car engines, and just anybody can operate a car engine on a reasonable fuel consumption rate, and it doesn’t matter how much there is in between the ear cups (mmh, Donut! 
).
Not so in airplanes, where still a lot of knowledge is necessary to get anywhere near the most efficient way to operate the engine.
I think the main benefit is (a) press a button to start rather than some byzantine startup procedure and (b) single lever operation.
But he’s right. People make a lot of noise about how out of date Lyco/Continentals are, and how much better car engines are, but when it comes to getting people to open their wallets, their tune changes completely and they’d rather have the Lycontisaurus after all (better the devil you know). This is borne out in the homebuilt scene, where you can get kits for auto engines for things like the Vans RV, but all the builders seem to end up choosing Lyco/Conti. People go on about “oh it’s the fault of certification”, but if even homebuilders who are unconstrained by certification are all flocking to Lyco/Conti, then a new engine basically doesn’t have a chance.
Good observation and indeed my first thought on the question above about converting a Cherokee to another engine was that it would free up an O-320 core for an RV-9.
Yeah but I think you may want to consider the customer type:
On one hand the guy who wants a sturdy Piper design, won’t necessarily want the fuzz of a total 915 (and lower TBO).
OTOH a lighter engine allows to create a lighter, smoother airplane (I have in mind sling TSi or MCR-4s) with maybe better performances that will suit others.
I see that as two different approaches to GA and I think there are more of the first kind.
Peter wrote:
very well informed
So it seems, but then you get to 12:05
This is kind of nuts. If BMW, VW, MB, Toyota, Honda etc went “all in” to develop an aircraft piston engine, we certainly would get several. They will never do that for obvious reasons (zero return of investments). This isn’t exactly news. Besides, car engines is one thing. a better comparison is boat engines. They aren’t exactly cheap either when rounding 200+ HP, and the market is at least 10k times larger.
The best GA aircraft engine today is electric, used in the Alpha Electro.
Well, boat engines aren’t much better.
The key is volume. Car makers put in a lot of work to get reliability and to get it cheap. It’s easy enough to get it expensively; getting it cheap is really hard.
An “electric engine” is just a 3 phase brushless motor, with nothing – short of manufacturing defects – to go wrong. Current implementations don’t even have a wound field; they use permanent magnets. The reliability will be determined by all the stuff around it.
LeSving wrote:
The best GA aircraft engine today is electric, used in the Alpha Electro.
Any engine is only as good as its energy supply limitations, and that’s where electrical engines (or more correctly “motors”?) are still lacking.
Thoroughly enjoyed the video (the guy never disappoints).
I liked the part best where he is mimicking the Cirrus hot start (very authentic).
He‘s also a reader here
Yes; he is a great presenter and with an excellent technical/enginering understanding of the various issues.
alioth wrote:
This is borne out in the homebuilt scene, where you can get kits for auto engines for things like the Vans RV, but all the builders seem to end up choosing Lyco/Conti.
First of all, this isn’t true. Second, it is very far from simple and cheap to convert an auto engine. Austro managed to do it, somewhat, but the engine weighs nearly twice as much as it needs to. From an engineering point of view it is a terrible engine because of that alone. As Paul Bertorelly say, it is a display of cheer will power to manage to do it, against all “better” knowledge. That is also the key point I get from Bertorelly about the subject. It’s not about money, it’s not about good engineering, it’s not about the market (or lack of), it’s not about TBO, maintenance and reliability. To be able to manufacture and sell new and “modern” engines requires tons of will power and perseverance, and nearly nothing else.
But back to Vans. All the aircraft are designed, and the kits are specifically manufactured to use Lycoming engines. Vans sell the engine as part of every kit, at a great discount as well. Going for a different engine, therefore requires you to re-engineer everything firewall FWD. This is not an easy task. The exception is the RV-12, designed and manufactured for the Rotax 912 (Vans also sell those, ULS and iS at discount prices). This is what Vans say about engines:
We are often asked about using non-aircraft engine conversions. We’d like to pass along a quote from a colleague in the home-built airplane business:
“The best conversion I know is to take $8000 and convert it into a good, used Lycoming.”
That may sound a bit narrow-minded, but it reflects the basic truth: No non-aircraft engine has yet proven to be as reliable, maintainable, available, and inexpensive (everything considered) as a traditional aircraft engine.
It seems magazines are always printing stories about automobile engines bought for junkyard prices, mated to inexpensive reduction drives and flown off into the sunset. It simply doesn’t work like that in the real world. The reliability we’ve all come to expect from aircraft engines is the result of years of development and refinement of engines designed specifically for the task. Automobile engines function well in their intended application: delivering low cruising power in vehicles with well-designed transmissions and power trains. Using them successfully in an airplane requires continuous high power outputs and reduction systems coupled to the propeller. This is completely foreign to their design intent. You can imagine the car engine designer banging his head slowly against his desk…”No, no, no… If I’d known you wanted to do that with it, I would have designed something different…” In fact, we’ve had those very conversations with auto engine designers!
With enough research and development effort, auto engines may be made to work acceptably or even well in an airplane. We are not opposed, in principle, to RV builders using alternate engines, but we would hope that this choice is made on facts, not hopes or dreams. Do you want to spend your time and effort on engine development or do you want to fly confidently behind an engine that has already been developed?
We, too, would like to see “something better” with regard to available aircraft powerplants. We are carefully watching a variety of developing alternatives. Meanwhile, the proven Lycomings do the job very well and are the best “available now” option. Despite the many claims and promises made by promoters, we feel that if you will look closely at what is actually available, how many are really flying, and how well they really perform, you will agree with our conclusions.
While we are not opposed to RV builders installing alternate engines, we simply cannot recommend or encourage the installation of any other engine – we don’t feel doing so would best serve the interest or safety of the builder.
Going against this recommendation is not for everyone. It’s only for the few. Nevertheless, people are indeed doing it, and it’s everything from auto engines to turbines to rotary engines. I have heard of no electric engines yet, but it wouldn’t surprise me if Vans themselves came out with a brand new aircraft designed for electric propulsion any time. They have already a TMG which never went into production, maybe?
