What is it about GenAv aircraft/engines? is it simply the age (condition) of the stock? The age (capability) of the designs? I've owned half a dozen engines in my life. None have developed cracks -- especially not in critical and substantial internal components -- without having been run into something hard at high speed. The only IC engines I know of that require this level of maintenance are those explicitly used for drag or track racing.
They're old and many have been overhauled many times. Some have had propstrikes that were never properly addressed. The old mechanics used to put a dial indicatior on the crank flange and if it was within .010" runout, they'd let it go. And the crank would sometimes then fail. The problem was that the crank would twist enough to start a crack, and spring back to nearly normal. But that crack would continue to grow. BTDT, in flight. No fun.
Have a one or two-year research period, identify a suitable engine to replace all 150-200hp powerplants, come up with a package that bolts it to an existing engine mount and a suitable fuel system mod to ensure it will run on pump gas at any altitude, and certify it for less than half the cost of an O-360. They'll sell like crazy, and the success will only come through producing them in great numbers.
Lycoming has its iE2 engine out for at least 15 years. Fully electronic ignition and fuel injection and FADEC, everything pilots and owners want, but how many are buying it? Nearly nobody. It's not cheap, as the R&D and certification isn't cheap. But pilots are cheap.
Consider this:
What other modern engines use magnetos instead of electronic ignition?
What other modern engines run on leaded fuel?
What other modern engines use carburetors instead of fuel injection?
What other modern engines use manual mixture control instead of closed-loop automated control?
What other modern engines must run at air densities from below MSL to 25,000+?
What other modern engines are air/oil cooled instead of water-cooled?
The list goes on and on. GA has boxed itself into a corner with our application requirements. As a result, we're on a technological island all by ourselves, with no other industry helping to share our development and tooling costs.
Almost all of what we have in the old engines was developed for the military and paid for by them. Anything new is paid for by we pilots or owners, since the military doesn't buy Lycomings or Continentals anymore, and hasn't for a long time.
But in my experience while an aircraft owner will gladly pay $150+/hour shop rate to have their vehicle worked on, a number of those same owners will cry bloody murder if they are charged over a $100/hr to work on their aircraft. And they act appropriately.
The guy
needs his car. He doesn't
need his airplane, so he complains. Add in the fact that he buys an old airplane for cheap and somehow thinks the maintenance should therefore be cheap, as if mechanics do this for fun, and the parts should be at the same prices as when the airplane was built. Wishful thinking, completely detached from reality.
A top fuel drag race engine (which requires a full rebuild per "use") is about 1cc/HP; most auto engines are in a range of 12-15.
Not on the chart, an IO-360 (5.9L) making 200 HP would be almost 30. That seems to me like we're not asking a lot of the metal.
That aircraft engine is made as light as possible for its power, and it is stressed. If the pilot abuses it, he will pay for it. Too many have no idea what mixture is all about, nor why he shouldn't bang the throttle open. And then the guys that ground-run the engine, thinking they're helping it last longer?
Surely by now someone has figured out a way to take one of those reliable, efficient, inexpensive auto engines and replace all our horrible airplane engines.
The homebuilders have been doing it since the 1930s. No conversion has been spectacularly successful. In fact, many fool with a conversion for a long time, trying to make it work well and safely, and ultimately give up and stick a Lyc on the nose and go flying. I've been there, installing a Subaru in a Glastar. Spent a lot of time working the bugs out of it, and even then it had shortcomings.
Also, just economy of scale.
How many airplane engines are made compared to automobile engines?
Well, for 2019, just before Covid, there were about 97 million cars and light trucks built worldwide. In that same year, 1100 light aircraft were built and delivered worldwide. The ratio is about 88,000:1. It is therefore amazing that airplanes and engines don't cost more than they do.
And why would a current magneto system fail?
Neglect, mostly. The manufacturers recommend 500-hour inspections (400 hours for Bendix/TCM) but most are run until they fail. In flight. Which is insanely stupid, in my view.
I would suggest looking at modern race engines for F1, LeMans, and Indycars. They are now getting better than 50% thermal efficiency and running hundreds of hours at full throttle.
And how much does one of those engines cost?
