From AOPA: https://www.aopa.org/news-and-media/all-news/2018/may/09/cessna-discontinues-turbo-skyhawk-jt-a?utm_source=ePilot&utm_medium=email&utm_content=tts&utm_campaign=180510epilot

I had one park next to me about 4 months ago at Flagler Beach. It was really weird listening to that engine and I new something wasn't right. 2 dudes got out and I asked whats under the hood of that thing....they laughed and said a Diesel........

I thought!!!!!!!!!!!!!!!!!!!! dang that's cool

And this folks is why you don't buy into bleeding edge technology. Huge investment, significant risk of depreciation. We've seen these orphans before Sky Catcher. DA40 in several engine variants, Bendix King KMD840 PFD, etc.

Let's see...

20 knots+ faster

4K increase in service ceiling

1000+ mile range

Single lever operation

Much better high and hot performance

Better fuel economy and fuel availability

Much quieter

Wait a minute, this is Cessna not Cirrus.

Nope, cancel that program and let's have a long lunch.

Downside? No sales. It's +$20,000.00 more expensive.

--paul

This is today corporate world:
Subject's of today meeting: "sales of the 172 diesel"

Board's question: "Can we make money right now? "
Response from analysis: " Well, not right now, it is aviation, and it takes a while to get things moving, but it is a really cool and better technology, we are getting some traction..."
CEO: " Ok, I see, let's hang on and make it work"
Board's response: " Kill the program. We want more money right now. Next?"

That's all folks.

I don't think those were the main issues.

Internationally, something that runs on jet fuel is hugely preferred. 100LL is a problem both in cost and availability in many parts of the world. Where it is available, jet fuel can be half or less of 100LL.

For example, EGNX (Gamston) in the UK is $2.96 for Jet-A, $9.88 for 100LL, per gallon. You make up at $20K price difference in only 2,900 gallons, or ~300 hours of operation.

A $20K price difference on a $500K airplane isn't much, either.

The real problems were technical. Certification was claimed to be "imminent" in 2014. Now 4 years later, no cert.

Diesel still has major plusses if it can be made to work: cheaper fuel, lower fuel consumption, unleaded fuel, more tolerant to misfueling, wider fuel availability, less fuel weight (more useful load) for a given flight, potentially more reliable (no ignition). So far, the promise remains unrealized, however.

Mike C.

Yes, good points, Mike.

I see the Continental CD-155 Diesel engine will be available as an STC through Continental for a Skyhawk. The engine conversion installed in your supplied Skyhawk will be $85,000.00.

That probably means few US sales, but you are right about the overseas economies.

--paul

Think about what happens if 100LL gets banned as the last leaded fuel in use in the US.

Mike C.

Not sure about the tolerant to misfueling. Seems that is its weakness. Unlike a turbine that can burn almost anything, a piston diesel will start ejecting parts if you put AV gas or MoGas in it. Seems like your average fueler is going to want to put LL into anything that looks like a Cessna piston.

How long did Honda take?

Think about what happens if 100LL gets banned as the last leaded fuel in use in the US.

Mike C.

I’m thinking the answer to the pending obsolescence of 100LL (due to its lead content) has been in front of us the whole time: automotive gas, regular old unleaded gas. It’s everywhere.

Granted, higher performance aviation engines (like my TSIO-520) can’t use it, but lots and lots of lower performance engines can and do run just fine on mogas.

When people tell me that GA is doomed because of the lead in 100LL, I think about the thousands of airplanes running just fine on mogas, and I wonder. What is doomed, exactly? Making 200 knots in the flight levels with a turbocharged big-bore Lycoming or Continental might well be threatened. A Cessna 150 putting along behind an O-200 is certainly not threatened, just get an auto gas STC and start saving money.

In the third world, it may also be a quality problem, ie, is automotive gas as consistent and predictable there as it is here? But is it wrong to think that unleaded automotive gasoline is probably available everywhere that has a large population?

My first airplane was a 1959 Cessna 172, with a Continental O-300 that ran just fine on pump gas, using the EAA auto gas STC. Current plane is a turbo 210 with a TSIO-520, yeah, that powerplant will probably not tolerate auto gas as-is. Anybody know if there’s a set of operating limitations (MP, fuel flow, power level, altitude) that would make premium unleaded gas viable in this engine?

It would be painful and expensive for folks (like me) with higher-performance aircraft, but one can easily configure a GA trainer and a GA ‘family station wagon’ for auto gas.

My $0.02. Worth what you paid for it... or maybe less!

This is the seesaw that all the diesel engine developers have been riding. When the odds of 100LL going away goes up, so do their chances of success. As long as 100LL (or a substitute) lives, no need for diesel engine Skyhawks.

Think about what happens if 100LL gets banned as the last leaded fuel in use in the US.

Mike C.