Plane & Pilot had a good read on the new diesel motors being certified. In the article it states with Mobil quitting 100LL production the others wouldn't be far behind and that within the next decade if your not able to use auto fuel in your planes your going to be in a crunch.

The turbo charged diesel they were testing in a C-182 gave pretty good results even though it was sixty or so pounds heavier. But the thing still had a 2000 TBO. I always thought one of the benefits of going diesel was their longevity over gas engines. Even if they had to time life the turbo to 2000 hours you'd think the engine would be good for at least a 3-4000 hr TBO. But then again being an air cooled diesel probably has some drawbacks.

There was a piece in AOPA Pilot last summer about the Thielert Diesel Skyhawk: http://www.centurion-engines.com/

Diesel engines are actually a really good fit for aviation. They're reliable, like constant rpms, and have long TBOs, and run on Jet-A which isn't going anywhere like the supposedly endangered 100LL. The weight is the only factor, but hopefully in the near future companies like this will whittle them down to at least the weight of current contemporary gas aviation engines.

I thought the aero-diesels were talking TBR instead of TBO. There is no "O". You have to replace the engine. They do, however, expect to extend that period to 2500 or 3000 hrs eventually. Haven't read the latest articles yet, so maybe something has changed?

Diesels could be a good choice. Without turbocharging, though, they are truly wimps, so if your turbo goes out, it is like half an engine failure. But in return, when everything is humming, you get full power up to class-A airspace. No worries about the mysteries of magneto and ignition harness devil -worship either.

Personally, I hope I live to see the aero engine that takes me coast-2-coast on the grass clippings from my lawn. I would love to cut out all the middle men.

YB

The one in the article was only certified for 12,000msl.

Missed the TBR part....

They said the thing would run on kerosene and gas in a pinch.

Wonder if they'll have an stc for auto diesel or bio-diesel.

In one of our trucks we have a Powerstroke Turbo Diesel with a five speed manual tranny thats an animal and reliable as heck.

Wonder if I can get a five speed tranny with the C-182 diesel and just run a fixed prop with steep pitch.

One of the reasons that the ceiling was limited to 12,000ft, the fact that the diesel engine is compression ignition. Which leads to the question of flame out at altitude. The air density could be low enough, causing lower compression presures and temperatures, and the end result, the fire won't lite.

The neat thing about a diesel that is turbocharged, if you want more power just add more fuel, in turn the turbo will generate more boost to burn the additional fuel. The limiting factor being, the temperature limits of the engine. In most common over the road truck engines, the turbo boost is in that 25-30 PSI range that is 51-61 INHG.

I was reading the article about the diesel Maule, and they said the manifold pressures were in the vicinity of 80 inches. That's a lot of pressure! I wonder if that as anything to do with the life span. I'm also interested to see if a small turbine will come to the rescue. I've not been to impressed with what I've seen so far, but who knows.

benflyn wrote:One of the reasons that the ceiling was limited to 12,000ft, the fact that the diesel engine is compression ignition. Which leads to the question of flame out at altitude. The air density could be low enough, causing lower compression presures and temperatures, and the end result, the fire won't lite.

The neat thing about a diesel that is turbocharged, if you want more power just add more fuel, in turn the turbo will generate more boost to burn the additional fuel. The limiting factor being, the temperature limits of the engine. In most common over the road truck engines, the turbo boost is in that 25-30 PSI range that is 51-61 INHG.

If you flame out at altitude the motor is already up to operating temps and should restart without a problem. Diesels usually have a hard time on initial cold startups only. If I remember correctly the cost of those euro diesels were $80,000+. That is a staggering price to me. For what it's worth, an Audi diesel powered prototype car won the 12 hours of Sebring today, a world first for diesel powered vehicles. It ran wide open all day boosted to 110 INHG. Think about that for a minute, you could tap into the intake manifold and fill up your 55 psi rated truck tires with the pressure from the turbo. !!!!!!!!!!!!!

For what it is right now the $80,000.00 is unreasonable. I expect the price would come down after full blown production begins, but to what range?

Even the diesels in pickups come with a pretty hefty premium, which is supposed to be offset by the additional miles they are good for. Don't see the additional value in aviation if the TBO or TBR is to remain at 2000 hours.

One experimental engine I've been following is the DeltaHawk. They've got one flying and say they're working on getting it certified. It's a v4 which can be installed right side up or inverted, it is turbo and supercharged (the small supercharger is to provide compression assistance during starting until the turbo spools up), and it is also liquid-cooled.

They list the TBO as an estimated 2000 hours, but the overhaul is quoted as being much less expensive than a gas engine.

They're working on 160, 180, 200 hp versions, and future plans for a v8 version.

Keeping my eye on it for future consideration.