Lycoming Has a Diesel

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    Ok, so now give us the low down…

    What’s your thoughts on it.



    For obvious reasons, there are limits to what I can say.

    Another article pointed out that it looks similar to a Thielert/Austro, which it does, but it doesn’t have a clutch in there which I think will be a major reliability hurdle. If I were looking at a plane that this engine would fit in, I’d prefer it to the other diesel options. The efficiency was quite nice, although I forget actual numbers. Probably in-line with the Thielert/Austros.

    That said, it will never go in a Twin Cessna. I doubt if there’s much room to go beyond the 205 HP listed. Some of the technology in there I think could be applied to a bigger engine.

    I saw some comments on the article about how stupid it was that Lycoming wasn’t certifying it since the military paid for the R&D. While that certainly does help, certification of a new engine is a daunting and expensive task. Because it would be the first of its type from Lycoming, it wouldn’t be able to certify by similarity to anything else, which is the basis of the certification of most piston aircraft engines for the past 40-50 years. And since the size of the engine will limit its market to 172s, PA28s, SR20s, and DA40/42s (which I don’t see Diamond going for considering they own the Austro), there’s certainly limits to how many could be sold. Retrofits would be expensive, and thus that will limit the market, too.

    Show me a 300-400 HP diesel, and now we’re talking.


    Show me a 300-400 HP diesel, and now we’re talking.

    Oh Oh!!! I can do that! 🙂

    Wait… they all say Cummins on them.


    I just had an image of two of the 6.7 straight six cummins that are in my truck mounted on a 421 belching noise and black smoke at 600+ takeoff horsepower! Of course the plane would have no useful load but who cares when you can go straight up 🙂 . Maybe a couple of cummins 4bt’s converted to aviation use. They are comparative lightweights at 700 pounds each. I love diesels but the weight really makes things dificult for aviation.


    I was thinking of the QSX15 15 Liters, they weigh around 3200 lbs. They wouldn’t turn a prop very fast, but they would turn a very very large one! 😉


    Actually, a Duramax diesel would be a potential for conversion to aviation use since it’s the lightest of the 3/4 and 1-ton truck diesels. Still weigh a couple hundred pounds more than a GTSIO-520, but any diesel is going to weigh more than its AvGas equivalent.

    A 4BT would still be too heavy. A 6BT, way too heavy. The Thielert Centurion 4.0 was a German V8 diesel of some sort, I forget whether it was Mercedes or Audi/VW. The 4-cylinder Centurions were a Mercedes diesel.

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