The answer to this question might be obvious to experienced aviators. But as an armchair enthusiast, I really couldn't find a satisfactory answer anywhere on the internet.

Below two pages came from companies that sells this engine

Below is an article talking about one successful application of this engine

On paper, this engine outperforms other common small piston aviation engines.

  • 300 hp
  • 4 cylinder
  • turbocharged
  • similar weight to Rotax 915iS

Fast planes such as Lanciar Legacy and Glasair III have engines output about 300 hp but are much heavier. Rotax 915iS, one of the most advanced small aviation engine, output about 145 hp.

Looking at the performance alone, Yamaha EPeX300Ti should dominate the market.

Why is there so little attention to this engine? Safety? Design flaws?

  • 1
    $\begingroup$ Steve Henry flies one. That’s a feather in their cap. $\endgroup$
    – Jim
    Jun 20, 2022 at 23:45
  • 1
    $\begingroup$ @jim yes, one of the links talks about Steve Henry's airplane. That's how I learned about this engine. $\endgroup$
    – crow
    Jun 20, 2022 at 23:57
  • 2
    $\begingroup$ If your car engine dies you coast to the side of the road, if your airplane engine dies chances are you do too. Power to weight ratio is only one factor in choice. Also keep in mind it's a conversion not a purpose built aero engine, so support is a big concern. $\endgroup$
    – GdD
    Jun 21, 2022 at 7:42
  • $\begingroup$ This question is too broad and opinion based. The answer will be different for every owner. The super short answer is individual value. But value is subjective and wraps up capital investment, reliability, maintenance, legal certification hassles, frame conversion hassles, confidence in finding parts and mechanics for the engine in 10 or 20 years, trust in the company, fuel burn, resale market value, even minor stuff like noise issues or shipping cost. $\endgroup$
    – Max Power
    Oct 1, 2022 at 23:51


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