Riff, read your paper: wow!
Looks to me as if the only reason this didn't happen was because of the diffculty in convincing investors of the market. Maybe that's about to change...
Soave, Frank Robinson himself admitted that at an RAES conference I attended. The difficulty here is that you don't want to take on a new engine in a new airframe - that really only left him with the diesel engines that were in the market place at that time. Post their LeMans endurance racing experience TEOS obviously gained enough practical design experience to convince Airbus to consider an EC120 prototype.
Onetrack, the bit that auto marketing men aren't telling you here is the common rail pressure that you need to more or less vapourise the diesel on injection - I'm told that 3000bar is probably where they need to be. The real problem is that a helicopter engine must reliably chug, whir, or hum away for at least 3000 hours before major overhaul. If competing with turbines then 10000 hours is the mark. The fuel injection system tends to be one of the main limiting factors to that TBO, so you can bet your bottom dollar the aero engineers pour over the reliability data before even mentioning the word "certification".
Edit: Just noticed that last paragraph did not make it clear that Jet-A1 has less lubricity than pump diesel.
Last edited by Graviman; 21st May 2014 at 17:51.