There's no secret we're fans of the in-development Graflight V-8 currently under development by Engineered Propulsion Systems. A completely new flat-8, turbocharged diesel with gear reduction, water cooling and sophisticated engine management by Bosch, the EPS engine promises to move general aviation piston engine technology into the modern era in one gigantic step.
But until AirVenture this year--where EPS is exhibiting--the new Graflight engine was destined strictly for certified applications. That appears to be changing.
EPS' certified-only stance was driven by the technological necessity of engineering each variant of their engine to the recipient airframe. This is still true, but with the strong interest shown by some kit manufacturers--meaning they're eagerly waving their checkbooks--EPS is considering Experimental fitments as long as EPS engineers the complete firewall-forward package.
This could easily breathe new life into legacy go-fast Experimental kits given the Graflight's unique combination of impressive power and fuel economy. Designed to fit existing 540 and 550 engine mounts and weight envelopes, the Graflight engine does not pose daunting installation challenges.
Of course, there are tall hurdles of initial cost (more expensive by some compared to the 350 horsepower turbo offerings from Lycoming and Continental) and unknown long-term reliability, but the promises of increased range, operating ease, practicality of Jet A fuel, TBOs ultimately as high as 3,000 hours and a 385-hp power rating are proving too great to ignore.
EPS reports FAA certification should be in hand by the end of this year or the first quarter of 2018 at the latest. The first 15 conformal test engines are being built as part of certification, a process the FAA and EPS are somewhat learning together as the FAA hasn't certified an all-new engine in over 40 years!
The engine shown here is in EPS' Air Venture booth and is the last to use billet aluminum timing and other covers. Castings for these parts are arriving, so all future engines will essentially be production engines. This is also our first look at the flat-8 without its large charge air cooler covering up the top of the engine.