A Wisconsin company working to bring the first clean-sheet aviation diesel to market has begun building pre-production versions of the Graflight V-8, hiring staff and tooling up for a certification push.
“Time is a critical resource and to that end, our presence at AirVenture this year will be very limited,” said Engineered Propulsion Systems President Michael Fuchs in a news release. “We have scheduled some key meetings, but have elected not to have an exhibit this year to allow us to continue to make progress.”
The second flight test phase will begin “soon,” the company announced, and EPS continues to analyze data gathered from the first phase of flight testing of an engine designed from a clean sheet for aviation. The Graflight V-8 has so far outperformed aviation diesel (compression-ignition) engines developed from automotive powerplants, reducing fuel consumption by 15 percent; compared to avgas engines, the hourly fuel cost was cut nearly in half, the company reports in data posted on its website. It can be configured for up to 380 horsepower; a 350-hp test version mounted on a Cirrus SR22 was flown by Dick Rutan in 2014, who declared it “a new paradigm in aviation propulsion.”
The company has set its sights on a 3,000-hour time between overhaul, and has refined elements of the design based on flight tests that began in May 2014 following a series of ground tests, some conducted in extreme environments. Founded in 2006 by Fuchs and Steven Weinzierl, both automotive industry veterans, EPS designed the Graflight to stand up to punishment, with a compacted graphite iron block and steel pistons instead of aluminum.
“Every modification to the engine is calculated to produce a safer, more reliable engine design and enhance its performance,” Fuchs said. “We expect Phase Two of the flight testing to begin soon.”
EPS is meanwhile seeking new patents on technologies developed during testing.
Several engine makers are working on new compression-ignition engines for general aviation, though most see the primary market overseas, where the high cost and low availability of avgas create a stronger incentive to retrofit.