EPS continues work on 320- to 450-hp, 4.3-liter, eight-cylinder aviation liquid cooled diesel “flat-vee” horizontal piston aircraft engine, the company reported this week at EAA AirVenture. EPS CEO Michael Fuchs said the engine yields fuel economies that are 30 to 50 percent superior those of avgas engines.

The company began working on the project in 2006 and took five years to design the basic engine that weighs 650 pounds—40 to 50 pounds more than a conventional engine, Fuchs said. It also requires additional radiator/cooling capacity, which adds about 30 pounds to an aircraft. Fuchs said the engine design features steel pistons, connecting rods, and crankcase to reduce wear and tear, which improves reliability.

According to Fuchs, the engine already has been tested for 25 hours on a Cirrus and has proved that it can fly farther, cheaper, and with more load. He said the company already had discussions with major fixed- and rotary-wing OEMs with regard to the engine, given the relative expense and scarcity of avgas outside the U.S., but acknowledged that EPS’s test program had been stymied in 2017 by “funding setbacks.”

However, he noted the company now has “investor opportunities ahead of us” including from a Fortune 500 company. He said the company continues to work on certification including software certification and that a new concept demonstrator would be coming online in the first quarter of next year. Fuchs estimated the engines’ cost at 30 to 40 percent more expensive than a comparable avgas engine.