A Wisconsin-based aircraft engine builder is introducing a diesel engine cast in compacted graphite iron, drawing on the material’s “strength and stiffness” to set new performance standards for general aviation. Engineered Propulsion Systems, New Richmond, WI, also credited the engine’s ‘flat V’ design in setting that standard.
The 4.3-liter, eight-cylinder engine is a compact, low profile package described as easy to install, durable, and maintaining low aerodynamic drag. The engine is intended for use in single and twin-engine aircraft, small helicopters, and unmanned military aircraft. Some marine engine applications also may be possible, according to EPS.
Grainger & Worrall Ltd., an English foundry using the SinterCast AB CGI technology, cast the engine block. Stockholm-based SinterCast Stockholm-based SinterCast is the world’s largest supplier of the control technology used by foundries to produce CGI — a lightweight alternative to gray iron and aluminum used mainly for automotive diesel engines and cylinder blocks, though some gasoline engine designs have been introduced in recent model years. Other applications include industrial power engines parts, which SinterCast notes range from 2 kg to 9 metric tons.
The SinterCast process is under license to 44 foundries and product development centers in 13 countries.
According to EPS, using CGI allowed the designers of the Graflight aero diesel engine to take a “clean sheet” approach to the project. Initial flight tests indicate the engine has a specific power of 105 horsepower/liter (77 kW/l), resulting in a total power output of 450 hp (332 kW.) The installed weight of the engine is just 45 lb. (20 kg), as compared to a 350-hp (257-kW) air-cooled turbocharged engine that would be a typical alternative for general aviation programs.
The Graflight aero diesel is further promoted as potentially more fuel-efficient than any general aviation engine currently available. “The diesel combustion process, together with the design freedom provided by high-strength CGI coupled with steel pistons, enable EPS to realize 30-50% lower fuel consumption and emissions compared to conventional aero engines,” according to a statement issued jointly by EPS, SinterCast, and Grainger & Worrall.
The CGI engine also contributes to increased range and payload for the aircraft. Pointing to the possibility that leaded aviation gasoline (avgas) may be prohibited, EPS noted the availability of low-cost and widely available diesel fuels provides a significant growth opportunity for the new engine.
EPS is conducting engine and flight tests now, and reportedly expects Federal Aviation Authority approvals during 2017.
Series production for the Graflight aero diesel engine has been awarded to the Grainger & Worrall foundry at Bridgnorth, Shropshire.
“Building on our design experience with automotive diesel engines, we knew that Compacted Graphite Iron was the optimal material for the crankcase of our Graflight V8,” stated Michael Fuchs, president of EPS. “The aero-engine industry has been relying on outdated engine technology and fuels for more than 20 years. Our use of modern technologies such as CGI, steel pistons, common rail fuel injection and electronic engine control form the basis of our competitive advantage, our contribution to the aviation industry, and our market opportunity.”