Engineered Propulsion Systems

About Engineered Propulsion Systems

Engineered Propulsion Systems (EPS) was a Wisconsin-based company focused on developing a next-generation diesel engine for the general aviation market.

Founded in 2006 by Michael Fuchs and Steven Weinzierl, the company embarked on a mission to create a more fuel-efficient and modern alternative to traditional leaded avgas engines. The founders' journey began with a patent for an aviation diesel engine built around a graphite block, aiming to address the high costs and environmental concerns associated with conventional powerplants. Over its lifespan, the company invested more than $60 million from private shareholders and government grants, including from the U.S. Air Force, to bring its vision to life.

EPS's core product was the Graflight V-8, a clean-sheet, liquid-cooled 4.3-liter diesel engine. This V-8 engine was designed to be a versatile powerplant for single-engine planes, light twins, small helicopters, and military drones. Key features included a fully electronic engine control unit from Bosch for simplified single-lever operation, which managed propeller pitch, fuel mixture, and engine temperature automatically to reduce pilot workload. The engine was built for durability, using a compacted graphite iron crankcase and steel pistons, targeting a time between overhauls (TBO) of 3,000 hours—a significant increase over the industry standard. The primary benefit was its fuel efficiency, burning 30-50% less fuel than comparable avgas engines and operating on more globally available and cheaper fuels like Jet A and diesel.

Despite promising technical developments, including successful high-altitude testing and a flight test program, EPS faced persistent funding challenges. The company needed an estimated $12 to $15 million more to complete the final stages of FAA certification. Unable to secure the necessary investment, Engineered Propulsion Systems filed for Chapter 11 bankruptcy protection in July 2020 and ceased operations.