A Wisconsin company said its new high-performance geared diesel aircraft engine reached a development milestone this week when it passed vibration tests done by propeller manufacturer Hartzell. Induced vibration through a gear reduction system eats props but Engineered Propulsion Systems (EPS) spokesman Steven Weinzierl said the integrated counter-vibration systems in the engine work and the engine runs more smoothly than many gasoline engines. "It's a distinct departure from prior engine designs, and we believe what Hartzell has now confirmed: induced vibration is no longer an issue," Weinzierl said. Hartzell said Engineered Propulsion Systems' Vision 350 easily met is durability standards when tested with traditional aluminum props, a carbon fiber model and its new five-bladed graphite/composite propeller. "We were very encouraged to see that the stresses on the propellers were acceptable and lower than most engines we have surveyed," said Hartzell spokesman Bruce Hanke. "We look forward to continuing to work with EPS on this innovative new product." As we reported in 2010, EPS is developing the engine as a direct replacement for high-horsepower gas engines that need leaded fuel to achieve full performance.
The Vision 350 will put out 350 horsepower burning Jet A or kerosene and the fuel burn at 60 percent cruise is 12.3 gph. The engine is a "flat vee" configuration with 4.4 liter displacement and develops full power at 3,800 rpm, hence the need for a gearbox. It's liquid cooled and its integrated preheating system burns fuel from the tanks to warm the coolant in the water jackets for cold starts. Weinzierl said the engine is designed specifically for aviation use and will find a market as a retrofit and new installation in high-performance piston aircraft. Cirrus has already expressed interest in the engine. The company is also targeting the military drone market. It's now building pre-production test articles but has not given a timeline on potential first deliveries.