The Centurion 4.0 by Thielert sports twin turbocharges to feed its eight cylinders that each breathe through four valves, which results in an output of 350 hp on a fraction of the fuel used by a comparable spark-ignition engine running on gasoline. Photo by Dave Higdon

Diesel power was a strong theme of the press conferences Tuesday morning in Oshkosh.

The morning started out with Powerplant Developments of West Sussex, England, announcing its Gemini Engine, a 100-hp, three-cylinder diesel designed for the light-sport aircraft market. The engine, which will run on diesel fuel or Jet A, is of a unique opposed-piston design. Each of the three cylinders contain two pistons and there are two half crankshafts, one on each side of the engine - hence the Gemini name.

The liquid-cooled engine is expected to have an installed weight of 166 pounds.

Prototype construction is underway with production versions planned to be available for E-LSA installations in April 2008, and for S-LSA installation by November 2008.

Frank Thielert of German manufacturer Thielert Aircraft Engines GMBH took the stage next. He reported that the 2-liter and 4-liter versions of their Centurion diesel engines are now installed in some 1,500 aircraft. Since their certification in 2002, the combined fleet has now amassed more than 500,000 hours of service.

Thielert expects 1,500 new engines will be produced this year, with that number growing between 30 and 40 percent in 2008.

A key challenge to diesel aircraft engine acceptance has been the availability of a suitable support network. Thielert announced that the world wide total of authorized service centers is now 200, with 50 added this year alone. Fifty of the 200 service centers are in the United States, with technician training underway at the company’s Superior Air Parts division in Texas.

Thielert indicated their approach is to develop their own supplemental type certificates (STCs) for installation of their engines in existing production airframes. Available STC’d models now include the Cessna 172, Piper Warrior, Cessna 206, and Cessna 340 twin. Other models are under development.

For installation in new airplanes, Thielert plans to develop entire firewall-forward powerplant systems and deliver complete kits to the original airframe manufacturer. He said the installations’ complexity requires the unique experience and capabilities his company has developed.

Thielert’s booth is #169, just outside of Exhibit Hangar A. More information is available on the Web at www.centurion-engines.com.

SMA’s new SR 305-230 diesel cycle engine provides more power on less fuel and has reduced maintenance demands compared to spark-combustion engines running on gasoline. Photo by Dave Higdon

The morning ended with Luc Pelon of French manufacturer SMA. He reported their SR 305-230 diesel engine, originally certified in 2002 and available for installation in the Cessna 182, is now in 51 airplanes around the world. That fleet has amassed over 10,000 hours of operation.

Pelon said SMA’s strategy all along has been to take the time to do things right. He indicated they now have validated all of the technical decisions made during the system’s development.

Unlike Thielert, SMA is not developing STCs for installation of their engine on other airframes. They did participate in developing the original Cessna 182 STC, but only to speed getting the engine into the field.

According to Pelon, SMA’s target is the professional flying market-like flight schools and freight operators. He indicated SMA’s developing service network will be geared toward supporting that style of flying.

Pelon also reported SMA has tested the engine with a blend of up to 70 percent biodiesel and that a new engine model is under development. Specifications for the new model are not being released yet.

Details about the SMA engine can be found at Booth 91, just outside of Exhibit Hangar D, or at www.smaengines.com.

It is apparent that diesel airplane power is a reality. While acceptance of the technology has been slow as the support network develops, the continuing increase in the price of 100LL avgas will certainly make the idea of piston engines burning Jet A, and burning it more efficiently than gasoline, a reality to many more airplane owners.