New Six-Cylinder Diesel From Continental To Debut At AirVenture
Continental Motors says it will take the wraps off a new 300-hp aircraft V-6 diesel engine at AirVenture in July, according to CEO Rhett Ross. Like the Centurion 2.0 and 2.0S diesels, the new engine leverages automotive technology from Mercedes Benz and is aimed at the high-performance single- and twin-engine segment not yet served by a high-horsepower production diesel engine. Ross said the company is hoping the engine will fly before AirVenture opens on July 28. He declined to reveal what aircraft the engine will fly in, other than to say it’s a “generic composite low wing.” Given the horsepower, a Cirrus SR22 seems to be the most likely test bed.
“My goal is that we will have a high-fidelity mock up, actual parts and pieces, but not an operable engine, at Oshkosh,” Ross told AVweb this week. “I’m hedging my bets, but I’m hoping to say within a matter of weeks, that test flights have been successfully completed,” he added.
The engine will fit into a product line that the Continental Motors Group will shortly rename, dropping the Centurion brand from the original four-cylinder diesel developed from the Mercedes Benz OM668 diesel and referring to the engines simply as Continental diesels of 135, 155, 230 and 300 horsepower. (The 230-hp engine is the current TD300, which Continental developed from base technology it bought from the French company SMA in 2010. The SMA version of that engine is used in the Cessna JT-A, which is still in certification trials.)
Ross declined to say which Mercedes diesel has been leveraged for the new 300-hp engine, but our guess is it’s related to the MB OM642, a 3-liter, aluminum block 24-valve turbocharged diesel with a 72-degree V. Like most modern diesels, the OM642 has common rail electronic fuel injection, which helps improve its fuel economy and reduce emissions. When the former Thielert Aircraft Engines, which Continental bought in 2013, adapted the MB OM648 for aircraft use, it used the same core engine, but added a gearbox and clutch mechanism and redesigned the fuel system to accommodate the lower lubricity of Jet A.
“We’re designing it to be an aviation engine. We’re designing out some of the things people grouse about on the 2.0. It’s going to have more accessory pads, it will be more flexible with propeller installations,” Ross said. In designing the engine, Ross said Continental approached all of the major OEMs and asked for data on interior cowl dimensions and developed modeling to assure that the engine will fit everything. “And we took all of those models and said, where are all the interferences? You don’t want half of your intercooler hanging out the side of the cowl,” Ross said. Continental already owns a type certificate for the 350-HP Centurion 4.0 developed by Thielert from Mercedes technology. But at more than 600 pounds installed, the engine proved too heavy to be attractive. Ross said the weight of the new engine “looks pretty good.”
“We’re not done. We haven’t done any true weight reductions, but it’s met our target weight to have what we expected, which will not be detrimental to any airframe it’s intended for,” he added.
AVweb recently visited the Continental Motors Group facilities in Altenburg and St. Egidien, Germany, and will have additional reporting on what’s going on at those plants later this month. One significant development, according to Ross, is that the TBRs—time between replacement—will be raised to 1800 hours by the end of this year or shortly thereafter, a change that will substantially lower operating costs for those engines. Currently, the 135-hp 2.0 is at 1500 hours and the 155-hp, which Piper chose for the new Archer DX, is at 1200 hours. Ross said Continental had hoped to raise the TBRs sooner, but wanted to incorporate some design improvements first.