U.S. light aircraft manufacturers Maule Air and Cirrus Design Aircraft are the first two customers for the new Societe de Motorisations Aeronautiques (SMA) SR305 diesel engine. This piston engine will power Maule’s M-7 single-engine series and Cirrus’ SR21tdi, derived from the SR22.

Cirrus reportedly has ordered an initial 30 engines, but the size of the Maule order has not been disclosed. Socata has ordered 100 of the new engines for its TB20GT series and other sizable contracts are anticipated shortly. The engine has also been developed with Piper, Mooney and Raytheon Beech light aircraft in mind.

According to Maule, first deliveries of the M-7 will occur at the end of this year. Cirrus has said that the first four-seat SR21tdi would be delivered in 2002.

The SR305 engine completed European certification on April 20. At a ceremony in Paris last Monday, the certificate was presented to SMA chairman and CEO Jean-Marc de Raffin Dourny by René Gaudin, of the French civil aviation authority’s certification department.

“We have good reasons to hope that our engine will be certified in the U.S. before the end of this year,” SMA’s marketing and communications manager Miriam Dunn told Aviation International News.
 

To date, more than 8,250 hr have been logged on the test bench, including brake, propeller, equipment and endurance evaluation. The engine has also flown 120 hr on both the Socata TB20 and a Cessna 182.

The SR305 is a turbocharged, four-stroke, direct injection engine. Unlike most piston engines, it operates on kerosene instead of avgas. The four flat, 305-cu-in. cylinders produce 230 hp at 2200 rpm. The turbocharger is a Garrett GT35.

The engine has a conventional tulip-type intake and exhaust valves. These are reported to be about 13 lb lighter than those of the Lycoming IO-360 piston engine.

The new powerplant’s digital engine control has a mechanical backup. The single lever controls both power and propeller pitch.

“Fuel consumption is expected to be 30 percent less than that of equivalent gasoline engines,” said Dunn, adding that the SR305 will also have about one-third fewer parts than competitors. “An onboard computer will allow reduced inspection frequency and maintenance hours. Maintenance and reliability goals are impressive with a targeted TBO of 3,000 hours.”

According to SMA, the SR305 boasts better climb performance and power retention at altitude, thanks to the turbocharger. The company believes this justifies the new engine’s high list price, which at $80,000 is 30 percent higher than equivalent Textron Lycoming or Teledyne Continental models.

“Our objective in the next three years is to market 2,000 engines per year, mostly in the U.S.,” said Dunn. Even more ambitiously, SMA is targeting 10,000 annual SR305 sales by 2010–some 70 percent of which are expected to come from North America. The production buildup schedule calls for 300 units to be delivered next year, followed by 1,000 in 2003, doubling to 2,000 in 2004 and then rising to 10,000.

Since 1999, SMA has been developing a technical and commercial partnership with Daytona Beach, Florida-based Embry-Riddle Aeronautical University. The SR305 engine is undergoing tests on a Cessna 182.

A supplemental type certificate (STC) is being prepared by Speed Merchants of Vero Beach, Florida. The company has launched an additional STC program on the Socata TB 20GT in France.

The equal shareholders in SMA are European Aeronautic Defence and Space (EADS), Renault Sport (a subsidiary of automaker Renault) and French aero engine group Snecma. Since February 2000, SMA has been based in Lognes, near a general aviation airport in the Paris area. It employs 45 people and should have a 70-strong workforce before the end of 2001. Negotiations are under way to develop a new production facility at Bourges in central France.
 

The SR305 will encounter fierce competition from Teledyne Continental and DeltaHawk, both of which have declared their intention to enter the emerging market for general aviation diesel engines. By contrast, Lycoming–the present world leader with as much as 80 percent of the market–seems to have slowed down its diesel research-and-development effort. For the time being, SMA does not regard it as a direct threat.

The French company is now laying plans for 300-hp-plus, turbocharged, six-cylinder diesel engine. It is expected to enter production by the end of 2003.

France’s SMA has at last received U.S. Federal Aviation Administration (FAA) approval for its SR305 piston engine. On July 8, the long-awaited FAR 33 certification was granted to this diesel cycle engine that operates on Jet A fuel.

SMA has reported some 200 firm orders for its 230-hp engine. It will power versions of Cessna, Maule or Cirrus light aircraft, among others. French car maker Renault, European aerospace giant European Aeronautics Defence & Space and French aero engine maker Snecma each have one-third of the joint venture.

During winter 2001, SMA was expecting European Joint Aviation Authorities (JAA) and FAA certification to come soon and almost simultaneously. JAA certification did come in April, but it was 15 months before FAA approval actually followed. Asked why, Sandrine Vacher, SMA’s spokeswoman, told Aviation International News that the U.S. administration had “asked for further information on various subjects.” According to her, the FAA did not ask for further tests or engine modification.

Type certification processes are under way at Maule Aircraft for the M-7 and at Cirrus Design for the SR21tdi. Work on supplemental type certificates is in progress on the Socata TB20, the Piper PA-34 Seneca and the Cessna 182. Embry-Riddle Aeronautical University, in the U.S., is working on the latter. “Coming up are the Piper PA-28 and the Cessna 337 push-pull,” Vacher told AIN.

In Europe, the first upgrade package will go to humanitarian association Aviation sans Frontières (ASF), which has ordered an engine retrofit for its Cessna 182. Re-engining work should be completed by the end of this summer, at Reims Aviation’s facility in Reims, France. “This will solve ASF’s problem of avgas availability in Africa,” SMA said in a press release.

Cessna and Socata may also launch type certification processes for the 182 and the TB20 respectively. However, Philippe de Segovia, Socata’s spokesman, told AIN, “Our engineers are pretty busy with a new version of the TBM700 right now and they will start working on the integration of the diesel engine on the TB20 afterwards.” This means that the delivery of an SMA-powered TB20 family aircraft from the airframer will not happen until “2004 or 2005.”

The first engines are being manufactured in Lognes, near Paris, where SMA has a small facility along with its headquarters. “There, we can make 30 engines per month,” Vacher told AIN. First deliveries are pegged for year-end. A bigger factory is set to open in Bourges, in the center of the country, in September. It should begin with 100 engines per month and reach a nominal production rate of 167 engines per month (2000 per year) in 2003.

“Seventy percent of the market is in the U.S.A.,” Vacher said. That’s why setting up a facility in the U.S. is a possibility in the long term, she added. Of the 200 engines already on order, the majority are for OEMs Maule and Cirrus.

STCs come under the responsibility of the Aeronexx network. SMA has set up three Aeronexx joint ventures so far, in Brazil, the U.S. and France, with local maintenance companies. These joint ventures will be in charge of obtaining the STCs and selling the upgrade packages.

SMA claims the SR305 will cut direct operating costs by 30 to 40 percent, when compared with existing engines. The fuel burn itself should be cut by 40 percent. Maintenance should be made easier by a 70-percent lower parts count.