SMA (Hall 5A, G6), the joint venture between Renault, EADS and Snecma, has fulfilled its parents' objectives: the first diesel engine operating on Jet fuel, designed for the General Aviation (GA) market, is now on sale. The SR305 will enter mass production of 2000 units a year in September when the Bourges, France located plant starts rolling.

The SR305 is such an innovative product that it proved difficult to obtain certification for the engine. US concerns about the new engine's impact on the domestic market, now dominated by Continental and Lycoming, apparently delayed US certification.

Operating on Jet A fuel, the SR305 reduces running costs by up to 60%. Jet A is cheaper than Avgas and the SR305 consumes 30-40% less than its rivals (45litres/hr instead of 64 at 230hp). It also promises relief from Avgas shortages which are a frequent limiting factor to operations in some regions of the world.

Visual checks

The SR305 offers improved performance with power at high altitude and increased comfort thanks to an easy-to-fly, single lever. An engine computer automates different functions and saves time.

With 230hp, the SR305 runs at a constant speed of 2,200rpm. Although it is slower than its competitors, it has advantages: reduced noise level (5-7Db) and reduced engine fatigue, allowing for a targeted TBO (Time Between Overhaul) of 3,000h, 500h more than the other engines on the market.

The modern design and manufacturing also allows for big savings on maintenance. The SR305 comes with 70% fewer parts than its rivals, requires inspections only every 100h instead of the usual 50h, and most of the checks can be made visually without taking off parts.

SMA currently markets its engine as a retrofit or as an original/prime engine. An upgrade package is available for the Cessna 182 and the Socata TB20, for which it expects to gain its STC (Supplementary Type Certificate) this summer. Maule Air and Cirrus, once they have STC, will also mount the SR305 directly on their M-9 and SR20 airframes, respectively.

SMA has already sold around 200 SR305-230s and plans a 300hp version for 2005.

Source: Flight Daily News