SMA unveiled at Sun n' Fun a new version of its SR305. The French manufacturer is attempting to drum up demand for the general aviation diesel engine after several years of sluggish sales.

The SR305-230 was certificated in 2001 and has been in production since 2003. But SMA chief executive Luc Pelon says that only 46 engines have been sold to date, all for retrofit on Cessna 182s. "The performance wasn't good enough for OEMs," he says.

But the SR305-230E doubles the ceiling to 20,000ft (6,100m) and while sold as a 230hp (170kW) engine it should be able to power aircraft requiring 250hp and perhaps up to 280hp.

Pelon says SMA is seeking an amended certificate for the SR305-230E from the FAA and the European Aviation Safety Agency based on the engine's original certification. SMA hopes the amended certificates will be secured before the Experimental Aircraft Association AirVenture show in July.

SMA is flight-testing the SR305-230E using a Socata TB20 and a Cessna 182, for which it will continue to be available as a retrofit. But falling aircraft values have damped the retrofit market, so Pellon says SMA is now trying to persuade Cessna to offer the -230E on new 182s and envisages the engine eventually being offered by several OEMs.

In 2002 the SR305-230 was selected by Cirrus to power new SR22s and by Maule to power M9s. The Cirrus partnership fizzled out and Georgia-based Maule has yet to certificate its new M9-230.

Maule director of sales and marketing Brent Maule says certification should come this year. He acknowledges the project has taken "way too long", but says it was complicated by Maule's decision to simultaneously pursue an increase in gross weight.

The five-seat M9 is a new variant for Maule, derived from the M7, with a gross weight of 1,270kg (2,800lb) compared with 1,1135kg on earlier models.

Maule says for it will remain loyal to the original SR305-230 for the time being, but later will consider upgrading to the -230E.

He says interest in Maules that can be flown with jet fuel "hasn't died" despite the certification delays and has been increasing.

Maule and SMA see strong demand for diesel engines in markets where there is limited or no avgas availability, but also predict strong long-term demand in North America.

"Initially it will be all outside the USA - Europe, Asia, South America and Africa. But eventually it will be big in the USA," Maule says.

Source: Flight International