It has never been easy rewriting the rulebook when it comes to designing light aircraft. Many new concepts have been tried in the past few decades and - with rare exceptions - struggled to attract finance, regulators' approval or customers often all three.
Europe's record has been particularly patchy, with a trail of failed projects, and it is partly why private airfields are lined with types first flown decades ago.
A French start-up - LH Aviation - believes it can offer something different with the LH-10 Ellipse, an all-carbon, two-pilot, piston single-pusher, now in early production at the firm's factory near Paris, and with initial deliveries from a 30-strong orderbook due in summer.
The all-carbon piston-single pusher LH-10 offers something different. Picture: LH Aviation
The €100,000 ($135,000) aircraft - with its engine behind twin cockpits connected to a four-blade propeller by carbonfibre driveshaft - is offered as a kit or ready to fly. It has a design unlike any other light aircraft and LH Aviation claims that it is the fastest non-jet on the market.
The Ellipse was the brainchild of then-engineering student Sebastien Lefebvre in 2003. The company was founded a few months later in 2004. Since then, Lefebvre - the chief executive - has painstakingly pulled together enough small packages of investment to secure and equip a rented large industrial unit at Melun-Villaroche airport, 35km (22 miles) south-east of the French capital and next to a large Safran engine plant and an early home of Dassault.
LH Aviation is a young company in more ways than one. Most of its 20 full-time employees - who include design engineers and technicians specialising in carbonfibre structures - are under 30. What they lack in experience they make up for in drive, with employees prepared to work for relatively modest salaries in return for a stake in a business they believe in, says sales manager Jean-Charles Devynck. "It's like a small Formula 1 team. Everyone has confidence in the project."
That commitment is one reason why investment in the project so far has amounted to just €2 million, enough for LH Aviation to build a prototype - which made its flying debut at last year's Paris air show - and two other aircraft, currently in final stages of production. These two will be shipped this summer to an unnamed overseas government that plans to use the Rotax 912-powered aircraft in a special-mission surveillance role.
Every cent of that €2 million has had to be scraped together from about seven investors. A big chunk of venture capital was out of the question. "Sebastien was just 24 when he started this. Can you imagine anyone giving you €10 million at that age if you went to them with an idea for an aircraft?" asks Devynck. However, he says talks are at an advanced stage with an unnamed source to secure finance "to take us to the next stage within three months".
That next stage will involve building around three kit and one ready-built aircraft every quarter.
Although the LH-10 is not offered as a fully certificated aircraft, LH Aviation has ambitions to be a volume producer, delivering 300 aircraft a year.
"In the future we want to be a manufacturer like Cirrus," says Devynck. "One day we will be their competitor. Our whole spirit and way of working here is like a company making certificated aircraft."
The philosophy behind the LH-10's design was to eliminate as much weight, wasted space and drag as possible to make the 5.1m (17ft)-long aircraft sporty, fuel-efficient and fast.
"We started by putting the engine in the back, behind the pilots," says Devynck. "With no engine at the front there is nothing to compromise the shape of the aircraft."
The result is an aircraft that LH Aviation claims can reach a maximum cruise speed of 200kt (370km/h), and with a full 70 litre (18.4USgal) tank of fuel can fly 1,480km (800nm) - the equivalent of Paris to Rome - with two pilots in 3.5h.
There were design challenges. One area of concern was the vulnerability of the 1.1m driveshaft connecting the engine to the rear-mounted Helix propeller. Devynck says the fact that the driveshaft is relatively short and of carbonfibre construction makes it "highly resistent" to wear.
Another challenge was to balance the aircraft's front and back. The centre of gravity is forward of the engine, under the rear seat and above the wing. If flown by one pilot, he or she must weigh at least 60kg and sit in the front seat.
LH Aviation uses an infusion technique with its composite materials, injecting resins between carbonfibre sheets to create the structures. Kevlar is added on the wing leading edges, the seats and the elevators. The fuselage is created on moulds in two halves and fused together. As a kit, the company says "a beginner" can construct the aircraft in 600h, with the wing and stabiliser detachable "in minutes" for loading on a truck.
With budgets still tight, Devynck says the priority this year will be to meet commitments to existing customers rather than spreading the word further. After its appearances at Le Bourget and at Farnborough in 2008 - "we went to get exposure to banks and possible partners" - LH Aviation will hold back on its air show appearances in 2010. However, it plans a French tour of airfields and local air shows and to set some performance records.
The world's biggest general aviation market also beckons and the company would like to "build a factory there at some point". However, he says any move into North America will have to wait. "In the USA, everybody wants something right now, and we are not ready."
The response to the LH-10 has surprised even its inventors. "At the beginning our aspiration was to replace older private and club aircraft, but now our ambitions have become higher," says Devynck. "We've had interest from the military, flying schools, professionals, aerial photographers and air taxi operators. We really think we have introduced some innovation to aviation."