Over 30% increase in fuel efficiency and less noise will be appreciated by users and by people living in the neighborhoods. Some of the small aircraft make more noise than an Airbus A-380.

First, I will say that I do think that this is an improvement over the lycoming or Continental gasoline engines that are normally found in these planes.

However, why someone would build an air-cooled engine and use mechanical injection is beyond understanding. I first saw this engine at the Oshkosh airshow about 10 years ago (2001?) For the same power, you build a lighter and more reliable engine using liquid cooling and you could save even more fuel and run cleaner and smoother with electronic injection.

I am currently building an experimental plane with a liquid-cooled Rotax 914. I would rather have a diesel engine but not an air-cooled engine. Anyway, this engine is too heavy and has too much power anyway for my use. I need about 100 to 140 hp.

This engine seems to come from two realities:

"Av gas is now more expensive than beer." That high octane lead fuel economic is intolerable.

Limited av gas supplies are so rare in some areas that it can cost $20/gal to be imported.

Jet A fuel flying at a fraction of current av gas rates will win out, besides the 30%+ higher efficiency.

Air cooling and mechanical injection have one major virtue:  they either can't fail, or tend to fail gently.

Delta Hawk has been working on a liquid-cooled aerodiesel for a very long time.  I have no idea how far along they are toward their goal of FAA certification.

@ HarveyD

" Some of the small aircraft make more noise than an Airbus A-380."

Oh really, care to mention which ones?

In this picture the Safran SMA engine shape reminds me of the OPOC engine, by EcoMotors (http://www.greencarcongress.com/2010/03/ecomotors-20100310.html).
Just wonder if the OPOC Engine could be used in aircraft. The designers said the first application to be for trucks, although it naturally looks as an aircraft engine, and would probably have less packaging issues than in trucks.

Mono-engine on floats (all of them) can be heard taking off and climbing from many miles. We hardly hear the A-380 taking off from 10 Km away. People living close to airports with flying schools want to sell but can't find buyers.

Engineer-Poet

I would disagree with you on the failure mode both on air-cooled engines and mechanical injectors. Air-cooled engines often fail catastrophically with a valve or piston failure leading to basically an engine explosion. Even in the best case, a valve is burned or a piston is holed.

Electronic injectors use a high pressure pump and a common rail. It is easy to provide a second pump for backup. I believe that the new electronic injection (gasoline) Rotax 912 has a complete independent injection system. With mechanical injection, the pump supplies both the pressure and the timing.

Electronic injectors stop working when the electrical system does.  The whole point of using magnetos on an engine is that they are independent of the rest of the aircraft's electrical system; building a compression-ignition engine dependent on bus power to run makes the powerplant far less reliable than before.

I was a member of a flying club.  We had engines experience difficulties due to mechanical failure, but the aircraft was still flyable and did not have to make an emergency landing.  That's the difference between partial and total failure.