I tend to agree that gasoline should be phased out in favor of diesel engines such as the DeltaHawk. Better aviation diesels are slowly being developed by firms that realize there are efficiency gains to be had through in high-pressure combustion that cannot be had with lower pressures. Perhaps they also want to offer a solution to the issue of oil dependence from natural reserves located in foreign lands which is a big issue to consider. There is also the possibility of an eventual depletion of natural reserves although the latter is not certain. In the meantime there must be a renewable non-leaded gasoline substitute for existing engines when 100LL is banned due to environmental rules. Clean turbo-diesel is a wonderful technology whose time has come in my opinion. The main barriers are high upfront investment figures and the slow sales of engines of this size. Here is a new aviation turbodiesel to add the the list:

500 hp [Raikhlin] diesel tested in Germany

(AOPA ePilot, 11/26, A.K. Marsh) "Raikhlin Aircraft Engine Developments (RED), a new venture founded by Wladimir Raikhlin and his associates, has flown a 500-horsepower diesel engine on a modified Yak 52. The propeller for the water-cooled, twelve-cylinder engine called RED A03 is gear driven. It was built by RED Aircraft GmbH in Adenau, Germany. The engine generates 500 hp for takeoff at 3,900 rpm. The engine weight at the moment is 705 pounds, according to diesel engine consultant Andre Teissier-duCros. The company brochure does not give the weight, marking that specification as “to be announced.” The weight includes two alternators, a starter, an engine/gearbox oil heat exchanger, and a prop governor..."


Thielert [maker of biofuel-compatible GA turbodiesels]: Profitable, Seeking Investors.

(AvWeb, P. Bertorelli, 11/30) "Thielert Aircraft Engines GmbH says it has returned to profitability, improved its engines and is now seeking investors to continue its revival... After its initial reorganization in 2008, Thielert’s attempt to find investors yielded no results because of the global financial crisis. Further, the company’s sales dipped as Diamond Aircraft, the principle civil buyer of its engines, turned to its own engine supplier, Austro, to provide engines for the popular DA42 light twin. Thielert has a significant military market in supplying engine for UAVs... As of last September, said Thielert, 3000 of its engines were operating worldwide, making it the most successful aircraft diesel in history. The lifetime of the Centurion 2.0 engine was recently increased to 1500 hours and clutch and gearbox lifespans were extended to 600 hours. Although the gearbox and clutch lifespans still fall short of what Thielert promised two years after the engine was introduced, the company now claims net operating costs and efficiency are better than ever..."