The return of Diesel engine in the aeronautic propulsion

The recent developments in piston engine technology have increased performances as specific power and specific fuel consumption; environmental concern and increasing fuel cost are the main driving factors of this evolution. New generations of turbo-diesel engines have been developed for automotive applications, being now competitive with their gasoline counterpart. The use of Diesel engine for aeronautical propulsion is a discussed topic. In the past few years there have been a number of attempts to produce diesel engines for aircraft/rotorcraft and to this aim the three most important objectives to be pursued are reliability, compactness and low weight to power ratio. In this paper an outline of the most challenging aeronautical applications for diesel engines and an overview of the most promising technical solutions are provided.