A diesel engine of unconventional configuration and construction is described with particular reference to general aviation propulsion application. The technical approach is justified and some supporting development experience is described. Some details are presented for a specific engine design to serve an aircraft application that requires 630 shaft horsepower at an altitude of 10,000 feet. This six-cylinder turbocharged engine displacing 9.0 liters was estimated to weigh 755 lb. and develop 980 BHP at sea level with a specific consumption of less than 0.36 lb./BHP-hr.