DeltaHawk, Racine, WI
The last couple of years development in aircraft engines has been more or less concentrating on diesels. We have seen one off installations to fully developed production lines. A number of companies are active on this market primarily due to major concern of long term availability and the relative high price of AVgas (Europe).
Diesel engines are able to use JET fuel (AVtur). This fuel is available worldwide and can also be made of renewable sources (algae) which should contribute to a cleaner environment.
The DeltaHawk family of heavy-fuel piston engines combines long-established diesel engine principles with modern materials and design to produce a high power-to-weight ratio product with the added benefit of reduced fuel consumption compared to equivalent gasoline engines.
This range of engines (160, 180 and 200 bhp) have been under development for a good number of years, its good to see something come to a flying prototype and production stages.
US Diesel Technology
The DeltaHawk engine is a two-stroke, piston-ported (loop scavenged), dry-sump, pressure lubricated, diesel-cycle piston engine. It is a liquid-cooled, turbo and supercharged, direct-drive, V configured monoblock engine. The engine is designed to develop rated horsepower at 2700 RPM burning fuels like Jet A, Jet A-1, JP-5, JP-8 or diesel fuel.
The primary design goals of the DeltaHawk engines are high fuel efficiency and light weight installation. The V-4 (160-200 hp) has targeted power to weight ratio of 1.75 to 1.50 lb/hp. Total weight of the V-4 engines is 330 lbs - including exhaust, turbocharger, alternator, and starter. Not including the propeller.
Turbo and Supercharger
The engine has a super- and turbocharger. A battery powered starter with flywheel provides the initial compression stroke. The belt-driven supercharger provides the starting air compression, delivering air on the first rotation of the engine. Once the engine has achieved sufficient RPM, the turbocharger comes online and takes over. The supercharger also provides "rescue power" in the event of a turbocharger failure (supplying approximately 50% power).
Other than initial startup, the supercharger remains inactive on the engine and sits along for the flight. This is the same principle the Wilksch engine uses.
Lubrication in this engine is accomplished by a gear-driven oil pump using a dry sump system. As a result air is not drawn through the crankcase. On top of that, the pistons are cooled by internal oil jets, to make sure that there is no shortage of lubrication for the pistons and connecting pins. The sump is internal to the engine, located in the "V" between the cylinders on the inverted model. The scavenge line comes out the side of the inverted engine, and out of the bottom in the upright version.
The fuel system includes a delivery pump and four high pressure (20,000 psi) mechanical injector pumps. The main pump has its own internal delivery pump which puts 50-90 psi fuel to the injector pumps, which add the final pressure increase. Fuel filtering is accomplished by a standard diesel fuel filter (30 micron filtration) with a water drain and a final fuel filter (3-5 micron) after the delivery fuel pump.
The current fuel system is entirely mechanical; electronic fuel management may be developed for special applications. This means that the basic engine does not need electrical power and a backup system to run.
The next link opens a window showing the DeltaHawk inverted V engine in greater detail: click here.
Text from the website of Deltahawk and modified to suit.