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. Originally designed for
aviation use, the family of engines also will be useful
for niche land-vehicle, marine, generator, compressor,
mineral exploration, and other space and weight restricted
applications where a simple, durable, compact heavy-fuel
engine is required.
model already developed produces from 160 to 200
horsepower. An opposed two-cylinder model being planned
now will extend the range downward, producing from 80 to
100 horsepower. Six and eight cylinder models will extend
the range upward to 450 horsepower. The whole family of
engines will use the same cylinder environment.
applications range from small two-seat Light Sport
Aircraft at the lower end of the power range, to 6-seat
single engine and 12-seat twin engine fixed wing aircraft
and 4-seat helicopters at the high end of the range.
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-supercharged, direct-drive, V
configured monoblock engine. The engine is designed to
develop rated horsepower at 2700 rpm burning Jet A, Jet
A-1, JP-5, JP-8 or diesel fuel.
The primary design
goals of the DeltaHawk engines are fuel efficiency and
light weight. 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.
The V-8 (300-450 hp)
will be nearly 1.00 lb/hp, with a projected weight of 465
lb. The mechanically injected V-4 has demonstrated BSFCs
of .38-.40 with expected values of .36-.38 with the
addition of EFI. A six-cylinder model may be developed to
address a mid range of power and weight requirements. A
two-cylinder model will be developed for Light Sport
Aircraft (LSA) and UAV use.
The engine is both
supercharged and turbocharged. 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. The supercharger also provides
"rescue power" in the event of a turbocharger failure
(supplying approximately 50% power)
.Lubrication in this
engine is accomplished by a gear-driven oil pump using a
dry sump system. Air is not drawn through the crankcase.
Additionally, the pistons are cooled by oil jets, so there
is no shortage of lubrication for the pistons and
wristpins. The sump is internal to the engine, in the "V"
between the cylinders on the inverted. The scavenge line
comes out the side of the inverted engine, and out of the
bottom in the upright.
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. An in-line starter-generator is in planning
currently holds five applied technology patents (U.S.
Patent Nos. 6,622,667 and RE40500, Australian Patent Nos.
2001280453 and 2005211638, and Canadian Patent Nos.
2430029) covering five aspects of the engine. A sixth will
be granted soon.
Mechanical design of
the engine incorporates various weight savings and
efficient manufacturing capabilities. A general layout of
the engine design is shown below.