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us that Sullivan has recently supplied its
first hybrid system, and as such is still
exploring the possibilities of hybrid power
for multi-rotor craft.
Power4Flight’s Jim Newton
explained
that his US company is
working in a three-way partnership with
Currawong Engineering (Australia-based)
and Cobra Aero (US-based) to develop a
range of UAV engines.
The team has developed the B29i
(also known as Corvid-29), a 29 cc
fuel-injected engine manufactured by
Currawong, with an advanced engine
calibration system developed by
Power4Flight and a specially designed
and manufactured low-noise exhaust
by Cobra Aero. Thirty engines have
been fielded and integrated into three
different airframes. Newton said they
also provide a 35 cc and a 50 cc
engine, and have plans to expand their
product range further.
Newton also introduced us to Cobra
Aero’s Sean Hilbert, whose company
is the lead developer of the A33-N, a
33 cc air-cooled single-cylinder which,
unusually for its market, will feature twin
spark plugs and a variable exhaust
system. The system shows excellent fuel
efficiency and noise output for loitering
mode he said.
The exhaust power valve is either fully
opened for maximum power or partially
closes the exhaust port for less noise
and greater fuel efficiency, such as when
the UAV is loitering as opposed to taking
off or climbing. It is used in conjunction
with an exhaust bypass valve that avoids
the use of the main noise attenuation
route in the exhaust when maximum
power is required.
The 2.1 kW A33-N features CNC
machine-finished transfer ports and uses
proven Currawong fuel injection using an
electrically driven positive displacement
piston fuel pump to deliver fuel – initially
gasoline – at around 3 bar to a solenoid-
type injector.
Currawong’s Gavin Brett noted that
this system overcomes the fuel delivery
issues that affect many small two-strokes
used in UAV applications. There are more
than 1000 Currawong fuel systems in the
field, he said.
Brett brought to our attention the
development of hybrid propulsion
systems for UAVs, combining internal
combustion (IC) and electric power.
Currawong is due to launch its hybrid
solution for multi-rotor craft and a parallel
hybrid solution for fixed-wing craft later in
2016 (along with other variations on these
June/July 2016 |
Unmanned Systems Technology
Power4Flight is partnering with two other
companies to develop a UAV engine range
Aeryon demonstrated its Aeryon Live platform using a SkyRanger