global briefing
Albatross-inspired
aircraft takes to
the skies
// The scale-model of the AlbatrossOne,
which is being used to investigate the
stability of the hinged wing tip concept
AEROSPACETESTINGINTERNATIONAL.COM // JUNE 13
Engineers from Airbus are developing an
aircraft with hinged wing tips that “flap”
while in-flight.
The design of the wing tips, which use a
“semi-aeroelastic hinge”, has been inspired
by bird-flight. They have been fitted to a
scale-model aircraft which is being tested in
Filton, UK.
The concept is intended to reduce drag
and overall wing weight, while combating the
effects of turbulence and wind gusts.
Folding wings are used by fighter jets that
are stored on aircraft carriers. Boeing is also
developing the 777X with folding wing tips,
which are required so the aircraft can fit
standard airport gates, for civilian use.
The remote-controlled model, which is
known as AlbatrossOne, has already taken its
first flights to prove the concept. The research
team is now conducting further testing
before the demonstrator, which is based on
the manufacturer’s A321 aircraft is scaled-up
for further testing.
Tom Wilson, loads and aeroelastics
engineer at Airbus said, “This is the first
aircraft ever to trial in-flight, freely-flapping
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wing tips to relieve the effects of wind gusts
and turbulence.
“We drew inspiration from nature – the
albatross marine bird locks its wings at the
shoulder for long-distance soaring but
unlocks them when wind-gusts occur or
when maneuvering is required.
“The AlbatrossOne model will explore the
benefits of unlockable, freely-flapping wing
tips – accounting for up to a third of the
length of the wing – to react autonomously
during in-flight turbulence and lessen the
load on the wing at its base, so reducing the
need for heavily reinforced wing boxes.”
The hinge is combined with a lock and a
clutched actuator to produce an adaptive
system which releases the wing tip in
response to a severe gust or manoeuvre, but
then “recovers” to its planar position
afterwards to continue efficient flight.
Jean-Brice Dumont, Airbus’ executive vicepresident
of engineering said, “When there is
a wind gust or turbulence, the wing of a
conventional aircraft transmits huge loads to
the fuselage. This means that the base of the
wing must be heavily strengthened, adding
weight to the aircraft.
“Allowing the wing tips to react and flex to
gusts reduces the loads and allows us to
make lighter and longer wings – the longer
the wing, the less drag it creates up to an
optimum, so there are potentially more fuel
efficiencies to exploit.”
The first test flights of AlbatrossOne were
concluded in February after a 20-month
development project. Research and
simulations have been done to understand
the physics of the wing tip, including how the
orientation of the hinge’s axis can be used to
avoid flutter and also analyze the levels of
load alleviation that are achievable, which
according to the research is approaching
20% in terms of wing root bending moment.
The static and dynamic stability of the
wing tip was also verified by wind tunnel
tests at the University of Bristol in the UK.
The flight test AlbatrossOne model has
been constructed from carbon fiber and glass
fiber-reinforced polymers, as well as 3D
printed components.
Testing of AlbatrossOne has so far
examined the demonstrator’s stability with
the wing-tips locked and completely
unlocked. Airbus research engineer James
Kirk said, “The next step is to conduct further
tests to combine the two modes, allowing the
wing-tips to unlock during flight and to
examine the transition.” \\
/AEROSPACETESTINGINTERNATIONAL.COM
/AerospaceTestingInternational.com