The project was purposely set at an
extremely fast pace, and with a nearly
“impossible” schedule to challenge the
team. Significant amounts of
computational fluid dynamics (CFD)
cases and finite element modeling
(FEM) were run, as well as extensive
rotor dynamics calculations and
analysis.
The full-size demonstrator’s rotors
are driven by advanced electric motors
powered by rechargeable batteries. (The
Project Zero testbed is also slated to test
future hybrid solutions, such as a diesel
engine to drive a generator.) The
aircraft’s flight control systems, nacelle
tilting mechanism, and landing gear all
use electromechanical actuators (EMAs),
eliminating any hydraulics onboard.
During cruise, the wings provide
most of the lift, with the blended
fuselage and shrouds around the rotors
also making contributions. Elevons
provide pitch and roll control in forward
flight, while the winglets and short V-tail
provide lateral/directional stability. The
aircraft is designed with detachable
outer wings for short-range missions
that would be performed primarily in
helicopter mode.
The all-electric approach eliminates
the complex and heavy transmission
system required by conventional
rotorcraft, and has very low acoustic and
thermal signatures in flight. The motors
also do not require oxygen, which
would permit the aircraft to fly at
extremely high altitudes or in heavily
polluted conditions, such as volcanic
eruptions or other toxic environments.
The demonstrator’s batteries can be
recharged on the ground by tilting the
rotors into the wind to act as turbines.
Wang says,“Electric technologies are
speeding ahead at a very fast pace. The
energy and power densities of
advanced batteries are moving in leaps
and bounds. The company and its
partners developed the electric motors,
inverter and electrical management
system specifically for the aircraft.
Rather than waiting for the battery to
become even better, then working on
electric aircraft technology, the team
has positioned itself to be ready for the
next generation of batteries. The aircraft
was also designed to accept different
energy sources for its electric motors,
such as a hybrid diesel electric
generator, and the work has already
been started.”
The aircraft incorporates more than
80% composites, including 100% of the
skins, rotor blades, shroud and spokes.
The structure is nearly all aluminum and
carbon – very little steel was used.
Rotor grips are titanium. Wang notes
that it was an extremely fast pace
research project, with AgustaWestland
looking for materials that would result
in the fastest speed in getting the
Vol. 59, No. 3
11
In this photo, the carbon skin construction joints and outer wing panel sections are clearly
discernible.
Members of AgustaWestland’s Advanced Concepts Group approach the aircraft in the only wide-angle photo that had previously been released of the
complete aircraft.
1,2 4,5,6,7