z More-electric aircraft
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APRIL 2015
AEROSPACETESTINGINTERNATIONAL.COMits eConcept vision using technologies
from the Distributed Electrical
Aerospace Propulsion (DEAP) project,
a research partnership with Rolls-
Royce and Cranfield University.
Other major Airbus Group projects
are the DA36 E-Star 2 two-seat hybrid/
electric-motor aircraft, developed with
Diamond Aircraft and Siemens, and
applications in unmanned aerial
systems such as the Quadcruiser,
which combines hover capabilities
with standard aircraft cruising speeds.
After limited MEA technology
applications on the A380 (and the
military Lockheed Martin F-35
fighter), Boeing has proclaimed its
extended use to replace pneumatics
and some hydraulics on the 787, whose
electrics are seen as easier to diagnose
and monitor. Almost everything
previously powered by engine bleed-
air is electric, according to Justin Hale,
formerly the program’s chief mechanic.
The US manufacturer says that 787
integrated power generation offers better
back-up (via a hybrid ram-air turbine
for emergency hydraulics, and lithium-
ion batteries). Electric power for brakes,
cabin air/pressurization, engine and
APU starting, landing-gear actuation,
and wing de-icing comes from four
250kVA engine-mounted generators
and two 225kVA units on the APU,
with engine inlet anti-icing the only
remaining bleed system. “More-electric
architecture dramatically simplifies the
flight deck,” says 787 chief pilot Randy
Neville. “Remote power distribution
permits use of electronic circuit breakers,
eliminating hundreds of physical units.
“Crew awareness of system state is
enhanced and part count is reduced.
For example, the 787 has 13 LRUs
for full-flight deck display,
communications, navigation and
surveillance – about half as many as
similar aircraft,” concludes Neville. z
Ian Goold is a UK-based aviation journalist,
specializing in the civil sector
UOC AND BOEING
University of Cambridge researchers have
flown an aircraft powered by parallel hybrid/
electric propulsion designed and built with
financial support from Boeing. Evaluation
flights, which have exceeded 1,500ft altitude,
will be used to optimize the system for best
performance and fuel economy.
The electric motor and Honda gasoline
engine combine when maximum power isrequired during take-off and climb. Cruising
in generator mode, the electric motor can
recharge the batteries (not done before in
the air). In motor-assist mode, it reduces
fuel consumption (said to be up to 30%
less than conventional gasoline-engined
craft). A power electronics module controls
current to and from 16 large lithium-polymer
cell batteries.AIRBUS CRI-CRI
The four-engine all-electric Cri-Cri was developed by
EADS innovation Works, Aero Composites Saintonge
and the Green Cri-Cri Association, as a low-cost
testbed for electrical technologies system integration.
“In all-electric mode, performance during climb and
aerobatics is better than a conventional aircraft of this
type,” according to program head Emmanuel Joubert.
The machine incorporates technologies such as
lightweight composite structures (that reduce airframe
weight and compensate for the additional mass of the
batteries), four brushless electric motors with counter-
rotating propellers (which propel it without CO 2
emissions and with lower noise compared with thermal
propulsion), and high energy-density lithium batteries.HONEYWELL SAFRAN EGTS
Honeywell/Safran joint venture
EGTS International has developed
the electric green taxiing system
(EGTS), which it demonstrated on
an Airbus A320 at the 2013 Paris Air
Show and expects to bring to
market in 2016. The APU powers
landing gear motors that enable the
aircraft to push back and taxi
autonomously without starting
the engines.The technology is said to cut fuel
consumption by up to 4% per flight
cycle while reducing noise and
carbon and nitrogen oxide emissions
during taxi operations. With short-
or medium-range aircraft each
spending up to 2.5 hours per day
taxiing, the system could save 600kg
of fuel daily, say Honeywell and
Safran. Pilots control aircraft speed
and direction during taxi operations.160
The number of AA batteries used
to fly an aircraft from
Matsushita Electric Industrial Co.
for 391 miles in 2006160
Cruise speed in km/h of the E-Fan
with a ‘possible’ range of 100km17,000
The number of solar cells on the
Solar Impulse aircraft on its
upcoming around-the-world flight