The birth of a quieter, greener plane: 35% more fuel-efficient; Cambridge-MIT Institute's 'Silent' Aircraft Initiative

http://news.bbc.co.uk/2/hi/business/6113418.stm
The birth of a quieter, greener plane
By Tim Bowler
Business reporter, BBC World Service

....

Now a team of researchers in Britain and the US has come up with a
revolutionary new aircraft design that could make a dramatic
contribution to curbing climate change.

The SAX-40, which has been developed by the Cambridge-MIT Institute,
is a radically different shape of aircraft.

Officially, it is what is known as a "blended wing". It has a tailless
wedge-shaped body with two bat-wings.

The Silent Aircraft Initiative (SAI) team has succeeded in coming up
with a radically quieter plane. Crucially, the SAX-40 is also 35% more
fuel-efficient than any airliner currently flying.

The case for radical change is getting stronger

Prof Ann Dowling, SAI's UK team leader

Oil prices may no longer be the $78 a barrel they were a few months
ago, but with high fuel costs likely to continue, fuel efficiency is a
major factor in all airlines' calculations.

Yet none of this means the SAX-40 will necessarily be built. Ever
since the Boeing 707 first flew in 1957 and ushered in the commercial
jet age, airliners have changed very little in their basic appearance.
Airliners still consist of a tube-like fuselage, with two swept-back
wings and engines slung underneath. (The world's first - but
commercially unsuccessful - passenger jet aircraft, the DeHavilland
Comet, had the engines integrated in its wing).

Innovation costs

There are good economic reasons why design has remained so
conservative.

By making the fuselage a tube, aircraft-makers can easily build a
family of larger or smaller variants, utilising many of the same
parts.

And by sticking engines under the wings, it's easier to maintain them,
or upgrade them halfway through an aircraft's 30-year lifespan.

Naturally, aircraft manufacturers have made considerable improvements
in the past 50 years, for instance using composite materials and
lighter, more efficient engines.


The SAX-40 will be far less noisy than current jets

Yet future improvements to the basic design are getting harder to
make, according to Professor Ann Dowling, professor of mechanical
engineering at Cambridge University and SAI team leader in the UK.

"The case for radical change is getting stronger," she says.

"It's only through such a change that one can achieve step-changes in
fuel burn."

But for aircraft manufacturers like Boeing or Airbus, any design
changes need to produce a quick return on their investment.

Boeing is working on developing fuel cells to power aircraft
air-conditioning and electrical systems. Currently, these are run off
a plane's engines, reducing their efficiency.

Bill Glover, Boeing's director of environmental performance,
commercial airplanes, says using fuel cells would give significant
savings.

"With fuel cells we can take conventional fuel, convert it into
hydrogen and produce electricity very efficiently," he says. "The only
other emission is water."

But even this is still 10 to 15 years in the future.

Radical shift?

There is a good reason for the aircraft manufacturers' caution.
Building totally new planes is both costly and risky.

After Boeing launched its Boeing 747 jumbo jet in 1968, it ran into
serious financial difficulties when the demand for its new plane
stalled.

To survive, the company slashed its workforce from 100,000 to 38,000.

Today, Airbus is also having financial problems with its giant
double-decker A380.


The Airbus A380 has run into difficulties in recent months

For manufacturers, it is much safer to develop new airframes out of
what has gone before, rather than re-tool completely with a brand-new
production line.

Yet with increasing concern over climate change, we could see a
radical shift in aircraft design.

This would be more likely if airlines had to pay "green" taxes on
their airliners' emissions of greenhouse gases.

But the skies are not going to fill with radically new aircraft shapes
any time soon.

When an airline buys a new plane, it will keep it flying for decades
in order to make it pay its keep.

Which means even if this design gets the thumbs-up from the
manufacturers, we won't be queuing up to board planes like the SAX-40
before 2030 at the earliest.








http://www.cambridge-mit.org/cgi-bin...D=6&NewsID=189
Boeing joins CMI's Silent Aircraft Initiative
Aug 31 2004

We are pleased to announce that The Boeing Company has formally
entered into a collaboration with the Cambridge-MIT Institute's
'Silent' Aircraft Initiative. This is a three-year project, sponsored
by the Cambridge-MIT Institute, aimed at a new generation of quiet
aircraft.

Under a recently signed memorandum of understanding, Boeing will allow
the Massachusetts Institute of Technology (MIT) to use some of its
advanced design software to design and analyse aircraft that are being
considered as conceptual design candidates. The software uses a state
of the art, multidisciplinary design optimisation framework that
considers aerodynamic, structural, stability, control, and mission
performance factors. Noise prediction models will be added to this, to
aid in the design of the 'Silent' Aircraft.

The Cambridge-MIT Institute's 'Silent' Aircraft Initiative was
launched in November 2003 with a bold aim: to discover ways to reduce
aircraft noise dramatically, to the point where it would be virtually
unnoticeable to people outside the airport perimeter. The initiative
is bringing together leading academics from Cambridge University and
the Massachusetts Institute of Technology (MIT) with an extended
'Knowlege Integration Community' of representatives from all parts of
the civil aerospace/aviation industry. They include BAA, Boeing,
British Airways, the Civil Aviation Authority, Lochard, Marshall
Aerospace, National Air Traffic Services, the Royal Aeronautical
Society, and Rolls-Royce. Members of the 'Silent' Aircraft Community
are working together, sharing knowledge and developing the design for
an aircraft that has noise reduction as its primary consideration.

In addition to the design software, Boeing will also provide technical
consultation services to the 'Silent' Aircraft Initiative's integrated
team of researchers at both MIT and Cambridge. Providing consultation
will be Dr Robert Liebeck, head of an advanced Transports and Tankers
design group in the Boeing Phantom Works advanced research and
development (R&D) unit. Dr Liebeck, who is also a Professor of the
Practice at MIT, will be working with Karen Willcox, Professor of
Aeronautics and Astronautics at MIT. Prof Willcox leads the
Integration research work within the 'Silent' Aircraft Initiative and
worked briefly with Dr Liebeck at Boeing before she joined the MIT
faculty.

Prof Ed Greitzer, who is leading the 'Silent' Aircraft research team
at MIT, says: "The connection with Boeing presents several excellent
opportunities for the 'Silent' Aircraft project. These include the
ability to draw on Boeing design knowledge acquired over many years,
and to have students and faculty use industry-level tools for the
conceptual design and analysis of innovative aircraft that are
designed with noise as the primary consideration."

Dr Robert Liebeck says: "This is an ideal opportunity to examine the
upper bound of silence for a next-generation of subsonic transport,
and the cost/benefit of achieving said silence."