Aviation Week & Space Technology - 30 March-12 April 2015

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Graham Warwick Brussels

Balancing Act

Europe sets sights on 2050

targets for civil aviation with Clean

Sky 2 research program

B

alancing demand for large-scale integrated demonstra-

tions to mature technologies with the need to keep the

pipeline of new ideas flowing could prove the defining

challenge for the Clean Sky 2 civil aviation research program

getting underway in Europe.

Now in its culminating phase of technology demonstra-

tions, the original Clean Sky program (CS1) is firmly focused

on helping meet the European aviation industry’s environ-

mental goals for 2020. But the much-larger Clean Sky 2 (CS2)

has the dual task of finishing up that work while also setting

of down the path to meeting even more aggressive targets

industry has set for 2050.

Clean Sky was created as a public-private partnership to

bring both government and industry investment to bear on

preparing for the next generation of European civil aircraft.

From laminar-flow wings to noise-shielding tails, open-rotor

engines to low-emission turbofans, more-electric systems

to more-efcient rotors, CS1 is raising technology readiness

levels (TRL) across a wide spectrum for future airliners, re-

gional aircraft, business jets and rotorcraft.

CS1 ends in 2017, but CS2 extends the public-private part-

nership to 2024, and expands it to encompass large-scale

flight and ground demonstrations of open-rotor and ultra-

high-bypass propulsion, hybrid laminar flow control (HLFC),

integrated cabin systems and struc-

tures, and next-generation cockpits.

The program will fly both compound

and tiltrotor high-speed rotorcraft,

and show technologies for a 90-seat

turboprop and a 19-seat transport.

“Clean Sky 2 has more emphasis on

very integrated flight demonstrations,

but also far-reaching low-TRL research

targeted at 2030-35,” says Eric Dautriat,

executive director of the Clean Sky

Joint Undertaking, which manages

the programs. He cites the Airbus-led

Large Passenger Aircraft (LPA) inno-

vative aircraft demonstrator platform

(IADP), which will include both near-

term maintenance technology develop-

ment and far-term hybrid propulsion

research “in the same package.”

Where CS1 is a €1.6 billion ($1.8 bil-

lion) program, with funding split 50:50

between government and industry,

CS2 is €4 billion efort, with €1.75 billion from the European

Union (EU). This represents 85% of EU funding for aero-

nautics research, up from 50% for CS1, and leaves only $200

million in funding over 10 years for European collaborative

research outside CS2. That means ensuring there is oppor-

tunity for far-term research projects within the nearer-term

IADPs and integrated technology demonstrations (ITD) that

make up Clean Sky 2. “The IADPs are where we will see full-

scale, fully-integrated demonstrations for large passenger

aircraft, regional turboprops and fast rotorcraft,” says Ron

van Manen, Clean Sky 2 program manager. These are largely

continuations of ITDs within CS1, “but take the next half step

integration beyond that,” he says, to achieve Clean Sky’s end

goal of maturing technologies to TRL 6.

Focused on commercial airliners, Large Passenger Aircraft

is the biggest of the three IADPs within CS2, at almost €1.1

billion, and a follow-on to the smaller Smart Fixed-Wing Air-

craft (SFWA) ITD within CS1. As with SFWA, LPA is also

applicable to large business jets, which is why Dassault is a

lead on airframe work. Within LPA are three “platforms”:

advanced engine and aircraft configurations; innovative

physical integration of cabin systems and structure; and

next-generation cockpits, systems and avionics.

SFWA started with two objectives: to flight test a natural

laminar-flow wing and an open-rotor engine. The project to

demonstrate robust laminar flow in a real operating environ-

ment is still part of CS1, but delays pushed the open-rotor

flight demonstrator into CS2. An Airbus A340 has now ar-

rived at Tarbes in France to be fitted with new outboard wing

sections representing two diferent approaches to designing

and manufacturing wings to the tight tolerances required to

maintain smooth laminar flow.

The laminar demonstrator, called Blade, has proved chal-

lenging, particularly certifying the safety of the refurbished

and highly instrumented A340-300 test aircraft after such

Modifying an A340 test aircraft

with new natural-laminar-flow

outer wing sections has proved to

be challenging.

AIRBUS