ightglobal.com 18-31 August 2015 | Flight International | 31
RUSSIA
SUPERJETcalled Superjet NG does not start with a clean
sheet of paper, Sukhoi is working on a pack-
age of major performance improvements that
could alter the shape and lifting characteris-
tics of the wing, exchange Western-based sup-
pliers of systems and avionics with Russian
firms, but possibly leave the powerplant
largely the same; albeit slightly more efficient.
A 100-seat regional jet stands out in Suk-
hoi’s traditional product portfoilo, which con-
sists exclusively of fighters and aerobatic air-
craft. Until former Sukhoi and United Aircraftchief executive Mikhail Pogosyan launched
the Superjet programme, passenger aircraft
were solely the domain of design bureaus
such as Ilyushin, Tupolev and Yakovlev (now
part of Irkut).
But the Superjet programme’s association
with the same designers responsible for high-
performance fighters such as the Su-27 clearly
had an effect.
The Superjet on paper boasts one of the most
efficient wings for any commercial aircraft. By
one standard measure of efficiency, the Superjet
wing’s aspect ratio is a highly respectable 10,
equalled or exceeded only by aircraft such as
the Bombardier CSeries and Boeing 787.
“We already know quite well the Bom-
bardier product. We are looking at the new
generation Embraer product. But I believe it
will be quite close to the aspect ratio level
already achieved. So it is between 10 and- I do not think Embraer will take the risk
to increase the aspect ratio to more than
12,” Dolotovsky says.
“You know there is a big research activity
in the aviation industry now to find a solution
to buffeting to increase the efficiency of the
wing,” Dolotovsky says. “And there is a goal
after 2020 just to find a preliminary technical
solution which could be recommended in in-
dustry to be used for advanced projects after - So in this direction there is no way to
increase the lift over drag ratio from my point
of view for close to 20 years.”
INCREASING STRENGTH
For the stretched model, Sukhoi is considering
ways to slightly improve the performance of
the wing, but such a task is complicated. Mak-
ing the wing more efficient has the effect of in-
creasing the aerodynamic loads, which, in
turn, requires the designers to increase struc-
tural strength from the wingtip to the torsion
box where the wing meets the fuselage.STEPHEN TRIMBLE PARISThe Superjet marked Sukhoi’s
first foray into passenger jets“Compared with the existing
product on the market, the
SaM146 is better by 1-2%”
ALEXEI DOLOTOVSKI
Deputy chief designer, Sukhoi❯❯S
ingle-model product offerings are so
rare in the commercial aircraft busi-
ness that they usually represent a
strategic miscalculation made some-
where at the beginning of an unexpectedly
long development process.
The Sukhoi Superjet arguably makes a
good example.
Launched 15 years ago as a replacement
for the Tupolev Tu-134 and Yakovlev Yak-42,
the original Superjet concept included a fam-
ily of three products – a 60-seater, a 75-seater
and a 95-seater.
As the development schedule dragged on,
it became clear the 60-seat concept so popular
in the late-1990s regional jet boom had fallen
out of favour. By the time Sukhoi finally de-
livered the first operational product – and
largest of the three original variants – in 2011,
interest in completing development of the
75-seater had also dried up.LARGER FOCUS
The Superjet family of aircraft is now back on
the agenda, but the focus has shifted from
smaller aircraft to a larger model. The Super-
jet NG also offers Sukhoi and the greater Rus-
sian industry a unique opportunity to im-
prove aircraft performance.
The stretch project is currently in the pre-
liminary research phase, Sukhoi deputy chief
designer Alexei Dolotovsky tells Flight Inter-
national in an interview. He describes the sta-
tus in mid-June as between gates 2 and 3 of
Sukhoi’s internal development process.
The original Superjet was proposed in
2000, a year after Embraer launched the first
version of its E-Jet family. Thirteen years
later, the 95-seat version of the Superjet had
just entered service, but Embraer launched
the second-generation of the E-Jet family
with a new wing and new engines – the
Pratt & Whitney PW1700G and PW1900G
geared turbofans.
Sukhoi claimed a 6% cash operating cost
advantage for the Superjet over the original
E-Jet series. It would have to do something
with the Superjet to respond to the improved
performance of the E-Jet E2 series.
But Sukhoi also faced several constraints.
Embraer has received orders for more than
1,000 E-Jets, creating a strong financial base to
develop the improved version. Sukhoi has
struggled to attract non-Russian buyers for the
Superjet, with certain exceptions, such as
Mexico’s Interjet. But the Sukhoi programme
lacks the financial power offered by the E-Jet
series. The Superjet programme also fell
deeply into debt, which was relieved earlier
this year with a commitment from the Krem-
lin to invest in a nearly $2 billion bail-out.
SukhoiWhile the design for the stretched, so-