A year after its dramatic unveiling at last year's
convention in Las Vegas, Aerion Corp.'s supersonic business jet (SBJ) project
has vaulted its first hurdle with the completion in September of Phase 1 basic
design. As vice chairman, Brian Barents explained at an eve-of-show press
conference, "We have made substantial progress since last year, [and] technical
viability has been confirmed by wind tunnel and computer analysis. We are now
ready to present the design to potential partners."
The machine in current artists' impressions differs in
several details from that shown last year. The T-tail has been replaced by one
of cruciform design; fuselage cross-section has been refined; wing planform is
modified with raked tips and reduced in area; wingroot strakes have been shrunk and modified for better
low-speed stalling characteristics; and flap design has changed.
In these two last-mentioned areas, the Aerion SBJ has unique
features. As explained by chief technology officer Richard Tracy, the thin wing
precludes slotted flaps to reduce landing speed, so it has been fitted with
plain flaps that have a half-chord split flap in their lower surface and
additionally function as flaperons. Airflow at the wing leading edge/fuselage
interface has been improved by a curved notch at the intersection.
Interestingly, the SBJ has fly-by-wire controls, but it is
naturally stable, so a failure of the stability augmentation system will not be
critical providing the actuators continue to function. Natural stability means
a "bigger tail and the C of G range farther forward," says Tracy. "There is
some [performance] penalty, but it is not large."
This, indeed, encapsulates the Aerion approach. The aircraft
does not rely for its viability upon large forward strides in technology—P&W
JT8D-219 turbofans do the Mach 1.6 business without variable geometry intakes
or nozzles—or contentious legislation being passed to allow overland
super-sonic flight. The Aerion SBJ is "achievable at low technical risk,"
according to chairman Robert Bass.
And the risk-sharing partners who are needed to take Aerion
to its next stage? "We can't announce them yet," Bass says.
Maybe we'll have to come back to Orlando next October to ask
again.
