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By Eric Hagerman | March 2007If you’re
ever lucky enough to fly a Quiet Supersonic Transport
between New York and Los Angeles, you’ll have just enough
time to get through a movie—a short one. Instead of the
usual six hours, it will be a 1,100mph, two-hour hop. The
QSST, as the proposed luxury private jet is known, could be
the first civilian supersonic plane approved for overland
routes, thanks to aerodynamics designed to muzzle its sonic
boom. Lockheed Martin’s Skunk Works has been developing the
project for six years under a $25-million contract from
Supersonic Aerospace International (SAI), founded by Michael
Paulson, son of Gulfstream founder Allen Paulson. The
12-passenger QSST would fly at between 47,000 and 57,000
feet with a range of 4,600 miles (Chicago to Rome, for
example), and it doesn’t need an extended runway. Configured
with 12 club chairs, a spacious bathroom and a sweet A/V
system, the QSST is aimed at diplomats or executives with
plenty of money—but little time—to spare.
Designed to fly between Mach 1.6 and 1.8 (1,056 to 1,188
mph), the two-engine gull-wing aircraft would leave a sonic
wake that’s only one hundredth the strength of the Mach
2–capable Concorde, the 100-seat speed demon that wound up
permanently grounded following a fatal accident in 2000.
(High maintenance costs for the aging fleet and a struggling
airline industry also contributed to its demise.)
Eliminating bone-rattling sonic booms is a major feat of
aerodynamic hocus-pocus. When an aircraft travels faster
than the speed of sound, it creates pressure waves in the
air that collide with one another faster than they can
dissipate, resulting in a loud crack, or sonic boom. The
QSST, though it shares its general shape with the Concorde
is less than half the size and uses fine-tuned aerodynamics
to control the pressure generated as the plane displaces air
at supersonic speeds. With air disturbances along the craft
evened out, the QSST generates more shockwaves of smaller
magnitude rather than two explosive reports. Tom Hartmann,
the program manager at Lockheed, expects the boom to be
imperceptible—quieter than a kite flying overhead.
Another key to quiet flight is its broad distribution of
lift-generating surfaces. The QSST’s canards—the small wings
near the front of the fuselage—and swept-V tail provide
substantial lift, preventing the sharp, loud-boom-generating
pressure change typical of larger, wider wings. Hartmann
says the QSST is so sleek that it can fly 10 percent farther
on its fuel supply supersonically than it can at subsonic
speeds. “We could easily design a low-sonic-boom aircraft if
it didn’t have to fly anywhere,” he says—that is, if the
design didn't have to take fuel efficiency into
consideration. “The challenge is to fly a long way. The hard
part of this was to develop a low-drag design.”
The inverted-V tail also allows the two engines to be
mounted far aft— a design feature that further separates the
pressure waves and keeps them from crashing into one
another. Normally, this engine placement would require extra
material to support the cantilevered weight, but the
inherent strength of the V tail's truss shape compensates.
The Federal Aviation Administration restricted the Concorde
to transoceanic flights because that craft created sonic
booms strong enough to rattle dishes on the ground below.
Paulson says the QSST will meet the FAA’s stringent new
noise regulations, which took effect at the beginning of
2006, and he’s hopeful that the quiet design will prompt a
lifting of the ban on overland supersonic flights.
SAI is evaluating engine designs from General Electric,
Pratt & Whitney and Rolls-Royce for a unit that produces
33,000 pounds of thrust (on par with a midsize airliner),
for 66,000 pounds of total thrust from two engines. Paulson
plans to settle on a design in the next year, assemble an
international consortium to manufacture the jet, and put it
on the market by 2014 for about $80 million. He’d like to
roll out a fleet of 300 to 400 in the next 20 years. “The
Concorde was a magnificent aircraft,” Paulson says, “but
basically, it was 1960s technology. This is an idea whose
time is overdue.”
Quiet Supersonic Transport (QSST)
Purpose: High-speed private flights over land and sea
Manufacturer: Lockheed Martin and Supersonic Aerospace
International
Range: 4,600 miles
Speed: Mach 1.6 to 1.8 (approx. 1,056 mph to 1,188 mph)
Dimensions: 132.1 ft. length, 63 ft. wingspan
Capacity: 12 passengers, 3 crew
Cost (projected): $2.5 billion development cost; $80 million
per aircraft
First flight (projected): 2011 |
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