Changes In Wing Design, Flaps, Canopy
Aviation Technology Group, Inc. told Aero-News Wednesday the
company has made several design changes to its Javelin two-seat jet
aircraft, all with an eye towards making the plane safer to
operate. The changes include an increase in wing size, enhancement
of wing lift devices, and improvement to the canopy opening
mechanism.
In order to achieve a lower stall speed, designers at ATG have
increased the wing span by 1.85 feet, and the wing area by 29
square feet. To allow for slower approaches and landings, the wings
were further enhanced with Fowler flaps, and leading edge flaps.
Aerodynamicists expect the wing improvements to yield a 5 to 7-knot
decrease in stall speed, which would lower the Javelin’s
stall speed to 90 knots.
"ATG has always emphasized safety as a priority," said ATG
president Charlie Johnson. "And, lower stall speed provides an
extra margin of safety during critical takeoff and landing
phases.”
Engineers also implemented design improvements to the Javelin's
canopy system. Under advisement from ATG’s Pilot-vehicle
Interface Working Group, designers selected an aft-hinge canopy
opening mechanism to replace the less conventional side-opening
arrangement.
Removal of the side hinges gives the new canopy a more
aerodynamic profile, enables ground operations with an open canopy
in winds up to 40 knots, and allows Javelin pilots to taxi with
improved visibility and cockpit ventilation. The new canopy also
features a gas spring and electric motor combination, which allows
pilots to open and close the canopy with the push of a button.
ATG says these improvements are the last major design changes to
the Javelin, freezing its configuration to enable suppliers to
start producing the production airframe parts.
Alas, the changes haven't come without a slight performance
penalty. ATG says the improvements to the wing and canopy designed
have resulted in a nominal weight increase, and a small decrease
the Javelin's cruise speed to 500 knots.
After a thorough review and acceptance by ATG engineering staff
and executive management, the overall benefits of these final
design changes were confirmed by a series of wind tunnel tests
conducted at the University of Washington Aeronautics Laboratory in
May.
The company reports it is ontrack to begin customer deliveries
of the FAA-certified Javelin in 2008.