Aviation Technology Group in late June announced several design changes to its two-place Javelin twinjet. These include an increase in wing size, enhancement of wing high-lift devices and improvement of the canopy opening mechanism. According to Englewood, Colo.-based ATG, these are the last major design changes to the Javelin design, freezing its configuration to enable suppliers to start building production airframe parts.

To reduce the stall speed, ATG increased the Williams FJ33-powered twinjet’s wingspan by 1.85 feet and the wing area by 29 sq ft. The wings were further enhanced with Fowler flaps and leading-edge flaps, ATG said. The company expects these wing improvements to yield a five- to seven-knot reduction in stall speed, to 90 knots.

On the advice of ATG’s pilot-vehicle interface working group, ATG engineers selected an aft-hinged canopy mechanism to replace the less conventional side-opening arrangement. According to the company, removal of the side hinges gives the new canopy a more aerodynamic profile, enables open-canopy ground operations in wind speeds of 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 will allow pilots to open and close the canopy with the push of a button.

ATG said changes to the wing and canopy have raised the mtow to 6,900 pounds (from 6,200 pounds, for an increase of more  than 10 percent) and decreased cruise speed from 520 knots to 500 knots. ATG added that the overall benefits of these changes were confirmed by a series of wind-tunnel tests conducted at the University of Washington Aeronautics Laboratory.

Certification of the $2.795 million Javelin is pegged for late 2008.