The four windows will wrap around the cockpit to enhance visibility and aerodynamics, with the large windshields formed into complex, compound shapes. Three plies of Herculite II chemically strengthened glass will afford strong, lightweight transparencies. The windshields will be designed to resist impact by a 4-pound bird at 300 knots.
Rain-repellent Surface Seal coating on the windshields will maintain visibility in rain conditions, enabling Bombardier Learjet to eliminate windshield wipers on the aircraft to save weight and reduce aerodynamic drag.
New PR-1425CF chromate-free sealant by PPG used as the outboard moisture seal will provide ultraviolet and weather exposure resistance in an environmentally responsible formulation. Proprietary new PR-2060 sealant used as an internal moisture seal will provide an additional barrier to further reduce moisture ingress and extend service life, according to Scott. Highly resistant to moisture damage, S-123 urethane by PPG will be used as the interlayers to bond the glass substrates, affording more elasticity than vinyl to eliminate cold chipping and defend against delamination.
PPG is designing and will produce the windshields and side cockpit windows for the Learjet 85 aircraft at its Huntsville aircraft transparencies facility with deliveries expected to begin the first quarter 2011 to Bombardier Learjet's Wichita, Kansas facility.
Launched on Oct. 30, 2007, the new Learjet 85 aircraft will be the first Bombardier Aerospace jet and first business jet designed for type certification under U.S. Federal Aviation Administration FAR Part 25 to use composite materials for all external primary structures.