My 1999 GCAA has a fully opening left side window. The latch consists of a two metal prongs mounted on the exterior window frame and two small rollers mounted on the underside of the wing. The prongs on the window frame are spread by the rollers and then grasp onto the rollers. Very similar to the latches used on some kitchen cabinets. I am sure the the parts are available from American Champion. The latch is only for use on the ground. My POH reccommends allowing the window to "float" if opened in flight. Also the airspeed is restricted to something like less than 90 mph with the window open. However, it sure is nice on the ground in the summer to be able to latch the window open.
