Abstract: Sections of extruded rigid plastics material form a rectangular main frame including a pair of vertical jamb members, a top head member and a bottom sill member connected by welded mitered corners. An extruded plastic astragal member is spaced between the jamb members and has laterally projecting stop portions and internal walls which are rigidly connected by long screws to the head and sill members. A fixed door panel and a pivotal door panel have extruded plastic rectangular frames with welded mitered corner joints and which surround corresponding glazing panels. A continuous gear hinge has an inactive leaf secured to the astragal member and a slightly shorter active leaf. The door panel frames have internal walls which cooperate with the welded corner joints to maintain each frame flat, and long screws positively connect the leaves of the gear hinge to the pivotal door panel frame and the astragal member.

Abstract: Sections of extruded rigid plastics material form a rectangular main frame including a pair of vertical jamb members, a top head member and a bottom sill member connected by welded mitered corners. An extruded plastic astragal member is spaced between the jamb members and has laterally projecting stop portions and internal walls which are rigidly connected by long screws to the head and sill members. A fixed door panel and a pivotal door panel have extruded plastic rectangular frames with welded mitered corner joints and which surround corresponding glazing panels. A continuous gear hinge has an inactive leaf secured to the astragal member and a slightly shorter active leaf which covers an edge portion of the pivotal door panel. The door panel frames have internal walls which cooperate with the welded corner joints to maintain each frame flat, and long screws positively connect the leaves of the gear hinge to the pivotal door panel frame and the astragal member.

Abstract: Sections of extruded rigid plastics material form a rectangular main frame including a pair of vertical jamb members, a top head member and a bottom sill member connected by welded mitered corners. An extruded plastic astragal member is spaced between the jamb members and has laterally projecting stop portions and internal walls which are rigidly connected by long screws to the head and sill members. A fixed door panel and a pivotal door panel have extruded plastic rectangular frames with welded mitered corner joints and which surround corresponding glazing panels. A continuous gear hinge has an inactive leaf secured to the astragal member and a slightly shorter active leaf which covers an edge portion of the pivotal door panel. The door panel frames have internal walls which cooperate with the welded corner joints to maintain each frame flat, and long screws positively connect the leaves of the gear hinge to the pivotal door panel frame and the astragal member.

Abstract: An aircraft attitude indicator employing a gyro driven tape display. The tape takes the form of a closed loop stretched about a carrier mechanism, and includes a viewable horizon indication. The tape further includes a set of perforations which, preferably, are engaged and driven by sprocket teeth borne on a sprocket wheel member attached to the pitch gimbal of the gyro. The tape travels in response to tilt of the gyro spin axis relative to the aircraft, and in a direction so that reversed pitch sensing is accomplished.