Transport Conversion.

         Another feature of the interior arrangement of the airplane is that all of the equipment, furnishings and so forth within the main cabin are designed to be readily removable so that when required the airplane can be used as a cargo or personnel transport.

        In addition to the tactical installations, the operating systems also involved considerable development.

        The flight control system is basically the same as that of the Britannia and consists of tabs on all of the main control surfaces which are operated through semi-irreversible screw jacks. These jacks are driven from the pilot's station through a torque tube system. There is no direct connection between the pilot's controls and the main flying controls surfaces.

        In the CL-28, the cockpit controls have been redesigned to conform with American military standards.

        Because of the revised structure, the fuel tankage of the CL-28 is somewhat different from that of the Britannia and the fuel system itself has been revised considerably to meet RCAF requirements. To ensure adequate operation of the system, a full-scale test tank was constructed and the venting, refueling and fuel feed systems were checked and the fuel quantity measuring system calibrated.

        A completely new engine lubricating oil system had to be developed to cater for the R-3350 engine. A fullscale oil system rig was built for the development of the system, particularly with respect to venting, de-aeration, oil dilution and oil cooling.

        The hydraulic system, which is normally off-loaded in flight, is used to operate the undercarriage retraction system, the nose wheel steering system, the braking system and the bomb door actuating system. To ensure satisfactory operation and reliability of the hydraulic system, a full-scale test rig was constructed and many cycles of operation of the various systems carried out.

        The wing flaps are electrically actuated as are the power plant cowl flaps. In this connection it is worth noting that as far as possible all electrical actuating motors have been designed to operate directly from the constant frequency ac system as a means of weight reduction.

Wind Tunnel Tests.

         In addition to the test programs referred to in the foregoing description, extensive wind tunnel tests were carried out at National Aeronautical Establishment, Ottawa. These tests were directed mainly toward determining the effect on drag and other aerodynamic characteristics of the power plants and the various protuberances; developing the wing spoiler system referred to previously; and determining the dropping characteristics of various stores and items of equipment.

        A full-scale structural test of the fuselage is being carried out. Because of the size of the fuselage a special rig had to be built for this purpose consisting of an immense structural steel platform on which the fuselage is mounted; the loads being applied through a system of hydraulic jacks.

        The foregoing description, limited as it is by security and space, only highlights some of the engineering problems encountered in developing the largest airplane yet built in Canada.