The undercarriage is definitely innovative. The main advantage of its design is in the reduced longitudinal dimension together with its flexibility of use. In the airplanes with engine and gear located in the fuselage, it is necessary that the dimension of the undercarriage is minimized. The operation of the undercarriage is electric drive by an electric motor and a speed adaptor with high gear ratio; the input to the adaptor is double: from one side there is the electric motor and from the other side there is a shaft in connection with the cabin, where the pilot can command it manually in the event of electric failure. The motor-gear group is located in “dry area”, whereas the lags and the front wheel are located in a flooded vane; the vane is covered by a door activated by the motion of the undercarriage itself.
Main undercarriage
The main undercarriage has been object of several studies leading to different solutions. The undercarriage is definitely innovative and patented. The main characteristic is its reduced dimension in the longitudinal direction together with a high flexibility of use. In an airplane as the present one where, in the undercarriage area, the fuselage has inside the engine and the gear, it is necessary that all component dimensions are minimized; moreover, it shall be guaranteed that a proper accessibility to the inside even with a certain lag length, once the dimension from the external beam of the undercarriage to the ground has been fixed, Some positions of retracted and extended undercarriage are depicted in figure 24.
The undercarriage is made by an external pipe fixed to the fuselage sides by two flanges as shown in the figure and by a movable internal pipe; this pipe can translate and also rotate thanks to a pair of rollers sliding in a slot on the external pipe. When the undercarriage is retracted, lags are located in a longitudinal position in two lateral vanes in the fuselage (on the right and on the left) and they are covered by an aerodynamic door restoring the original shape of the fuselage. During the extraction, the lags translate towards the external and rotate back, at the same time the door is lift up in such a way to make possible the motion of the damper during the contact with the ground. The movement of the mobile pipe can be controlled by different ways.