Construction Design of the Floater Considering the Free-Falling Impact of the Floatplane on Calm Water

The floatplane-type aircraft is very suitable to be developed as a means of transportation connecting the scattered islands in Indonesia, as it has floats under the fuselage to make landings and operate on the water surface. In bad weather, a floatplane can lose lift, resulting in a free fall from an abnormal height and a violent collision between the floatplane structure and the water surface. Meanwhile, regulations require that the strength of the structure be able to withstand the impact load due to an emergency landing. This paper proposes a floater construction design for the N219 floatplane with three scantling variations of 5083 H321 aluminium material that considers the total payload and take-off weight. The magnitude of the impact load on the bottom of the float with the water surface in the case of free fall at 0.5 m and 1 m height is predicted by the Wegner equation model at each cross section along the float. The magnitude of stress in each floater construction design is evaluated by the principle of the finite element method using commercial software. The simulation results show that all models have a maximum stress less than permissible stress and also maximum deformation is unsignificant.