Stir together flour, sugar, baking soda, salt and cinnamon in a large bowl. Beat together the eggs, oil, vanilla, pineapple and banana. Add to the flour mixture and mix well by hand. Stir in walnuts. Pour into a greased and floured 10 inch tube or bundt pan and bake 1 hour to 1 hour 15 minutes at 350 degrees or until cake is golden brown and tests done. cool on a rack for 15 minutes before removing from pan and cooling completely on a wire rack. Sprinkle with confectioners' sugar before serving.