Sift together flour, 1 c. sugar, baking powder and salt.
In a large mixing bowl, beat egg whites until frothy. Add cream of tartar. Gradually beat in ½ c. sugar, a little at a time; beat until whites form stiff, not dry peaks.
In a small bowl, combine egg yolks, water, vanilla and sifted dry ingredients. Beat at a medium high speed for 4 minutes or until mixture is light and fluffy. Fold yolk mixture gently, but thoroughly into beaten egg whites. Turn into an ungreased 10" tube pan. Bake in moderate oven (350°) about 45 minutes. Invert pan on rack to cool. Frost with Creamy Pineapple Frosting.