Preheat oven to 325 degrees.
In a large mixing bowl, blend flour, 1 cup sugar, baking powder and salt. Add oil, egg yolks, water, orange juice, rind, and vanilla. Mix until smooth.
Beat egg whites with cream of tartar. Gradually add sugar, and beat to form soft peaks. Fold egg whites into batter.
Pour into a 10-inch ungreased tube pan. Bake for about 1 hour. Test with a cake tester. Invert until cold. Loosen cake with knife. Unmold. Cover with orange fluff icing.
ORANGE FLUFF ICING
Place all ingredients in a mixing bowl.
Beat with a whisk over adouble boiler until peaks start to form.
Remove from heat, beat for 2 to 3 more minutes or icing is at a spreadable consistency.
Cover chiffon cake.