Sift together flour, sugar, baking powder and salt. Place in a large bowl and make a well in the center. Add oil, egg yolks and orange juice; beat with a spoon until smooth.
In a bowl, beat egg whites and cream of tartar until stiff. Gradually add batter, folding gently until blended. Pour into an ungreased 9x5-in. loaf pan. Bake at 325° for 50-55 minutes. Invert immediately on wire rack, but keep in pan. When cool, remove cake from pan and slice into 12 pieces. Top each slice with berries, ice cream and whipped cream.