Separate eggs; the whites in a smaller mixing bowl and the yolks in the large mixing bowl. Add 1/2 tsp Cream of tartar to whites and beat until very stiff. Set aside.
Add cups cold water to yolks. Beat for 5 minutes.
Add sugar. Beat for 4 minutes.
Add 1 1/2 cups flour and 1 tsp vanilla. Mix lightly.
Gently fold beaten egg whites into batter. Pour into angel food cake pan.
Bake for one hour at 325 degrees.
Remove from oven and turn pan upside down for 15 minutes to cool slightly, then separate cake from sides of pan with a butter knife and tip out.