Fitz Water Wheels

Fitz Water Wheel Math

In 1984 a research hobbyist, R.L. Omland wrote a series of four articles for the Society for the Preservation of Old Mills on the Fitz waterwheel and the mathematics behind the wheel. Some of his statements he made are represented here:

Because most Fitz wheels have a standard bucket design you can figure that for every 1 ft of width of the bucket you will be able to handle 2.7 cfm of water.
The number of buckets on a waterwheel is relative to the circumference of the wheel in feet, and that the spacing for buckets should be about 1 foot apart. One can use the following in determining the number of buckets (n) in a wheel. (n) = Pi * (D)iameter of the wheel. Once you know (n) you can determine the spacing (s) by using s = (pi*D)/n.
The velocity of the water entering the water wheel should be about twice that of the rotation of the wheel.
HorsePower at the shaft of a waterwheel can be determined by knowing the (D)iameter of the wheel, (Q)uanity of water in cfs [Cubic Feet/Second] by a constant of .1135 times the efficiency of the waterwheel. So HP = .1135 *Q*D*Eff