Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

535 OF ENGINEERING FOEMULÆ. Overshot and Bbeast Wheels. Fairbairn’s ventilating • BUCKETS. The spaces for ventilation are about 1 inch wide. Tubbines. jonval’s low-pressure, For falls of 30 feet and under. Ä = Head of water in feet. Q = Quantity of water in cube feet per second. P = Horse-power (actual). A = Area of sum of orifices of buckets in feet. D = Diam. of centre of motion of buckets in ft. V = Velocity of buckets at centre of motion in feet per second. d = Depth of guides. d' = Depth of buckets. D = 1’33 A/ Va ' Q = 12-67-£• P=‘079QÅ. h V =6 V d = D x ‘26. d' = D x • 18. No. of buckets = 17 V D. No. of guides = No. of buckets X ’ 7, * The orifices are the distances a1 b, a2 b1, &c., &c. X width 3f the buckets w. See diagrams, next page.