stage efficiency	(23.1)

or,	(23.2)

or,	(23.3)

Optimum blade speed of a single stage turbine

		(23.4)

where, = friction coefficient

	= Blade speed ratio	(23.5)

is maximum when also

or,

or,	(23.6)

is of the order of 18⁰ to 22⁰

Now, (For single stage impulse turbine)

The maximum value of blade efficiency

	(23.7)

For equiangular blades,

	(23.8)

If the friction over blade surface is neglected

	(23.9)