The above graph shows that as the tip radius is increased, the maximum value of CP increases and the inflow velocity at which it occurs also increases until some optimum radius value is reached. Beyond this optimum, the maximum value of CP begins to decrease but the inflow velocity at which it occurs continues to increase. Increasing tip radius and maintaining rotational velocity will result in increased tip velocities and as such, cavitation will become an issue beyond a certain point, depending on your rotational speed and aerofoil choice.
