A type of reaction turbine (generates power from the combined forces of pressure and moving water). Propeller turbines generally have a runner with three to six blades. Water contacts all of the blades constantly with constant pressure. The pitch of the blades may be fixed or adjustable. The major components besides the runner are a scroll case, wicket gates, and a draft tube. There are several different types of propeller turbines including Kaplan, bulb, straflo and tube.