A ram air turbine (RAT) is a small wind turbine that is connected to a hydraulic pump, or electrical generator, installed in an aircraft and used as a power source. The RAT generates power from the airstream by ram pressure due to the speed of the aircraft. It may be called an air driven generator (ADG) on some aircraft.
Ram air turbine on a Republic F-105 Thunderchief fighter-bomber
Convair F-102 Delta Dagger. The yellow circle highlights a ram air turbine with five blades
Ram air turbine in a Lockheed F-104 Starfighter fighter-bomber
Argus As 410 engine and ram air turbine used to power the actuator of the variable-pitch propeller, which is visible in front of the engine and behind the ram air turbine
Small wind turbines, also known as micro wind turbines or urban wind turbines, are wind turbines that generate electricity for small-scale use. These turbines are typically smaller than those found in wind farms. Small wind turbines often have passive yaw systems as opposed to active ones. They use a direct drive generator and use a tail fin to point into the wind, whereas larger turbines have geared powertrains that are actively pointed into the wind.
Diagram of a small wind turbine and repeller.
A 1 kW micro windmill installed in the suburbs of Lahore, Pakistan.
Ground mounted small wind turbines are typically supported by four guy-wire, and a gin pole used to raise and lower the tower. Full mounting sets called "tower kits" are available.
Wind turbines small enough to be held by a single steel pipe are often secured with scaffold base plate mounted to a concrete foundation. A hinged design allows easy lowering for maintenance.
