Rotational speed of a spray arm is regulated based on centrifugal force and a liquid jet to create a variable angle corner spray nozzle. The regulator includes a weight on a pivot and a fluid jet, the weight having a curved surface to produce a variable angle corner spray nozzle depending on the weight angle. Centrifugal force created during rotation pushes the weight outward, which increases as the spray arm rotation speed increases. The liquid jet is located out from a pivot point and tends to push the weight inward. The pushing force of the liquid jet is maximum when the weight is most inward and minimum when the weight is most outward. The regulator stabilizes the arm speed at a specific speed independent from center pivot friction and the spray arm nozzle's orientation tolerance. Speed stabilizes when centrifugal force on the weight is equal to the pushing force of the fluid jet.

An aimable sprinkler is disclosed. The sprinkler can be mounting on an end of a traveling sprinkler system that moves in a linear direction or one that rotates about a center pivot tower. The sprinkler can include a base for connecting to the traveling sprinkler system and a turret coupled to the base so as to move in both yaw and pitch directions relative to the base. The sprinkler aims at discrete points within an irrigation area to achieve an even distribution of water.