Picking a good place for your Ferguson windmill water pump...

WIND  Naturally, you want a location with a reliable wind.  The best place, of course is in the middle of an open field or on top of an open hill.

Any trees or buildings nearby will disrupt the airflow and reduce the efficiency of the windmill.  Farmers who plant windbreaks arlready know this.  The rule of thumb is that an obstacle will interfere with the airflow for a distance about 5 times the height of the obstacle.  When you want to protect the soil from wind erosion, you put the windbreaks around the field.

For a windmill, we want to place it away from any windbreaks, trees, or buildings.  Because the windmill blades are high above the ground, the distance is reduced.  Measure the height difference between the obstacle and the windmill hub heights.  Multiply this difference by 5.  Ideally, the windmill water pump should be farther than this distance from the obstacle.

Sometimes, an ideal location is not available.  In this case, place the windmill water pump as far as practical from the nearby obstacles.  You may consider purchasing the optional mast extension to raise the height of the windmill blades.

Based on the prevailing winds, the windward (up-wind) side of a hill is a good place to put a windmill water pump.  This type of topography amplifies the wind speed.

Conversely, you want to avoid the leeward (down-wind) side of a hill.  The hill acts like a huge obstacle and reduces the wind speed on the down-wind side for a great distance.

WATER  You want to place the windmill water pump near the water source.  The pump works by suctioning water from water supply and pushing it out the outlet pipe.

Pump efficiency can be improved by reducing the height that the water is lifted.  The smaller the lift height, the less of the wind-supplied power used to lift the water and the more power available for increasing the output head or the volume pumped.

Even better, if the water supply is higher than the water, gravity feeds the water to the pump.  The pump can use all of its wind-supplied power to increase the head in the outlet pipe.

The suctioning is the just like slurping on a straw.  When a pump applies suction to one end of a water-filled pipe, the air pressure on the other end pushes the water towards the pump.  There is a limit though.  If the pump pulls a perfect vacuum at one end of the pipe, and you are at sea level, the highest the water in the pipe can be pushed is 32 feet above the surface of the water source.  To allow for a real-world pump, we recommend that the water source level be no more than 25 feet (7.5m) below the pump level.  In the thin air at 10,000' (3000m) elevation, we recommend no more than 18 feet (5.5m).