How many blades does your ceiling fan have? Most probably three or four?
Did you know that there are ceiling fans with just ONE blade or as many as FIFTEEN (!) blades? But, are they all good enough?
The more the number of blades in a fan, the better it can move the air around it. So, why are all three-blade fans not replaced with the seven-blade ones?
The fan blades, while rotating, experience opposing force from the air (drag). The more the number of blades, larger is the drag and the total weight. It then needs a more powerful motor to spin the blades against the force, which means higher electric bills as well as noise.
The final goal is to cool down effectively while avoiding a power-hungry motor, which is basically a balancing act between several factors!
To get the maximum airflow, scientists have demonstrated that an ideal fan would have four blades made out of metal, tilted at an angle of 45 to 55 degrees to the direction of airflow and at an angle of 6 degrees from the floor (phew!). I hope the fan manufacturers are listening.
As a home experiment, where do you experience the most airflow: under the fan center or under the blade tips? Research has answer to that as well (HINT: 50-50).
Isn’t it amazing how science and engineering always just blow you away?!
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