Electric fan air output counter

[thebluser]

hey, so let's say i have an electric fan with something like 2, 1/4 in. blades, 60 rpm, and 10 cm diameter and i want to attach it to an object and turn it on so it would fly (like a quadrotor)
before i try, i want to know if it is possible by knowing how much counter force can it make on the object (exclude all technological stuff). so my general question is: how can i know how much counter force can an electric fan make with knowing its detailes?(like the one i described or even more detailes)

 

[Bobbywhy]

You might put the fan on a bathroom scale, point it exactly upward, and turn it on. The thrust of the fan would be shown as an increase downward force on the scale. Just read the difference between fan on and fan off.