Need help constructing a wind tunnel

[chappy-13]

i'm currently building a wind tunnel for year 11 physics and need help mounting the aerofoil. The wind tunnel is basic (just cardboard and is circular), and i need a way to mount the aerofoil inside. The mounting has to be sturdy so that the aerofoil can have an adjustable angle of attack and will keep the same angle of attack when the fan is blowing on it, however it needs to be relatively free so that i can measure the lift using a fishing line which is attached to a triple beam balance or spring balance/scale.

any ideas?

p.s the aim of the experiment is to determine critical angle of attack, and angle of attack which produces zero lift, etc

 

[redargon]

I discussed something similar with someone before, have a look: https://www.physicsforums.com/showthread.php?t=251942