Morgan Olsson wrote:

> Tomorrow I will add another nozzle of same size in the straight
> opposite side.

  You are using high pressure/ velocity air to drive a low pressure/
velocity fan.  You are probably impinging on an unnecessarily small
point on the blades.

  I would suggest arranging the nozzle inside a venturi assembly,
perhaps two inch intake diameter and ¸" just after the nozzle, then
expanding back to either two inch or the whole fan aperture.  If you can
thus entrain a much larger air volume, it should be more efficient and
may be quieter, albeit larger.

  Material?  PVC piping, heated while rolling in front of a hot air
blower, and "drawn" out like glass.
-- 
  Cheers,
        Paul B.