fanduct mount for HTA3d extruder

I want to see what's going on at the nozzle, so mixed a fanduct with a much smaller mouth. Will have to see wether it delivers quality.

Update 20180914: sufferd a bit of jerking at the back of print's, could be caused by insufficient airflow from the cooling fan, but could also be caused by the temp of the hotend, flowrate or printspeed.