The stock fan is too close to the heat block and my one had a hole in it where it had melted, and this was just from printing PLA at 210 max.
This improved design makes it clear the block so it isn't touching it and melting. It's the same design other than that, because I've been getting good results with overhangs etc.
This is a work in progress as I'm still experimenting with not having the air blow on the nozzle too much, and blow on the plastic as it comes out, as I think I'm getting inconsistent temp readings on the thermistor. I would be interested to hear any feedback on this design which may help me improve it.
To print in Cura:
Go to rotate, and click "LAY FLAY"