"Mistral 2.1" Extruder Cooling Duct for the Anet A8 Printer

I've been designing and printing all kinds of cooling ducts for the last 2 months as I just wasn't happy with what I had. Even the popular round ducted coolers just don't do a good job in directly cooling the filament whilst keeping the heat block hot. Also many found on the internet are too clunky, too heavy or are IMHO just terribly designed.
With the new Marlin and other 3D printer firmware's incorporating thermal protection mechanism it now becomes even more important to have a design that will not cause false alarms. This is particularly the case when the cooling ducts blow air on the heat block and not below the nozzle onto the filament.
That is why I created "Mistral" : http://www.thingiverse.com/thing:2086191
Mistral serves 90% of all objectives needed to get good printing results when it comes to cooling. One area it lacks however is cooling on rear overhangs because not enough cooling air could reach the filament sufficiently and in time.

That is why after 2 months development and countless prints and tests I designed "Mistral 2.x".
It uses two ducts set at 90° for the air reach the backside of the printing object.
90° was chosen to dissipate the heat as quickly as possible and to ensure that the air would not collide (e.g. a problem with 120° fan ducts) but still ensure constant air flow from front to rear over the whole nozzle end area.

<B>Design objectives:</B>
- Blow high volume air on the filament just beyond the nozzle.
- Avoid getting any…