Best cooling fan and mount for RepRap Prusa Mendel

Hello,

I've calibrated my Prusa Mendel by printing thin wall (0.5mm) calibration object (from PLA), and playing with parameters like layer height, speed, temperature, feedrate multiplier and else, but this not helped to improve quality significally.
But when I've took a small PC fan and run print again while holding fan in my hands - I've noticed really HUGE improvement of quality. There are almost no any visible issues, no rough surfaces, no curling up corners.
So obviously I want to make model cooling like a permanent solution, i.e. buy good fan, mount it on printer, plug it to RAMPS.
The problem is that I've not found any relevant pages about it on RepRap wiki. So I would like to ask you guys, to share some of your experience about this.

The main question is - what is the best way to mount cooling fan?
I see three possible ways:

1. Mount fan on frame (between two triangle frames) and direct it on the print bed, so it will cool whole model (requires big fan).
2. Mount fan on the X carriage, and direct it on the nozzle, so it will cool part of the model and hot extruded filament.
3. Use some king of printed cone mounted on X carriage (this or this), so air flow will be more intensive and will be directed at the place where new hot filament is extruded.

Currencly I'm thinking of third variant, i.e. printed cone and a 40-50mm fan mounted on X carriage.
Any suggestions/comments highly appreciated.

So, it seems like nobody is using cooling fan with Prusa Mendel

I'm using this shroud and mount attached to my X carriage with a 10.5 CFM 40mm fan.

Other mounts might be better, or allow you to get away with a slower fan, but that's what I use and I haven't had any problems with my bridges or curling upwards between layers. Nice part about that mount is that I was able to print a functional copy of it without a fan at all... but it did take a little babysitting and reflexes to sneak in and snip the upwards-curling corners on the flat mounting part during the print to keep the nozzle from crashing and dislodging the print, and I wound up having to drill the holes anyway because they were horrible. But it works and that's what counts, and I was able to print a better copy of the same part later.

It would be great if a fan mount could become part of the standard-issue plastic parts, since PLA really seems to need it. Those printing in ABS won't have an issue because they can just keep the fan off.

Mazaw, thanks for your response.
Your shroud and mount looks good, I'll try to print one. BTW, did you printed it from PLA? And if yes - is it not melts near hotend?

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It would be great if a fan mount could become part of the standard-issue plastic parts, since PLA really seems to need it.
I completely agree. In RepRap wiki HPB and cooling fan are like an "optional things", but without these two improvements print quality is not really good. It's really strange that standard Prusa pritned parts set is not includes any mount for cooling fan.

It is in PLA and I have experienced no melting at all, but I have only printed PLA and having a running fan probably helps prevent that.

If I decide to start printing ABS I'll definitely switch the fan off and maybe that might encourage softening, but, really, on my carriage it's not terribly close to my Makergear hot end. Right now I'm using the Prusa i2 LM8UU x-carriage.

Just a small update: I've tried Brix' fan mount and it helped a lot - problems with curled corners, overhangs and bridges are almost gone.

However for some large models with heavy overhangs on opposite sides, cooling only from one side seems insufficient.
So I've designed this fan mount and mounted 50mm fan on the frame's threaded rod. I just direct this fan on the place I need and turn it on manually, when I need some extra cooling. Also I'm using it to cool model after printing is finished (hate to wait until it cools ).

I've been using Brix' fan mount for the past few days, but I have to work to make sure it doesn't trigger the cold extrusion prevention on Pronterface.