Running the MM passively cooled only?
 

You think it would be possible to run the MMM passively cooled only (no fan)? I would CNC a complete new case/house for the electronics board in aluminum acting as a oversized heat sink. Would it be worth a shot or should I just forget about it?

Well, the fan only kicks in at ~150°F on newer versions ( anything newer than v2 I think- I love my v1 & it's constant fan :mdr: ), so unless you are really hammering it the fan doesn't tend to kick in very often, and only for a minute or so based on what I've seen.

A larger heatsink on the FETs would be a good start, just carefully peel off the stock one & maybe use thermal adhesive to put the new one on, rather than thermal sticky pads ( better contact & heat transfer ). A heat-sink case may not do much as there are few components on the underside of the esc's PCB that generate much heat, and due to height differences you'd have to use thermal pads again..

Sounds like it's not a stillborn project then. Thanks. :) I'll give it some more thought and see if I can come up with a design that could work.

Your idea works extremely well actually. and with a little twist you can make it waterproof and capable of handling more current continuously than the standard version.

I see this idea being used a lot on Russian forums.
Here is a link. www.savage-central.com/modules.php?name=Forums&file=viewtopic&t=97406

He used it on his build.
Sometimes I get mixed up, hope it's okay to post links to other rc forums.