Hi Loopman,
The Himax will run quite hot inside the ALFA fan unit shroud.
Suggest you look at the mods that ANDY STEER has done to his (and posted on the internet,) to to help alleviate the heat problem.
See:
http://astro.umsystem.edu/andy/rc/mig15/
and go right through the site.
N.B. The recommended MPJET motor also gets hot, so don't worry that you've may be purhased a problem.
Let us know how your bird flies. It's always good to get feedback, we're all interested.
Good Luck.