Hellis don't have enough power to take off.

Ok so the problem is you have to use SFM (Standard Flight Mode) not AFM (Advanced Flight Mode)

Here is why as stated by hcpookie " this was never built around AFM so I cannot guarantee it will work as expected with AFM. It works *perfectly* with Standard Flight Model. Since AFM is a "black box" for editing (no one has a good idea how to go about editing it) that will not be adjusted until more information about AFM is made available."

Hope this solves your problem
-EJRONAN