I don't own one of these, so I didn't read all posts, so this
may be in here already.
The extra servo header on the PCB is a direct throttle output
for an aftermarket ESC (brushless too).
HOW COOL IS THAT !!
Just found that out watching an F45 brushless mod video.
If I am thinking clearly, this means you could use this PCB
in all kinds of models.
Looks like I'm buying one of these babies too !!