I have been Reading Chris Olsen posts and watching his videos on Arducopter with traditional Helis using a Pixhawk.

I have inherited an older Trex 450 heli with the old Align 3G FBL hardware.  The FBL controller appears to be bad.  So I have an old APM 2.5 without a compass or GPS on board.  I just want to replace the failed Align 3G FBL system with the APM.

Now I have to mount the APM under the skids on the heli so the APM will be upside down.

I have Two questions.

1)  Is the AHRS_ORIENTATION=8 Parameter supported in Arducopter 3.2.1 (the APM board will not support a higher rev of Arducopter)

2)  Do I have to have an 8 channel xmtr and receiver to build this system?  Chris Olsen indicated that throttle control on Arducopter MUST be on channel 8.  Is this correct?  I only have 7 channel radio gear.  Am I out of luck?

Thanks in advance for replies and comments.