here are a few different examples of shots positions.
https://www.youtube.com/watch?v=DtmfYZZLaP8
This is a shot firing backward attached to the glass with no external mic other than the enclosed open back panel that comes with the Hero 3. Minimal wind noise and you get a nice (less overpowering) exhaust note
https://www.youtube.com/watch?v=JzDUY4B9P5I