From my experience, the GoPro Suction Cup is by far one of the best suction cups to insure you don't lose your action camera. Check out the videos.
I use it in aviation, I have placed it on different parts of the plane including wing tips, and upto 140 kts.
Note. It is important to make sure the surface is clean before applying the suction cup. Also the suction cup should be stored in the provided bag to protect the suction cup from dust, dirt ot scratches which may make it less suction resistenet.You can get some amazing shots. For extra safety, also attach a zip tie to a tie down loop, or some duct tape (american tape) over the suction cup.