- Just do it. Experiment with it. See what works for you.
- If you're filming through the prop, due to the way the GoPro shutter works, the prop will look really distorted. This can be fixed by inserting a "Neutral Density" filter between the GoPro lens and the housing. An ND filter removes a certain percentage of the available light (all colors equally), thus forcing the GoPro to use a slower shutter speed. This blurs the prop so the distortion becomes less visible.
- Consider the GoPro to be a fire-and-forget camera. Turn it on before taking off, then forget about it until after landing. It's very, very easy to become distracted from flying, because you also want to be a full-time cameraman.
- You may want to get the proper adapter cable if you want to record intercom audio too.
There are some legal aspects to consider when mounting the camera outside. In short: It's most likely illegal, but it's only illegal when you get caught, right? (Apart from that, more and more clubs are now prohibiting this too.) If you do want to mount the camera outside:
- Forget about sound quality. Just use the waterproof housing in case of precipitation.
- Only mount the camera on the fuselage or wings. Not on any moving surface such as the ailerons or rudder, or all-moving tailplane. Apart from the fact that your movie frame will move, there's also the issue of control surface balance to consider. If the control surface is not properly balanced, then it may be far more susceptible to flutter. Which can be deadly.
- When you tether the camera to something, consider what happens when the camera does fall off. Will it bang in the slipstream against the fuselage or wing, possibly doing 100's or even 1000's of euros worth of paint damage? In that case it's probably better to lose the camera altogether. Furthermore, make sure that there is no opportunity for the tether to jam a control surface somehow.
- To see if the suction is strong enough, mount the camera at the desired spot and just leave it in place for a few minutes. If the camera is still safely in place after a few minutes, then it's most probably good enough for flight. In my experience, the camera falls of all by itself in the first few minutes, or it will not fall off at all.
- I have personally never experienced an aerodynamic disadvantage of mounting a GoPro outside. Not even in gliders, not even at the wingtips.
For editing afterwards, I've got an iPad 2 with the Apple iPad Camera Kit and iMovie. Works great, very easy to learn, and can export direct to YouTube, Facebook and whatnot. The only thing I can't do yet with that combination is convert a series of timelapse photos into an MP4.
Here's an example of what you can achieve. 100% GoPro Hero 2.
(Note that the intended audience for the video is the participants of this gliding week, not the general public. At over 10 minutes it's too long to be used as a promotion video. That's also the reason it's unlisted.)