You know, I was going to add a caveat about the possibility of fuselage pressurization in my post, and then I forgot. My Giant Stik, for example will do that. I have a battery hatch with two four strong rare earth magnets holding it on just behind the wing. In a dive, that hatch will blow right off from the fuselage getting pressurized through some holes in the firewall for fuel lines, spark plug wire, etc. that are a little too big for what passes through them.

They are getting hard to find unless you know a professional photographer, but the small round plastic film containers for 35mm film work great for a static line setup too. Just add a hole for the tubing and a pin hole to allow pressure sensing.

AV8TOR