Actually, I think that this valve will fit a propane/butane fuel tank (even though it just says propane tank):
With this valve, you have to connect the hose to the aircraft and then screw the valve down to open it - or you could put an on/off valve inline to turn it on and off. Just be sure to unscrew the valve before you put the gas away, least it leak out and you have an explosion hazard in your garage or trailer...
The one I bought a few years ago had an on/off screw in plunger built into it, which is handy.
Bob