You stated that you have been flying for a while, if this includes setting up and flying planes with glow motors, I can understand your issues with the noise. On the other hand I can also understand your flight time concern with electrics. If my assumption of you flying glow engines is correct you might want to consider a diesel engine. If you have an 8oz tank and a .40 diesel you will regularly see a 30 minute run time if properly prop-ed and moderate throttle is used. Additionally diesels are infinately quieter than glow (and noisy electrics in some cases too). If you have no one in your area that uses diesel then I would tend towards the electric, and if you are not familiar with engines I would also tend towards the electric. I agree that a glider may be your best bet. Good Luck