The tanks were filled to the tabs, both sides. The fuel selector was set to Off (both tanks). For one reason or another, I haven't flown my plane in a month. I did a pre-flight this morning, and the right tank is down about 3 gallons. No smell, no wet spots, no blue stain anywhere. I even ran my hand along the inside of the wing and it was dry. It's in a locked hangar, and no-one flew it without my knowledge.
Anyone have an idea where my fuel went?