slowmover wrote:Cessna 180K with 88 gal wet wings and 84 useable. I only fill up a few times a year when I'm going someplace or when I come across a place with a deal. I don't like carrying the weight when I'm just poking around. I'm also deathly afraid of fire, and so I figure less fuel is risk mitigation (to a point of course).

I typically add 30 or 40 gallons at a time. I always keep at least an hour of useable fuel in the tanks... except that one time I didn't and the airplane took 77 gallons. That's 7 useable gallons on an engine that runs about 11-12 gal an hour. Never again.

But, related question for those of you who don't consistently top off your tanks... how do you really know how much fuel you have?

I don't have a fuel totalizer or anything other than stock Cessna fuel gauges. But I did mark a 1" wooden dowel in 10 gallon increments for my aircraft. It's accurate to within a gallon or so, and I dip the tanks on every preflight plus every time I top off the tanks.

I also track all my fuel purchases on a spreadsheet. This allows me to track my fuel burn in gallons per hour and average cost per gallon over the past 14 years. Most expensive gas ever was $11/gal in Tok. I only bought enough to get to Whitehorse. I later heard that's the tourist rate and there's a deal for people who know enough to ask. Cheapest fuel I ever bought was $3.15/gal in Sherman Texas back in 2016. I filled it up then. I suppose I could total up the entire fuel cost over the past 1366 hours of flight, but of course that would violate one of the cardinal rules of aircraft ownership! In any case, it's been worth it.