Bookworm,
I did say "up to". However, in such an aircraft 3 hours is not bad when you take in bladder endurance.
However, 3 hours flying is 21 gallons per side i.e. 42 USG total. Can be 18 a side if I am careful or even less with a tailwind.
You must have some heavy friends.
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I don't call that a 4 person airplane by a lot shot, that's 6 plus luggage plus full fuel.
Have you had to sit (as an adult) in the back row for any length of time?
I am not big but it is far from comfortable.
However, 2 Adults and 4 Children works a treat.
Regards,
DFC