Originally Posted by
ITCZ
The plumbing in the Cessnas runs from the inboard of the tank, down through the forward door pillar, under your feet and then to the fuel tank selector, then onwards to the firewall.
The
Main Fuel pipe from each tank, actually runs down the rear of the door frame, with a supplementary pick up at the front of the tank.
Earlier (1960's 100 series) Cessna only had the rear outlet resulting in a quantity of fuel being unavailable in all attitudes (about 1/4 of tank unusable except in level flight). the main reason that bladders may lift off the bottom of the tank is that the underwing vent is blocked or the little rubber flap on the underside of the filler cap is stuck and not venting.
Pretty sure that most 172's had either metal tanks or a wet wing configuration. Wet wings can develop leaks all over the place along lap joints due to failure of the tank sealant. Wet wings are prone to this in rough operations like Seaplane Ops. Bladders are usually the choice in Cessna Seaplanes such as the 185 and 206.
I believe the rotary fuel tank selector is the same valve in all 100 and 200 series Cessnas, allowing for selection of LEFT, RIGHT, BOTH and OFF except in some models the BOTH (pointing forward) selection is not available due to the design of the centre console. Unless of course when you are in real trouble and you grab your leatherman, undo the handle and use the leatherman to turn the spindle to a BOTH position
Some if not most 206/210's have only left and right selections due to the design of the fuel return system, associated with the fuel injection system.
"Both" is not an option regardless of whether the console blocks this option.
I believe the last 206/210 of the 1980's had Both tanks available at once.
My old 185A (fuel injected) had the best system of all, ON or OFF. You couldn't park it on a slope though, as all the fuel would run from the high tank into the low tank and out the underwing vent onto the ground.
My latest one (1979) has left/ right/both.
Speed2height, Uneven fuel burn between tanks, is a normal thing in most cessna aircraft. it can be dependent on how well you keep the machine in balance.
185.