The International Cessna 170 Association

Any basis out there for modifying the 175 fuel tank pickups to the same location as the 170, to decrease unusable fuel?

My IA was going to sign it off with stating tank was modified to stock 170 tank location, but I can forsee some shops not being as agreeable to that. I would rather do it the right way and not let a future owner to have to deal with it.

Any info on this? Did you complete it?

I thought I read somewhere of not just moving the pickup but adding one to reduce unusable fuel, I can't find it any more. If anyone has info please let me know. I have 175 wings on my 170B

I’m not confident that simply relocating the fuel indication pickup point accomplishes any decrease in unuseable fuel.

Unuseable fuel is the fuel that is not available (useable) in all normal attitudes of flight.

The 175 tank has a larger capacity (due to it’s L-shape) than the standard tank. In a normal climb/descent… there is more room for the fuel within the tank to occupy the larger end of the tank because of the larger volume there. Therefore, less fuel is available in an extreme attitude than the regular (square) tank. (While 2.5 gals might still reach the fuel tank’s exit line in the 170 tank….that amount of fuel would not be able to reach the exit due to the larger volume at the larger end of the 175 tank.)

That’s how I see it anyway.

Makes sense. And if it had been done ever it woulda been done by now. Thanks