The International Cessna 170 Association

I am confused after looking at some old posts....and then glancing at my cruise performance chart that I got from "somewhere." Are the original tanks (on a '48 170) 25 gal r/s and 12.5 gal l/s "total" or is that the useable fuel per side? Chart says that the ranges and endurances are for 37 gal of fuel.....and if you add up the numbers from the 7500' section.... 6 gph will get you 6.2 hrs @2300 rpm = 37.2gal orrrrr 5gph will give you 7.4hrs @2100 rpm=37gal It sounds to me as though there are 37 gal useable .......that is IF this is the proper chart. A little insight from you more knowledgeable 170 guys and gals...please

From TCDS A-799 the 48 170 has 3 12.5 gallon tanks. Several have added the 4th tank on the pilot's side (field approval)

Fuel Capacity 37.5 gal. total, 33.5 gal. usable (three 12.5 gal. tanks in wings at +45). See NOTE 1 for
weight of unusable fuel

170 has three 12.5 gallon tanks. 37.5 gallons total, 33.5 gallons useable.

170A and 170B have two 21 gallon tanks. 42 gallons total, 37 gallons useable.