C172M   C-GHUU     Fuel Stick Analysis
Litres to U.S. Gallons Conversion Factor = 3.785412  &  Full tanks taken to be 26 US Gallons
  Aird's  000825  Port Side Dry Tank test with rulers. Extract for Graphing
Pump inches add Litres US Gals inches pump Total litres US Gals Inches U.S.Gallons
0.210 dry 5.00 1.3 0.500 5.210 5.00 1.3 0.500 1.3
5.210 0.500 5.47 1.4 0.875 10.680 10.47 2.8 0.875 2.8
10.680 0.875 4.55 1.2 1.375 15.226 15.02 4.0 1.375 4.0
15.226 1.375 4.95 1.3 1.500 20.180 19.97 5.3 1.500 5.3
20.180 1.500 5.03 1.3 1.750 25.210 25.00 6.6 1.750 6.6
25.210 1.750 5.00 1.3 2.125 30.208 30.00 7.9 2.125 7.9
30.208 2.125 5.00 1.3 2.250 35.208 35.00 9.2 2.250 9.2
35.208 2.250 5.00 1.3 2.750 40.208 40.00 10.6 2.750 10.6
40.208 2.750 5.01 1.3 3.000 45.220 45.01 11.9 3.000 11.9
45.220 3.000 4.99 1.3 3.250 50.206 50.00 13.2 3.250 13.2
50.206 3.250 10.00 2.6 3.500 60.202 59.99 15.8 3.500 15.8
60.202 3.500 10.01 2.6 4.250 70.208 70.00 18.5 4.250 18.5
70.208 4.250 9.99 2.6 5.000 80.202 79.99 21.1 5.000 21.1
80.202 5.000 5.02 1.3 5.250 85.220 85.01 22.5 5.250 22.5
85.220 5.250 4.998 1.3 5.500 90.218 90.01 23.8 5.500 23.8
90.218 5.500 8.362 2.2 6.000 98.580 98.37 26.0 6.000 26.0
98.580 6.000 2.824 0.7 7.000 101.404 101.19 26.7 7.000 26.7
Notes:
We ran the port tank dry (engine cut-out) and checked it dry again 2 minutes later.
Aeroplane appears level: Front olio strut showing 2.125 inches of chrome
We filled the bottom half of the port tank in 5 litre increments, and the top half in 10 litre increments.
While filling the very top of the port tank we noted a definite cross-over flow to the other tank.
Final inspection of the Port tank showed the level had dropped down almost to the filler neck (bottom) - we assumue X-over drain.
P.O.H. says 24 US Gallons usable =  90.8 litres
Bottom of Filler neck is 6.25 inches, full to overflow is seven inches
Subsequently filled the starboard tank which was about half full at 3.25" when we started:
101.404 3.25 48.324 12.8 full 149.728 149.518 39.5
Conclusion:
With 3.25" (50 litres) in the Starboard Tank and a dry port tank we added 149.5 litres according to the pump.
That indicates a total of 200 liters usable capacity (filled to overflowing) which is: 52.8 U.S. Gallons usable
The only possible errors can be that the pump indicated wrong or that 3.25" is not 50 litres.
  Calculations for Dipstick  (shaded lines are calculated)   Calculations for 1/8" increments  
litres per 1/2" litres per 1/8" Inches % inches U.S.Gallons litres % Litres liter/inch variance Diff Inches Diff Gals Qty of 1/8" Gals/ eighth Imperial Gallons
5.0 1.25 0.500 8% 1.3 5.0 5% 3%     1.1
  1.82 0.625 10% 1.8 6.8 7% 3% 0.38 1.45 3 0.482 1.5
  1.82 0.750 12% 2.3 8.6 9% 3%         1.9
  1.82 0.875 14% 2.8 10.5 11% 3%     2.3
6.6 1.14 1.000 16% 3.1 11.6 12% 4% 0.50 1.20 4 0.300 2.6
  1.14 1.125 18% 3.4 12.7 13% 5%         2.8
  1.14 1.250 20% 3.7 13.9 14% 6%         3.1
  1.14 1.375 22% 4.0 15.0 15% 7%     3.3
8.4 4.95 1.500 24% 5.3 20.0 20% 4%     4.4
  2.52 1.625 26% 5.9 22.5 23% 3% 0.25 1.33 2 0.664 4.9
  2.52 1.750 28% 6.6 25.0 25% 3%     5.5
  1.67 1.875 30% 7.0 26.7 27% 3% 0.38 1.32 3 0.440 5.9
8.4 1.67 2.000 32% 7.5 28.3 29% 3%         6.2
  1.67 2.125 34% 7.9 30.0 30% 4%     6.6
  5.00 2.250 36% 9.2 35.0 36% 0%     7.7
  1.25 2.375 38% 9.6 36.2 37% 1% 0.50 1.32 4 0.330 8.0
9.2 1.25 2.500 40% 9.9 37.5 38% 2%         8.3
  1.25 2.625 42% 10.2 38.7 39% 3%         8.5
  1.25 2.750 44% 10.6 40.0 41% 3%     8.8
  2.51 2.875 46% 11.2 42.5 43% 3% 0.25 1.32 2 0.662 9.4
7.5 2.51 3.000 48% 11.9 45.0 46% 2%     9.9
  2.49 3.125 50% 12.5 47.5 48% 2% 0.25 1.32 2 0.659 10.5
  2.49 3.250 52% 13.2 50.0 51% 1%     11.0
  5.00 3.375 54% 14.5 55.0 56% -2% 0.25 2.64 2 1.320 12.1
15.0 5.00 3.500 56% 15.8 60.0 61% -5%     13.2
  1.67 3.625 58% 16.3 61.7 63% -5% 0.75 2.64 6 0.441 13.6
  1.67 3.750 60% 16.7 63.3 64% -4%         13.9
  1.67 3.875 62% 17.2 65.0 66% -4%         14.3
6.7 1.67 4.000 64% 17.6 66.7 68% -4%         14.7
  1.67 4.125 66% 18.1 68.3 69% -3%         15.0
  1.67 4.250 68% 18.5 70.0 71% -3%     15.4
  1.67 4.375 70% 18.9 71.7 73% -3% 0.75 2.64 6 0.440 15.8
6.7 1.67 4.500 72% 19.4 73.3 75% -3%         16.1
  1.67 4.625 74% 19.8 75.0 76% -2%         16.5
  1.67 4.750 76% 20.3 76.7 78% -2%         16.9
  1.67 4.875 78% 20.7 78.3 80% -2%         17.2
6.7 1.67 5.000 80% 21.1 80.0 81% -1%     17.6
  1.67 5.125 82% 21.6 81.7 83% -1% 0.25 1.33 2 0.663 18.0
  3.35 5.250 84% 22.5 85.0 86% -2%     18.7
  2.50 5.375 86% 23.1 87.5 89% -3% 0.25 1.32 2 0.660 19.3
10.0 2.50 5.500 88% 23.8 90.0 91% -3%     19.8
  1.39 5.625 90% 24.1 91.4 93% -3% 0.75 2.21 6 0.368 20.1
  1.39 5.750 92% 24.5 92.8 94% -2%         20.4
  1.39 5.875 94% 24.9 94.2 96% -2%         20.7
5.6 1.39 6.000 96% 25.3 95.6 97% -1%         21.0
  1.39 6.125 98% 25.6 97.0 99% -1%         21.3
  1.39 6.25 100% 26.0 98.4 100% Filler Neck     21.6
7.0 2.82 7.00 26.7 101.2 103%     22.3