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New Oil Drums Question

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  • New Oil Drums Question

    Supposedly ID 330723 is the new oil drums question, however It is not appearing in the bank!

    Question is:-

    For a flight to a destination airfield a refueling stop will have to be planned. The refuel airfield is remote and fuel will have to be ordered and prepositioned 45USG oil drums. The capacity of the aircraft tanks is 1400Ib, and on landing, the expected fuel remaining in the aircraft 300Ib. If the SG of the fuel is 0.79, how many oil drums should be ordered?





    There seems to be some confusion in recent feedback between it being 3 or 4. Since there is no explanation maybe someone could shed more light on this one?

    I myself get 3, using the CRP-5

    Last edited by AeroSpace1; 08-04-2018, 20:01.

  • #2
    Hmm, this is what I'm getting;

    (specific gravity = Kg / litres)

    1400lbs capacity minus 300lbs left in the tanks leaves 1100lbs to uplift.

    Each barrel is 45USG, which equals 170.3 litres (x3.785). Because this is the unit we use in that equation;

    0.79 = x / 170.3 -----or------ x = 0.79 x 170.3 = 134.5kg.
    (SG = mass / volume)-------(mass = SG x volume)

    Finally, convert this into pounds (x2.2) which equals 296lbs.

    Each barrel at this specific gravity therefore provides 296lbs mass.

    1100 / 296 = 3.7 barrels required. I would therefore have gone with the answer 4.

    Anyone think different?



    • #3
      Hi binners

      Ye I get the same!


      1100 at a specific gravity of 0.79 = 167 USG

      167/45 = 3.7 >>>>> =4 Barrels

      However if the question asks for imperial gallons the answer would be 3 barrels as 139 imperial gal / 45 = 3.08

      All according to CRP-5

      Do correct me if im wrong!


      • #4
        Only ever use the information provided in the question. The explanation given by Binners is correct.
        BGS TKI


        • #5
          Question from feedback - numbers approximate.

          Assume 1100 lb of fuel required

          On the back of the CRP 5:

          Align CURSOR with OUTER SCALE Sp.G lbs scale 0.79

          Rotate inner scale to align 1100 with the CURSOR

          Rotate CURSOR to align with the US. Gal ↓

          On the inner scale, read 166 USG against the CURSOR.

          166 USG .... this requires 4 x 45 USG oil drums
          Last edited by Tom; 09-04-2018, 16:42.


          • #6
            Thank you Tom!