Before clicking on to one more page, take into consideration this: fuel thickness makes the difference in between making point A to suggest B because that any plane that flies an ext than one hour away from home. This provides a difference for any long draw airplane.

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We flew the GV for years knowing that we might do mountain Francisco to Tokyo non-stop even with a headwind, but the return trip was not always possible. Us couldn"t ever put top top a complete load of fuel in Japan however gallons are gallons, right? as it turns out, fuel density was the culprit and also nobody knew that until Gulfstream go a study and released the results in the October 28, 2005 Breakfast Minutes. As it turns out, "The aircraft selection is established by fuel weight, no volume," for this reason if her gauges to speak you have less gas, possibilities are girlfriend do.

If you room planning on flying to the airplane"s maximum variety you need to recognize fuel density, particularly if operation out that Asia.

Our Boeing 747"s had actually a full fuel volume of 300,000 lbs, which meant a most range. However sometimes we ended up through a many extra selection or a lot of less. We didn"t recognize fuel density and we should have. Come us, density was a puzzle.

Everything below is from the references presented below, with a few comments in an alternative color.


Fuel thickness Defined

Scientific definition of density: thickness (ρ) the a human body is the ratio of its massive (m) to its volume (V). Density of fuel is “the massive of fuel every unit volume”. In some situations the thickness is expressed together a specific gravity or family member density, in which case it is express in multiples the the density of some various other standard material, generally water or air. Reference: ASTM D1655 specification, Jet A-1 fuel has actually a density of between 775.0 and 840.0 kg/m3. Thickness ranging from 37 to 51 °C API repair to 15 °C or 60 °F.

When it involves fuel, higher density way more "bang because that the buck." The thickness is established by the top quality of the crude used to produce the fuel and the refining process.

Measuring Fuel Density

Fuel density is commonly measured with a hydrometer, i beg your pardon is nothing an ext than a glass tube v a load bottom that sinks come a level proportional to the thickness of the liquid. The hydrometer is calibrated against a scale used to recognize the thickness for a offered temperature.


Figure: Fuel density hydrometer, indigenous Fuel dealing with Jet Quality and also Test Procedure, figure 1.8.

Fuel density versus Weight

Using a fuel density of 6.75 pounds per gallon at 60°F, the complete usable fuel capacity of a G450 is 29,500 lb. (13,380 kg), because that a full of 4,370 united state gallons (16,542 liters). The is permissible come exceed 29,500 lbs the fuel (due to fuel densities) so lengthy as the preferably ramp and takeoff weights are not exceeded.

All that being said, why is it that you cannot constantly get 29,500 lbs or 4,370 us gallons top top the airplane?

The variables include:

Aircraft perspective during refueling soup volume Fuel amount Measuring device (FQMS) accuracy Fuel temperature Fuel density

Gulfstream conducted a examine on this subject once the GV was the queen of the fleet, but the lessons learned use to the G450 as well. Because that the sake of the study, keep in mental a GV"s published fuel capacity is 41,300 lbs.

Impact Comparisons

plane Attitude influence on Fuel volume

The GV"s fuel volume was designed v the aircraft perspective at 1-1/2° sleep down, but the maximum variation because of ramp attitude was found to be only 22 gallons / 148 pounds.

wing Volume impact on Fuel volume

Aircraft since GV sn 529 have been experiment for full volume capacity and found "satisfactory."

FQMS Accuracy affect on Fuel capacity

The architecture specification that the FQMS is ±300 lbs. Typical performance is ±200 lbs. Point out checks have been discovered "satisfactory."

Fuel Temperature influence on Fuel volume

The Gulfstream GV research revealed that each 10°F boost in fuel temperature lessened the GV"s fuel capacity by 200 lbs. The variation between -20°C and +50°C, because that example, have the right to be almost 1,400 lbs.

Using these numbers, a G450"s released capacity of 29,500 lbs (4,370 us Gallons) at 60°F will drop to 28,900 lbs in ~ 90°F.

Fuel Density impact on Fuel capacity

Fuel density has the greatest impact on fuel capacity. A GV"s preferably fuel volume is 6,118 USG, this does not change. Sport in world fuel thickness can cause the GV"s best fuel capacity to change more than 5,000 lbs.

Jet-A fuel density boundaries are established by the American culture for Testing and Materials (ASTM) Specification D1655. At 60°F the density boundaries are indigenous 6.46 to 6.99 lbs/gallon.

In a G450, this amounts to a range of:

28,230 lbs in ~ 6.46 lbs/gallon 30,546 lbs in ~ 6.99 lbs/gallon

A sport of 2,316 lbs.

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Surveys reveal this trend:


Example Fuel density Charts

Michael McLeod has actually gone with the occupational on a couple of aircraft to administer fuel density charts.