Fuel Fraction Solution

STEP 0: Pre-Calculation Summary
Formula Used
Fuel Fraction = Fuel Weight to be Carried/Desired Takeoff Weight
Ff = FW/DTW
This formula uses 3 Variables
Variables Used
Fuel Fraction - Fuel Fraction is the ratio between weight of fuel caried by a plane to the aircraft total take off weight.
Fuel Weight to be Carried - (Measured in Kilogram) - Fuel Weight to be Carried is defined as the total mass of the fuel to be carried (usually includes reserve fuel).
Desired Takeoff Weight - (Measured in Kilogram) - Desired Takeoff Weight (or mass) is the weight of the aircraft.
STEP 1: Convert Input(s) to Base Unit
Fuel Weight to be Carried: 100000 Kilogram --> 100000 Kilogram No Conversion Required
Desired Takeoff Weight: 250000 Kilogram --> 250000 Kilogram No Conversion Required
STEP 2: Evaluate Formula
Substituting Input Values in Formula
Ff = FW/DTW --> 100000/250000
Evaluating ... ...
Ff = 0.4
STEP 3: Convert Result to Output's Unit
0.4 --> No Conversion Required
FINAL ANSWER
0.4 <-- Fuel Fraction
(Calculation completed in 00.004 seconds)

Credits

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Created by Vedant Chitte
All India Shri Shivaji Memorials Society's ,College of Engineering (AISSMS COE PUNE), Pune
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Verified by Ravi Khiyani
Shri Govindram Seksaria Institute of Technology and Science (SGSITS), Indore
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25 Preliminary Design Calculators

Velocity at Maximum Endurance given Preliminary Endurance for Prop-Driven Aircraft
​ Go Velocity for Maximum Endurance = (Lift to Drag Ratio at Maximum Endurance*Propeller Efficiency*ln(Weight of Aircraft at Beginning of Loiter Phase/Weight of Aircraft at End of Loiter Phase))/(Power Specific Fuel Consumption*Endurance of Aircraft)
Preliminary Endurance for Prop-Driven Aircraft
​ Go Endurance of Aircraft = (Lift to Drag Ratio at Maximum Endurance*Propeller Efficiency*ln(Weight of Aircraft at Beginning of Loiter Phase/Weight of Aircraft at End of Loiter Phase))/(Power Specific Fuel Consumption*Velocity for Maximum Endurance)
Velocity for Maximizing Range given Range for Jet Aircraft
​ Go Velocity at Maximum Lift to Drag Ratio = (Range of Aircraft*Power Specific Fuel Consumption)/(Maximum Lift-to-Drag Ratio of Aircraft*ln(Weight of Aircraft at Beginning of Cruise Phase/Weight of Aircraft at End of Cruise Phase))
Optimum Range for Jet Aircraft in Cruising Phase
​ Go Range of Aircraft = (Velocity at Maximum Lift to Drag Ratio*Maximum Lift-to-Drag Ratio of Aircraft)/Power Specific Fuel Consumption*ln(Weight of Aircraft at Beginning of Cruise Phase/Weight of Aircraft at End of Cruise Phase)
Optimum Range for Prop-Driven Aircraft in Cruising Phase
​ Go Optimum Range of Aircraft = (Propeller Efficiency*Maximum Lift-to-Drag Ratio of Aircraft)/Power Specific Fuel Consumption*ln(Weight of Aircraft at Beginning of Cruise Phase/Weight of Aircraft at End of Cruise Phase)
Preliminary Endurance for Jet Aircraft
​ Go Preliminary Endurance of Aircraft = (Maximum Lift-to-Drag Ratio of Aircraft*ln(Weight of Aircraft at Beginning of Cruise Phase/Weight of Aircraft at End of Cruise Phase))/Power Specific Fuel Consumption
Maximum Lift over Drag
​ Go Maximum Lift-to-Drag Ratio of Aircraft = Landing Mass Fraction*((Aspect Ratio of a Wing)/(Aircraft Wetted Area/Reference Area))^(0.5)
Preliminary Take Off Weight Built-up for Manned Aircraft
​ Go Desired Takeoff Weight = Payload Carried+Operating Empty Weight+Fuel Weight to be Carried+Crew Weight
Payload Weight given Takeoff Weight
​ Go Payload Carried = Desired Takeoff Weight-Operating Empty Weight-Crew Weight-Fuel Weight to be Carried
Empty Weight given Takeoff Weight
​ Go Operating Empty Weight = Desired Takeoff Weight-Fuel Weight to be Carried-Payload Carried-Crew Weight
Crew Weight given Takeoff Weight
​ Go Crew Weight = Desired Takeoff Weight-Payload Carried-Fuel Weight to be Carried-Operating Empty Weight
Fuel Weight given Takeoff Weight
​ Go Fuel Weight to be Carried = Desired Takeoff Weight-Operating Empty Weight-Payload Carried-Crew Weight
Preliminary Take off Weight Built-Up for Manned Aircraft given Fuel and Empty Weight Fraction
​ Go Desired Takeoff Weight = (Payload Carried+Crew Weight)/(1-Fuel Fraction-Empty Weight Fraction)
Fuel Fraction given Takeoff Weight and Empty Weight Fraction
​ Go Fuel Fraction = 1-Empty Weight Fraction-(Payload Carried+Crew Weight)/Desired Takeoff Weight
Empty Weight Fraction given Takeoff Weight and Fuel Fraction
​ Go Empty Weight Fraction = 1-Fuel Fraction-(Payload Carried+Crew Weight)/Desired Takeoff Weight
Payload Weight given Fuel and Empty Weight Fractions
​ Go Payload Carried = Desired Takeoff Weight*(1-Empty Weight Fraction-Fuel Fraction)-Crew Weight
Crew Weight given Fuel and Empty Weight Fraction
​ Go Crew Weight = Desired Takeoff Weight*(1-Empty Weight Fraction-Fuel Fraction)-Payload Carried
Takeoff Weight given Empty Weight Fraction
​ Go Desired Takeoff Weight = Operating Empty Weight/Empty Weight Fraction
Empty Weight given Empty Weight Fraction
​ Go Operating Empty Weight = Empty Weight Fraction*Desired Takeoff Weight
Empty Weight Fraction
​ Go Empty Weight Fraction = Operating Empty Weight/Desired Takeoff Weight
Winglet Friction Coefficient
​ Go Coefficient of Friction = 4.55/(log10(Winglet Reynolds Number^2.58))
Takeoff Weight given Fuel Fraction
​ Go Desired Takeoff Weight = Fuel Weight to be Carried/Fuel Fraction
Fuel Weight given Fuel Fraction
​ Go Fuel Weight to be Carried = Fuel Fraction*Desired Takeoff Weight
Fuel Fraction
​ Go Fuel Fraction = Fuel Weight to be Carried/Desired Takeoff Weight
Design Range given Range Increment
​ Go Design Range = Harmonic Range-Range Increment of Aircraft

Fuel Fraction Formula

Fuel Fraction = Fuel Weight to be Carried/Desired Takeoff Weight
Ff = FW/DTW

What is Fuel Weight?

The total weight of fuel carried by an aircraft during whole flight is called as fuel weight. The fuel weight varies with the flight, as the fuel is burnt in the engines the weight of fuel reduces. For Fuel Fraction the maximum amount of fuel is considered.

What is Importance of Fuel Fraction?

In aerospace engineering, an aircraft's fuel fraction, fuel weight fraction, or a spacecraft's propellant fraction, is the weight of the fuel or propellant divided by the gross take-off weight of the craft (including propellant).
The fractional result of this mathematical division. For aircraft with external drop tanks, the term internal fuel fraction is used to exclude the weight of external tanks and fuel.
Fuel fraction is a key parameter in determining an aircraft's range, the distance it can fly without refueling. Breguet’s aircraft range equation describes the relationship of range with airspeed, lift-to-drag ratio, specific fuel consumption, and the part of the total fuel fraction available for cruise, also known as the cruise fuel fraction, or cruise fuel weight fraction.

How to Calculate Fuel Fraction?

Fuel Fraction calculator uses Fuel Fraction = Fuel Weight to be Carried/Desired Takeoff Weight to calculate the Fuel Fraction, The Fuel Fraction of an aircraft is a parameter used in aircraft design and performance calculations to represent the proportion of the total weight of the aircraft at takeoff that is attributed to fuel. Fuel Fraction is denoted by Ff symbol.

How to calculate Fuel Fraction using this online calculator? To use this online calculator for Fuel Fraction, enter Fuel Weight to be Carried (FW) & Desired Takeoff Weight (DTW) and hit the calculate button. Here is how the Fuel Fraction calculation can be explained with given input values -> 0.4 = 100000/250000.

FAQ

What is Fuel Fraction?
The Fuel Fraction of an aircraft is a parameter used in aircraft design and performance calculations to represent the proportion of the total weight of the aircraft at takeoff that is attributed to fuel and is represented as Ff = FW/DTW or Fuel Fraction = Fuel Weight to be Carried/Desired Takeoff Weight. Fuel Weight to be Carried is defined as the total mass of the fuel to be carried (usually includes reserve fuel) & Desired Takeoff Weight (or mass) is the weight of the aircraft.
How to calculate Fuel Fraction?
The Fuel Fraction of an aircraft is a parameter used in aircraft design and performance calculations to represent the proportion of the total weight of the aircraft at takeoff that is attributed to fuel is calculated using Fuel Fraction = Fuel Weight to be Carried/Desired Takeoff Weight. To calculate Fuel Fraction, you need Fuel Weight to be Carried (FW) & Desired Takeoff Weight (DTW). With our tool, you need to enter the respective value for Fuel Weight to be Carried & Desired Takeoff Weight and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.
How many ways are there to calculate Fuel Fraction?
In this formula, Fuel Fraction uses Fuel Weight to be Carried & Desired Takeoff Weight. We can use 1 other way(s) to calculate the same, which is/are as follows -
  • Fuel Fraction = 1-Empty Weight Fraction-(Payload Carried+Crew Weight)/Desired Takeoff Weight
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