Thrust Specific Fuel Consumption Calculator Formula

Understand the math behind the thrust specific fuel consumption calculator. Each variable explained with a worked example.

Use the Thrust Specific Fuel Consumption Calculator

Formulas Used

TSFC

tsfc_kg_kn_h = fuel_flow / thrust

TSFC (SI)

tsfc_g_kn_s = fuel_flow / thrust / 3.6

Variables

VariableDescriptionDefault
fuel_flowFuel Flow Rate(kg/h)2500
thrustNet Thrust(kN)100
thrust_nDerived value= thrust * 1000calculated

How It Works

Thrust Specific Fuel Consumption

TSFC measures how efficiently a jet engine converts fuel into thrust. Lower values indicate better fuel economy.

Formula

TSFC = fuel_flow / Thrust

where fuel_flow is in kg/h and thrust in kN for the common industry unit of kg/(kN·h). Modern high-bypass turbofans achieve TSFC values around 15-20 g/(kN·s). Turbojet engines are less efficient at about 25-30 g/(kN·s).

Worked Example

A turbofan engine producing 100 kN of thrust while burning 2500 kg/h of fuel.

fuel_flow = 2500thrust = 100
  1. 01TSFC = 2500 kg/h ÷ 100 kN = 25 kg/(kN·h)
  2. 02Convert to SI: 25 / 3.6 = 6.944 g/(kN·s)

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