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I am trying to create a small version of a high bypass turbofan engine but I can't seem to find any materials that show how to calculate thrust but on a 7th grade level. If anyone here can help me I would appreciate it immensely. Also I know that engineering and physics are pretty complicated subjects usually taught at a higher grade but I just really do need the help at this moment for what I am doing.

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  • $\begingroup$ That's going to be a stretch (unless you can assume knowledge of air flow). You can find online course notes from universities, duckduckgo.com/… ... It would be a 3rd or more likely 4th year class in aerospace specialty, and would build heavily on fluid mechanics and engineering thermodynamics. $\endgroup$
    – Pete W
    Mar 19 at 19:20

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Forces have the units of mass times distance divided by time squared. So kg meter/sec^2 is standard in the metric system. 1 kg meter/second^2 is called a Newton. If you are talking about solid objects like rocks, this gets factored as Force = Mass x Acceleration. Here Mass is in kg and Acceleration is in meters/sec^2. This is the way it is usually taught first is school.

But there are other ways to factor kg meter/sec^2. If you are talking about a fluid process like a jet engine, we can say Force is equal to the Mass Flux X the change in Velocity (kg/sec X meter/sec). You get the same kg meter/sec^2 that way as you did with F = Mass X Acceleration.

So you can calculate the Thrust force of the turbofan by calculating the mass flux of air that goes into the jet core, and the mass flux of fuel that goes into the jet core and adding these together. Take the sum of the mass fluxes and multiply by the jet core exhaust velocity in meters per second. That gets you core thrust. Bypass thrust is similar, but there isn't any fuel mass. Just multiply the mass flux of bypass air times the velocity of the fan exhaust.

The internals of the fanjet extract energy from the core to drive the fan. The core usually ends up producing little thrust directly since most of the energy is taken to drive the fan.

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