Does anyone know of any formulas for calculating engine thrust?

Here is what I am planning on doing.... Any suggestions

I have a nice engine test stand I will mount on a a moving platform.. Actually a skate board mounted on a rail.

I will mount the engine, prop and associated equipment on the skate board.

So I will have the weight of the associated engine components and the weight of the moving platform.

When I run the engine I will measure the engine thrust with a fish scale connected between the moving platform and a fixed stop.

How would I get the accurate thrust of the engine? I realize I need to calculate the weight of the engine and it's components and deduct the weight of the test stand and the moving platform.

I think interesting data could be developed with actual measured thrust of various engines, props and fuel.

I am a short distance from Joe Noll so I am thinking about doing it there as well.

Anyone interested?

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