BRYCEM
If you manage to control your emotions for a moment you will find that over-dosing on grump is clouding your vision.
Your statement that
On modern (high bypass) engines, the bulk of the thrust is obtained at the fan.
is ture but not relevant to the question
Now the question becomes, "So if the thrust isn't acting on the nozzle, what is it acting on"?
We are talking about the nozzle at the back end of the jet pipe.
By the time the air reaches this nozzle it has already passed through the low pressure turbine so its effect on the fan is almost zero (back pressure effects only).
Cristiaan J
We are not talking about a condi nozzle, just a plain old convergent one.
FE Hoppy
If we were taliking about a condi-nozzle then some of the thrust would be acting on that part of the nozzle that is downstream of the throat.
Awblain.
Your statement that
The nozzle is thus pulled off the engine with 800,000lb of force, while the combustion chamber is pushed up into the engine by 1,200,00lb, giving a net 400,000lb.
is along the right lines.
JT
You are of course correct (as usual).
But I think that your statement about
integrating the pressures......
probably leaves many readers none the wiser.
The best answers (those from which we learn the most) are often not the ones that we get from books, but the ones that we get from within our own heads. Spending a little bit of time pondering this type of question can often be very useful (even if the questions are sometimes rather irritating).