So if you have one vertical vector with length 2 ( v=(2,0) ) and one horizontal vector of length 2 ( u=(0,2) ) their resultant would not have the length 4, it would have the length of the vector w=(2,2) which in this case would just be sqrt(2^2 + 2^2) ≈ 2.83
And in this case its horizontal and vertical so they ALWAYS meet at 90 degrees. Meaning that simple sine/cosine math works just fine. Because the resultant will always be the hypothenuse of the two vectors right angle triangle.
Yes its already known that sine in particular is what is used to determine the final vector regardless.
If you recall what I said earlier simply dividing the nozzle angle by 90 to get the approximate resultant vector.
This holds up and will only result in a small percentile change when compared to the correct vector (60 degree nozzle angle approximation is only 3% different then the corrected math) and magnitude. As the resultant vector does not have any of the Pythagorean math added too it. Seeing as the resultant is actually the Hypotenuse of the 2 vectors if they meet at 90 degrees.
I did this so its just easy for anyone to get an approximate answer.
It was completely unnecessary to dive into any of this to find an average to begin with. (There was also a chart that told him exactly what the thrust split was for the selected nozzle angle)
So again slapping COS(60) into a calculator because the nozzle angle was 60 degrees isn’t correct. Seeing at the vector of the nozzle angle at 60 degrees it no longer acts horizontally and vertically.
The problem isn’t about vector addition, its that the guy just took the horizontal component of thrust and started calculating with it, ignoring the vertical component and its effect on the aircraft. Maybe I’m missing something too, but it looks far from the truth.