Okay, I reviewed my calculations and, in general, they look okay. One challenge was that I have been using 'merican units (mostly feet and lbs) rather than SI units (N, kg, and meters), which meant that I had to remember to divide by gravity in a couple of places. What units are you using?
Perhaps, as you suggested, it would be better if we just compared notes, especially if you are using different units than I am. This exercise has reminded me that, if I am going to create a generalized program, I need to accommodate different units of measurement. So if you are using different units, I wouldn’t mind converting my spreadsheet to those units and, then, we could compare the results that you get from cannon.js. Ideally, they should be the same. And, if it works as planned, you could use the worksheet to try out different values for your aircraft (e.g. weight, coefficient of drag, lifting surface, etc.) and should have a good idea of what kind of performance to expect.
Looking at your program, I see that you are computing vectors for thrust, lift and drag. Are you (or cannon.js) computing lift by taking into account the angle of attack? If so, how are you (or cannon.js) computing the angle of attack? Are you (or cannon.js) computing induced drag (the drag caused by lift)? Or are you using a more simplified approach for now?
That is where I am at the moment as I add back the vectors on my demo. Eventually, I will add back the computations for induced drag and for lift using angle of attack to my demo since those are the factors that make a flight simulator more realistic and interesting.