Originally Posted by
keith williams
PDR1
In your second diagram the aircraft is climbing at constant speed and constant roc, so the forces must be in equilibrium. You show the thrust and drag as being in equilibrium, but we need to look a bit more closely at lift and weight [...]
This made me pause and think, and you're quite right. I fell into the trap of doing a quick sketch containing the details I thought were relevant rather than doing an actual vector diagram which (as you point out) would need to show an equilibrium. If I had actually drawn the proper diagram I would have filled in the extra items which immediately show the obvious conclusion - that I've been talking out of my arse!
No excuses - saw something which made me jump to a particular conclusion but completely failed to do a proper analysis before spouting off. Please accept my apologies.
PDR