Keith, reference your quote "I think that the fault in your argument lies in the fact
that the thrust does not remain unchanged as you climb"
I’m talking instantaneous climb gradient, instantaneous climb rate. I know that normally
thrust decreases as you climb. I’m not trying to suggest this scenario can occur at any other speed
other than at, or very close to V md. And certainly, I understand best ROC is at max excess power etc.
My scenario has been at ONE altitude, say 1000 ft msl., and only at V md. And, most importantly,
with CONSTANT THRUST AS TAS CHANGES WITH TEMPERATURE.
I’m still don’t see why my argument isn’t sound.
IE
1. Regardless of temperature, climbing at V min drag gives a constant amount of excess thrust.
2. This constant amount of excess thrust gives a constant climb angle.
3. This constant climb angle gives a higher rate of climb on cool days than very cold days
What I SUSPECT is the problem, is that the caveat that I’ve put in, that thrust be considered
constant with a change in temperature (note, I’m not also adding altitude, since I’m looking at
instantaneous gradient/rate) IS TOO FAR OFF from the real world, even in pure jets, to have the
effect I’m expecting on gradient, and ROC.