Originally Posted by
Brercrow
You give two examples in #133 Both compare two states of equilibrium and do not consider what is happening DURING the turn
In the second example the math is wrong (500+1) - (500-1) = 2 not 1000
OK, let's talk about what's happening DURING the turn then. Do you notice anything unusual during the turn as you turn through the thousand knot self-created shear within a second? I don't. And my math is right, I just rechecked it:
final groundspeed minus initial groundspeed
(airspeed + tailwind) - (airspeed - headwind)
(1+500)-(1-500)
501-(-499)
1000
If you don't think that's right, compare it with the ealier Cessna example, where the self-created windshear is 20 knots:
final groundspeed minus initial groundspeed
(airspeed + tailwind) - (airspeed - headwind)
(100+10)-(100-10)
110-90
20
For both examples, the final and initial groundspeeds are states of equilibrium. But the 1000 knot and 20 knot wind shears? Those are happening
during the turn, just as you say.
I refer you to post #116 for an example of what happens at jet/Jetstream speeds
The situation that post 116 is a reply to, is a nonstarter. First, it's on an arrival procedure, where your track is anchored to the ground. So it does not apply to our discussion, which is premised on the motions being isolated to the airmass. Second, it
starts with a tailwind and turns away from it (equivalent to turning into a headwind), so any purported effect should be an increase in performance and not a decrease! You note the same thing and dismiss the nose down effect as PIO overshoot of an initial nose up.