Originally Posted by
AerocatS2A
Thanks. I had seen that graphic but it still didn't click. I think I've got it now. Basically the penalty of a higher sink rate in a headwind is offset by the benefit of the faster speed. You are trading time in the air for penetration.
TO help solidify it in your mind, try this thought experiment. It's essentially what Gysbreght said in a previous post, but in my experience it halos to throw some numbers on it and think through it little.
Let's say that you're flying an airplane with a angle of glide speed of 65 knots. You're flying into a 65 knot headwind at 6000 ft AGL. The wind is constant all the way to the ground. You have an engine failure. You immediately pitch to your glide speed of 65 knots. Your descent rate is 1500 ft/ minute. You will glide for 4 minutes. How far forward do you go?
If your airspeed is 65 kt, and the headwind is 65 kt, then your groundspeed will be zero, and obvious you will not move forward at all with a groundspeed of zero.
So what happens if you were to pitch over further to glide at 75 knots? Now your groundspeed is 10 knots because your airspeed exceeds your headwind. Now, obviously, if you are moving forward, you're going to travel further than if you were not moving forward, so it can be seen that increasing the speed at which you glide into a headwind will increase the the power off glide distance.