Originally Posted by
A Squared
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.
That doesn't really help. I was thinking that to increase speed you would increase your descent angle so you'd actually just end up going backwards. What I wasn't getting was that the trade off between descent rate and airspeed is not linear.