Hi,
I agree with Helmut Reichmann on this topic. Thermals move with the wind.
Optimizing speed between them has nothing to do with the wind speed. If you
were flying downwind between thermals would you slow down? No.
Of course it is all different when you are on final glide. At that point
you do want to factor in the effect of wind if you are trying to optimize
distance. All the final glide computers that I am aware of have no way to
tell them than you are on final glide and always give speed to fly commands
for interthermal flying. That is because they are helping you optimize
speed around a task, not distance from a given point. They also work well
to help you determine at what altitude to leave the last thermal. Just set
the MacCready setting on the final glide computer or software to your actual
climb rate in the last thermal. When it says you can make it home you
should leave. That will optimize your final glide time. That is also from
Reichmann's excellent book.
Good Soaring,
Paul Remde
Cumulus Soaring, Inc.
http://www.cumulus-soaring.com
"John Cotter" wrote in message
ups.com...
To quote page 116 of Reichmann's "Cross-Country Soaring" 7th edition,
"The problem is definitely a different one from that of greatest
distance described above. Then we were optimizing for distance; now we
are optimizing for cruise speed: how fast should we fly from thermal to
thermal to realize the best average speed. Since the best cruise
airspeed will result in the best ground-speed as well, there is no need
to calculate the effects of wind."
Tony Verhulst wrote:
.... Best avg XC speed
will be achieved through answer c.
Ok, answer C says "The best lift/drag speed with no regard to wind
velocity.".
So, my best lift/drag speed is 50 knots and I'm flying into a 50 knot
headwind at 50 indicated. And, I'm going ... where? "A" is the correct
answer, IMHO. Answer "A", in the above example, would get you a ground
speed of 25 knots (75 - 50)- you're not going to do much better than
that. The question, though, is poorly worded.
Tony V.