Whirley:
You are correct, wind shear will affect airspeed.
And the exact same effect of wind shear will be encountered whether you are turning down wind or up wind or cross wind or any combination thereof.
A suggestion for those of you who think turning downwind is dangerous if you maintain airspeed.....always fly into wind, that way you will get to see more places.
Oh by the way anyone here have any opinions on the flat earth theory ?
Chuck