water ballast

At 14:49 14 July 2015, Chris Rollings wrote:
Some of the confusion is caused by the fact that (at least some years ago
maybe not now, I don't know) the FAA written (on line) exam for a glide
pilot certificate required one to give the factually wrong answer to
question about inter-thermal speeds into and down-wind, in order to get
th
mark for the question. You had to answer that it was correct to fly
faste
between thermals when going into wind than when going down wind. This i
nonsense, but drawing the mistake to the attention of an FAA Inspector
onl
got his agreement and regret that he could do nothing about it.

The only time head or tail-wind affects inter-thermal speed or the need
fo
ballast is when the glide is to a fixed point on the ground, either a tur
point to be rounded before the next thermal is taken or a final glide t
landing.

Chris, you should perhaps read Brigliadori's Competing in Gliders. They
make a pretty convincing argument for flying a bit faster into wind between
thermals. Its in the appendices.

Jim