Low approaches in ground effect

Imagine you get things wrong and are caught out low on final,
still a fair distance out, and it looks marginal whether you
are going to reach the runway or not.

One technique I have sometimes heard described is to dive for
the deck and complete the remaining distance in ground effect.
For the sake of the argument we can assume fairly flat ground,
free of obstacles, though not necessarily landable.


A few years ago Soaring Magazine reported experiments on this
undertaken (I believe) by the airforce glider program. They used
Blaniks and a very long runway. The conclusion was that it was better
to stay at max glide and not dive for the ground. I forget though how
much wind they had -- there is some headwind (50 mph) and gradient (to
zero at ground level) where it has to be better to dive. And Blaniks
are pretty bad at high speed -- though will have more induced drag at
any speed in ground effect too.

John Cochrane BB