A few more thoughts that a private email question spurred me to sha

We were almost exactly at 90 degrees to each others nose at the time of
collision. I could probably have looked 45 degrees to the left and not seen
him in peripheral vision because there was no relative change in his
position to mine. Despite our relative locations though, we had enough
closure for a serious collision. The other oddity; though he was banking
away from me, he was just at his point in the circle where my flight path
was tangent to the outside of his turn. Thus he probably had to look OVER
the high side of his cockpit to see me or perhaps I was even hidden under
his nose as he came around. Judging by his position when I heard his call
over the radio, he saw me in the former situation, probably because he at
first was looking for me in a turn behind him and not out in front.

I realize now that scanning from 100 to 80 degrees on either side of the
cockpit was something I almost never did outside of turns. When I would
make small course adjustments or was flying straight ahead, I think it was
rare for me to look farther than 60 degrees to the side. Also, when IN
turns I think I tend to look around the corner of my turn more often than
straight ahead, perhaps Will did the same thing. With an audio vario my
guess is a pilot might stop looking down to the instrument panel after
establishing a turn and centering the yaw string. If somebody was on a
tangent that would intercept a turn, they might appear right in front or
perhaps under the nose of the glider and stationary. His DG-400 surely had
a few knots over my Libelle, so it may very well have been one of those
situations mentioned in a previous post about lower performance glider
boxing in higher performance glider.

Paul