"Derrick Steed
It happens to some extent to all GRP gliders as they age (some say PIK's
are immune - hmmm...), and it's due to shrinkage of the GRP.


I reprofiled some PIK wings some years ago - they are different but they
aren't immune. Interestingly, I think the PIK was Dick Johnson's first
major profile job.

Of course if you just splash some water on that airfoil the waviness can be
ignored...