I had asked similar question. And the answer is just google for "laminar airfoil waviness"Found an older post on this subject, hence the subject line
Are laminar flow wings/fuselage always impossible with aluminum construction regardless of construction methods?
Does no construction method exist to solve this issue?
Prebent/molded thicker wing skins, aluminum over foam or other substructure, spar less, high AR wings with small distance between front and rear spars etc... does nothing solve this problem?
Understand the solution may not be worth the effort or weight, but still wondering if a solution exists.
Thanks in advance
And the biggest issue is any local imperfection like rivet, or panel joint. Not some kind of flexible panel..
Structure - if no fuel in tank - foam cored wing with carbon fiber is the lightest option. But it will need some filling/sanding for glass like surface. Here are some calculations
Wing design for lightest possible wing