On Wednesday, July 31, 2019 at 6:34:52 PM UTC-4, Bob Kuykendall wrote:
On Tuesday, July 30, 2019 at 9:00:34 PM UTC-7, wrote:
Can anyone tell me specifically how to tell how closely a wing is following its intended shape or to know if it has "issues"? Also, if I'm sanding, polishing or refinishing it, how do I accurately correct for any deficiencies? Asking for a friend... : )

It depends entirely on the nature of the wing. For aggressively laminar profiles like the old FX67, it can matter a lot. For others, it matters a lot less.

In my direct experience, freedom from waviness (Johnson reading below 0.004" per linear inch) is a lot more important than absolute fidelity to contour. Time spent trying to impose some sort of theoretically ideal contour with filling and sanding is a lot better spent just getting any big waves out and then concentrating on soaring strategy and tactics.

Case in point: Do a template check on any LS6 or LS8. I can probably loan you the templates for that, though I haven't seen them for a while. Anyhow, what you find is that the camber lines for the right and left wings are substantially different. The template for one wing fits the opposite wing like maybe they're from two different gliders. This applies to all of the six or eight ships I've checked, and all of them have been different in pretty much the same ways, so I'm pretty sure that's how they come out of the molds. But these are not dogmeat gliders-- they go like stink, fly arrow straight if they're tuned properly, and have won regional and national contests. Who's to say whether the right or the left wing has the correct profile and the other not? They both seem to work pretty damn well.

--Bob K.

Bob said it well.
There is very little data available for the airfoils on the modern(last 20 years) ships.
Best bet is fill the spar shrink and don't screw up the leading edge.
If I'm doing a "serious" job I pull templates of the leading edge 4 inches back every 24 inches so it is back to "correct" before finish spraying.
Fair warning: More ships have been made worse by people who did not know what they were doing and the list of projects abandoned part way through is long.
UH