well yes ! Well no! I mean 12.7 cm ! Sorry. I have been making measurements in 2 and 2.5 mm the last few nights and miss spoke. It is at 12.7 cm or 5 inches if you use that cumbersome base 12 English measurement system. That would be at exactly the half mark on the length of the wing chord. Still to me always seemed wrong when I first looked at it.....but I really don't know.