What is the purpose of the white lines on the leading edge of the wing near the guns?
Attachment:
P-47 Wing Markings (Reduced).png [ 1.87 MiB | Viewed 947 times ]
(Source:
Preflight Study Manual for Civil Air Patrol Cadets (Headquarters AAF, Office of Flying Safety, n.d.) 3-7.)
The explanations I have come up with or heard so far is that they are either for boresighting the guns, measuring wind drift angle, or bomb aiming.
I know that the Ju 87 has dive lines painted on the pilot's canopy...

(Source:
War Thunder)
...the Il-2 has level bombing lines painted on the engine cowling...
Attachment:
post-19-0-68504000-1490948712 (Cropped).jpg [ 291.97 KiB | Viewed 947 times ]
(Source:
IL2Sturmovik.com)
...and the B5N has similar lines on the tail as well as the nose.

(Source:
War Thunder Wiki)
Some P-47s apparently also had flap angle lines painted on the trailing edge of the wing, so maybe that's where the idea came from.
Attachment:
P47_1 (Reduced, Cropped).jpg [ 74.65 KiB | Viewed 947 times ]
(Source:
RCUniverse.com)
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Tri-State Warbird Museum Collections Manager & Museum AttendantIn a perfect world we would be flying only replicas. (Or at least only non-combat veterans.)
Means of Imperialistic Air Attacks