Target visibility

[6S.Manu]

It's not an official document but I think the site's name is notable.

http://www.globalsecurity.org/milita...raft-early.htm

During World War I (!!!), visual detection in daylight did not exceed 15 miles. Experiments with stealth capabilities occurred as far back as the early part of the 1900s when Germany tested an aircraft with a transparent wing, designed to make it difficult to spot by observers on the ground.

During WWII, The US Navy's Project Yehudi used lights mounted on the leading edges of the wings of a torpedo bomber to successfully hide the plane in broad daylight when attacking a submarine. Visual detection range in the tests dropped substantially from 12 to 2 miles.

EDIT: About Project Yehudi, in the test they used an TBM 3D Avenger.

http://books.google.com/books?id=q06...bomber&f=false