[Hoverbug]

Originally Posted by Blackdog_kt

Some aircraft might also have specialized equipment. In B17 the mighty 8th, the navigator had a scope that looked down towards the ground. It had some continuous horizontal lines running across the scope view, as well as dotted lines that could be rotated. The idea was to rotate the dotted line lens until the view seemed to be moving without any drift (it's been a few years, don't remember it exactly), then you could read out the drift from the markings on the wheel that turned the dotted lines.

This would have been a B-3 or B-5 drift meter. Pretty much any medium or heavy bomber would have had one. This was direct evolution of Harold Gatty's drift meter of the early 1930s.

http://www.nasm.si.edu/collections/a...d=A19500075025

Here's one with all the bits:

http://cgi.ebay.com/ebaymotors/Bendi...-/360240715244


Here's the B-5:

http://www.questmasters.us/sitebuild...er-423x366.jpg