re: WWII Item - Bombs Away, or Where's Chicken? Part I & II

The purple lines are magnetic variation lines, used to correct the magnetic compass as they were likely often flying by dead reckoning. There’s not much variation near the equator, but near the poles things vary quite a lot.

240 is probably an elevation of the town nearby

Latitude lines run EW and Longitude lines run NS.

The other handwritten numbers may be the plotted nautical miles travelled during the mission.

If you can measure the distance between 260 and 300, it should be roughly 40NM if that’s a correct assumption.

To measure distance (nm), each minute on the latitude scale (left or right side of the map) will be 1NM.

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This looks like two different flight paths at different times... I am unsure... But the straight line marking I assume are naviagation courses... IS the point a degree variation via compass?

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Not a degree variation via compass. The point is likely a visible landmark not annotated on the map which the navigator, using a stop watch, timed to mark either an arrival point to verify position, or to make a heading change at the line intersection point at the aircraft's normal cruising speed during low visibility weather.

Keep in mind there were no electronic nav aids or GPS in the early 40's, especially in Northern Africa. They flew mainly by compass heading on timed dead reckoning to visible landmarks. Flying in lousy weather makes it all the more difficult and important to hit timed landmarks at the correct estimated time of arrival.

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For some reason there are these circles located all over the map. They are not part of the map but drawn on... There are scattered all over the map.. Also note the 1'00 W 1942... Someone please explain these if you can.. Thanks.

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The circles were points of interest, military camps, prominent landmarks and such that the user didn't describe on the map to keep it somewhat clean. He'd have kept those in a separate written log book and because they aren't described or numbered on the map, he was perhaps concerned about security.

The 1' 00" W is magnetic declination along that line calculated for that area in 1942 by a land surveyor. The magnetic pole wobbles over time and magnetic north isn't usually coincident with mapping datums or true north.

Runways are surveyed for true (grid) north so that pilots can set their magnetic compass to that value before takeoff, i.e. runway 210 is at a heading of 210 degrees relative to true north.

My best guess and what I'd do if flying in a remote, hostile area in 1942.

The Brits were and are masters of land and nautical surveying, and it's obvious they constructed this map. Good stuff.

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I love your threads

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Thank You Buddy...