Need help! aircraft identification publication
This has me stumped.:confused:
does anyone have a clue as to where and by whom this would have been used?
does anyone have a clue as to where and by whom this would have been used?
due to the fact they are not printed on "economy" paper and the aircraft included i would guess printed around 1940/41?
the publsher is BTH (British Thomson-Houston) an large engineering firm who were based not far from me in warwickshire.
during the war i believe they produced aircraft magnetos amongst other things.
I cant find anything like these books online.
Also what is a "50mph relative speed ring"???
any ideas greatly welcome!!!