There's a fascinating thread on another forum I visit on Western observers' take on new Soviet aircraft designs post war, featuring aircraft such as the MiG-29, Su-27, Su-24 etc and their interpretation of blurry satellite images and hurriedly snapped pictures at May Day flyovers, in books and magazines. Some real beauties.
Prior to the war, nations wanted to sell their aircraft to foreign buyers and advertised them in magazines (the Italians because they had no money and wanted hard currency, but that's another story) and extrapolations were made from these ads and eyewitnesses that had spied the aircraft at airfields and events they took part in. The saga of how the Bf 109E got its centreline engine cannon came from an interpretation of different sources in an issue of Aeroplane magazine, where the enthusiastic artist drew a cutaway of an aircraft that vaguely resembled a Bf 109 but really looked nothing like one. Nonetheless, folklore took over and its been repeated in books and magazines for years that the Bf 109E had a centreline gun when it didn't. Although to be fair, it was intended on doing so, but no production aircraft were so fitted.
The legend of the He 113 came from a propaganda exercise and evolved into a new Heinkel fighter spotted by RAF fighter pilots in the heat of battle, with entries in official RAF Air Publications, recognition models and various other things, although it was fictional. Drawings look like the He 100 and the Germans used it as the basis of their propaganda effort.