Very cool concept on the latest drawing. Looks like it'd be right at home in "The Sky Crawlers".
One thing though, no way would synchronized guns be possible with contra-rotating, four bladed propellers. North American couldn't make them work with one four bladed prop on the Mustang, which is why the P-51 versions with that prop only had wing guns.
Search YouTube for Jon Gnagy. There's a few episodes of his "Learn to Draw" show from the 1950's on there. Other good YouTube searches, learn to draw and how to draw, followed by the subject you're interested in, like airplanes, aircraft, perspective etc.
There was another guy with a TV drawing show I used to watch on PBS in the 70's, but I can't remember his name or the name of the show. He used pencils and charcoal like Jon Gnagy.