In general, trumpet forums speak at great length to the development of players, the development of playing styles, etc. Seldom do they address the very instrument that we play. "Are piston valves better than rotary valves", "Why rotary valves in the first place", "What brands are modelled on what historic instrument".
http://www.usd.edu/smm/ deals with many of those questions with some mighty fine descriptions and cut-away drawings. Learn what styles of rim there have been over the years (and where they were developed). Dig around...it's a superb and fun place to "surf".
(Yeah, Dizzy's "idea" was predated by about 100 years!)
