@Mad,
When I was a student (not exactly yesterday...) we had sheets and sheets of 'parametric charts', with for instance, in this context, things like 'length vs weight' etc. etc. for dozens of widely different types of aircraft.
Some were really just 'scatter' charts with some effort at finding a trend, some were very interesting.
Probably mostly composed by student assistants with time to spare and a library at their disposal.
Do they still exist, are they still used as teaching tools, and are some of them on the 'net somewhere?
raptorva might like to see some of them.
CJ