Here are a few links with useful and/or interesting information.
Tips (updated 01-21-2025)
eCalc can calculate just about anything you want to know about your airplane.
Conversion calculator. Formulas and calculators for just about everything.
How To
How to sheet foam wings, a wing sheeting tutorial by Terry Brox
A long and detailed paper on how to design your RC model. Introduction to Radio Control Model Aircraft Design and Designing Radio Control Model Aircraft