ACP Composites: Good source for raw composite material and resins
APC Props: Most active USA propellor Supplier
Cox Engines: Best source for parts and available for the old Cox 0.049 engines
Goodwinds: Various composites including pultruded carbon fiber pre-forms
RC Groups: Venerable RC discussion forum, lots of data and activity
Wind Catcher RC: Good source for EPP of any thickness