Here's the plans of a tough little 48" aerobatic slope ship called the Slopebat. She'll fly in fairly light winds, take a lot of abuse and, unlike most EPP ships, she has plenty of open space inside to hold radio gear without major surgery.

The combination of fiber reinforced strapping tape over EPP foam blocks separated by light ply longerons and bulkheads creates a very stiff but relatively light structure. The foam blocks are trimmed prior to insertion between the light ply so the structure is hollow.

Since the light ply bulkheads define the ship's cross-section at several points it is very easy to finish sand the ship to its final shape. Because the EPP is supported by wood, it is practical to create small or large cross sections where they're needed for scale accuracy. This technique is especially useful for very large ships.