The purpose of this report is to summarize the work that has been done on the development of reinforced plywood truss ribs, comparing this type of rib with other types, and drawing conclusions from the test results in regard to data to be used in further design work. The problem primarily has been to develop large ribs which should possess the following characteristics: 1. Adequate strength. 2. Minimum weight. 3. Low production cost. 4. Simplicity of construction. 5. Rigidity. 6. Reliability. 7. Economy of material.