- The Proportional Governor Patent Number 2,474,140.
- The Proportional Governor Control System.
- The Proportional Governor Control System.
- The Proportional Governor Control System.
- The Proportional Governor Control System.
- The Proportional Governor Control System.
- The Proportional Governor Control System.
- Instruction Manual for Curtiss Electric Propellers.
- Brad's 80 year old manual that started the Curtiss-Wright Company history search.