DEI uses pre-impregnated materials almost exclusively for consistency of strength, stiffness, and resin content, all of which provide excellent control over blade mass properties. Articulated and Instrumented Rotor Hub Hubs for model rotor systems are designed to be near-replica or general purpose. If the intent is to test a fully scaled model, a near-replica hub will be required. Otherwise, the hub will be designed to be a general-purpose article to test range of blade types and styles. Most hubs are articulated, meaning that they incorporate hinges in the flapping and lead-lag axes.
Some applications use a composite flexbeam between the hub and the blade, which acts as the hinge.
Hubs are usually machined from aluminum or steel, or a combination of the two. Data Acquisition Systems Strain Gage and Pressure Transducer Instrumentation and Data Acquisition on Rotor Blades Data acquisition for a rotor test system in accomplished using a multi-channel data acquisition system. In many cases, the existing wind tunnel data system is used, but in cases where sophisticated on-blade data is required, a separate data system will be necessary. In such cases, the data system must be considered an integral part of the rotor test system to fully integrate and optimize all hardware and software components of the total system. Often, blades are instrumented with gages at multiple locations along the span to provide significant information regarding the in-flight loads on the blades.