Flow-Through Balance for Reaction Control Testing

Atmospheric entry vehicles undergo wind tunnel testing during development and the flight certification process. During testing, reaction control system (RCS) thrusters are simulated using high-pressure fluid to validate RCS design and enable developing controller algorithms. Traditionally, flowing high-pressure fluid through a six-component balance has been impractical using conventional manufacturing, and has limited force measurement to five components (no axial force). A new six-component flow-through balance enabled by additive manufacturing was developed, which is suited for RCS ground testing fluid pressures up to 13.8MPa (2000 psi). Multiple prototypes with compliant flow passages were designed and fabricated to enable axial force measurements. One selected design was fully fabricated, instrumented, and evaluated. Results confirmed finite element analysis (FEA) predictions of gage outputs, flow passage compliance, and successfully demonstrated the high-pressure flow-through concept.