The Virtual Center type External Balance is designed to measure six components of force and moment with very high precision. The balance is fabricated from square steel tubing, custom weldments, and ten (10) precision load cell flexures. The metric load frame connects the Model Support System (metric) to the live end of all the load cells; the non-metric frame connects all the ground ends of the load cells to ground. The External Balance is designed to measure moments about a point at or near the tunnel centerline. The balance is designed to be compact, yet rigid. The natural frequencies are high and the deflections are extremely low. The models are attached by various support systems.