Pyramidal Balance can be divided into two main groups: internal and external. The group names are derived from their location relative to the test model and wind tunnel test section internal balances reside inside a test model, while external balances reside outside the test section. During the early years of wind tunnel testing, Forces and Moments were literally measured through pan-type balances. Although technology has advanced dramatically since those early days, the term balance is still applied to the devices used for Force and Moment measurements today.
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