# Calibration of a 3-Component External Balance for MAVs Wind Tunnel Research
## 5 Conclusions  
This paper presents the mechanical design and the calibration process of a 3-component external balance for measuring aerodynamic forces on a Micro Air Vehicle. The entire process, from fabrication to calibration, was carried out at the Experimental Aerodynamics Department of the National Institute for Aerospace Technology (INTA). The balance features a complex metallic structure, utilizing high-precision strain gauge cells strategically placed to measure lift and drag forces and pitching moments. Moreover, the calibration bench built for this external balance is also described, and it is intended for future wind tunnel testing. Notably, the measurement errors of the external balance obtained during calibration and verified using different loads (from those used in calibration) were low, with maximum errors of 1.78% FS for lift force, 0.73% FS for aerodynamic drag, and 0.98% FS for pitching moment (Table 9). This high level of accuracy ensures reliable results for aerodynamic testing and provides a robust tool for future wind tunnel experiments. Conceptualization, R.B., A.A.R.-S., E.B.B., S.S. and J.C.M.G. ; methodology, R.B., A.A.R.-S., E.B.B., S.S. and J.C.M.G. ; software, J.C.M.G. and E.B.B. ; validation, R.B., A.A.R.-S., E.B.B., S.S. and J.C.M.G. ; formal analysis, R.B.M, A.A.R.-S., E.B.B., S.S. and J.C.M.G. ; investigation, R.B., A.A.R.-S., E.B.B., S.S. and J.C.M.G. ; resources, J.C.M.G. and E.B.B. ; data curation, R.B., A.A.R.-S., E.B.B., S.S. and J.C.M.G. ; writing--original draft preparation, R.B., A.A.R.-S., E.B.B., S.S. and J.C.M.G. ; writing--review and editing, R.B., A.A.R.-S., E.B.B., S.S. and J.C.M.G. ; visualisation, R.B. ; Supervision, R.B. ; project administration, R.B. ; funding acquisition, R.B. All authors have read and agreed to the published version of the manuscript. This study is partially funded by the \"Termofluidomianica\" program 464A 64 1999 14 205 0005 of the Spanish Ministry of Defense with INTA internal code IDATEC S.IGB21001. * (9) [PERSON]; [PERSON]; [PERSON]. Calibration uncertainty estimation of a strain gauge external balance. _Measurement_**2013**, _46_, 24-33. [CrossRef]
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