The accurate measurment of the axial force component, acting on small wind-tunnel models, has traditionally been a difficult problem. The use of integral sting balances eliminated many accuracy problems, such as friction and hysteresis, but is also introduced interactions between the various force and moment sensing elements due to nonlinear elastic phenomena. The reduction of these interactions usually calls for complicated designs, expensive manufacturing, hard to handle calibration processes and cumbersome data reduction programs. In spite of all these efforts, axial force measurement still lacks accuracy. A new approach, based on an external axial force measuring element, avoids the ill conditioned design problems of integral balances. This approach, however, has to encounter other obstacles such as friction, misalignment and relative motion between metric elements. The way these problems were dealt with, is presented in this paper. Calibration and test results prove the ability of the new approach in duplicating and surpassing the results of much more complicated and expensive integral balances. The advantages of the new design make it the only acceptable solution for particular measurement problems.
An external drag measuring element
Ein externes Luftwiderstands Messelement
ICIASF '87 record ; 269-273
1987
5 Seiten, 6 Bilder, 5 Quellen
Aufsatz (Konferenz)
Englisch
Overview of external Nacelle drag and interference drag
NTRS | 1975
|Summary of External-Store Drag
NTRS | 1966
|Turbulent drag reduction for external flows
AIAA | 1983
|External Drag of Fuselage Side Intakes
AIAA | 1972
|