AUTOMATIC BALANCE CALIBRATION SYSTEM (ABCS)

Automatic Balance Calibration System (ABCS)

A precise and accurate measurement of aerodynamic forces and moments in the wind tunnel is possible only if the strain gauge balances are calibrated frequently, and prior to the tests. For best results, the calibration equipment should be able to replicate “the real life” six degrees of freedom combined loadings encountered in wind tunnel tests.

ABCS provides this facility. The calibration can also be simulated to the range of loads experienced by the models during wind tunnel tests

In a conventional calibration rig, the loading is done manually and the deflections are corrected using a suitable repositioning mechanism. The total time taken for the calibration, including data reduction, is usually about seven days.

In ABCS, the typical calibration time, involving acquisition of 1000 combined loadings and data reduction for a six-component balance, is only about three hours.

Loads as per a programmed load schedule are automatically applied through six servo-controlled hydraulic actuators and are measured by precision load cells. The deflections are measured through accurate position sensors.

Features of ABCS

• Combined load calibration

• Non repositioning type

• Balances ranging from 0.75 inch dia to 2.5 inch dia can be calibrated

• Typical calibration time for 1000 combined loadings for a six component balance : 3 hours

• The balance and the ABCS are protected using four safety loops

• Load cell accuracy : ±0.015 %

• Position sensor accuracy : ±2.0 microns

• Balance calibration accuracy : ±0.1 %

• Calibration matrix: choice of second order matrix with 84 coefficients including asymmetric terms and third order matrix with 96 coefficients including asymmetric terms.

 Maximum loading capacity