A Description Of Sub-Systems And Calibration Formulations Of The NAL Automatic Balance Calibration System (ABCS)

A Description Of Automatic Balance Calibration System (ABCS) Recently Installed And Commissioned At NAL Is Presented . The Description Includes Details Of The,Major Subsystems, Viz, Loading System, Measuring System And Data Acquisition And Processing System. Details Of The Various Calibration Formulations (Or The Mathematical Models) Adopted In The ABCS To Generate Different Types Of Calibration Matrices Are Presented. Methods Used For Determining The Calibration Co-Efficients And The Balance Loads Using The Outputs Are Briefly Described. A General Description Based On A Brief Review Of The Calibration Methods Of Balances Is Included For A Better Understanding Of The Methods Adopted In ABCS And Facilitate Effective Utilization Of The System. Balance Calibration Procedure Is Briefly Described And Details Of Various Data And Setup Files I That Are Required To Be Created Are Noted.Calibration Results Of A Typical 6-Component Balance, Consisting Of The Set Of 6 X 84 Calibration Co-Efficients, Plots Of Load Measurement Errors And Overall Measurement Accuracy Are Included

PSP Measurements on an Aircraft Wing-Body and Slenderbody Models in the NAL1.2m Trisonic Wind Tunnel.

This is the closure report submitted to the project sponsors AR&DB at the AR&DB project review meeting held on 03/5/2003 at DISC, Bangalore . An experimental study of PSP measurements was undertaken on aircraft and slenderbody models in the 1 .2m trisonic wind tunnel . A major objective of this programme was to provide a correction method of the drop in total temperature of the tunnel on PSP data and estimate accuracy of PSP measurements in a blowdown wind tunnel environment. Tests were made at Mach numbers of 0 .6 and-0 .8 at angle of attack of 6° and 100. A correction method for temperature effects on PSP data was evaluated and found very effective. The PSP results (using above correction method) showed very good agreement with pressure port data on the aircraft model . The accuracy of PSP results so obtained are considered to be about as good as those obtained in wind tunnels elsewhere in the world at transonic speeds

Flow quality improvements in a blowdown wind tunnel 13; 13;

Acoustic baffles installed in the extended settling chamber of the NAL 1.2-m tunnel have substantially reduced the noise levels in its settling chamber and the SW test section. The quieter test-section flow has led to (1) a substantial improvement in the measurement accuracy of pulsation level data in air-intake models at supersonic speeds and (2) an improvement in light buffet onset measurement capability at subsonic/transonic speeds in the tunnel. However, the noise level in the PW test section is still high. Acoustic treatment of the plenum chamber aimed at mitigating the low-frequency tone observed in the PW test section is planned as a follow-on action. (CSA