Automatic Reduction of Wind Tunnel Data

Abstract

For an exact duplication of the present equipment it is estimated that it would cost about $9000. This unit contains ten information channels and five dc operational amplifiers. With this equipment it is possible to obtain three-component information - lift, drag and center of pressure; or ten channels of pressure coefficients. To obtain six-component balance information it is estimated that $3000 additional will be required. Several features of this equipment appear to be new or novel and might be of value in many general problem solutions. One feature is the application of analogue techniques to data handling and reduction; a second feature is the method of obtaining amplitude stability for the carrier; a third is servo balancing for zero shift; a fourth is the moderately low cost of duplication of the equipment; a fifth is the ease of maintenance and checking of the individual parts and the unit as a whole; a sixth is the versatility of the unit to be used for many types of similar problems; a seventh is the ability to follow dynamic phenomena and perform computations with sinusoid components up to 500 cps. Any of these features may border on being trivial by itself, but the overall system is thought to be a large step forward in moderate accuracy data handling; particularly for test installations where it is (or might be) advisable for the test conductor to have or see the results of the test during or immediately after completion of a run.