Search

The use of centrifuges for human research has been reported for almost 200 years. Centrifuges have been used for research, medical treatment, and training of flight crew. These centrifuges have been designed and built in a variety of configurations with arms as short as 1.5 m and as long as 15 m. Acceleration on a centrifuge is usually measured in Gs which is the acceleration divided by the standard acceleration of gravity. The forces encountered in a centrifuge are the simple application of Newton's Three Laws of Motion. Axes have been defined for G vectors in relation to the human body. These are designated Z (aligned with the spine), Y (left to right), and X (front to back). Most research and training is in Gz and there are two methods of maintaining alignment with that axis. The USAF is examining the possibility of building a large radius centrifuges (200 m or larger) on a track to avoid the inertia of such a long arm. This type of machine could have advantages over the conventional centrifuge.

Six anti-G valves (i.e., valves designed to rapidly deliver output pressures proportional to + Gz forces acting upon valve control elements) were evaluated for performance under conditions simulating the spectrum of Gz-onset conditions likely to be encountered by pilots of current U.S. Air Force high- performance aircraft. This Engineering Test and Evaluation Task was conducted on-site at Brooks Air Force Base, Texas, using the School of Aerospace Medicine (USAFSAM) human centrifuge facility. One objective was validation of uniform testing procedures for evaluation of anti-G valves under controlled conditions of: acceleration, source pressure, valve angles, and simulated anti-G suit volumes. A second objective was measurement of actual dynamic performance of the standard ALAR High-flow Ready-pressure; ALAR High-flow; Garrett Electronic/ Pneumatic; Hymatic VAG-110-022; and AAMRL Electropneumatic ('Bang Bang'). The battery of test conditions employed was divided into three phases: Phase I- Maximum Flow Capacity Testing; Phase II - Dynamic Response Testing; and Phase III-Complex Dynamic Response Testing. Results of testing under all conditions are presented for each valve and the performance characteristics of all six valves are compared., See also Part 1, ADA185658.

In this volume, an examination of anti-G valve failures is reported, as well as the results of 9 short-term investigation dealing with acceleration protection equipment and studies on the USAFSAM Human Centrifuge. These studies involved: the CWU-9/P undergarments; the Statham PM131TC pressure transducer; the Ready Pressure Anti-G valve; the ALAR 'High flow' and 'Special' anti-G valves; accelerometer calibration, continuous ECG recording; control-center data distribution; closed-loop centrifuge control; and the Medilog recorder. (Author)

In this final volume of a three-volume study report, a protocol for testing anti-G suits is described and the test results from 6 test items are reported. These items are: 3 inservice units from USAF and USN; an RAF unit; and 2 experimental units (lower body full pressure, and capstan). The study of the capstan suit is extended to investigate the man-suit interface. Field-test protocols for anti-G suits and anti-G valves are also proposed. (Author)

In the first volume of the three in this study report, the instrumentation, data recording, and computerized data analysis techniques for acceleration sensitivity studies are described in detail. The results of acceleration sensitivity tests on 7 test items are reported. These items are: a mass spectrometer, 4 physiologic pressure transducers, an ear oximeter, and a retrograde inflation anti-G suit. (Author)

In this second volume of a three-volume study report, a protocol for testing anti-G valves is described and the test results from 6 specimens are reported. The test items include 2 inservice USAF units, 2 RAF units and 2 prototype experimental units (electronic and fluidic). A suggested standardized performance evaluation protocol for future applications is proposed. (Author), See also Volume 3, AD-A059 122.