UH - 60 A Black Hawk engineering simulation program. This mathematical model is total systems definition of the Black Hawk helicopter represented at a uniform level of sophistication considered necessary for handling qualities evaluations.
The model is a total force, large angle representation in six rigid body degrees of freedom.
Rotor blade flapping, lagging, and hub rotational degrees of freedom are also represented. In addition to the basic helicopter modules, supportive modules were defined for the landing interface, power unit, ground effects, and gust penetration.
Information defining the cockpit environment relevant to pilot in the loop simulation is presented. Helicopter external air transportation plays an important Aero systems engineering inc dba asexual definition in today's world. For both military and civilian helicopters, external sling load operations offer an efficient and expedient method of handling heavy, oversized cargo. With the ability to reach Aero systems engineering inc dba asexual definition otherwise inaccessible by ground transportation, helicopter external load operations are conducted in industries such as logging, construction, and fire fighting, as well as in support of military tactical transport missions.
Historically, helicopter and load combinations have been qualified through flight testing, requiring considerable time and cost. With advancements in simulation and flight test techniques there is potential to substantially reduce costs and increase the safety of helicopter sling load certification.
Validated simulation tools make possible accurate prediction of operational flight characteristics before initial flight tests. Real time analysis of test data improves the safety and efficiency of the testing programs. To advance these concepts, the U. Army and NASA, in cooperation with the Israeli Air Force and Technion, under a Memorandum of Agreement, seek to develop and validate a numerical model of the UH - 60 with sling load and demonstrate a method of near real time flight test analysis.
This thesis presents results from flight tests of a U. Army Black Hawk helicopter with various external loads. Tests were conducted as the U. The primary load was a container express box CONEX which contained a compact instrumentation package.
The flights covered the airspeed range from hover to 70 knots. Primary maneuvers were pitch and roll frequency sweeps, steps, and doublets. Results of the test determined the effect of the suspended load on both the aircraft's handling qualities and its control system's stability margins.
Included were calculations of the stability characteristics of the load's pendular motion. Prolonged restricted sitting effects in UH - 60 helicopters.
Advances in flight technologies and the demand for long-range flight have increased mission lengths for U. Army Black Hawk UH - 60 crewmembers.
Prolonged mission times have increased reports of pilot discomfort and symptoms of paresthesia thought to be due to UH - 60 seat design and areas of locally high pressure. Discomfort created by the seat-system decreases situational awareness, putting aviators and support crew at risk of injury. Therefore, the purpose of this study was to examine the effects of prolonged restricted sitting in a UH - 60 on discomfort, sensory function, and vascular measures in the lower extremities.
During the session, subjective discomfort, sensory function, and vascular function were measured. Across 4 h of restricted sitting, subjective discomfort increased using the Category Partitioning Scale The results suggest that prolonged sitting in a UH - 60 seat increases discomfort, potentially through a peripheral nervous or vascular system mechanism.
Further research is Aero systems engineering inc dba asexual definition to understand the etiology and onset of pain and paresthesia during prolonged sitting in UH - 60 pilot seats.
Full-scale flight-test pilot floor vibration is modeled using neural networks and full-scale wind tunnel test data for low speed level flight conditions. Neural network connections between the wind tunnel test data and the tlxee flight test pilot vibration components vertical, lateral, and longitudinal are studied.
Using neural networks, the flight-test pilot vibration is modeled using the wind tunnel rotating system hub accelerations, and separately, using the hub loads. The results Aero systems engineering inc dba asexual definition that the wind tunnel rotating system hub accelerations and the operating parameters can represent the flight test pilot vibration.
The present neural network connections can significandy increase the value of wind tunnel testing. Simulator and aircraft mean flight performance. Simulator scatter plot, hover turn maneuvers. The present quantitative effort on the UH - 60 A Black Hawk hub accelerations considers the lateral and longitudinal vibrations. An earlier study had considered the vertical vibration.
A physics based "maneuver-effect-factor MEF ", derived using the roll-angle and the pitch-rate, is used. Fundamentally, the lateral vibration data show high vibration levels up to 0. The results show that the advance ratio and the gross weight together can predict the vertical and the longitudinal vibration. However, the advance ratio and the gross weight together cannot predict the lateral vibration.
The hub accelerations and the advance ratio can be used to satisfactorily predict the vertical, lateral, and longitudinal vibration. The present study shows that neural network based representations of all three UH - 60 A pilot floor vibration components vertical, lateral, and longitudinal can be obtained using the hub accelerations along with the gross weight and the advance ratio.
The hub accelerations are clearly a factor in determining the pilot vibration. The present conclusions potentially allow for the identification of neural network relationships between the experimental hub accelerations obtained from wind tunnel testing and the experimental pilot vibration data obtained from flight testing. A successful establishment of the above Aero systems engineering inc dba asexual definition network based link between the wind tunnel hub accelerations and the flight test vibration data can increase the value of wind tunnel testing.
Adaptive neuro-fuzzy relationships have been developed to model the UH - 60 A Black Hawk pilot floor vertical vibration. A point database that approximates the entire Aero systems engineering inc dba asexual definition - 60 A helicopter flight envelope is used for training and testing purposes. The present study is conducted in two parts. The first part involves level flight conditions and the second part involves the entire point database including maneuver conditions.
The results show that a neuro-fuzzy model can successfully predict the pilot vibration. Also, it is found that the training phase of this neuro-fuzzy model takes only two or three iterations to converge for most cases.
Thus, the proposed approach produces a potentially viable model for real-time implementation. UH - 60 Airloads Program Tutorial. Army flew a flight test program using a UH - 60 A helicopter with extensive instrumentation on the rotor and blades, including pressure transducers. Over this period, approximately 30 flights were made, and data were obtained in level flight, maneuver, ascents, and descents.
Coordinated acoustic measurements were obtained with a ground-acoustic array in cooperation with NASA Langley, and in-flight acoustic measurements with a YO-3A aircraft. NASA has sponsored the creation of a "tutorial' which covers the depth and breadth of the flight test program with a mixture of text and graphics.
The primary purpose of this tutorial is to introduce the student to what is known about rotor aerodynamics based on the UH - 60 A measurements. The tutorial will also be useful to anyone interested in helicopters who would like to have more detailed knowledge about helicopter aerodynamics. Analysis of propulsion system dynamics in the validation of a high-order state space model of the UH - Frequency responses generated from a high-order linear model of the UH - 60 Black Hawk have shown that the propulsion system influences significantly the vertical and yaw dynamics of the aircraft at frequencies important to high-bandwidth control law designs.
The inclusion of the propulsion system comprises the latest step in the development of a high-order linear model of the UH - 60 that models additionally the dynamics of the fuselage, rotor, and inflow.
A complete validation study of the linear model is presented in the frequency domain for both on-axis and off-axis coupled responses in the hoverflight condition, and on-axis responses for forward speeds of 80 and knots.
Based upon previous findings, significant differences in modal data existed and were attributed to assumptions regarding the influence of secondary structure contributions in the preliminary NASTRAN modeling. An analysis of an updated finite element model including several secondary structural additions has confirmed that the inclusion of specific secondary components produces a significant effect on modal frequency and free-response shapes and improves correlations at lower frequencies with shake test data.
Several fixed-winged airplanes have successfully used fly-by-wire FBW technology for the last 40 years. This technology is now beginning to be incorporated into rotary wing aircraft. By using FBW technology, manufacturers are expecting to improve upon the weight, maintenance time and costs, handling and reliability of the aircraft.
Before mass production of this new system begins in new models such as the UH - 60 MU, testing must be conducted to insure the safety of this technology as well as to reassure others it will be worth the time and money to make such a dramatic change to a perfectly functional machine.
This project deals with specific designs and analyses of unique RASCAL aircraft subsystems and their modifications to conduct flight mechanics research. The experiment was a continuation of previous work to develop a simple, but validated, turbulence model for hovering rotorcraft. To validate the METS model, two experienced test pilots replicated precision hover tasks that had been conducted in an instrumented UH - 60 helicopter in turbulence. Objective simulation data were collected for comparison with flight test data, and subjective data were collected that included handling qualities ratings and pilot comments for increasing levels of turbulence.
Analyses of the simulation results show good analytic agreement between the METS model and flight test data, with favorable pilot perception of the simulated turbulence. Comparisons of the empirically derived METS model with the theoretical SORBET model show good agreement providing validation of the more complex blade element method of simulating turbulence.
Helicopter handling qualities research requires that a ground-based simulation be a high-fidelity representation of the actual helicopter, especially over the frequency range of the investigation. The approach used was to compare the simulation to the flight vehicle for a series of tasks performed in flight and in the simulator.
The results show that subjective handling qualities ratings from flight to simulator overlap, and the mathematical model matches the UH - 60 A helicopter very well over the range of frequencies critical Aero systems engineering inc dba asexual definition handling qualities evaluation.
Pilot comments, however, indicate a need for improvement in the perceptual fidelity of the simulation in the areas of motion and visual cuing. The methodology used to make the fidelity assessment proved useful in showing differences in pilot work load and strategy, but additional work is needed to refine objective methods for determining causes of lack of fidelity.
An accelerated aging investigation of critical aviation bearings lubricated with MIL-PRF- grease was conducted to derive an understanding of the mechanisms of grease degradation and loss of lubrication over time. The current study focuses on UH 60 Black Hawk viscous damper bearings supporting the tail rotor driveshaft, which were subjected to more than hours of testing in a heated environment to accelerate the deterioration of the grease.
Over the course of testing, vibration and temperature monitoring of bearings was conducted and trends for failing bearings are presented. Hawking radiation from black rings. Aero systems engineering inc dba asexual definition calculate the quantum radiation from the 5-dimensional charged rotating black rings by demanding the radiation eliminate the possible anomalies on the horizons.
It is shown that the temperature, energy flux, and angular-momentum flux exactly coincide with those of the Hawking radiation.