Flight-Time Identification of a UH-60A Helicopter and Slung Load
| Author | : |
| Publisher | : |
| Total Pages | : 30 |
| Release | : 1998 |
| Genre | : |
| ISBN | : |
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Flight Test Identification and Simulation of a UH-60A Helicopter and Slung Load
| Author | : |
| Publisher | : |
| Total Pages | : 98 |
| Release | : 2001 |
| Genre | : |
| ISBN | : |
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Helicopter slung-load operations are common in both military and civil contexts. Helicopters and loads are often qualified for these operations by means of flight tests, which can be expensive and time consuming. There is significant potential to reduce such costs both through revisions in flight-test methods and by using validated simulation models. To these ends, flight tests were conducted at Moffett Field to demonstrate the identification of key dynamic parameters during flight tests (aircraft stability margins and handling-qualities parameters, and load pendulum stability), and to accumulate a data base for simulation development and validation. The test aircraft was a UH-60A Black Hawk, and the primary test load was an instrumented 8- by 6- by 6-ft cargo container. Tests were focused on the lateral and longitudinal axes, which are the axes most affected by the load pendulum modes in the frequency range of interest for handling qualities; tests were conducted at airspeeds from hover to 80 knots. Using telemetered data, the dynamic parameters were evaluated in near real time after each test airspeed and before clearing the aircraft to the next test point. These computations were completed in under 1 min. A simulation model was implemented by integrating an advanced model of the UH-60A aerodynamics, dynamic equations for the two-body slung-load system, and load static aerodynamics obtained from wind-tunnel measurements. Comparisons with flight data for the helicopter alone and with a slung load showed good overall agreement for all parameters and test points; however, unmodeled secondary dynamic losses around 2 Hz were found in the helicopter model and they resulted in conservative stability margin estimates.
FLIGHT-TIME IDENTIFICATION OF UH-60A HELICOPTER AND SLUNG LOAD... NASA/TM-1998-112231... OCT. 27, 1998
| Author | : United States. National Aeronautics and Space Administration |
| Publisher | : |
| Total Pages | : |
| Release | : 1999* |
| Genre | : |
| ISBN | : |
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Flight-Time Identification of a Uh-60a Helicopter and Slung Load
| Author | : National Aeronautics and Space Administration (NASA) |
| Publisher | : Createspace Independent Publishing Platform |
| Total Pages | : 26 |
| Release | : 2018-07-03 |
| Genre | : |
| ISBN | : 9781722242022 |
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This paper describes a flight test demonstration of a system for identification of the stability and handling qualities parameters of a helicopter-slung load configuration simultaneously with flight testing, and the results obtained.Tests were conducted with a UH-60A Black Hawk at speeds from hover to 80 kts. The principal test load was an instrumented 8 x 6 x 6 ft cargo container. The identification used frequency domain analysis in the frequency range to 2 Hz, and focussed on the longitudinal and lateral control axes since these are the axes most affected by the load pendulum modes in the frequency range of interest for handling qualities. Results were computed for stability margins, handling qualities parameters and load pendulum stability. The computations took an average of 4 minutes before clearing the aircraft to the next test point. Important reductions in handling qualities were computed in some cases, depending, on control axis and load-slung combination. A database, including load dynamics measurements, was accumulated for subsequent simulation development and validation. Cicolani, Luigi S. and McCoy, Allen H. and Tischler, Mark B. and Tucker, George E. and Gatenio, Pinhas and Marmar, Dani Ames Research Center RTOP 581-30-22...
Flight Testing and Real-Time System Identification Analysis of a UH-60A Black Hawk Helicopter with an Instrumented External Sling Load
| Author | : Allen H. McCoy |
| Publisher | : |
| Total Pages | : 96 |
| Release | : 1997-12 |
| Genre | : Science |
| ISBN | : |
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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 US 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 US Army Black Hawk helicopter with various external loads. Tests were conducted as the US first phase of this MOA task. 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 it's control system's stability margins. Included were calculations of the stability characteristics of the load's pendular motion. Utilizing CIFER software, a method for near-real time system identification was also demonstrated during the flight test program.
Flight Testing and Real-Time System Identification Analysis of a Uh-60a Black Hawk Helicopter with an Instrumented External Sling Load
| Author | : National Aeronautics and Space Administration (NASA) |
| Publisher | : Createspace Independent Publishing Platform |
| Total Pages | : 92 |
| Release | : 2018-07-06 |
| Genre | : |
| ISBN | : 9781722400941 |
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Helicopter external air transportation plays an important role 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 areas 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.S. 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.S. Army Black Hawk helicopter with various external loads. Tests were conducted as the U.S. first phase of this MOA task. 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. Utilizing CIFER(R) software, a method for near-...
Flight Evaluation of the UH-60A Helicopter with the Pitch Bias Actuator Centered and Electrically Disconnected
| Author | : Reginald C. Murrell |
| Publisher | : |
| Total Pages | : 279 |
| Release | : 1986 |
| Genre | : |
| ISBN | : |
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Testing was conducted to evaluate handling qualities of the UH-60A helicopter with the pitch bias actuator (PBA) centered and electrically disconnected and with various modes of automatic flight control system (AFCS) degradation. A total of 46.4 productive flight hours were flown between 4 April 1985 and 2 July 1986. Two shortcomings and two Prime Item Development Specification noncompliances were identified. The handling qualities of the UH-60A helicopter with the PBA centered and electrically disconnected are essentially unchanged from those with the PBA operational, except for; (1) slightly degraded static longitudinal stability, (2) slightly degraded dynamic stability, and (3) a shortcoming, the poor maneuvering stability characteristics. One additional shortcoming is the strong pitch-due-to-sideslip coulping, which is unrelated PBA centered and electrically disconnected are satisfactory to continue flight under both visual and instrument meteorological conditions with any degradation of the AFCS.
UH-60A Expanded Gross Weight and Center of Gravity Evaluation
| Author | : |
| Publisher | : |
| Total Pages | : 125 |
| Release | : 1985 |
| Genre | : |
| ISBN | : |
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Testing was conducted to obtain performance and handling qualities at the limits of the expanded gross weight and center of gravity (cg) envelope of the UH-60A helicopter. A total of 38.5 productive flight hours were flown at Edwards Air Force Base, California between 9 June and 22 November 1983. Equivalent flat plate area was minimum with the cg at a fuselage station (FS) of approximately 360 and increased at a more forward and aft cg tested (FS 347 and 366). One deficiency, three shortcomings, and three Prime Item Development Specification noncompliances were identified. One shortcoming, neutral stick- fixed static longitudinal stability in intermediate rated power climb, was associated with envelope expansion. The 4-per-rotor-revolution vibration characteristics, previously identified as a shortcoming, generally were unaffected by increasing gross weight but were aggravated by moving the longitudinal cg further aft. Except for the shortcoming pertaining to neutral static longitudinal stability, the handling qualities were essentially unchanged from those previously reported.
Level Flight Performance Evaluation of the UH-60A Helicopter with the Production External Stores Support System and Ferry Tanks Installed
| Author | : Robert M. Buckanin |
| Publisher | : |
| Total Pages | : 71 |
| Release | : 1986 |
| Genre | : |
| ISBN | : |
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Limited level flight performance testing was conducted on a sixth year production UH-60A helicopter equipped with a production external stores support system (EESS) and four preproduction external fuel tanks. These tests were conducted to provide the US Army Aviation Systems Command with level flight power required data to determine if the UH-60A would still meet the self deployment requirement described in the Material Need Document if the General Electric T700-GE-701's. Sikorsky Aircraft Division of United Technologies Corporation claimed a drag reduction for the production ESSS over the prototype previously tested. A total of 13.9 productive flight hours were flown at Edwards AFB, and Bakersfield, California between 28 May and 19 June 1986. The installation of the production ESSS and four external fuel tanks increased the drag of the normal utility configured UH-60A by approximately 4.5 square feet of equivalent flat plate area. This represents a drag reduction of approximately 4. 5 square feet for the production ESSS from the prototype ESSS previously tested. The takeoff characteristics were similar to a normal utility configured UH-60A and remain a shortcoming. Ground taxi characteristics of the UH-60A at gross weights above 23,000 pounds at a forward center of gravity were unusual in that precise flight control positioning, concentrated pilot effort and high workload was required during these operations. The ground taxi characteristics are a shortcoming, however, they are adequate for the self-deployment mission.
Airworthiness and Flight Characteristics Test of a Sixth Year Production UH-60A.
| Author | : Robert M. Buckanin |
| Publisher | : |
| Total Pages | : 115 |
| Release | : 1985 |
| Genre | : |
| ISBN | : |
Download Airworthiness and Flight Characteristics Test of a Sixth Year Production UH-60A. Book in PDF, ePub and Kindle
Testing was conducted to obtain performance data for inclusion in the sixth year production UH-60A helicopter operator's manual. A total of 58 productive flight hours were flown at five different test sites between 3 and 20 October 1983 and 29 February and 18 September 1984. The out-of-ground effect hover gross weight capability was 16,526 pounds for 95 percent intermediate (30 minute limit) rated power available at 4700 feet pressure altitude and 35 C temperature. The increase in equivalent flat plate area of the sixth year production aircraft configuration over the first year configuration over the first year configuration was 5 square feet in level flight at a referred rotor speed (N sub R/sqare rot theta) of 258 revolutions per minute. Of this increase, 2.5 was attributed to the External Stores Support System fixed provision fairings, 1.5 sq ft to the external mounting brackets of the AN/ALQ-144(V) infrared countermeasures set and M130 chaff dispenser, and 1.0 sq ft to numerous other minor external changes. However, throughout the N sub R/square root theta range, the difference in power required between the first and sixth year production aircraft does not equate to a constant Fe. A limited investigated did not completely account for the power differences noted when flying at different dimensional conditions that produce the same nondimensional thrust coefficient.
