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  • 1
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    Model rotor icing tests in the NASA. Lewis Icing Research Tunnel (1991)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: Tests of a lightly instrumented two bladed teetering rotor and a heavily instrumented subscale articulated main rotor were conducted in the NASA Lewis Icing Research Tunnel (IRT). The first was an OH-58 tail rotor which had a diameter of 1.575 m and a blade chord of 0.133 m, and was mounted on a NASA designed test rig. The second, a four bladed articulated rotor, had a diameter of 1.83 m with 0.124 m chord blades specifically fabricated for the experiment. This rotor was mounted on a Sikorsky Aircraft Powered Force Model, which enclosed a rotor balance and other measurement systems. The models were exposed to variations in temperature, liquid water content, and medium droplet diameter, and were operated over ranges of advance ratio, shaft angle, tip Mach number (rotor speed), and weight coefficient to determine the effect of these parameters on ice accretion. In addition to strain gage and balance data, the test was documented with still, video, and high speed photography, ice profile tracing, and ice molds. The sensitivity is presented of the model rotors to the test parameter and a comparison of the results to theoretical predictions.
    Keywords: AIR TRANSPORTATION AND SAFETY
    Type: AGARD, Effects of Adverse Weather on Aerodynamics; 25 p
    Format: text
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    NASA TECHNICAL REPORTS
  • 2
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    Results of a sub-scale model rotor icing test (1991)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A heavily instrumented sub-scale model of a helicopter main rotor was tested in the NASA Lewis Research Center Icing Research Tunnel (IRT) in September and November 1989. The four-bladed main rotor had a diameter of 1.83 m (6.00 ft) and the 0.124 m (4.9 in) chord rotor blades were specially fabricated for this experiment. The instrumented rotor was mounted on a Sikorsky Aircraft Powered Force Model, which enclosed a rotor balance and other measurement systems. The model rotor was exposed to a range of icing conditions that included variations in temperature, liquid water content, and median droplet diameter, and was operated over ranges of advance ratio, shaft angle, tip Mach number (rotor speed) and weight coefficient to determine the effect of these parameters on ice accretion. In addition to strain gage and balance data, the test was documented with still, video, and high speed photography, ice profile tracings, and ice molds. The sensitivity of the model rotor to the test parameters is given, and the result to theoretical predictions are compared. Test data quality was excellent, and ice accretion prediction methods and rotor performance prediction methods (using published icing lift and drag relationships) reproduced the performance trends observed in the test. Adjustments to the correlation coefficients to improve the level of correlation are suggested.
    Keywords: AIR TRANSPORTATION AND SAFETY
    Type: AIAA PAPER 91-0660
    Format: text
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    NASA TECHNICAL REPORTS
  • 3
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    A review of ice accretion data from a model rotor icing test and comparison with theory (1991)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: An experiment was conducted by the Helicopter Icing Consortium (HIC) in the NASA Lewis Icing Research Tunnel (IRT) in which a 1/6 scale fuselage model of a UH-60A Black Hawk helicopter with a generic rotor was subjected to a wide range of icing conditions. The HIC consists of members from NASA, Bell Helicopter, Boeing Helicopter, McDonnell Douglas Helicopters, Sikorsky Aircraft, and Texas A&M University. Data was taken in the form of rotor torque, internal force balance measurements, blade strain gage loading, and two dimensional ice shape tracings. A review of the ice shape data is performed with special attention given to repeatability and correctness of trends in terms of radial variation, rotational speed, icing time, temperature, liquid water content, and volumetric median droplet size. Moreover, an indepth comparison between the experimental data and the analysis of NASA's ice accretion code LEWICE is given. Finally, conclusions are shown as to the quality of the ice accretion data and the predictability of the data base as a whole. Recommendations are also given for improving data taking technique as well as potential future work.
    Keywords: AIR TRANSPORTATION AND SAFETY
    Type: AIAA PAPER 91-0661
    Format: text
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    NASA TECHNICAL REPORTS
  • 4
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    Study of the impact of cruise speed on scheduling and productivity of commercial transport aircraft (1977)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A comparison is made between airplane productivity and utilization levels derived from commercial airline type schedules which were developed for two subsonic and four supersonic cruise speed aircraft. The cruise speed component is the only difference between the schedules which are based on 1995 passenger demand forecasts. Productivity-to-speed relationships were determined for the three discrete route systems: North Atlantic, Trans-Pacific, and North-South America. Selected combinations of these route systems were also studied. Other areas affecting the productivity-to-speed relationship such as aircraft design range and scheduled turn time were examined.
    Keywords: AIR TRANSPORTATION AND SAFETY
    Type: NASA-CR-145189 , LR-28114
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 5
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    Icing tests of a model main rotor (1990)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: A NASA-sponsored consortium conducted an experimental program to investigate the characteristics of a model rotor under icing conditions. This project resulted in the first U.S. test of a heavily instrumented model rotor conducted in the controlled environment of a refrigerated wind tunnel, the NASA Lewis Icing Research Tunnel. The tunnel entry used a powered force model with a 1.83-m-diameter main rotor, with 0.124-m-chord main rotor blades fabricated specially for this experiment. Test conditions included a range of liquid water content and median volume droplet diameters that fell within the FAA and DOD icing envelopes. The test data show the effects of icing on rotor lift, rotor torque, blade loads, and vibration. Ice shapes and ice dimensions were taken, and molds were made of three ice shapes. High-speed movies were taken to document ice shedding. The results have been compared with analytical accretion predictions.
    Keywords: AIR TRANSPORTATION AND SAFETY
    Type: AHS, Annual Forum; May 21, 1990 - May 23, 1990; Washington, DC; United States
    Format: text
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    NASA TECHNICAL REPORTS
  • 6
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    Icing Research Tunnel test of a model helicopter rotor (1989)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: An experimental program has been conducted in the NASA Lewis Research Center Icing Research Tunnel (IRT) in which an OH-58 tail rotor assembly was operated in a horizontal plane to simulate the action of a typical main rotor. Ice was accreted on the blades in a variety of rotor and tunnel operating conditions and documentation of the resulting shapes was performed. Rotor torque and vibration are presented as functions of time for several representative test runs, and the effects of various parametric variations on the blade ice shapes are shown. This OH-58 test was the first of its kind in the United States and will encourage additional model rotor icing tunnel testing. Although not a scaled representative of any actual full-scale main rotor system, this rig has produced torque and vibration data which will be useful in assessing the quality of existing rotor icing analyses.
    Keywords: AIR TRANSPORTATION AND SAFETY
    Type: AHS Annual Forum; May 22, 1989 - May 24, 1989; Boston, MA; United States
    Format: text
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    NASA TECHNICAL REPORTS
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