P Erforma N Ce An Alysis Of A Ut Ility H Elicop Ter Wi Th S Tan D Ard .
Performance Analysis of a Utility Helicopter with Standard and Advanced RotorsHyeonsoo YeoRaytheon ITSSWilliam G. BousmanArmy/NASA Rotorcraft DivisionAeroflightdynamics Directorate (AMRDEC)US Army Aviation and Missile CommandWayne JohnsonArmy/NASA Rotorcraft DivisionNASA Ames Research CenterMoffett Field, Californiais necessary to assess their accuracy and reliability.Comparison of comprehensive analysis performancecalculations with helicopter flight test data is crucial tosuch an assessment.AbstractFlight test measurements of the performance of theUH-60 Black Hawk helicopter with both standard andadvanced rotors are compared with calculations obtainedusing the comprehensive helicopter analysis CAMRADII. In general, the calculated power coefficient showsgood agreement with the flight test data. However, theaccuracy of the calculation degrades at high gross weightfor all of the configurations. The analysis shows fairto good correlation for collective and longitudinal cyclicangles and pitch attitude, and poor to fair correlationfor the lateral trim quantities (lateral cyclic angle androll attitude). The increased solidity of the wide chordblade appears to be a dominant factor in the performanceimprovement at high gross weight by reducing bladeloading and thus delaying stall.With the completion of recent flight tests, performanceand dynamic data are available for the standard UH60 blades tested on a UH-60A airframe [1]; thestandard blades on a UH-60L airframe [2]; and severaldifferent versions of the wide chord blades on thesame UH-60L airframe [2]. These extensive flighttest data sets provide a valuable bench mark for theevaluation of comprehensive methods. In this study,performance calculations were carried out using theanalysis CAMRAD II and the results are compared withthese UH-60 flight test data.Flight Test DataTest data with the UH-60A standard (STD) blades wereobtained on a UH-60A airframe in the NASA/Army UH60A Airloads Program conducted from August 1993 toFebruary 1994 [1]. The test aircraft, 82-23748, is a sixthyear production aircraft. The data obtained from thetest are stored in an electronic data base at NASA AmesResearch Center. The standard blade is constructed usinga titanium spar with a fiberglass outer contour. The bladeuses two airfoils, the SC1095 and SC1094 R8. This bladehas been used on the Black Hawk over the last 25 years.NotationCpCwDMq!!sµ"power coefficientweight coefficientfuselage dragMach numberdynamic pressureangle of attackaircraft pitch attitudeadvance ratiosolidityThe wide chord blade (WCB) is a development bladewhich has an all composite graphite/glass tubular spar.The wide chord blade incorporates an increased chord(10% increase of solidity), advanced airfoils (SC2110and SSCA09), and a swept-tapered tip with anhedral.Six configurations or variants of the wide chord bladehave been tested: configurations 1, 2, 3, 4, 4A, and5. The differences between these configurations aremostly in the mid-span and leading edge tip weights.All the results shown here are for configuration 4A. Thestandard and wide chord blade planforms are shown inFigure 1. The wide chord blade data used here wereIntroductionThe ability to accurately predict the performance of ahelicopter is essential for the design of future rotorcraft.Before prediction codes can be successfully used, itPresented at the American Helicopter Society Aerodynamics, Acoustics,and Test and Evaluation Technical Specialist Meeting, San Francisco,CA, January 23-25, 2002. This paper is declared a work of the U.S.Government and is not subject to copyright protection in the UnitedStates.1
obtained from a joint Sikorsky/Army feasibility flighttest program conducted from November 1993 throughOctober 1995 (Appendix B of Ref. 2). The wide chordblades were tested on an aircraft 84-23953, which is aUH-60A upgraded to a UH-60L for test purposes.basic fuselage and the tail on configuration includes thestabilator, vertical tail, and tail rotor head as well. Thezero angle of attack drag value depends upon the aircraftconfiguration and tends to increase as new modificationsare made to the aircraft. However, it is assumed that themeasured variation of drag with angle of attack is notaffected by these aircraft configuration changes.CAMRAD II ModelingThe UH-60 Black Hawk was modeled in CAMRAD II [3]as an aircraft with single main and tail rotors. Thecurrent model has been updated from a previous UH60A study [4] using CAMRAD II. The UH-60A masterinput database is available to qualified researchers. Minorchanges have been made in chord length, quarter chordlocation, c.g. offset, pitch link geometry and the detailedrepresentation of material properties. The SC1095 andSC1094 R8 airfoil decks are same as used in Ref. 4.There are four possibilities for the equivalent flat platearea of the Airloads Program aircraft and these aresummarized in Table 1.These four cases differdepending upon both baseline drag and the drag ofaircraft modifications. There are two baseline values for azero angle of attack drag. One is Sikorsky’s value, 25.69ft2 from their flight manual performance substantiatingreport [7], which is the basic reference for the aircraft’shandbook performance. The other value, 26.2 ft2 , is fromthe study by Shanley [12], which was performed under aNASA contract.The wide chord blade structural and aerodynamicproperties were obtained from Ref. 5. Section lift,drag, and moment values for the SC2110 and SSCA09airfoils were obtained from airfoil C81 decks developedby Sikorsky Aircraft.The aircraft as tested in the Airloads Program differsfrom the baseline in two respects. First, the aircraft isa sixth-year production version and therefore includesthe External Stores Support System (ESSS) fairings andmiscellaneous changes such as a deice system distributorassembly and an ice detector probe. In addition, a wirestrike kit has been added to this aircraft to upgrade itto fleet standard. Sikorsky [7] has computed the effectsof these modifications differently than the US ArmyAviation Engineering Flight Activity (AEFA) [9–11].Sikorsky’s estimate of the equivalent flat plate area ofESSS fairings, miscellaneous, and wire strike kit was0.78 ft2 , 0.63 ft2 , and 0.21 ft2 respectively. AEFA’sestimate for those components was 2.5 ft2 [9], 1.0ft2 [10], 1.0 ft2 [11]. Second, specific instrumentationwas added to the aircraft for the test program. The dragfor the Blade Motion Hardware (BMH), Low AirSpeedSensing and Indicating Equipment (LASSIE), and testinstrumentation was determined by AEFA. The drag ofthe Rotating Data Acquisition System (RDAS) was basedon its projected area.The trim solution used in CAMRAD II is based onthe aircraft gross weight, c.g., flight speed, rotor rpm,density, and outside air temperature and solves for thecontrols and aircraft attitudes that balance the forces andmoments with zero sideslip angle. For the standardblade on the UH-60A aircraft, the horizontal stabilatorangle was set to match the measured flight test valuesfrom the UH-60A Airloads Program. No equivalentmeasurement was available for the UH-60L test data sothe stabilator angle was set based on Airloads Programmeasurements at given Cw and µ values. An aerodynamicinterference model in CAMRAD II was used for theperformance calculations. This includes the main rotorinflow interference effects on wing-body and tail andthe tail rotor, as time-averaged wake-induced velocitychanges. No empirical factor was used for the calculationof the interference.The aerodynamic characteristics of the UH-60 fuselageare based on 1/4th scale wind tunnel tests reportedin Ref. 6. Only fuselage drag value was updated toaccommodate configuration changes.The equivalent flat plate area of the Airloads Programaircraft was calculated based on the following equation:Fuselage Drag ConfigurationAirloads Program A/C Baseline UH-60A (1st yearA/C) ESSS fairing wire strike kit misc. BMH/LASSIE test instrumentation RDASThe baseline UH-60A fuselage drag equations from thewind tunnel test [6] are:D q ft2D q ft219 022 00 0095 1 66 !s0 0160 1 66 !s22The four possible cases shown in Table 1 are: (1) Case1 : Sikorsky’s baseline drag Sikorsky’s drag build-up,(2) Case 2 : Shanley’s baseline drag Sikorsky’s dragbuild-up, (3) Case 3 : Sikorsky’s baseline drag AEFA’sdrag build-up, and (4) Case 4 : Shanley’s baseline drag AEFA’s drag build-up. The final flat plate area, then,varies from 32.95 ft2 to 36.34 ft2 . The current analysisTail offTail onwhere q is dynamic pressure and !s is pitch attitude indegrees. The tail off configuration includes only the2
uses a zero angle of attack drag value of 35.14 ft2 for theUH-60A, which is very close to the Case 3 value. For theUH-60L, a flat plate area of 35.04 ft2 was used, as thisprovided the best match of parasite drag at high speed.This value is about 10% higher than the value specifiedby Sikorsky [2] for this configuration. The fuselage dragequations used in the present calculations are:D q ft235 14 0 016 1 66 !s 2for UH-60A (Airloads Program)D q ft235 04 0 016 1 66 !sfor UH-60LFigure 4 compares the calculated tail rotor power withthe test data. Tail rotor power coefficient data werecalculated based on the measurement of the intermediateshaft torque. The analysis underpredicts at low speedsand overpredicts at moderate speeds up to Cw of 0.0091.However, an overprediction is observed at all speeds atCw of 0.010 and 0.011. Tail rotor power is sensitive to theaircraft trim, in particular, the sideslip angle, and this willbe examined in the next section.Trim Effects on UH-60A Performance2The trim results at Cw of 0.0065 (Cw " 0.08)are investigated in detail in Figures 5 through 8.Aircraft attitudes and pilot control angles are shown inFigure 5. The analysis shows fair to good correlationfor collective and longitudinal cyclic angles and pitchattitude. However, a large difference is observed inthe lateral trim quantities (lateral cyclic angle and rollattitude). Within the data scatter, the flight data wereobtained for a zero roll angle, that is, no steady lateralacceleration on the pilot. To accomplish this, the pilottends to fly with a small amount of sideslip and usesthe aircraft’s static dihedral to zero the roll angle. TheCAMRAD II trim for µ 0 2 is clearly outside thisscatter.Results and DiscussionUH-60A PerformanceThe total power coefficient for the UH-60A wascalculated using CAMRAD II and is compared withlevel flight data obtained in the Airloads Program forsix weight coefficients in Figure 2. The total powercoefficient is the sum of each engine’s power, based onan engine output shaft torque sensor and the output shaftspeed. The trim solution used in CAMRAD II solvesfor the controls and aircraft attitudes that balance theforces and moments in flight with zero sideslip angle.Performance was calculated using nonuniform inflowwith a free wake geometry and a zero angle of attackdrag value of 35.14 ft2 . CAMRAD II calculates only themain rotor and tail rotor power. Thus the fixed accessorypower of 65.8 HP [7] was added to the CAMRAD IIcalculations.Figure 6 shows blade flap and lag hinge rotationangles. The calculated coning angles are comparedwith measured values from blades 1 and 2. Steadyconing can also be derived from the blade thrust andthe centrifugal force (70,883 lb.).The calculatedconing angles show good agreement with CAMRAD IIestimated values. Thus, it is concluded that there wasa bias error in the coning angle measurements. Thecalculated mean lag angle shows good correlation at µ0.3, considering the scatter of the measured data. Athigher speeds, however, the measured data agree wellwith each other and the analysis shows an overprediction.The calculated longitudinal flapping angles show goodcorrelation up to µ of about 0.2, but overpredict as speedincreases. CAMRAD II captures the sudden increase ofthe longitudinal flapping angle at µ 0.35. However,the analysis shows a much larger change than the data.The analysis underpredicts lateral flapping angles at allspeeds. This is similar to the poor lateral trim predictionsshown in Figure 5.In general, the estimated power coefficient shows goodagreement with the flight test data. At low speeds(µ 0 1), the analysis tends to underpredict the powercoefficient. The reasons are threefold: (1) airspeedmeasurements degrade at lower airspeeds as the dynamicpressure is reduced, (2) trim conditions are moredifficult to maintain, and (3) computed power is stronglyinfluenced by induced power which is more sensitiveto wake effects. This correlation will be discussedquantitatively in the section “Quantitative PerformanceCorrelation.” As weight coefficient increases, largerdifferences are seen between the calculations andmeasurements.The calculated main rotor power coefficient is comparedwith the measured value in Figure 3. This is the samecalculation as in Figure 2, except that only main rotorpower is compared. Main rotor power coefficient data forthe UH-60A were calculated based on the measurementof the main rotor torque. The analysis shows goodagreement with the flight test data. Slightly bettercorrelation is observed than with the total engine power.The calculated main rotor shaft pitch and roll momentsare compared with flight test data in Figure 7. The trendis the same as the longitudinal and lateral flapping angles.The calculated tip path plane angles in an inertialcoordinate system are compared with measured valuesin Figure 8 to see the combined effects of a rotor and afuselage. The tip path plane tilt angles are defined as:3
Longitudinal TPP tilt angle #1c (longitudinal flappingangle) aircraft pitch attitude 3 shaft pre-tiltLateral TPP tile angle #1s (lateral flapping angle)aircraft roll attitudeFigure 12. The total power coefficient is the sum of eachengine’s power and it is normalized to protect Sikorsky’sproprietary data. The standard blade was tested on aUH-60L, aircraft 84-23953, as part of the developmenttesting of the wide chord blade. The only difference inmodeling between the UH-60A and the STD/UH-60Lis the flat plate area of the fuselage. The calculatedpower coefficient for the STD/UH-60L matches themeasured values quite closely. Figure 13 compares thecalculated performance of the WCB/UH-60L with flighttest data. The normalized power coefficient (C̃ p ), whichis different from C̄ p used for the STD/UH-60L, is usedfor this comparison. The analysis shows good correlationup to a weight coefficient Cw0 009. However, anunderprediction is observed at high gross weight andspeed. These correlations will be discussed quantitativelyin the next section.The longitudinal tip path plane tilt angles show goodcorrelation at all forward speeds. This result shows thatthe rotor propulsive force, thus the airframe drag value,is accurate. However, there seems to be an inaccuracyin the lift and pitching moment of the fuselage andstabilator. The calculated lateral tip path plane tilt anglesshow good correlation up to µ of around 0.2 and thenoverpredict as speed increases. Although the correlationappears to be better than with roll attitude, there stillmay be uncertainties other than fuselage aerodynamiccharacteristics.To understand the poor to fair correlation of the tail rotorpower and lateral trim values, the effect of sideslip wasevaluated by looking at changes of 5 degrees. Thesechanges have little influence on the main rotor powerand longitudinal TPP tilt angle. As shown in Figure 9,however, a 5 degree sideslip angle trim slightly reducesthe tail rotor power at moderate and high speeds, andthus improves the correlation. However, the aircraft rollattitude is increased significantly so that the lateral TPPtilt angle is far from the flight test data. A 5 degreesideslip angle trim shows better correlation for the rollattitude and lateral TPP tilt angle but overpredicts the tailrotor power at moderate and high speeds. The lateralflapping angle shows no sensitivity to the sideslip anglechange.CAMRAD II was used to investigate the effects of thenew airfoils alone and combined with the increasedsolidity. Figure 14 shows the angles of attack versusMach number at Cw 0.011 and µ 0.24. These valuesare calculated from CAMRAD II and plotted at threedifferent spanwise locations (r/R 0.5, 0.7, and 0.9) andat every 15 degree azimuth angle. At this high grossweight condition, most of baseline blade experiencesstall on the retreating side. The addition of the newairfoils to the standard blade has little influence on theangle of attack distribution, and thus stall characteristics.However, the wide chord blade, due to increased solidity,reduces blade loading and thus delays stall inception atthis high weight coefficient.The effect of a main rotor to airframe aerodynamicinterference on the performance and longitudinal trimvalues is shown in Figure 10. The main rotor to airframeinterference has a small influence on the main rotorand tail rotor power required. The pitch angles areslightly underpredicted at moderate and high speed rangewithout interference. The longitudinal flapping angles,however, show good correlation without interferenceeffects, especially at µ 0.2.Quantitative Performance CorrelationTo characterize the accuracy of the correlation, theperformance data have been examined quantitatively.Figures 15 through 17 compare the calculated andmeasured performance of the UH-60A. Only data forµ 0 11 is included in Figure 15. The 45 deg diagonalline represents a perfect match between analysis and test.The calculated power coefficients lie above the 45 degline if the analysis overpredicts, and below the line ifthe analysis underpredicts. The correlation is assessed byfitting a least squares regression line and computing theslope, m. A second measure is the correlation coefficient,r, which provides an indication of dispersion. A thirdmeasure is the RMS error from the 45 deg line. A similarapproach can be found for the harmonic correlationfor oscillatory flap bending moment by Bousman andMaier [8]. CAMRAD II shows good correlation at µ0 11. Excluding Cw of 0.011 which has few data points,the worst values are: m 1.060, r 0.970, and RMSerror 4.6508E-5. Estimated power is underpredicted atlow speed (µ 0 11) except Cw of 0.01, thus both m andThe effect of a fuselage flat plate area changes on thepower coefficient and longitudinal trim values is shownin Figure 11. A 10% change of the flat plate areafrom the baseline value changes the required power bya maximum of 6.5%. A 10% reduction of the fuselagedrag shows good correlation for the longitudinal TPPtilt angle. However, the pitch attitude and longitudinalflapping angle show larger deviations at high speeds.STD/UH-60L and WCB/UH-60L PerformanceThe total power coefficient (C̄ p ) for the STD/UH-60Lis calculated and compared with level flight test data in4
r are significantly less than unity as shown in Figure 16.The main rotor power correlation shows better agreementthan the total engine power (Figure 17). Excluding Cw of0.011, the worst values are: m 1.045, r 0.990, andRMS error 3.4586E-5.3. The tip path plane tilt angles in an inertialcoordinate system show that there seems tobe an inaccuracy in the fuselage longitudinalaerodynamic characteristics. Although sideslip hasa significant influence on the tail rotor power andthe aircraft roll attitude, no consistent improvementis obtained.The STD/UH-60L correlation also shows goodagreement as in Figure 18. The analysis appears toslightly overpredict at moderate speeds, as was seenwith the UH-60A prediction. However, the analysisshows good correlation at moderate speeds in theWCB/UH-60L case as shown in Figure 19.STD/UH-60L and WCB/UH-60L1. The analysis shows the same trends as the flighttest data. However, an underprediction is observedfor the performance of the WCB/UH-60L at highgross weight and speed. The degradation of theability of the analysis to predict the performance athigh gross weight occurs for all the configurationscalculated.In general, CAMRAD II underpredicts performance athigh gross weight and high speed. Thus, the slope departsfrom 1, although the correlation coefficient indicates littledispersion. The m, r, and RMS error values for thethree aircrafts are tabulated in Table 2 and also shownin Figure 20. The scale of RMS error values of theUH-60L correlation is different from that of the UH60A correlation due to the normalization of the powercoefficients for UH-60L.2. Increased solidity of the wide chord blade appearsto be a dominant factor in the performanceimprovement at high gross weight by reducingblade loading and thus delaying stall inception.The ability of the analysis to predict the performancedegrades for all the configurations as the gross weightincreases. To understand the performance predictiondegradation at high gross weight, the effects of dynamicstall (Leishman-Beddoes model) on the performancewere investigated for the wide chord blades. Theparameters required for the Leishman-Beddoes modelwere calculated using CAMRAD II because test valueswere not available. The calculation with dynamic stallshowed minor effects at moderate speed while the powerwas slightly reduced at high speed.AcknowledgmentThe authors would like to express thanks to Dr. JohnBerry, Mr. James O’Malley, and Mr. Douglas A. Ehlertat US Army AMCOM and Mr. T. Alan Egolf at SikorskyAircraft Corporation for their sharing of valuable dataand knowledge.References[1] Kufeld, R. M., Balough, D. L., Cross, J. L.,Studebaker, K. F., Jennison, C. D., and Bousman,W. G., “Flight Testing of the UH-60A AirloadsAircraft,” American Helicopter Society 50thAnnual Forum Proceedings, Washington D.C., May1994.ConclusionsThe analysis CAMRAD II has been used to predict theperformance of the UH-60 Black Hawk helicopter withstandard and advanced rotors. The analysis has beencorrelated with the flight test data both qualitatively andquantitatively. From this study the following conclusionsare obtained:[2] Bednarczyk, R., Boirun, B., DiPierro, A.,Fenaughty, R., Sheets, F., Trainer, T., and West,A., “Growth Rotor Blade Feasibility DemonstrationFlight Test Report,” SER 702183, May 1996.UH-60A1. The predicted total engine power and main rotorpower show good agreement with the flight testdata at µ 0 11. However, an underprediction isobserved at µ 0 11.[3] Johnson, W., “Rotorcraft Aerodynamics Models fora Comprehensive Analysis,” American HelicopterSociety 54th Annual Forum Proceedings,Washington, D.C., May 1998.2. The analysis shows fair to good correlation forcollective and longitudinal cyclic angles and pitchattitude and poor to fair correlation for thelateral trim quantities (lateral cyclic angle and rollattitude).[4] Kufeld, R. M., and Johnson, W., “The Effects ofControl System Stiffness Models on the DynamicStall Behavior of a Helicopter,” Journal of theAmerican Helicopter Society, Vol. 45, No. 4,October 2000.5
[5] Mudrick, M., “Main Rotor System Loads,” SER [9] “UH-60A External Stores Support System Fixed702603, September 1999.Provision Fairings Drag Determinations,” FinalReport, USAAEFA Project No. 82-15-1, May 1984.[6] Bernard, R., “YUH-60A/T700 IR Suppressor FullScale Prototype Test Report,” SER 70094, June[10] “Airworthiness and Flight Characteristics Test of1976.a Sixth Year Production UH-60A,” Final Report,[7] Boirun,B.,“Flight Manual PerformanceUSAAEFA Project No. 83-24, June 1985.Substantiating Report for the UH-60A HelicopterBased on the Multi-Year II Configuration,” SER [11] “Baseline Performance Verification of the 12th Year70279-1, May 1988.Production UH-60A Black Hawk helicopter,” FinalReport, USAAEFA Project No. 87-32, January 1989.[8] Bousman, W. G., and Maier, T. H., “An Investigationof Helicopter Rotor Blade Flap Vibratory Loads,”American Helicopter Society 48th Annual Forum [12] Shanley, J. P. “Validation of UH-60A CAMRAD/JAInput Model,” SER 701716, November 1991.Proceedings, Washington, D.C., June 1992.Table 1 Flat plate area calculationBaseline UH-60AEquivalent Flat Plate Drag (sq. ft.)Case 1Case 2Case 3Case 425.69 [7] 26.2 [12] 25.69 [7] 26.2 [12]ESSS fairingwire strike kitmisc.BMH/LASSIEtest 32.81UH-60A (Airloads program)32.9533.4635.8336.346
Table 2 Slope, correlation coefficient, and RMS error 480.498UH-60ArRMS(µ 11)0.995 2.0225E-50.995 2.8172E-50.994 2.2579E-50.970 4.0415E-50.992 4.6508E-50.867 � 11)0.944 6.2228E-50.916 8.1571E-50.844 7.1231E-50.956 15.240E-50.593 6.1474E-5N/AN/AUH-60A (MR)rRMS(µ 11)0.997 1.4217E-50.997 1.2302E-50.995 2.9285E-50.975 3.4586E-50.990 1.9127E-50.908 30.0151970.0396250.066199
Elastic axisC.G. axisQuarter chordin.SC1095SC1094 /R(a) Standard 60.7r/R(b) Wide chord bladeFig. 1 UH-60 Black Hawk rotor blade planform80.80.91
0.00120.0012FLT 850.001FLT 840.001CAMRAD IICAMRAD 00020000.10.20.30.400.1µ(a) Cw0.20.30.4µ0 0065(b) Cw0.00120 00740.0012FLT 880.0010.001CAMRAD 0002FLT 89CAMRAD II0000.10.20.30.400.1µ(c) Cw0.20.30.4µ0 0083(d) Cw0 00060.00060.0004FLT 900.0004CAMRAD IIFLT 900.0002CAMRAD II0.00020000.10.20.300.40.1(e) Cw0.20.3µµ0 010(f) Cw0 011Fig. 2 Calculated and measured power coefficient for UH-60A (Airloads Program)90.4
0.00120.0012FLT 850.001FLT 840.001CAMRAD IICAMRAD II0.00080.0008CCP MR0.0006P 1µ(a) Cw0.20.30.40.30.4µ0 0065(b) Cw0.00120 00740.0012FLT 880.001FLT 890.001CAMRAD IICAMRAD II0.00080.0008CCP MR0.0006P 1µ(c) Cw0.2µ0 0083(d) Cw0 00910.00140.0012FLT 900.0012CAMRAD II0.0010.0010.0008C0.0008P MR0.0006CP MR0.00060.0004FLT 900.00040.0002CAMRAD II0.00020000.10.20.300.40.1(e) Cw0.20.30.4µµ0 010(f) Cw0 011Fig. 3 Calculated and measured main rotor power coefficient for UH-60A (Airloads Program)10
0.0050.005FLT 850.004FLT 840.004CAMRAD II0.003CAMRAD II0.003CCP TRP TR0.0020.0020.0010.0010000.10.20.30.400.1µ(a) Cw0.20.30.4µ0 0065(b) Cw0.0050 00740.005FLT 880.004FLT 890.004CAMRAD II0.003CAMRAD II0.003CCP TRP TR0.0020.0020.0010.0010000.10.20.30.400.1µ(c) Cw0.20.30.4µ0 0083(d) Cw0.0050 00910.005FLT 900.004FLT 900.004CAMRAD II0.003CAMRAD II0.003CCP TRP TR0.0020.0020.0010.0010000.10.20.30.400.1µ(e) Cw0.20.30.4µ0 010(f) Cw0 011Fig. 4 Calculated and measured tail rotor power coefficient for UH-60A (Airloads Program)11
1216FLT 85FLT 85CAMRAD II812Pitch attitude (deg.)Collective angle (deg.)CAMRAD II8440-40-800.10.20.300.40.1µ0.2(a) Collective angle12FLT 85FLT 85CAMRAD IICAMRAD II812Roll attitude (deg.)Lateral cyclic angle (deg.)0.4(b) Pitch c) Lateral cyclic angle(d) Roll attitude020FLT 8515-4Sideslip angle (deg.)Longitudinal cyclic angle (deg.)0.3µ-8FLT 85-12CAMRAD IICAMRAD II1050-5-16-1000.10.20.30.40µ0.10.20.3µ(e) Longitudinal cyclic angle(f) Sideslip angleFig. 5 Aircraft attitude and pilot control angles for UH-60A at Cw120 00650.4
4FLT 85 (Blade 1)FLT 85 (Blade 2)Coning needed to match blade thrustCAMRAD II8FLT 85 (Blade 1)FLT 85 (Blade 2)CAMRAD II2Mean lag angle (deg.)Coning angle (deg.)10640-2-42-6000.10.20.300.40.1(a) Coning angle0.48(deg.)FLT 85 (Blade 1)FLT 85 (Blade 2)CAMRAD II61s6(deg.)FLT 85 (Blade 1)FLT 85 (Blade 2)CAMRAD IILateral flapping angle, !1c0.3(b) Mean lag angle8Longitudinal flapping angle, !0.2µµ420-2420-200.10.20.30.40µ0.10.20.3µ(c) Longitudinal flapping angle(d) Lateral flapping angleFig. 6 Blade flap and lag hinge rotation angle for UH-60A at Cw130 00650.4
4 1044 104FLT 85CAMRAD IIShaft roll moment (in-lb)Shaft pitch moment (in-lb)FLT 850-4 104-8 1045CAMRAD II0-4 104-8 1045-1.2 10-1.2 1000.10.20.30.400.1µ0.30.40.30.4µ(a) Shaft pitch moment(b) Shaft roll momentFig. 7 Main rotor shaft moment for UH-60A at Cw160 006516FLT 85 (Blade 1)FLT 85 (Blade 2)CAMRAD II12Lateral TPP tilt angle (deg.)Longitudinal TPP tilt angle (deg.)0.2840-4FLT 85 (Blade 1)FLT 85 (Blade 2)CAMRAD II12840-400.10.20.30.40µ0.10.2µ(a) Longitudinal tilt angle(b) Lateral tilt angleFig. 8 TPP tilt angle in an inertial coordinate system for UH-60A at Cw140 0065
160.0050.004Lateral TPP tilt angle (deg.)FLT 85Baseline (Sideslip 0 deg.)Sideslip 5 deg. trimSideslip -5 deg. trim0.003CP TR0.0020.001FLT 85 (Blade 1)FLT 85 (Blade 2)Baseline (Sideslip 0 deg.)Sideslip 5 deg. trimSideslip -5 deg. trim12840-4000.10.20.300.40.1(a) Tail rotor power0.30.4(b) Lateral TPP tilt angle128FLT 85 (Blade 1)FLT 85 (Blade 2)Baseline (Sideslip 0 deg.)Sideslip 5 deg. trimSideslip -5 deg. trim6Lateral flapping angle, !1s(deg.)FLT 85Baseline (Sideslip 0 deg.)Sideslip 5 deg. trimSideslip -5 deg. trim8Roll attitude ) Roll attitude(d) Lateral flapping angleFig. 9 Effects of sideslip angle for UH-60A at Cw150 00650.30.4
0.0050.0012FLT 85Baseline (with interference)Without interference0.001FLT 85Baseline (with interference)Without interference0.0040.00080.003CP MR0.0006CP 4µ(a) Main rotor power(b) Tail rotor power128Baseline (with interference)Without interferenceLongitudinal flapping angle, !1c8FLT 85 (Blade 1)(deg.)FLT 85Pitch attitude (deg.)0.240-4-8FLT 85 (Blade 2)Baseline (with interference)6Without interference420-200.10.20.30.400.1µ0.20.3µ(c) Pitch attitude(d) Long
inß ow interference effects on wi ng-body and tail and the tail rotor, as tim e-averaged w ake-induced velocity changes. No em piricalfactor w as used for the calculation of the interference. T he aerodynam ic characteristics of the UH- 60 fuselage are based on 1/4th scale wi nd tunnel tests reported in R ef. 6. On ly fuselage drag value w as .
additif alimentaire, exprimée sur la base du poids corporel, qui peut être ingérée chaque jour pendant toute une vie sans risque appréciable pour la santé.5 c) L’expression dose journalière admissible « non spécifiée » (NS)6 est utilisée dans le cas d’une substance alimentaire de très faible toxicité lorsque, au vu des données disponibles (chimiques, biochimiques .
Safety Code for Elevators and Escalators, ASME A17.1-2013, as amended in this ordinance and Appendices A through D, F through J, L, M and P through V. Exceptions: 1.1. ASME A17.1 Sections 5.4, 5.5, 5.10 ((and)) , 5.11, and 5.12 are not adopted. 1.2. ASME A17.1 Section 1.2.1, Purpose, is not adopted. 2015 SEATTLE BUILDING CODE 639 . ELEVATORS AND CONVEYING SYSTEMS . 2. Safety Standard for .
ASTM C 1701 is recommended for acceptance testing and in-service performance of PICP by the Interlocking Concrete Pavement Institute (Smith 2011). A minimum infiltration rate acceptance for new construction of 7 x 10-4 m/sec is recommended. The same rate is recommended for acceptance testing of pervious concrete pavement in a New York State Department of Transportation specification (NYSDOT .
ASTM C 1702 – Heat of hydration using isothermal calorimetry Heat of Hydration. is the single largest use of isothermal calorimetry in the North American Cement industry Other major applications include . Sulfate optimization . and . admixture compatibility Several Round Robins in North America and Europe on Heat of Hydration .
Thermal and System Management Approach for Exhaust Systems Amit Deshpande, Frank Popielas, Chris Prior, Rohit Ramkumar, Kevin Shaver Sealing Products Group, Dana Holding Corporation Abstract: The automotive and heavy-duty industry (off- and on-highway) requirements for emission, noise and fuel reduction and control have become more stringent. Based on the complexity of the system with its .
The Baldrige framework is used extensively as a foundation for internal systems, but there has been a substantial decrease in the number of manufacturing organizations applying for the award. This research study validates some of the reasons associated with that development. The Value of Using the Baldrige Performance Excellence Framework in Manufacturing Organizations Prabir Kumar .
5National Institute of Basic Biology, Okazaki, Aichi, 444-8585 Japan 6Present address: The University of Tokyo, Nikko, Tochigi, . 26 bryophyte (Smith and Read 2008). The AM fungi provide host plants with phosphate taken up from the 27 soil, and in return receive carbon from the host plants. This symbiosis was already thought to be 28 present more than 400 million years ago when the .
The Millennium Bridge is the first new bridge across the river Thames in London since Tower Bridge opened in 1894, and it is the first ever designed for pedestrians only. The bridge links the City of London near St Paul’s Cathedral with the Tate Modern art gallery on Bankside. The bridge opened initially on Saturday 10th June 2000. For the .
