Airfoils for rotor blades of rotary wing aircrafts
An airfoil for a rotor blade of a rotary wing aircraft, the airfoil having a predetermined maximum thickness to chord ratio and comprising, between a leading edge and a trailing edge, an extrados and an intrados, the intrados being defined by predetermined intrados coordinate value pairs and the extrados being defined by predetermined extrados coordinate value pairs, wherein a maximum error of each one of the predetermined intrados coordinate value pairs and the predetermined extrados coordinate value pairs amounts to ±3%.
1. An airfoil for a rotor blade of a rotary wing aircraft, the airfoil having a maximum thickness to chord ratio of 12% and comprising, between a leading edge and a trailing edge, an extrados and an intrados, the intrados being defined by predetermined intrados coordinate value pairs x/c, y int /c and the extrados being defined by predetermined extrados coordinate value pairs x/c, y ext /c, wherein x is a distance from the leading edge to the trailing edge along a chord line of the airfoil, c is a length of the airfoil in chord direction, y int is a distance between the chord line and a respective intrados surface and y ext is a distance between the chord line and a respective extrados surface, wherein the predetermined intrados coordinate value pairs x/c, y int /c and the predetermined extrados coordinate value pairs x/c, y ext /c are as follows:
x/c
y int /c
x/c
y ext /c
0.000000
0.000000
0.000000
0.000000
0.000077
−0.001398
0.000077
0.001446
0.000307
−0.002749
0.000306
0.002940
0.000690
−0.004055
0.000689
0.004483
0.001226
−0.005315
0.001226
0.006071
0.001915
−0.006532
0.001914
0.007707
0.002756
−0.007707
0.002756
0.009385
0.003750
−0.008838
0.003750
0.011105
0.004897
−0.009926
0.004896
0.012865
0.006195
−0.010971
0.006194
0.014662
0.007644
−0.011971
0.007644
0.016492
0.009245
−0.012928
0.009244
0.018354
0.010996
−0.013840
0.010995
0.020243
0.012897
−0.014710
0.012896
0.022155
0.014947
−0.015537
0.014947
0.024087
0.017146
−0.016325
0.017146
0.026035
0.019494
−0.017076
0.019494
0.027995
0.021989
−0.017793
0.021989
0.029962
0.024631
−0.018478
0.024630
0.031932
0.027418
−0.019136
0.027418
0.033902
0.030351
−0.019769
0.030351
0.035867
0.033429
−0.020380
0.033428
0.037823
0.036649
−0.020971
0.036649
0.039766
0.040012
−0.021544
0.040012
0.041694
0.043517
−0.022102
0.043517
0.043603
0.047162
−0.022644
0.047162
0.045489
0.050946
−0.023172
0.050946
0.047350
0.054869
−0.023685
0.054868
0.049183
0.058929
−0.024185
0.058928
0.050985
0.063124
−0.024671
0.063124
0.052754
0.067454
−0.025143
0.067454
0.054487
0.071918
−0.025602
0.071917
0.056181
0.076514
−0.026048
0.076513
0.057837
0.081240
−0.026482
0.081239
0.059451
0.086096
−0.026902
0.086095
0.061022
0.091079
−0.027311
0.091078
0.062551
0.096189
−0.027708
0.096188
0.064035
0.101424
−0.028093
0.101423
0.065474
0.106782
−0.028467
0.106781
0.066868
0.112262
−0.028830
0.112261
0.068216
0.117862
−0.029182
0.117862
0.069519
0.123581
−0.029524
0.123580
0.070777
0.129416
−0.029853
0.129416
0.071989
0.135367
−0.030173
0.135366
0.073156
0.141431
−0.030481
0.141430
0.074278
0.147607
−0.030778
0.147606
0.075355
0.153892
−0.031064
0.153891
0.076387
0.160285
−0.031338
0.160284
0.077373
0.166784
−0.031601
0.166783
0.078315
0.173388
−0.031852
0.173387
0.079210
0.180093
−0.032092
0.180092
0.080058
0.186899
−0.032319
0.186898
0.080856
0.193802
−0.032535
0.193802
0.081606
0.200802
−0.032739
0.200801
0.082302
0.207896
−0.032930
0.207895
0.082944
0.215082
−0.033110
0.215081
0.083529
0.222358
−0.033276
0.222357
0.084054
0.229722
−0.033431
0.229721
0.084516
0.237171
−0.033574
0.237170
0.084914
0.244703
−0.033703
0.244702
0.085243
0.252317
−0.033819
0.252316
0.085502
0.260010
−0.033924
0.260009
0.085689
0.267779
−0.034017
0.267778
0.085805
0.275622
−0.034096
0.275621
0.085848
0.283538
−0.034166
0.283537
0.085821
0.291523
−0.034222
0.291522
0.085722
0.299575
−0.034269
0.299574
0.085557
0.307693
−0.034304
0.307692
0.085328
0.315873
−0.034330
0.315872
0.085037
0.324113
−0.034346
0.324112
0.084689
0.332411
−0.034353
0.332410
0.084288
0.340764
−0.034350
0.340763
0.083837
0.349170
−0.034340
0.349169
0.083342
0.357627
−0.034321
0.357626
0.082805
0.366131
−0.034294
0.366130
0.082231
0.374680
−0.034259
0.374679
0.081625
0.383273
−0.034214
0.383272
0.080987
0.391905
−0.034163
0.391905
0.080323
0.400576
−0.034103
0.400575
0.079635
0.409282
−0.034035
0.409281
0.078926
0.418020
−0.033958
0.418019
0.078196
0.426788
−0.033873
0.426787
0.077447
0.435584
−0.033779
0.435583
0.076679
0.444405
−0.033678
0.444404
0.075896
0.453248
−0.033567
0.453247
0.075093
0.462110
−0.033448
0.462109
0.074273
0.470990
−0.033322
0.470989
0.073436
0.479884
−0.033187
0.479883
0.072580
0.488790
−0.033045
0.488789
0.071707
0.497705
−0.032894
0.497705
0.070816
0.506627
−0.032735
0.506626
0.069907
0.515553
−0.032568
0.515552
0.068981
0.524480
−0.032393
0.524479
0.068037
0.533405
−0.032210
0.533405
0.067076
0.542327
−0.032017
0.542326
0.066097
0.551242
−0.031818
0.551242
0.065104
0.560148
−0.031609
0.560147
0.064093
0.569042
−0.031394
0.569042
0.063069
0.577922
−0.031169
0.577921
0.062029
0.586785
−0.030936
0.586784
0.060976
0.595627
−0.030694
0.595627
0.059910
0.604448
−0.030445
0.604447
0.058833
0.613244
−0.030187
0.613243
0.057745
0.622012
−0.029919
0.622011
0.056647
0.630750
−0.029641
0.630750
0.055540
0.639456
−0.029355
0.639455
0.054426
0.648126
−0.029059
0.648125
0.053303
0.656759
−0.028751
0.656758
0.052171
0.665351
−0.028433
0.665350
0.051030
0.673900
−0.028103
0.673900
0.049879
0.682404
−0.027759
0.682404
0.048717
0.690861
−0.027402
0.690860
0.047544
0.699266
−0.027028
0.699266
0.046357
0.707619
−0.026640
0.707619
0.045158
0.715917
−0.026232
0.715917
0.043942
0.724157
−0.025804
0.724157
0.042711
0.732337
−0.025356
0.732336
0.041464
0.740454
−0.024883
0.740454
0.040199
0.748506
−0.024388
0.748506
0.038920
0.756491
−0.023867
0.756491
0.037626
0.764407
−0.023322
0.764406
0.036317
0.772250
−0.022751
0.772249
0.034996
0.780019
−0.022156
0.780018
0.033664
0.787711
−0.021536
0.787710
0.032324
0.795324
−0.020893
0.795324
0.030978
0.802856
−0.020227
0.802856
0.029628
0.810305
−0.019541
0.810305
0.028278
0.817668
−0.018834
0.817668
0.026929
0.824944
−0.018109
0.824944
0.025584
0.832130
−0.017366
0.832129
0.024246
0.839223
−0.016608
0.839223
0.022916
0.846223
−0.015835
0.846223
0.021597
0.853126
−0.015050
0.853126
0.020291
0.859932
−0.014255
0.859931
0.019000
0.866637
−0.013451
0.866636
0.017726
0.873240
−0.012643
0.873239
0.016472
0.879738
−0.011831
0.879738
0.015238
0.886131
−0.011019
0.886131
0.014030
0.892416
−0.010213
0.892416
0.012851
0.898591
−0.009416
0.898591
0.011704
0.904655
−0.008633
0.904655
0.010596
0.910605
−0.007871
0.910605
0.009532
0.916440
−0.007134
0.916440
0.008516
0.922158
−0.006430
0.922158
0.007556
0.927758
−0.005764
0.927758
0.006655
0.933238
−0.005141
0.933237
0.005821
0.938595
−0.004564
0.938595
0.005056
0.943830
−0.004039
0.943830
0.004363
0.948939
−0.003564
0.948939
0.003743
0.953922
−0.003142
0.953922
0.003197
0.956325
−0.002953
0.958777
0.002723
0.959739
−0.002725
0.963503
0.002318
0.963158
−0.002563
0.968098
0.001979
0.966579
−0.002457
0.970001
0.001854
0.970001
−0.002402
0.976001
0.001909
0.976001
−0.002347
0.982001
0.001964
0.982001
−0.002293
0.988001
0.002019
0.988001
−0.002238
0.994000
0.002073
0.994000
−0.002183
1.000000
0.002128
1.000000
−0.002128
wherein a maximum error of each one of the predetermined intrados coordinate value pairs x/c, y int /c and the predetermined extrados coordinate value pairs x/c, y ext /c amounts to ±3%.
2. An airfoil for a rotor blade of a rotary wing aircraft, the airfoil having a maximum thickness to chord ratio within a range from 9% to 15% and comprising intrados coordinate value pairs and extrados coordinate value pairs that are determined on the basis of a reference airfoil, the reference airfoil being defined by the airfoil according to claim 1 .
3. The airfoil according to claim 1 , wherein an associated leading edge radius of a leading edge circle that defines an underlying curvature at the leading edge of the airfoil amounts to r/c=0.01314, the leading edge circle having its associated center of circle located at x/c=0.01314 and y int /c=y ext /c=0.00000.
4. The airfoil according to claim 1 , wherein a trailing edge tab is provided at the trailing edge of the airfoil, the trailing edge tab being defined by an at least essentially straight and parallel intrados and extrados.
5. The airfoil according to claim 4 , wherein the trailing edge tab comprises a length in a range from 2% to 10% of the length of the airfoil in chord direction with a maximum inclination error of ±5° relative to the chord line of the airfoil.
6. A rotor blade of a rotary wing aircraft, the rotor blade comprising at least one airfoil according to claim 1 .
7. An airfoil for a rotor blade of a rotary wing aircraft, the airfoil having a maximum thickness to chord ratio of 9% and comprising, between a leading edge and a trailing edge, an extrados and an intrados, the intrados being defined by predetermined intrados coordinate value pairs x/c, y int /c and the extrados being defined by predetermined extrados coordinate value pairs x/c, y ext /c, wherein x is a distance from the leading edge to the trailing edge along a chord line of the airfoil, c is a length of the airfoil in chord direction, y int is a distance between the chord line and a respective intrados surface and y ext is a distance between the chord line and a respective extrados surface, wherein the predetermined intrados coordinate value pairs x/c, y int /c and the predetermined extrados coordinate value pairs x/c, y ext /c are as follows:
x/c
y int /c
x/c
y ext /c
0.000000
0.000079
0.000000
0.000079
0.000100
−0.000821
0.000100
0.001156
0.000400
−0.001602
0.000400
0.002431
0.000901
−0.002314
0.000901
0.003855
0.001601
−0.002993
0.001601
0.005382
0.002500
−0.003661
0.002500
0.006983
0.003599
−0.004331
0.003599
0.008637
0.004896
−0.005009
0.004896
0.010336
0.006392
−0.005694
0.006392
0.012070
0.008086
−0.006381
0.008086
0.013836
0.009977
−0.007067
0.009977
0.015625
0.012063
−0.007745
0.012063
0.017432
0.014346
−0.008412
0.014346
0.019249
0.016823
−0.009067
0.016823
0.021067
0.019494
−0.009707
0.019494
0.022879
0.022357
−0.010332
0.022357
0.024678
0.025412
−0.010940
0.025412
0.026457
0.028658
−0.011532
0.028658
0.028211
0.032092
−0.012105
0.032092
0.029937
0.035714
−0.012660
0.035714
0.031632
0.039523
−0.013196
0.039523
0.033296
0.043517
−0.013713
0.043517
0.034926
0.047694
−0.014211
0.047694
0.036523
0.052053
−0.014692
0.052053
0.038087
0.056592
−0.015154
0.056592
0.039615
0.061309
−0.015598
0.061309
0.041106
0.066203
−0.016025
0.066203
0.042558
0.071272
−0.016435
0.071272
0.043968
0.076513
−0.016831
0.076513
0.045335
0.081926
−0.017212
0.081926
0.046656
0.087506
−0.017580
0.087506
0.047929
0.093254
−0.017935
0.093254
0.049154
0.099165
−0.018280
0.099165
0.050329
0.105239
−0.018615
0.105239
0.051455
0.111472
−0.018941
0.111472
0.052533
0.117862
−0.019258
0.117862
0.053563
0.124407
−0.019567
0.124407
0.054546
0.131105
−0.019868
0.131105
0.055482
0.137952
−0.020161
0.137952
0.056373
0.144946
−0.020446
0.144946
0.057218
0.152085
−0.020723
0.152085
0.058018
0.159365
−0.020991
0.159365
0.058772
0.166784
−0.021250
0.166784
0.059482
0.174339
−0.021500
0.174339
0.060148
0.182027
−0.021740
0.182027
0.060769
0.189845
−0.021971
0.189845
0.061348
0.197791
−0.022193
0.197791
0.061885
0.205860
−0.022405
0.205860
0.062380
0.214050
−0.022609
0.214050
0.062833
0.222358
−0.022805
0.222358
0.063246
0.230781
−0.022992
0.230781
0.063619
0.239314
−0.023172
0.239314
0.063953
0.247956
−0.023345
0.247956
0.064250
0.256703
−0.023511
0.256703
0.064510
0.265551
−0.023668
0.265551
0.064736
0.274497
−0.023818
0.274497
0.064928
0.283537
−0.023961
0.283537
0.065087
0.292669
−0.024095
0.292669
0.065213
0.301888
−0.024222
0.301888
0.065306
0.311191
−0.024341
0.311191
0.065366
0.320574
−0.024453
0.320574
0.065392
0.330034
−0.024557
0.330034
0.065382
0.339567
−0.024654
0.339567
0.065337
0.349170
−0.024742
0.349170
0.065255
0.358838
−0.024822
0.358838
0.065136
0.368569
−0.024893
0.368569
0.064980
0.378357
−0.024954
0.378357
0.064786
0.388201
−0.025006
0.388201
0.064554
0.398095
−0.025047
0.398095
0.064285
0.408036
−0.025078
0.408036
0.063977
0.418020
−0.025097
0.418020
0.063630
0.428043
−0.025106
0.428043
0.063246
0.438102
−0.025104
0.438102
0.062822
0.448192
−0.025090
0.448192
0.062359
0.458310
−0.025065
0.458310
0.061857
0.468451
−0.025027
0.468451
0.061314
0.478613
−0.024977
0.478613
0.060730
0.488790
−0.024914
0.488790
0.060105
0.498979
−0.024838
0.498979
0.059437
0.509177
−0.024750
0.509177
0.058725
0.519378
−0.024648
0.519378
0.057968
0.529580
−0.024534
0.529580
0.057165
0.539778
−0.024406
0.539778
0.056314
0.549969
−0.024265
0.549969
0.055414
0.560148
−0.024110
0.560148
0.054465
0.570312
−0.023943
0.570312
0.053466
0.580456
−0.023762
0.580456
0.052418
0.590577
−0.023568
0.590577
0.051323
0.600670
−0.023360
0.600670
0.050182
0.610733
−0.023138
0.610733
0.048997
0.620761
−0.022902
0.620761
0.047772
0.630750
−0.022650
0.630750
0.046508
0.640696
−0.022383
0.640696
0.045209
0.650596
−0.022100
0.650596
0.043880
0.660446
−0.021799
0.660446
0.042523
0.670241
−0.021482
0.670241
0.041142
0.679979
−0.021146
0.679979
0.039742
0.689655
−0.020793
0.689655
0.038325
0.699266
−0.020421
0.699266
0.036897
0.708808
−0.020030
0.708808
0.035460
0.718277
−0.019619
0.718277
0.034019
0.727670
−0.019188
0.727670
0.032577
0.736983
−0.018734
0.736983
0.031138
0.746212
−0.018256
0.746212
0.029705
0.755355
−0.017751
0.755355
0.028280
0.764406
−0.017218
0.764406
0.026864
0.773364
−0.016653
0.773364
0.025461
0.782224
−0.016056
0.782224
0.024070
0.790983
−0.015426
0.790983
0.022693
0.799638
−0.014765
0.799638
0.021332
0.808185
−0.014075
0.808185
0.019986
0.816622
−0.013359
0.816622
0.018658
0.824944
−0.012623
0.824944
0.017349
0.833149
−0.011872
0.833149
0.016061
0.841233
−0.011110
0.841233
0.014799
0.849193
−0.010343
0.849193
0.013565
0.857027
−0.009576
0.857027
0.012365
0.864731
−0.008815
0.864731
0.011204
0.872303
−0.008066
0.872303
0.010088
0.879738
−0.007335
0.879738
0.009023
0.887036
−0.006632
0.887036
0.008016
0.894192
−0.005964
0.894192
0.007072
0.901204
−0.005340
0.901204
0.006198
0.908069
−0.004767
0.908069
0.005400
0.914785
−0.004253
0.914785
0.004684
0.921349
−0.003800
0.921349
0.004056
0.927758
−0.003413
0.927758
0.003520
0.934010
−0.003091
0.934010
0.003077
0.940103
−0.002832
0.940103
0.002727
0.946035
−0.002633
0.946035
0.002463
0.951802
−0.002490
0.951802
0.002276
0.957403
−0.002395
0.957403
0.002153
0.962836
−0.002339
0.962836
0.002083
0.968098
−0.002311
0.968098
0.002049
0.973188
−0.002302
0.973188
0.002039
0.978104
−0.002303
0.978104
0.002042
0.982843
−0.002309
0.982843
0.002052
0.987404
−0.002316
0.987404
0.002064
0.991785
−0.002323
0.991785
0.002074
0.995984
−0.002328
0.995984
0.002084
1.000000
−0.002332
1.000000
0.002092
wherein a maximum error of each one of the predetermined intrados coordinate value pairs x/c, y int /c and the predetermined extrados coordinate value pairs x/c, y ext /c amounts to ±3%.
8. An airfoil for a rotor blade of a rotary wing aircraft, the airfoil having a maximum thickness to chord ratio within a range from 7% to 12% and comprising intrados coordinate value pairs and extrados coordinate value pairs that are determined on the basis of a reference airfoil, the reference airfoil being defined by the airfoil according to claim 7 .
9. The airfoil according to claim 7 , wherein an associated leading edge radius of a leading edge circle that defines an underlying curvature at the leading edge of the airfoil amounts to r/c=0.00481, the leading edge circle having its associated center of circle located at x/c=0.00481 and y ext /c=0.00008.
10. The airfoil according to claim 7 , wherein a trailing edge tab is provided at the trailing edge of the airfoil, the trailing edge tab being defined by an at least essentially straight and parallel intrados and extrados.
11. The airfoil according to claim 10 , wherein the trailing edge tab comprises a length in a range from 2% to 10% of the length of the airfoil in chord direction with a maximum inclination error of ±5° relative to the chord line of the airfoil.
12. An airfoil for a rotor blade of a rotary wing aircraft, the airfoil having a maximum thickness to chord ratio of 8% and comprising, between a leading edge and a trailing edge, an extrados and an intrados, the intrados being defined by predetermined intrados coordinate value pairs x/c, y int /c and the extrados being defined by predetermined extrados coordinate value pairs x/c, y ext /c, wherein x is a distance from the leading edge to the trailing edge along a chord line of the airfoil, c is a length of the airfoil in chord direction, y int is a distance between the chord line and a respective intrados surface and y ext is a distance between the chord line and a respective extrados surface, characterized in that the predetermined intrados coordinate value pairs x/c, y int /c and the predetermined extrados coordinate value pairs x/c, y ext /c are as follows:
x/c
y int /c
x/c
y ext /c
0.000000
0.000215
0.000000
0.000215
0.000108
−0.000757
0.000078
0.001200
0.000411
−0.001747
0.000327
0.002240
0.000926
−0.002750
0.000739
0.003360
0.001662
−0.003727
0.001310
0.004558
0.002616
−0.004655
0.002049
0.005839
0.003800
−0.005525
0.002973
0.007227
0.005244
−0.006340
0.004129
0.008754
0.006978
−0.007128
0.005577
0.010448
0.009067
−0.007908
0.007390
0.012337
0.011619
−0.008697
0.009666
0.014451
0.014783
−0.009530
0.012523
0.016812
0.018750
−0.010418
0.016062
0.019413
0.023722
−0.011352
0.020339
0.022198
0.029809
−0.012304
0.025333
0.025063
0.036922
−0.013230
0.030955
0.027888
0.044810
−0.014099
0.037107
0.030586
0.053218
−0.014906
0.043702
0.033107
0.061943
−0.015652
0.050680
0.035432
0.070873
−0.016345
0.058002
0.037567
0.079906
−0.016990
0.065631
0.039529
0.088988
−0.017593
0.073520
0.041336
0.098046
−0.018154
0.081608
0.043000
0.107068
−0.018678
0.089839
0.044528
0.116047
−0.019169
0.098172
0.045923
0.124990
−0.019632
0.106577
0.047188
0.133918
−0.020068
0.115037
0.048325
0.142864
−0.020484
0.123550
0.049337
0.151836
−0.020880
0.132127
0.050232
0.160857
−0.021259
0.140777
0.051020
0.169928
−0.021623
0.149509
0.051716
0.179052
−0.021972
0.158319
0.052338
0.188212
−0.022307
0.167169
0.052894
0.197390
−0.022628
0.176050
0.053383
0.206574
−0.022937
0.184960
0.053815
0.215752
−0.023233
0.193877
0.054190
0.224921
−0.023518
0.202805
0.054506
0.234080
−0.023790
0.211741
0.054767
0.243213
−0.024051
0.220690
0.054973
0.252331
−0.024302
0.229653
0.055126
0.261430
−0.024541
0.238634
0.055229
0.270527
−0.024771
0.247642
0.055289
0.279620
−0.024990
0.256664
0.055307
0.288732
−0.025198
0.265716
0.055288
0.297858
−0.025397
0.274800
0.055241
0.307010
−0.025588
0.283904
0.055169
0.316188
−0.025771
0.293030
0.055078
0.325380
−0.025946
0.302179
0.054971
0.334565
−0.026112
0.311343
0.054856
0.343733
−0.026272
0.320511
0.054731
0.352895
−0.026423
0.329689
0.054599
0.362062
−0.026567
0.338869
0.054462
0.371226
−0.026705
0.348043
0.054319
0.380408
−0.026835
0.357211
0.054168
0.389592
−0.026960
0.366378
0.054008
0.398773
−0.027082
0.375537
0.053840
0.407948
−0.027194
0.384693
0.053659
0.417114
−0.027296
0.393848
0.053468
0.426264
−0.027388
0.403006
0.053265
0.435411
−0.027472
0.412163
0.053052
0.444557
−0.027545
0.421324
0.052828
0.453708
−0.027610
0.430488
0.052595
0.462868
−0.027663
0.439656
0.052354
0.472038
−0.027705
0.448824
0.052104
0.481218
−0.027736
0.457990
0.051848
0.490405
−0.027757
0.467151
0.051581
0.499600
−0.027765
0.476316
0.051306
0.508797
−0.027761
0.485468
0.051024
0.517989
−0.027743
0.494612
0.050728
0.527173
−0.027713
0.503750
0.050418
0.536346
−0.027668
0.512886
0.050095
0.545491
−0.027609
0.522011
0.049757
0.554621
−0.027536
0.531136
0.049400
0.563731
−0.027444
0.540266
0.049029
0.572814
−0.027339
0.549383
0.048643
0.581885
−0.027215
0.558500
0.048237
0.590939
−0.027072
0.567617
0.047814
0.599982
−0.026910
0.576733
0.047374
0.609025
−0.026731
0.585841
0.046918
0.618071
−0.026516
0.594933
0.046442
0.627122
−0.026269
0.604018
0.045944
0.636179
−0.025988
0.613076
0.045422
0.645255
−0.025677
0.622116
0.044865
0.654342
−0.025340
0.631136
0.044278
0.663446
−0.024980
0.640125
0.043651
0.672559
−0.024601
0.649101
0.042983
0.681681
−0.024204
0.658056
0.042268
0.690809
−0.023791
0.667004
0.041505
0.699940
−0.023364
0.675947
0.040692
0.709072
−0.022922
0.684895
0.039831
0.718204
−0.022468
0.693854
0.038922
0.727323
−0.022000
0.702833
0.037972
0.736438
−0.021514
0.711841
0.036986
0.745545
−0.021011
0.720869
0.035967
0.754646
−0.020488
0.729930
0.034916
0.763749
−0.019946
0.739005
0.033838
0.772838
−0.019385
0.748093
0.032735
0.781925
−0.018800
0.757187
0.031610
0.791017
−0.018195
0.766273
0.030463
0.800106
−0.017569
0.775334
0.029305
0.809195
−0.016921
0.784371
0.028132
0.818292
−0.016252
0.793385
0.026950
0.827400
−0.015566
0.802375
0.025754
0.836515
−0.014864
0.811351
0.024551
0.845633
−0.014148
0.820321
0.023336
0.854759
−0.013419
0.829305
0.022108
0.863883
−0.012681
0.838309
0.020864
0.872989
−0.011934
0.847334
0.019607
0.882064
−0.011172
0.856389
0.018334
0.891090
−0.010393
0.865463
0.017051
0.900055
−0.009580
0.874538
0.015760
0.908968
−0.008727
0.883610
0.014463
0.917793
−0.007820
0.892663
0.013166
0.926569
−0.006869
0.901705
0.011868
0.935039
−0.005887
0.910726
0.010564
0.943157
−0.004809
0.919634
0.009266
0.950722
−0.003725
0.928288
0.007973
0.958140
−0.003014
0.936612
0.006671
0.965683
−0.002577
0.944461
0.005343
0.973486
−0.002486
0.952013
0.004032
0.981658
−0.002497
0.959220
0.003090
0.989505
−0.002498
0.966334
0.002578
0.996281
−0.002499
0.973827
0.002484
1.000000
−0.002500
0.981787
0.002497
0.989536
0.002498
0.996283
0.002499
1.000000
0.002500
wherein a maximum error of each one of the predetermined intrados coordinate value pairs x/c, y int /c and the predetermined extrados coordinate value pairs x/c, y ext /c amounts to ±3%.
13. An airfoil for a rotor blade of a rotary wing aircraft, the airfoil having a maximum thickness to chord ratio within a range from 6% to 10% and comprising intrados coordinate value pairs and extrados coordinate value pairs that are determined on the basis of a reference airfoil, the reference airfoil being defined by the airfoil according to claim 12 .
14. The airfoil according to claim 12 , wherein an associated leading edge radius of a leading edge circle that defines an underlying curvature at the leading edge of the airfoil amounts to r/c=0.00502, the leading edge circle having its associated center of circle located at x/c=0.00502 and y ext /c=0.00028.
15. The airfoil according to claim 12 , wherein a trailing edge tab is provided at the trailing edge of the airfoil, the trailing edge tab being defined by an at least essentially straight and parallel intrados and extrados.
16. The airfoil according to claim 15 , wherein the trailing edge tab comprises a length in a range from 2% to 10% of the length of the airfoil in chord direction with a maximum inclination error of ±5° relative to the chord line of the airfoil.