Date: Sun, 23 Aug 1998 23:05:50 +0100
From: Andrew Hollom 
To: m-selig
Subject: AH21 aerofoil ordinates

Hello Michael,

I have been looking at your wonderful database of aerofoil sections when
I noticed a section attributed to Althaus called AH21. Looking at the
GIF image of it, it was remarkably similar to one I designed, also
called AH21! I then inspected it closer to make sure, and I'm certain it
is mine. The only anomoly is in the x/c values, because when I designed
the section, I was trying to improve on G15 and so I used the same x/c
values.

Please find enclosed the ordinates for AH21 at 9% and 7%. The section
was designed at 9%, but performed better at 7%. I hope the enclosed is
of interest.


Andrew Hollom.
AH21          61
  0  1.0000000  0.0000000
  1  0.9967100  0.0007263
  2  0.9872600  0.0027842
  3  0.9723700  0.0059238
  4  0.9524800  0.0098924
  5  0.9276400  0.0144732
  6  0.8981000  0.0194013
  7  0.8642700  0.0244167
  8  0.8266000  0.0293058
  9  0.7855700  0.0339044
 10  0.7416500  0.0380931
 11  0.6953700  0.0417822
 12  0.6472300  0.0449123
 13  0.5977800  0.0474415
 14  0.5475300  0.0493465
 15  0.4970200  0.0506155
 16  0.4467600  0.0512481
 17  0.3972700  0.0512518
 18  0.3490400  0.0506421
 19  0.3024800  0.0494383
 20  0.2580900  0.0476672
 21  0.2162400  0.0453569
 22  0.1773000  0.0425391
 23  0.1416100  0.0392481
 24  0.1094500  0.0355178
 25  0.0810800  0.0313845
 26  0.0567300  0.0268869
 27  0.0365800  0.0220640
 28  0.0207600  0.0169527
 29  0.0093200  0.0115649
 30  0.0023500  0.0059036
 31  0.0000000  0.0000000
 32  0.0033600 -0.0044914
 33  0.0124700 -0.0081771
 34  0.0267000 -0.0112875
 35  0.0459600 -0.0139233
 36  0.0701000 -0.0161019
 37  0.0989600 -0.0178315
 38  0.1322400 -0.0191149
 39  0.1696300 -0.0199613
 40  0.2107300 -0.0203837
 41  0.2550900 -0.0204007
 42  0.3022100 -0.0200365
 43  0.3515600 -0.0193205
 44  0.4025700 -0.0182875
 45  0.4546300 -0.0169779
 46  0.5071300 -0.0154364
 47  0.5594400 -0.0137126
 48  0.6112800 -0.0118476
 49  0.6624400 -0.0098805
 50  0.7123700 -0.0078675
 51  0.7603700 -0.0058781
 52  0.8057500 -0.0039899
 53  0.8477900 -0.0022899
 54  0.8858300 -0.0008691
 55  0.9192500  0.0001818
 56  0.9474800  0.0007871
 57  0.9700300  0.0009163
 58  0.9865300  0.0006426
 59  0.9966000  0.0002120
 60  1.0000000  0.0000000
AH21               61
   1   1.0000000   0.0000000
   2   0.9967100   0.0009314
   3   0.9872600   0.0035706
   4   0.9723700   0.0075969
   5   0.9524800   0.0126863
   6   0.9276400   0.0185609
   7   0.8981000   0.0248808
   8   0.8642700   0.0313127
   9   0.8266000   0.0375827
  10   0.7855700   0.0434800
  11   0.7416500   0.0488517
  12   0.6953700   0.0535828
  13   0.6472300   0.0575969
  14   0.5977800   0.0608404
  15   0.5475300   0.0632834
  16   0.4970200   0.0649109
  17   0.4467600   0.0657221
  18   0.3972700   0.0657269
  19   0.3490400   0.0649449
  20   0.3024800   0.0634012
  21   0.2580900   0.0611299
  22   0.2162400   0.0581671
  23   0.1773000   0.0545534
  24   0.1416100   0.0503329
  25   0.1094500   0.0455491
  26   0.0810800   0.0402484
  27   0.0567300   0.0344806
  28   0.0365800   0.0282955
  29   0.0207600   0.0217406
  30   0.0093200   0.0148312
  31   0.0023500   0.0075710
  32   0.0000000   0.0000000
  33   0.0033600  -0.0057599
  34   0.0124700  -0.0104865
  35   0.0267000  -0.0144754
  36   0.0459600  -0.0178557
  37   0.0701000  -0.0206495
  38   0.0989600  -0.0228677
  39   0.1322400  -0.0245135
  40   0.1696300  -0.0255990
  41   0.2107300  -0.0261407
  42   0.2550900  -0.0261625
  43   0.3022100  -0.0256954
  44   0.3515600  -0.0247772
  45   0.4025700  -0.0234525
  46   0.4546300  -0.0217730
  47   0.5071300  -0.0197961
  48   0.5594400  -0.0175855
  49   0.6112800  -0.0151937
  50   0.6624400  -0.0126711
  51   0.7123700  -0.0100895
  52   0.7603700  -0.0075383
  53   0.8057500  -0.0051168
  54   0.8477900  -0.0029367
  55   0.8858300  -0.0011146
  56   0.9192500   0.0002332
  57   0.9474800   0.0010094
  58   0.9700300   0.0011751
  59   0.9865300   0.0008241
  60   0.9966000   0.0002719
  61   1.0000000   0.0000000