Here is the Honda's tech paper about the SHM-1 airfoil (which was designed for the Honda-Jet). The airfoil includes features which are not important on low speed low Reynolds number flight but it also has features which makes it ideal for lower speed concepts:
http://hondajet.honda.com/pdf/tech_papers/Journal_of_Aircraft_Vol40_No4_P609_P615_SHM_1_NLF.pdf
SHM-1 could be a good starting point for an airfoil for GA-use. The Re area for the SHM-1 is a lot higher than needed by GA, so it may not be directly applicable, but the ideology in the SHM-1 seems just what would be needed for also high speed high efficiency, long endurance GA aircraft, which in addition to having low drag and high Clmax also exhibits good behavior.
KS20 airfoil simulation
KS20:
Cl - Cd(low reynolds numbers also included, plus also flapped version (+10deg and +20 deg)
L/D vs. alpha:
Cm vs. Alpha:
Cl - alpha:
Printable profile picture of KS20 (black on white background):
KS20.dat Airfoil file for QFLR5, XFLR5 or Xfoil
Cl - Cd(low reynolds numbers also included, plus also flapped version (+10deg and +20 deg)
L/D vs. alpha:
Cm vs. Alpha:
Cl - alpha:
Printable profile picture of KS20 (black on white background):
QFLR5_v.0001
Calculated polar for: KS20
1 1 Reynolds number fixed Mach number fixed
xtrf = 1.000 (top) 1.000 (bottom)
Mach = 0.270 Re = 5.000 e 6 Ncrit = 9.000
alpha CL CD CDp CM Top Xtr Bot Xtr Cpmin Chinge XCp
------- -------- --------- --------- -------- ------- ------- -------- --------- ---------
-2.500 0.0172 0.00639 0.00156 -0.0630 0.5734 0.1263 -0.9628 0.0000 3.9974
-2.000 0.0779 0.00594 0.00135 -0.0638 0.5687 0.2065 -0.7727 0.0000 1.0832
-1.500 0.1376 0.00529 0.00111 -0.0647 0.5613 0.3515 -0.6885 0.0000 0.7246
-1.000 0.1985 0.00466 0.00091 -0.0657 0.5560 0.4943 -0.7241 0.0000 0.5818
-0.500 0.2604 0.00434 0.00082 -0.0667 0.5474 0.5909 -0.7638 0.0000 0.5048
0.000 0.3235 0.00430 0.00084 -0.0677 0.5380 0.6224 -0.8063 0.0000 0.4565
0.500 0.3863 0.00438 0.00088 -0.0686 0.5260 0.6346 -0.8489 0.0000 0.4238
1.000 0.4491 0.00445 0.00094 -0.0696 0.5127 0.6478 -0.8954 0.0000 0.4002
1.500 0.5115 0.00461 0.00102 -0.0704 0.4945 0.6510 -0.9563 0.0000 0.3823
2.000 0.5732 0.00475 0.00111 -0.0712 0.4723 0.6587 -1.0304 0.0000 0.3682
2.500 0.6344 0.00497 0.00124 -0.0719 0.4472 0.6628 -1.1188 0.0000 0.3567
3.000 0.6941 0.00529 0.00142 -0.0723 0.4114 0.6656 -1.2143 0.0000 0.3470
3.500 0.7516 0.00577 0.00168 -0.0724 0.3616 0.6675 -1.3096 0.0000 0.3385
4.000 0.8098 0.00619 0.00194 -0.0726 0.3230 0.6691 -1.4113 0.0000 0.3313
4.500 0.8664 0.00670 0.00226 -0.0725 0.2804 0.6702 -1.5275 0.0000 0.3247
5.000 0.9229 0.00719 0.00260 -0.0724 0.2437 0.6718 -1.6463 0.0000 0.3189
KS20.dat Airfoil file for QFLR5, XFLR5 or Xfoil
First attempt on airfoil design
I created these:
KaroliinaNLF1016.dat
KaroliinaNLF1016F-5.dat
X-foil is predicting for KaroliinaNLF1016F-5 (-5 degrees cruise flap for low altitude) exactly what I was looking for. The KaroliinaNLF1016 is decambered and a bit thickened (16%) version of NASA NLF1015. According to quick analysis, laminar bucket has same shape as NLF1015 has, L/D and minimum Cd is the same, but it has been lowered to a bit lower Cl and also the useful Cl is a bit lower than on NLF1015. However, this way, the unacceptable cruise performance at low altitude theoretically gets acceptable. I need to experiment more and try out with different Re numbers. I was testing at only Re = 1000000 since that is where I was targeting the high altitude cruise. However, the Re is a lot higher at low altitude, gets easily to 5000000, so I will need to try more analysis on the airfoil tomorrow.
HALE airfoil
DESIGN OF AN AIRFOIL FOR
A HIGH-ALTITUDE, LONG-ENDURANCE REMOTELY PILOTED VEHICLE
http://www.rollinghillsresearch.com/Aero_Research/Files/AIAA-2003-0211_NLFairfoil.pdf
NLF1015 coordinates
NLF1015 picture
More accurate picture of NLF1015
KS20 airfoil simulation
KS20:
Cl - Cd(low reynolds numbers also included, plus also flapped version (+10deg and +20 deg)
L/D vs. alpha:
Cm vs. Alpha:
Cl - alpha:
Printable profile picture of KS20 (black on white background):
KS20.dat Airfoil file for QFLR5, XFLR5 or Xfoil
Cl - Cd(low reynolds numbers also included, plus also flapped version (+10deg and +20 deg)
L/D vs. alpha:
Cm vs. Alpha:
Cl - alpha:
Printable profile picture of KS20 (black on white background):
QFLR5_v.0001
Calculated polar for: KS20
1 1 Reynolds number fixed Mach number fixed
xtrf = 1.000 (top) 1.000 (bottom)
Mach = 0.270 Re = 5.000 e 6 Ncrit = 9.000
alpha CL CD CDp CM Top Xtr Bot Xtr Cpmin Chinge XCp
------- -------- --------- --------- -------- ------- ------- -------- --------- ---------
-2.500 0.0172 0.00639 0.00156 -0.0630 0.5734 0.1263 -0.9628 0.0000 3.9974
-2.000 0.0779 0.00594 0.00135 -0.0638 0.5687 0.2065 -0.7727 0.0000 1.0832
-1.500 0.1376 0.00529 0.00111 -0.0647 0.5613 0.3515 -0.6885 0.0000 0.7246
-1.000 0.1985 0.00466 0.00091 -0.0657 0.5560 0.4943 -0.7241 0.0000 0.5818
-0.500 0.2604 0.00434 0.00082 -0.0667 0.5474 0.5909 -0.7638 0.0000 0.5048
0.000 0.3235 0.00430 0.00084 -0.0677 0.5380 0.6224 -0.8063 0.0000 0.4565
0.500 0.3863 0.00438 0.00088 -0.0686 0.5260 0.6346 -0.8489 0.0000 0.4238
1.000 0.4491 0.00445 0.00094 -0.0696 0.5127 0.6478 -0.8954 0.0000 0.4002
1.500 0.5115 0.00461 0.00102 -0.0704 0.4945 0.6510 -0.9563 0.0000 0.3823
2.000 0.5732 0.00475 0.00111 -0.0712 0.4723 0.6587 -1.0304 0.0000 0.3682
2.500 0.6344 0.00497 0.00124 -0.0719 0.4472 0.6628 -1.1188 0.0000 0.3567
3.000 0.6941 0.00529 0.00142 -0.0723 0.4114 0.6656 -1.2143 0.0000 0.3470
3.500 0.7516 0.00577 0.00168 -0.0724 0.3616 0.6675 -1.3096 0.0000 0.3385
4.000 0.8098 0.00619 0.00194 -0.0726 0.3230 0.6691 -1.4113 0.0000 0.3313
4.500 0.8664 0.00670 0.00226 -0.0725 0.2804 0.6702 -1.5275 0.0000 0.3247
5.000 0.9229 0.00719 0.00260 -0.0724 0.2437 0.6718 -1.6463 0.0000 0.3189
KS20.dat Airfoil file for QFLR5, XFLR5 or Xfoil
First attempt on airfoil design
I created these:
KaroliinaNLF1016.dat
KaroliinaNLF1016F-5.dat
X-foil is predicting for KaroliinaNLF1016F-5 (-5 degrees cruise flap for low altitude) exactly what I was looking for. The KaroliinaNLF1016 is decambered and a bit thickened (16%) version of NASA NLF1015. According to quick analysis, laminar bucket has same shape as NLF1015 has, L/D and minimum Cd is the same, but it has been lowered to a bit lower Cl and also the useful Cl is a bit lower than on NLF1015. However, this way, the unacceptable cruise performance at low altitude theoretically gets acceptable. I need to experiment more and try out with different Re numbers. I was testing at only Re = 1000000 since that is where I was targeting the high altitude cruise. However, the Re is a lot higher at low altitude, gets easily to 5000000, so I will need to try more analysis on the airfoil tomorrow.
HALE airfoil
DESIGN OF AN AIRFOIL FOR
A HIGH-ALTITUDE, LONG-ENDURANCE REMOTELY PILOTED VEHICLE
http://www.rollinghillsresearch.com/Aero_Research/Files/AIAA-2003-0211_NLFairfoil.pdf
NLF1015 coordinates
NLF1015 picture
More accurate picture of NLF1015
Low pitching moment NLF airfoil with low sensitivity to bugs and dirt
Here is the Honda's tech paper about the SHM-1 airfoil (which was designed for the Honda-Jet). The airfoil includes features which are not important on low speed low Reynolds number flight but it also has features which makes it ideal for lower speed concepts:
http://hondajet.honda.com/pdf/tech_papers/Journal_of_Aircraft_Vol40_No4_P609_P615_SHM_1_NLF.pdf
SHM-1 could be a good starting point for an airfoil for GA-use. The Re area for the SHM-1 is a lot higher than needed by GA, so it may not be directly applicable, but the ideology in the SHM-1 seems just what would be needed for also high speed high efficiency, long endurance GA aircraft, which in addition to having low drag and high Clmax also exhibits good behavior.
http://hondajet.honda.com/pdf/tech_papers/Journal_of_Aircraft_Vol40_No4_P609_P615_SHM_1_NLF.pdf
SHM-1 could be a good starting point for an airfoil for GA-use. The Re area for the SHM-1 is a lot higher than needed by GA, so it may not be directly applicable, but the ideology in the SHM-1 seems just what would be needed for also high speed high efficiency, long endurance GA aircraft, which in addition to having low drag and high Clmax also exhibits good behavior.
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