Wing
Airfoil selection Aerodynamic characteristics (Kmax, CLmax, stall characteristics) Structural reasons;
1
Airfoil geometry
Airfoil geometryCamber line Leading edge Chord Maximum thickness
Trailing edge Maximum thickness position Maximum camber Maximum camber position
2
Angle of attack definition
V
AoA
StallAoA=0 Separation point
AoA=10
AoA=15
AoA=20
3
Airfoil aerodynamic characteristicsLift coefficient (Cz or CL)C L MAXStall
Drag coefficient (Cx or CD )
dC l /d a0
KR
Airfoil aerodynamic characteristics
Design Cz
4
Airfoil aerodynamic characteristicsGliding ratio (Cz / Cx) Power factor (Cz3 / Cx2 lub Cz1,5 /Cx)
Airfoil aerodynamic characteristicsPitching moment coefficient Cm Derivative dCm/dCz is an indicator of stability. It is negative for stable aeroplanes and positive for unstable aeroplanes.
5
Maximum thickness t/cMaximum thickness - t
Chord - c
Effect of airfoil thickness on lift coefficient6% 8% 10% 12% 14% 16%
18%
20%
6
Effect of airfoil thickness on lift coefficient
Effect of airfoil thickness on drag coefficient6% 8% 10% 12% 14% 16%
18%
20%
7
Effect of airfoil thickness on gliding ratio6% 8% 10% 12% 14% 16%
18%
20%
Effect of airfoil thickness on power factor6% 8% 10% 12% 14% 16%
18%
20%
8
CamberCamber line
Maximum camber
Effect of airfoil camber on lift coefficient0%
0,5% 1% 1,5% 2%
2,5%
3% 3,5%
9
Effect of airfoil camber on drag coefficient0%
0,5% 1% 1,5% 2%
2,5%
3% 3,5%
Effect of airfoil camber on gliding ratio0%
0,5% 1% 1,5% 2%
2,5%
3% 3,5%
10
Effect of airfoil camber on power factor0%
0,5% 1% 1,5% 2%
2,5%
3% 3,5%
Effect of airfoil camber on moment coefficient0%
0,5% 1% 1,5% 2%
2,5%
3% 3,5%
11
Position of maximum thicknessMaximum thickness
Position of maximum thickness
Boundary layer developmentlaminar turbulent separated
transition separation
12
Effect of airfoil laminarity on drag coefficient15%
20%
25%
30% 35%
40% 45%
50%
Effect of airfoil laminarity on lift coefficient15%
20%
25%
30% 35%
40% 45%
50%
13
Effect of camber line shape on moment coefficient35% 0
2 4
6
28%
22%
15%
Effect of camber line shape on gliding ratio35% 0%
2% 4%
6%
28%
22%
15%
14
Reynolds number effect on aerodynamic coefficients
Effect of Mach number on lift coefficient
15
Effect of Mach number on drag coefficient
Effect of Mach number on moment coefficient
16
Critical Mach number
Historical values of an aeroplane airfoil thickness as a function of Mach number
17
Critical Mach number
Critical Mach number
18
Calculate Reynolds number for design airspeed
Airfoil selection500 000>Re Selig catalogue Summary of low speed airfoil data Vol.1-3 Airfoils at low speeds
Re>3 000 000 Calculate Mach number for maximum airspeed
3 000 000>Re>500 000 Wortmann catalogue Stuttgarter Profilkatalog Vol.1 i 2
Mmax>0,75
Mmax