44
Drag Reduction of MAV by Biplane Effect Chinnapat THIPYOPAS Graduate student, Department of Aerodynamics and Jean-Marc MOSCHETTA Associate Professor of Aerodynamics, Department of Aerodynamics Ecole Nationale Supérieure de l’Aéronautique et de l’Espace (SUPAERO) 10 Av. Ed. Belin, Toulouse, France P1/2 9

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Drag Reduction of MAV by Biplane Effect. Chinnapat THIPYOPAS Graduate student, Department of Aerodynamics and Jean-Marc MOSCHETTA Associate Professor of Aerodynamics, Department of Aerodynamics Ecole Nationale Supérieure de l’Aéronautique et de l’Espace (SUPAERO) - PowerPoint PPT Presentation

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Page 1: Drag Reduction of MAV  by Biplane Effect

Drag Reduction of MAV by Biplane Effect

Chinnapat THIPYOPASGraduate student, Department of Aerodynamics

and

Jean-Marc MOSCHETTA Associate Professor of Aerodynamics, Department of

Aerodynamics

Ecole Nationale Supérieure de l’Aéronautique et de l’Espace (SUPAERO)

10 Av. Ed. Belin, Toulouse, France

P1/29

Page 2: Drag Reduction of MAV  by Biplane Effect

Contents

• Introduction• Part 1 Optimization - (Experimental)

- (Numerical)

• Part 2 Biplane Combinations • Part 3 Propeller Influence• Conclusions

Department of Aerodynamics SUPAERO P2/29

Page 3: Drag Reduction of MAV  by Biplane Effect

Contents

• Introduction• Part 1 Optimization - (Experimental)

- (Numerical)

• Part 2 Biplane Combinations • Part 3 Propeller Influence• Conclusions

Department of Aerodynamics SUPAERO P3/29

Page 4: Drag Reduction of MAV  by Biplane Effect

Monoplane MAV concepts

Minus-Kiool57g - 20.6 cm

Plaster64g - 23 cm

Department of Aerodynamics SUPAERO P4/29

Page 5: Drag Reduction of MAV  by Biplane Effect

Monoplane-MAVs

Total Drag = Parasite Drag + Induced drag

100 % 20-30 % 70-80 %

Plaster, SUPAERO

Drenalyne, SUPAERO Biplane

Concept !!

Maxi-Kiool, SUPAERO

Induced Drag 76%*

* J.L’HENAFF, SUPAERO 2004

Department of Aerodynamics SUPAERO

P5/29

Page 6: Drag Reduction of MAV  by Biplane Effect

Monoplane vs. biplane

1 FD iD maxP

2 2/FD iD maxP

2 2FD 2/iD maxP

Constant lift, speed & overall dimension

wing drag = Parasite Drag + Induced Drag

Parasite drag is a function of Skin-Friction which depends on Wing Chord

Induced Drag is very strongly effected by Aspect Ratio

Department of Aerodynamics SUPAERO

P6/29

Page 7: Drag Reduction of MAV  by Biplane Effect

Contents

• Introduction• Part 1 Optimization - (Experimental)

- (Numerical)

• Part 2 Biplane Combinations • Part 3 Propeller Influence• Conclusions

Department of Aerodynamics SUPAERO P7/29

Page 8: Drag Reduction of MAV  by Biplane Effect

Design Constraints• Maximum overall dimension : 20 cm• Lift at 10 m/s = Weight = 80 grams• Manoeuvrability :

Cost function

• Minimum Drag at cruise condition

2)(

)(

max

L

cruiseL

C

C

Optimization process

Department of Aerodynamics SUPAERO

20 grams min.

for payload

P8/29

Page 9: Drag Reduction of MAV  by Biplane Effect

Experimental setup• Wind tunnel

– Test Section 45cm x 45cm – Velocity 10 m/s

• Measurement– 3-component balance

• Models– 16 flat-plate wing models

• Aspect ratio 1 – 4• Taper ratio 0.2 – 1.0• Sweep angle 0 - 50°

• Reference surface/length– For comparison, every model

is referenced by same area, length

Strut

AR1, Taper 1, No Swept

20cm.AR2.5, Taper0.6, Swept25°

Department of Aerodynamics SUPAERO P9/29

Page 10: Drag Reduction of MAV  by Biplane Effect

Model’s Drag Correction

Model

Strut

Strut

Model is not attached to strut

mod el total strutDrag Drag Drag

Department of Aerodynamics SUPAERO P10/29

Page 11: Drag Reduction of MAV  by Biplane Effect

Results

LC minDCminDC maxLC KAC Monoplane

AoADC DL /

Biplane

DC DL / AoA

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

No.

A4S50T1

A4S50T0.6

A4S50T0.2

A4S25T0.6

A4S0T1

A4S0T0.2

A2,5S50T1

A2,5S25T1

A2,5S25T0.6

A2,5S0T1

A2,5S0T0.6

A1S50T1

A1S50T0.2

A1S25T0.6

A1S0T1

A1S0T0.2

Disc

Model Name

15.13.5080.091---5.3110.27810.4240.03680.01413.598376.7

14.93.5330.091---5.950.30560.4420.02390.00953.488379.5

14.33.4990.092---5.2210.29430.4810.02950.01243.392684.1

7.65.6130.058---3.2610.23630.4180.02750.01334.946896.6

9.834.3860.074---1.4970.24550.3810.03450.01674.553994.1

8.465.4040.060---2.4530.24130.3550.03260.01664.327399.3

11.54.5520.071---5.7660.3190.5350.01310.00673.0513102.9

6.55.2270.061---4.5030.26830.6010.0290.024.0961137.9

6.386.386.2886.2880.0520.052---4.9040.30320.6190.02340.01723.6615146.7

7.445.8990.054---2.430.29660.5720.01620.01123.556137.9

6.386.386.0366.0360.0550.055---3.0990.28140.6270.02730.023.7786146.7

12.23.9670.08121.82.5520.2527.6330.37380.9440.02810.01832.4902130.2

11.34.1280.078212.5300.2569.9670.41781.0460.02240.01632.4114144.0

7.565.5320.05813.513.53.9533.9530.1640.1648.9260.38571.6210.010.01122.4667224.8

8.564.390.07314.63.3990.1895.3360.38881.4490.02140.02192.5556200.0

12.33.8030.085232.2090.2936.1760.51270.8870.02020.01462.1647144.0

4.65.8710.0558.568.565.0525.0520.1270.1278.320.35781.9970.01470.02322.8223314.2

(cm.)

***Area

Red color is a value referenced by wing’s area

Department of Aerodynamics SUPAERO

P11/29

Page 12: Drag Reduction of MAV  by Biplane Effect

Numerical method

• Vortex lattice method : code TORNADO v126b [T. Melin; KTH]

• Drag evaluationParasite Drag = 1.5 of equivalent flat plate skin friction drag (Blasius Eq. + Thwaites formula)

+

Induced drag (TORNADO)

• Various models : – aspect ratio– taper ratio– sweep angle

Department of Aerodynamics SUPAERO P12/29

Page 13: Drag Reduction of MAV  by Biplane Effect

ResultsThe variation of Lift to Drag ratio

0

1

2

3

4

5

6

7

8

9

10

0 1 2 3 4 5AR

L/D

1 0.80.6 0.4

1 0.80.6 0.41 0.80.6 0.4

1 0.80.6 0.41 0.80.6 1

0.8 0.61 0.80.6 0.6

Monoplane

Triplane

The variation of Cruising angle of attack

0

5

10

15

20

25

30

35

40

0 1 2 3 4 5ARAo

A

S 10.8 0.60.4 10.8 0.60.4 10.8 0.60.4 10.8 0.60.4 10.8 0.61 0.80.6 10.8 0.60.6

An approximate stall angle curve

Biplane

• L/D at cruise cond. increases with AR• Poor manoeuvrability of monoplane wings with AR 2 and higher• greater L/D for biplanes

• L/D of Triplane AR4 is smaller than biplane because of high parasite drag.

• Biplane AR2-3 is suitable for flight

Department of Aerodynamics SUPAERO P13/29

Page 14: Drag Reduction of MAV  by Biplane Effect

-50

0

50

100

150

200

250

0 0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,4

Drag

Mas

s

Monoplane

Biplane

60 grams

Monoplane

Biplane

Biplane vs. monoplane

Department of Aerodynamics SUPAERO

80

P14/29

Page 15: Drag Reduction of MAV  by Biplane Effect

Contents

• Introduction• Part 1 Optimization - (Experimental)

- (Numerical)

• Part 2 Biplane Combinations • Part 3 Propeller Influence• Conclusions

Department of Aerodynamics SUPAERO P15/29

Page 16: Drag Reduction of MAV  by Biplane Effect

Zimmerman

Planform Area (m2) CL (max) CD (min) L/D (max)

Zim1 0.0264 1.251 0.0533 4.03

Zim2 0.0173 0.586 0.0419 5.21

Zim1Inv 0.0264 0.986 0.0538 3.75

Zim2Inv 0.0173 0.605 0.0344 4.96

Plaster1 0.0245 0.909 0.0411 4.92

Plaster2 0.0166 0.605 0.0354 5.47

Drenalyne1 0.0273 1.260 0.0528 4.46

Drenalyne2 0.0173 0.585 0.0375 4.81

-95

-75

-55

-35

-15

5

25

45

65

85

0 20 40 60 80 100 120 140 160 180 200

-100

-80

-60

-40

-20

0

20

40

60

80

100

0 20 40 60 80 100 120 140 160 180 200

Plaster

Other planforms

Drenalyne

-100

-80

-60

-40

-20

0

20

40

60

80

100

0 20 40 60 80 100 120 140

Department of Aerodynamics SUPAERO P16/29

Page 17: Drag Reduction of MAV  by Biplane Effect

Inverse ZimmermanTorres et al., Univ. Florida, 1999

Plaster wingReyes et al., SUPAERO, 2001

Calculation

Biplane type L/D cruise L/D max. CLmax/CLcruise Cm0

BSWE1 5.16 5.16 1.71 -0.0371BSWE2 5.6 5.83 1.64 -0.0260BSWE3 5.01 5.07 1.54 -0.0042BPLA1 7.03 7.19 2.04 0.0418BPLA2 7.89 8.63 2.02 0.0198BPLA3 6.67 6.76 1.79 -0.0107BZIM1 6.85 7.07 2.32 0.0603BZIM2 7.66 7.95 2.06 -0.0347BZIM3 6.28 6.44 1.87 -0.0165

Department of Aerodynamics SUPAERO P17/29

Page 18: Drag Reduction of MAV  by Biplane Effect

Scale 1(SUPAERO)

Parameters• Gap• Stagger• Decalage angle

Side View

U

Lower Wing

Gap

Stagger Upper Wing

Decalage angle

End-plates

Scale 3(S4, ENSICA)

Department of Aerodynamics SUPAERO P18/29

Page 19: Drag Reduction of MAV  by Biplane Effect

GapInfluent of Gap (Bi-Zim)

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

-10 0 10 20 30

AoA

CL

CL Gap3

CL Gap5

CL Gap7

Pitching moment coefficient curve for stagger constant (S0)

-1.5

-1

-0.5

0

0.5

1

-20 -10 0 10 20 30 40

AoA

Cm CMaT1 G0.75 S0

CMaT1 G1.0 S0

CMaT1 G1.25 S0

CMaT1 Mono wo winglet

Lift to drag ratio for stagger constant (S0)

-10

-8

-6

-4

-2

0

2

4

6

8

-20 -10 0 10 20 30 40

AoA

L/D

Finesse G0.75 S0

Finesse G1.0 S0

Finesse G1.25 S0

Finesse Mono wo winglet

• Reduced an influence between both wings

• Increase lift slope and maximum lift

• Not change position of aerodynamics center

• Increase drag from the structure L/D not change

Department of Aerodynamics SUPAERO

P19/29

Page 20: Drag Reduction of MAV  by Biplane Effect

StaggerInfluent of Stagger and tandem

(Bi-Zim Gap5)

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

-10 0 10 20 30

AoA

CL

Cz Tandem2Cz Tandem1CL S2CL S4CL S6CL Gap5 S0

Influent of Stagger and tandem (Bi-Zim Gap5)

-4

-2

0

2

4

6

8

-10 0 10 20 30

AoA

L/D

L/D Tandem2 L/D Tandem1

L/D S2 L/D S4

L/D S6 L/D Gap5 S0

The effect of stagger to pitching moment

-1.5

-1

-0.5

0

0.5

1

1.5

-20 -10 0 10 20 30

AoA

Cm CMaT1 G0.75 S+30

CMaT1 GO.75 S+15CMaT1 G0.75 S0CMaT1 G0.75 S-15

• Increase lift slope and maximum lift

• Aerodynamics center is between two wing

• No stagger has more L/D

• Local AoA of fore-wing is bigger

Department of Aerodynamics SUPAERO P20/29

Page 21: Drag Reduction of MAV  by Biplane Effect

Decalage Angle

Decalage angle influence

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

-15 -5 5 15 25

AoA

CL

CL D+9 CL D+7CL D+3 CL D+0CL D-3 CL D-5CL D-7

Decalage angle influence

-4

-2

0

2

4

6

8

-15 -5 5 15 25

AoA

L/D

L/D D+9 L/D D+7L/D D+3 L/D D+0L/D D-3 L/D D-5L/D D-7

Done with positive stagger model

• Strongly effect to stall angle and L/D

• Negative decalage give highest wing performance

Department of Aerodynamics SUPAERO P21/29

Page 22: Drag Reduction of MAV  by Biplane Effect

Visualisation

S4, ENSICA

Department of Aerodynamics SUPAERO P22/29

Page 23: Drag Reduction of MAV  by Biplane Effect

Contents

• Introduction• Part 1 Optimization - (Experimental)

- (Numerical)

• Part 2 Biplane Combinations • Part 3 Propeller Influence• Conclusions

Department of Aerodynamics SUPAERO P23/29

Page 24: Drag Reduction of MAV  by Biplane Effect

Propeller Effect (S4)

Motor & propeller

Test section

Power supplyMoveable system

TubeTest section

Upper Wing

Lower Wing

U Motor

Side View

7 4 6 5

1 2 3

Front View

Half Span

Center line

Upper wing

Lower Wing

• 7 motor positions

were observed.

Inf luent of motor to lif t coeff icient

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

10 15 20 25 30AoA

CL

CL no motor

CL motor

Upper wing stalls

• At pre-stall regime, lift is increased due to propeller.

Lift increases

Lower wing stall at 22°

Lower wing not stalled

• The stall angle is delayed, lower wing is still not stall at AoA 22°

• Lift, maximum lift and L/D are increased.

Department of Aerodynamics SUPAERO P24/29

Page 25: Drag Reduction of MAV  by Biplane Effect

Propeller Effect (Scale 1)

• Zim2 wing planform scale 1 (20cm. Max dim.)

• Motor in front of wing gives highest performance.

• The motor countering / encountering wingtip vortex effects are very small.

Monoplane Wing

P25/29

Page 26: Drag Reduction of MAV  by Biplane Effect

Propeller Effect

-2

-1

0

1

2

3

4

5

6

7

-10 -5 0 10 20 25

Incidence

B = mid position

R = upper wingG = lower wing

L/D

155

• Motor on upper and lower wing have the same effect

• Middle position is poorest

Moter's influent

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

-10 0 10 20 30

AoA

CL

Cz bz1

Cz bz2m

Cx bz2mh1

Cx bz3m

Cx bz3mh1

• Attached on upper and lower wing

• Same efficiency• Delay stall

phenomena, increase maximum lift

Attach Motor to the model

Motor sting

Model struts

Effect of induced flow to model

P26/29

Page 27: Drag Reduction of MAV  by Biplane Effect

Contents

• Introduction• Part 1 Optimization - (Experimental)

- (Numerical)

• Part 2 Biplane Combinations • Part 3 Propeller Influence• Conclusions

Department of Aerodynamics SUPAERO P27/29

Page 28: Drag Reduction of MAV  by Biplane Effect

Conclusions• Biplane is better than monoplane for this design criteria

• Wind tunnel measurements and numerical calculations confirm the interest for biplane MAV wings.

• AR 2.5 to 3 are appropriate for biplane MAV concepts.

On-going developments

• More accuracy measurement

• Further optimization of motor position (wingtip)

• Optimizing biplane-connecting structure

• Pototype of Biplane MAV

Department of Aerodynamics SUPAERO

P28/29

Page 29: Drag Reduction of MAV  by Biplane Effect

Thank you for your attention

P29/29

Page 30: Drag Reduction of MAV  by Biplane Effect

Drag Reduction of MAV by Biplane Effect

Chinnapat THIPYOPASGraduate student, Department of Aerodynamics

and

Jean-Marc MOSCHETTA Associate Professor of Aerodynamics, Department of

Aerodynamics

Ecole Nationale Supérieure de l’Aéronautique et de l’Espace (SUPAERO)

10 Av. Ed. Belin, Toulouse, France

Page 31: Drag Reduction of MAV  by Biplane Effect

Parasite and Induced Drag

Drag of drag biplane and monoplane

02040

6080

100120

140160

0 20 40 60 80 100% Do

Do (monoplane) Di (monoplane) Dt (monoplane)Do (biplane) Di (biplane) Dt (biplane)

The zone which biplane has total drag less than monoplane configuration

(when Induced drag > 45% total drag)

55

Department of Aerodynamics SUPAERO

Page 32: Drag Reduction of MAV  by Biplane Effect

Parasite and Induced Drag

Drag of drag biplane and monoplane

02040

6080

100120

140160

0 20 40 60 80 100% Do

Do (monoplane) Di (monoplane) Dt (monoplane)Do (biplane) Di (biplane) Dt (biplane)

case a.)AR1

b.)AR2

c.) 2 x AR2

total

Surface S S/2 S/2

Lift for each wing W W W/2

Max. Lift L L/2 L/2 L

Lift coef. CL 2CL CL

Skin friction drag Df Df/1.414 Df/1.414 1.414Df

Induced drag coef. CDi 2CDi CDi/2

Induced drag Di Di Di/4 Di/2

Total drag 1.5Df + Di 1.5Df /1.414 + Di 1.5*1.414Df + Di/2

Airplane drag = Parasite Drag + Induced Drag

Parasite drag is a function of Skin-Friction which depends on Wing Chord

Induced Drag is very strongly effected by Aspect Ratio

The zone which biplane has total drag less than monoplane configuration

(when Induced drag > 45% total drag)

55

Page 33: Drag Reduction of MAV  by Biplane Effect

Results

• Reynolds number effect on L/D

• Winglet can improve wing performance

• Gap increases the lift slope and maximum lift

• L/D increased by positive stagger

• Stall angle and maximum lift changed by decalage angle

• Parasite drag from the strut between two wing is very important

Lift to drag ratio, influent of velocity and winglet

-10.0

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

10.0

-20 -10 0 10 20 30 40

AoA

L/D

Finesse Mono w o w inglet

Finesse V. 5

Finesse V. 15

Finesse w inglet

Lift coefficient curve for stagger constant (S0)

-1.5

-1

-0.5

0

0.5

1

1.5

2

-20 -10 0 10 20 30 40

AoA

CL

CZa G0.75 S0

CZa G1.0 S0

CZa G1.25 S0

CZa Mono wo winglet

The effect of stagger to lift to drag ratio

-10

-8

-6

-4

-2

0

2

4

6

8

10

-20 -10 0 10 20 30

AoAL

/D

Finesse G0.75 S+30Finesse GO.75 S+15Finesse G0.75 S0Finesse G0.75 S-15

Lift coefficient

-1.5

-1

-0.5

0

0.5

1

1.5

2

-20 -10 0 10 20 30

AoA

CL

CZa S0 D-6°CZa G1.0 S0CZa S0 D+6°

Page 34: Drag Reduction of MAV  by Biplane Effect

Propeller-induced lift

Increasing in lift

Page 35: Drag Reduction of MAV  by Biplane Effect

Why are these 16 models ?

• The Taguchi method was used in the first experimental design table. But an interaction between each parameters is very strong.

• To determine the optimizing model, some interpolation was formed to complete the experimental table.

Page 36: Drag Reduction of MAV  by Biplane Effect

Gap effectLift coefficient curve for stagger constant

(S0)

-1.5

-1

-0.5

0

0.5

1

1.5

2

-20 -10 0 10 20 30 40

AoA

CL

CZa G0.75 S0

CZa G1.0 S0

CZa G1.25 S0

CZa Mono wo winglet

Lift - drag coefficient curve for stagger constant (S0)

-1.5

-1

-0.5

0

0.5

1

1.5

2

0 0.2 0.4 0.6 0.8

CD

CL

CXa G0.75 S0

CXa G1.0 S0

CXa G1.25 S0

CXa Mono wo winglet

Pitching moment coefficient curve for stagger constant (S0)

-1.5

-1

-0.5

0

0.5

1

-20 -10 0 10 20 30 40

AoA

Cm CMaT1 G0.75 S0

CMaT1 G1.0 S0

CMaT1 G1.25 S0

CMaT1 Mono wo winglet

Lift to drag ratio for stagger constant (S0)

-10

-8

-6

-4

-2

0

2

4

6

8

-20 -10 0 10 20 30 40

AoA

L/D

Finesse G0.75 S0

Finesse G1.0 S0

Finesse G1.25 S0

Finesse Mono wo winglet

Page 37: Drag Reduction of MAV  by Biplane Effect

Stagger effectThe effect of stagger to lift coefficient

-1.5

-1

-0.5

0

0.5

1

1.5

2

-20 -10 0 10 20 30

AoA

CL

CZa G0.75 S+30

CZa GO.75 S+15CZa G0.75 S0

CZa G0.75 S-15

The effect of stagger to drag coefficient

-1.5

-1

-0.5

0

0.5

1

1.5

2

0 0.2 0.4 0.6 0.8

CD

CL

CXa G0.75 S+30CXa GO.75 S+15CXa G0.75 S0CXa G0.75 S-15

The effect of stagger to pitching moment

-1.5

-1

-0.5

0

0.5

1

1.5

-20 -10 0 10 20 30

AoA

Cm CMaT1 G0.75 S+30

CMaT1 GO.75 S+15CMaT1 G0.75 S0CMaT1 G0.75 S-15

The effect of stagger to lift to drag ratio

-10

-8

-6

-4

-2

0

2

4

6

8

10

-20 -10 0 10 20 30

AoA

L/D

Finesse G0.75 S+30Finesse GO.75 S+15Finesse G0.75 S0Finesse G0.75 S-15

Page 38: Drag Reduction of MAV  by Biplane Effect

Decalage effectLift coefficient

-1.5

-1

-0.5

0

0.5

1

1.5

2

-20 -10 0 10 20 30

AoA

CL

CZa S0 D-6°CZa G1.0 S0CZa S0 D+6°

Poar curve

-1.5

-1

-0.5

0

0.5

1

1.5

2

0 0.2 0.4 0.6 0.8 1

CD

CL

CXa S0 D-6°CXa G1.0 S0CXa S0 D+6°

Pitching moment coefficient

-1.5

-1

-0.5

0

0.5

1

1.5

-20 -10 0 10 20 30

AoA

Cm

CMaT1 S0 D-6°CMaT1 G1.0 S0CMaT1 S0 D+6°

Lift to drag ratio

-8

-6

-4

-2

0

2

4

6

8

-20 -10 0 10 20 30

AoA

L/D

Finesse S0 D-6°

Finesse G1.0 S0

Finesse S0 D+6°

Page 39: Drag Reduction of MAV  by Biplane Effect

Scale 1

• Sweptm Plaster and Inv-Zim planeform

• Connected with strut• Biplane

– parameters• Gap• Stagger• Decalage angle

Page 40: Drag Reduction of MAV  by Biplane Effect

Swept PlanformInfluent of stagger

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

-10 -5 0 5 10 15 20

AoA

CL Cz G5S0

Cz G5S2

Cz G5S4

Cz G5S6

Influent of stagger

-4

-2

0

2

4

6

8

-10 -5 0 5 10 15 20

AoA

L/D

L/D G5S0 L/D G5S2

L/D G5S4 L/D G5S6

Decalage angle influence

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

-15 -5 5 15 25

AoA

CL

CL D+9 CL D+7CL D+3 CL D+0CL D-3 CL D-5CL D-7

Decalage angle influence

-4

-2

0

2

4

6

8

-15 -5 5 15 25

AoA

L/D

L/D D+9 L/D D+7L/D D+3 L/D D+0L/D D-3 L/D D-5L/D D-7

Page 41: Drag Reduction of MAV  by Biplane Effect

Inverse-ZimmermanInfluent of Gap (Bi-Zim)

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

-10 0 10 20 30

AoA

CL

CL Gap3

CL Gap5

CL Gap7

Influent of Stagger and tandem (Bi-Zim Gap5)

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

-10 0 10 20 30

AoA

CL

Cz Tandem2Cz Tandem1CL S2CL S4CL S6CL Gap5 S0

Influent of Stagger and tandem (Bi-Zim Gap5)

-4

-2

0

2

4

6

8

-10 0 10 20 30

AoA

L/D

L/D Tandem2 L/D Tandem1

L/D S2 L/D S4

L/D S6 L/D Gap5 S0

Influent of Stagger and tandem (Bi-Zim Gap5)

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 0.2 0.4 0.6 0.8CD

CL

Cz Tandem2

Cz Tandem1

Cx S2

CL S4

CL S6

CL Gap5 S0

Page 42: Drag Reduction of MAV  by Biplane Effect

Visualisation

Tuft method

Smoke generation

Page 43: Drag Reduction of MAV  by Biplane Effect

Motor-Propeller Effect

• Attached on upper and lower wing• Same efficiency• Delay stall phenomena, increase

maximum lift

Moter's influent

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

-10 0 10 20 30

AoA

CL

Cz bz1

Cz bz2m

Cx bz2mh1

Cx bz3m

Cx bz3mh1

Motor's influent

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

CD

CL

Cz bz1

Cz bz2m

Cx bz2mh1

Cx bz3m

Cx bz3mh1

Page 44: Drag Reduction of MAV  by Biplane Effect

GEOBAT