Aerodynamics and Design for Ultra-Low Reynolds Number Flight

More documents

Recommendations

Info

Chapter 6 124 Aero-Structural Twist (deg.) 0.0 -0.5 -1.0 -1.5 -2.0 Epoxy Large Hub 30,000 RPM 35,000 RPM 40,620 RPM 46,790 RPM 50,760 RPM Aluminum Large Hub 0.0 0.2 0.4 0.6 0.8 1.0 r/R FIGURE 6.25 Predicted torsional deflections for large-hub four-blade rotors. The change in slope visible near the tips is the result of aerodynamic loading. In this case the lift coefficient is assumed to be 0.5 and the quarter chord pitching moment is set at -0.08. The effect of neglecting the aerodynamic forces and moments is displayed in Figure 6.26 for the large hub epoxy rotor. At both speeds, the tip deflection almost doubles. This demonstrates the importance not only of including these effects, but also the need to accurately predict, or converge to, the final static equilibrium loading.
Aero-Structural Twist (deg.) 0.00 -0.75 -1.50 -2.25 30,000 RPM 50,760 RPM 30,000 RPM, w/o Aero. 50,760 RPM, w/o Aero. -3.00 0.0 0.2 0.4 0.6 0.8 1.0 r/R FIGURE 6.26 Predicted torsional deflections with and without aerodynamic effects. Moving on to compare the large hub and small hub four-blade rotors, the dominant Chapter 6 reason for the dramatic difference in performance is revealed. Figure 6.27 compares the predicted torsional deflections for both rotors. For the small hub version, the lift coefficient specified in the structural analysis has been reduced to 0.15. This is still slightly above the values predicted by the performance analysis of the deformed blade. The smaller chords and reduced t/c cause roughly a nine degree deflection over the first 20% of the blade and larger variations across the speed range. This is the explanation for both the reduced thrust and power required seen in Figures 6.13 and 6.17. 125
Page 1 and 2:
AERODYNAMICS AND DESIGN FOR ULTRA-L
Page 3:
I certify that I have read this dis
Page 7 and 8:
Abstract Growing interest in micro-
Page 9 and 10:
Nomenclature A Rotor disk area B Nu
Page 11 and 12:
τ Shear stress ω, Ω Rotor angul
Page 13 and 14:
Contents Acknowledgments...........
Page 15 and 16:
Chapter 5..........................
Page 17 and 18:
List of Tables 3.1 Effect of Airfoi
Page 19 and 20:
List of Figures 2.1 Comparison of I
Page 21 and 22:
5.6 Small test fixture in the large
Page 23 and 24:
6.38 Predicted spanwise thrust dist
Page 25 and 26:
Chapter 1 Introduction 1.1 Looking
Page 27 and 28:
Chapter 1 wind-tunnel facilities an
Page 29 and 30:
1.3 Summary of Contributions Chapte
Page 31 and 32:
Chapter 2 Two-Dimensional Computati
Page 33 and 34:
Chapter 2 The artificial compressib
Page 35 and 36:
Chapter 2 The control volume method
Page 37 and 38:
2.2.4 Comparison with Experiment Th
Page 39 and 40:
Chapter 2 to diverge if significant
Page 41 and 42:
2.4 Flow Field Assumptions The INS2
Page 43 and 44:
Chapter 2 The results of these time
Page 45 and 46:
Chapter 3 Analysis and Design of Ai
Page 47 and 48:
Chapter 3 adverse gradient in the p
Page 49 and 50:
The canonical pressure coefficient
Page 51 and 52:
Chapter 3 reaches α=5.0 and a lift
Page 53 and 54:
��
Page 55 and 56:
Cl 0.50 0.40 0.30 0.20 0.10 0.00 -0
Page 57 and 58:
Re=6000 result due to Reynolds numb
Page 59 and 60:
FIGURE 3.10 NACA 0002 and NACA 0008
Page 61 and 62:
C l C l 0.8 0.7 0.6 0.5 0.4 0.3 0.2
Page 63 and 64:
Chapter 3 The maximum L/D for all n
Page 65 and 66:
3.5 Effect of Leading Edge Shape an
Page 67 and 68:
C l 0.60 0.50 0.40 0.30 0.20 0.10 0
Page 69 and 70:
Chapter 3 prominent droop near the
Page 71 and 72:
Chapter 3 Small improvements in lif
Page 73 and 74:
Chapter 4 Hybrid Method for Rotor D
Page 75 and 76:
Q/r D L Chapter 4 FIGURE 4.1 Typica
Page 77 and 78:
4.2.3 Elimination of Trigonometric
Page 79 and 80:
Chapter 4 applications of interest
Page 81 and 82:
4.2.7 The Distinction Between the A
Page 83 and 84:
Chapter 4 Two input parameters dete
Page 85 and 86:
Chapter 4 simplification, particula
Page 87 and 88:
4.3.3 Conservation of Angular Momen
Page 89 and 90:
Chapter 4 moves downstream is less
Page 91 and 92:
Chapter 4 of the pitch angle at the
Page 93 and 94:
FIGURE 4.6 Converged wake streamlin
Page 95 and 96:
Chapter 4 idealized models. The met
Page 97 and 98: ��
Page 99 and 100: Chapter 5 Overview of Experimental
Page 101 and 102: 1. Substrate Preparation 2. Polymer
Page 103 and 104: Chapter 5 surface finish and aids i
Page 105 and 106: FIGURE 5.5 Small test fixture in th
Page 107 and 108: Chapter 5 The direct influence of t
Page 109 and 110: FIGURE 5.9 Large test fixture in th
Page 111 and 112: 5.4.1 Motor Power Supply All tests
Page 113 and 114: Chapter 5 or roughly (+/-) 25% of t
Page 115 and 116: Chapter 5 newly forming blade tip v
Page 117 and 118: FIGURE 5.14 Near-body grid geometry
Page 119 and 120: Chapter 6 Design Examples and Compa
Page 121 and 122: Chapter 6 capable of speeds up to 1
Page 123 and 124: FIGURE 6.2 The Astro Flight Firefly
Page 125 and 126: t/c 0.5 0.4 0.3 0.2 0.1 0.0 FIGURE
Page 127 and 128: c/R 0.0 0.2 0.4 0.6 0.8 1.0 r/R Cha
Page 129 and 130: FIGURE 6.10 Carbon-fiber two-blade
Page 131 and 132: Power Req. (W) 3.5 3.0 2.5 2.0 1.5
Page 133 and 134: Chapter 6 TABLE 6.1 Comparison of p
Page 135 and 136: Electro-mechanical Efficiency 0.20
Page 137 and 138: these variations and possible solut
Page 139 and 140: upper and lower surface corners of
Page 141 and 142: Chapter 6 The Sample-1 rotor exhibi
Page 143 and 144: The static deformations described i
Page 145 and 146: Q( r) This problem is solved as a l
Page 147: Structural Analyses Chapter 6 The m
Page 151 and 152: Thrust (g) 5 4 3 2 1 0 10000 20000
Page 153 and 154: Thrust (g) 4.5 4.0 3.5 3.0 2.5 2.0
Page 155 and 156: Torque per unit span (g cm) 0.75 0.
Page 157 and 158: Thrust per unit span (g) 3.5 3.0 2.
Page 159 and 160: V total / ωr 1.0 0.9 0.8 Classical
Page 161 and 162: Torque per unit span (g cm) 0.75 0.
Page 163 and 164: Chapter 6 Recall that this rotor wa
Page 165 and 166: Incidence (deg.) 30 25 20 15 10 5 0
Page 167 and 168: Thrust (g) 9 8 7 6 5 4 3 2 38000 40
Page 169 and 170: x/R 0.4 0.2 0.0 -0.2 Chapter 6 FIGU
Page 171 and 172: Cl 0.64 0.62 0.60 0.58 0.0 0.2 0.4
Page 173 and 174: C f 0.125 0.100 0.075 0.050 0.025 0
Page 175 and 176: Chapter 7 Micro-Rotorcraft Prototyp
Page 177 and 178: This vehicle does not currently inc
Page 179 and 180: FIGURE 7.2 The 65g prototype electr
Page 181 and 182: 7.4 The 150g Prototype Chapter 7 Th
Page 183 and 184: At hover, with a mass of 153g, the
Page 185 and 186: Using the 150g prototype as an exam
Page 187 and 188: Chapter 7 Basic rotor theory has be
Page 189 and 190: most of the blade. These values are
Page 191 and 192: Chapter 7 For large scale helicopte
Page 193 and 194: Chapter 8 Conclusions and Recommend
Page 195 and 196: the significant performance gains a
Page 197 and 198: Chapter 8 are also opportunities to
Page 199 and 200:
Chapter 8 formation flight, and man
Page 201 and 202:
References [1] Spedding, G.R., Liss
Page 203 and 204:
[28] Lamb, Sir Horace, Hydrodynamic
show all

Aerodynamics and Design for Ultra-Low Reynolds Number Flight

Create successful ePaper yourself

Delete template?

Save as template?