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146 Referred Parameter Turboshaft Engine Model P/P 0 P/P 0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 1.8 1.6 1.4 1.2 1.0 0.8 0.6 temperature ratio θ MPC IRP MRP CRP Figure 18-7. Power variation with temperature ratio, static. 0.4 0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 temperature ratio θ MPC IRP MRP CRP Figure 18-8. Power variation with temperature ratio, 200 knots.
Chapter 19 AFDD Weight Models This chapter presents the rotorcraft weight models developed by the U.S. Army Aeroflightdynamics Directorate (AFDD). For some weight groups several models are available, designated AFDDnn. The weights are estimated from parametric equations, based on the weights of existing turbine-powered helicopters and tiltrotors. The figures of this chapter compare the weights calculated from these equations with the actual weights. The results of these equations are the weight in pounds, and the units of the parameters are noted in the tables. Technology factors χ are included in the weight equations. Typically the input includes a weight increment that can be added to the results of the weight model. Weights of individual elements in a group can be fixed by setting the corresponding technology factor to zero, hence using only the input increment. The weight models are implemented as part of the aircraft components. The weights are entered into the weight statement data structure (extended RP8A format) for each component, reflected in the organization of this chapter. 19–1 Wing Group The wing group consists of: basic structure (primary structure, consisting of torque box and spars, plus extensions); fairings (leading edge and trailing edge); fittings (non-structural); fold/tilt structure; and control surfaces (flaps, ailerons, flaperons, and spoilers). There are separate models for a tiltrotor or tiltwing configuration and for other configurations (including compound helicopter). 19-1.1 Tiltrotor or Tiltwing Wing Wing weight equations for a tiltrotor or tiltwing aircraft are based on methodology developed by Chappell and Peyran (refs. 1 and 2). The wing is sized primarily to meet torsional stiffness requirements. The primary structure weight is calculated from torque box and spar weights: Wbox = Atbρtbbw/etb Wspar = CtAspρspbw/esp wprim =(Wbox + Wspar)funits Wprim = χprimwprim A consistent mass-length-time system is used in the equations for Wbox and Wspar, which therefore have units of slug or kilogram. The primary structure weight Wprim however has units of pound or kilogram, hence a conversion factor funits = g is required for English units. The wing fairing (leading edge and trailing edge), control surface (flaps, ailerons, flaperons, and spoilers), fittings (non-structural), and
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NASA/TP-2009-215402 NDARC NASA Desi
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NASA/TP-2009-215402 NDARC NASA Desi
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TABLE OF CONTENTS CHAPTER 1 - INTRO
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TABLE OF CONTENTS (cont.) CHAPTER 1
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viii LIST OF FIGURES (cont.) Figure
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Chapter 1 Introduction The NASA Des
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Introduction 3 of rotorcraft config
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Introduction 5 previous case DESIGN
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Introduction 7 4) Scully, M.; and F
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Chapter 2 Nomenclature The nomencla
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Nomenclature 11 Fuel Tanks Power Na
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Nomenclature 13 Motion aF AC aircra
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Chapter 3 Tasks The NDARC code perf
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Tasks 17 engine group is found (inc
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Tasks 19 3-4 Maps 3-4.1 Engine Perf
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Chapter 4 Operation 4-1 Flight Cond
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Operation 23 e) Input payload weigh
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Operation 25 Table 4-1. Mission seg
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Operation 27 horizontal ground dist
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Operation 29 climb for zero power m
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Operation 31 a) Horizontal velocity
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Operation 33 From the pressure p =
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Chapter 5 Solution Procedures The N
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Solution Procedures 37 Sizing Task
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Solution Procedures 39 relaxation i
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Solution Procedures 41 Table 5-4. T
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Solution Procedures 43 successive s
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Solution Procedures 45 initialize e
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Chapter 6 Cost Costs are estimated
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Cost 49 Table 6-1. DoD and CPI infl
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Cost 51 predicted base price (1994$
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Chapter 7 Aircraft The aircraft con
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Aircraft 55 The tilt control variab
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Aircraft 57 forward axes for descri
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Aircraft 59 For steady-state flight
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Aircraft 61 where Δz F = z F − z
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Aircraft 63 disk area); or the drag
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Aircraft 65 7-10 Performance Indice
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Aircraft 67 WEIGHT EMPTY STRUCTURE
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Chapter 8 Systems The systems compo
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Chapter 9 Fuselage There is one fus
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Fuselage 73 αe = αfus − αzl, w
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Chapter 10 Landing Gear There is on
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Chapter 11 Rotor The aircraft can h
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Rotor 79 propulsion group. The driv
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Rotor 81 plane command. The collect
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Rotor 83 or just CSF = WCHF with no
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Rotor 85 If μ is zero, the equatio
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Rotor 87 The velocity ratio is fW =
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Rotor 89 T/T ∞ 1.3 1.2 1.1 1.0 Ha
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Rotor 91 TPP tilt / cyclic magnitud
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Rotor 93 with an average over the r
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Page 109 and 110: Rotor 97 κ 1.30 1.25 1.20 1.15 1.1
Page 111 and 112: Rotor 99 (C T /σ) s c d mean 0.20
Page 113 and 114: Rotor 101 11-5.1.3 Twin Rotors For
Page 115 and 116: Rotor 103 The wake is a skewed cyli
Page 117 and 118: Rotor 105 weight per lifting rotor;
Page 119 and 120: Chapter 12 Force The force componen
Page 121 and 122: Chapter 13 Wing The aircraft can ha
Page 123 and 124: Wing 111 denotes outboard edge, sub
Page 125 and 126: Wing 113 13-3.1 Lift The wing lift
Page 127 and 128: Wing 115 The wing interference at t
Page 129 and 130: Chapter 14 Empennage The aircraft c
Page 131 and 132: Empennage 119 14-4 Weights The tail
Page 133 and 134: Chapter 15 Fuel Tank 15-1 Fuel Capa
Page 135 and 136: Fuel Tank 123 if Wfuel >Wfuel−max
Page 137 and 138: Chapter 16 Propulsion The propulsio
Page 139 and 140: Propulsion 127 If the sum of the fi
Page 141 and 142: Chapter 17 Engine Group The engine
Page 143 and 144: Engine Group 131 The engine group p
Page 145 and 146: Engine Group 133 specific fuel cons
Page 147 and 148: Chapter 18 Referred Parameter Turbo
Page 149 and 150: Referred Parameter Turboshaft Engin
Page 157: Referred Parameter Turboshaft Engin
Page 161 and 162: AFDD Weight Models 149 The spar-cap
Page 163 and 164: AFDD Weight Models 151 19-1.2 Aircr
Page 165 and 166: AFDD Weight Models 153 where w = nz
Page 167 and 168: AFDD Weight Models 155 units as use
Page 169 and 170: AFDD Weight Models 157 Table 19-9.
Page 171 and 172: AFDD Weight Models 159 where fP = f
Page 173 and 174: AFDD Weight Models 161 The conversi
Page 175 and 176: AFDD Weight Models 163 19-12 Foldin
Page 177 and 178: AFDD Weight Models 165 error (%) er
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