曝光臺 注意防騙 網曝天貓店富美金盛家居專營店坑蒙拐騙欺詐消費者

Ni Inertia lagging moment about real or virtual hinge
Nv, Np, etc. Yawing moment derivatives
N1, P1, Q1, R1, S1, T1 Relate to B1c, C1, D1, E1
N2, P2, Q2, R2, S2, T2 Relate to A2, B2, C2, D2, E2
n Offset hinge factor = (1 – e)3 (1 + e/3)
n Static load factor (‘g’)
n Frequency of oscillation (Theodorsen), frequency/Ω
(Miller)
n Laplace transform of n (static load factor)
nv, np, etc. Non-dimensional normalised yawing moment derivatives
etc. Non-dimensional yawing moment derivatives
P Power to drive blade, or rotor
Pi Induced power
Pi, Qi, Si, Ti, Ui, Vi Coefficients of periodic terms in expressions for lateral
hub force components
Pin Inertia force acting on chassis
Pi0 Induced power for constant induced velocity
Pp Profile drag power
Pt Tail rotor power
P0 Induced power for constant induced velocity
P1(ψ), P2(ψ) Periodic functions
p Pressure
p Roll angular velocity
p Laplace variable
p Chassis frequency, and aerofoil stall flutter frequency
Non-dimensional roll velocity = p/Ω
p(t), q(t) Forcing function components (Coleman)
pl, pu Pressure on lower and upper sides of disc plane, or aerofoil
surfaces
p1, p2 Pressure just ahead of actuator disc, and pressure in far
wake
p∞ Ambient pressure
nv′, np′
ˆp
Notation xix
Q Rotor torque
Volume flow through control volume sides, or flux
Q(x) Blade torsion mode shape
QP Torque due to rotor profile drag
Qi Induced rotor torque
Q1(x) First blade torsion mode shape
q Pitching velocity
q Local fluid velocity
q Induced velocity vector at a point on blade
ˆ q Non-dimensional pitching velocity = q/Ω
qc Torque coefficient = Q/ρsAΩ2R3
qr Radial velocity component
qz Local fluid velocity in axial direction
qψ Tangential velocity component
R Rotor radius
R Routh’s discriminant
R Reaction forces at hinge = R1e1 + R2e2 + R3e3
RD Radius of blade drag centre from hub
Reff Effective blade radius (Prandtl)
R0 Far wake radius
R1, R2 Control surface and far wake radii
r Distance of blade element from hinge or axis of rotation
r Radial wake coordinate
r Position vector = xi + y j + zk
Tip vortex radial coordinate (Landgrebe)
rg Position vector of blade or system c.g. = xgi + yg j + zgk
r1 Radial position of vortex filament on blade
S Centrifugal force of blade
S Shear force
S(x) Flap bending mode shape
SB Projected side area of fuselage
SFP Fuselage equivalent flat plate area
ST Tailplane area
S1(x) First flap bending mode shape
s Rotor solidity = bc/πR
s Half width of vortex sheet, equivalent to half wing span
s Vortex axis vector = s1i + s2 j + s3k
sp Spacing of vortex sheets
st Tail rotor solidity
Normalised tail rotor solidity = stAt (ΩR)t /sAΩR
T Rotor thrust
T Periodic time
T Kinetic energy
T Moment of resultant external forces about O
Q
r
st
xx Notation
T Rotor/fuselage transfer matrix (active vibration control)
T(x) Lag bending mode shape
T1(x) First lag bending mode shape
TD Thrust referred to disc axes
Td Time to double amplitude
Tf Following time (inversely proportional to viscous damping)
– (Bell bar)
Th Time to half amplitude
Tt Tail rotor thrust
T0 Thrust for constant vi
t Time
Time non-dimensionalising factor = W/gρsAΩR
tc Thrust coefficient based on total blade area =T/ρsAΩ2R2
tcD Thrust coefficient referred to disc axes
U Velocity of wake normal to axis
U Strain energy
U, V, W Initial flight velocity components along x, y, z axes
UB Strain energy due to bending
UG Strain energy due to centrifugal tension
UP Component of air velocity relative to blade element
perpendicular to plane of no-feathering
UT Component of air velocity relative to blade element
tangential to plane of no-feathering
U0, U1, U2 Coefficients used in longitudinal response solution
u, v, w Perturbational velocities
u, v Coleman coordinates
u′, v′ Wake velocity components
Laplace transforms of u, v, w (perturbational velocities)
Non-dimensional perturbational velocities = u/ΩR, v/ΩR,
w/ΩR
uFn, vFn Unit force constants relating to nth blade element
(Myklestad)
uMn, vMn Unit moment constants relating to nth blade element
(Myklestad)
V Forward velocity of helicopter or relative velocity far
upstream of rotor
V Forward velocity vector of helicopter
　
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本文鏈接地址：Bramwell’s Helicopter Dynamics(6)