Basic Helicopter Aerodynamics, 3rd Edition

Notation

General

a	lift curve slope dCL/dα
a0	first term in Fourier expansion of β
a1	coefficient of second term in Fourier expansion of β
a2	coefficient of fourth term in Fourier expansion of β
A	area of rotor disc
Ab	total blade area (N blades)
A1	coefficient of second term in Fourier expansion of β
A2	coefficient of fourth term in Fourier expansion of β
Ap	projected frontal area of rotor head (Chapter 6)
As	flow spoiling factor (Chapter 6)
Az	boundary layer shielding factor (Chapter 6)
b1	coefficient of third term in Fourier expansion of β
b2	coefficient of fifth term in Fourier expansion of β
B	tip loss factor in r = BR
B1	coefficient of third term in Fourier expansion of β
B2	coefficient of fifth term in Fourier expansion of β
c	blade chord
CD	drag coefficient
CL	lift coefficient
CH	H-force coefficient
CP	power coefficient
CQ	torque coefficient
CT	thrust coefficient
d	differential operator
D	aerodynamic drag
e	hinge offset ratio
f	equivalent flat-plate area
H	H-force
I	moment of inertia
k	empirical constant in expression for profile power
K	empirical constant in Glauert expression for induced velocity
l	moment arm of tail rotor thrust about main shaft
L	aerodynamic lift
m	blade mass per unit span
M	figure of merit
M	Mach number
M	moment (Figures 8.4 and 8.5)
MT	aerodynamic moment about flapping axis
n	inertia number (Chapter 8)
N	number of blades
p	static pressure
P	power
q	dynamic pressure, ...