Cessna 620 -- Linear Model

Graduate Research done by Jeff Scott
Advisor: Prof. Michael Selig
Applied Aerodynamics Group
Department of Aeronautical and Astronautical Engineering
University of Illinois at Urbana-Champaign, Urbana, Illinois 61801

Last updated June 1, 2000

The linear aerodynamics model uses stability derivatives to approximate actual aircraft behavior. The Cessna 620 linear model is based on the following flight conditions (cruise):

Flight Conditions
Variable Variable
in Code 		Description Units Value(s) Source Notes
h Altitude altitude above sea level ft 18000 Roskam pg 515
Alpha angle of attack deg 0 Roskam pg 515
V V_true_kts velocity (true air speed) kts 217.2 Roskam pg 515 Mach 0.351
q Dynamic_pressure dynamic pressure lb/ft2 91.1 Roskam pg 515
C.G. - center of gravity location % 25 Roskam pg 515
CL CL lift coefficient - ? not available
CD CD drag coefficient - ? not available
Cm Cm pitching moment coefficient - ? not available

The data input into the simulator is listed in the following tables:

Geometry
Variable Variable
in Code 		Description Units Value(s) Source Notes
b bw wingspan ft 55.1 Roskam pg 515
cbar wing mean aerodynamic chord ft 6.58 Roskam pg 515
S Sw wing surface area ft2 340 Roskam pg 515

Control Surface Geometry
Variable Variable
in Code 		Description Units Value(s) Source Notes
emax demax maximum elevator deflection deg +20 - guess
emin demin minimum elevator deflection deg -20 - guess
amax damax maximum aileron deflection deg +20 - guess
amin damin minimum aileron deflection deg -20 - guess
rmax drmax maximum rudder deflection deg +20 - guess
rmin drmin minimum rudder deflection deg -20 - guess

Mass Data
Variable Variable
in Code 		Description Units Value(s) Source Notes
W Weight weight at flight condition lb 15000 Roskam pg 515 converted to Mass
[slug/ft3] in code
Ixx I_xx roll inertia slug ft2 64811 Roskam pg 515
Iyy I_yy pitch inertia slug ft2 17300 Roskam pg 515
Izz I_zz yaw inertia slug ft2 64543 Roskam pg 515
Ixz I_xz lateral cross inertia slug ft2 0 Roskam pg 515

Propulsion Data
Variable Variable
in Code 		Description Units Value(s) Source Notes
Tmax simpleSingleMaxThrust maximum thrust lb 1300 Roskam pg 516 estimated from CTx
at cruise

Aerodynamic Data
Variable Variable
in Code 		Description Units Value(s) Source Notes
CD0 CDo drag coefficient at =0 - 0.0322 Roskam pg 516
CD CD_a drag curve slope 1/rad 0.269 Roskam pg 516
CDe CD_de drag due to elevator 1/rad 0 Roskam pg 516 e positive down
CL0 CLo lift coefficient at =0 - 0.48 Roskam pg 516
CL CL_a lift curve slope 1/rad 5.55 Roskam pg 516
CL CL_adot lift due to angle of attack rate 1/rad 2.7 Roskam pg 516
CLq CL_q lift due to pitch rate 1/rad 7.5 Roskam pg 516
CLe CL_de lift due to elevator 1/rad 0.58 Roskam pg 516 e positive down
Cm0 Cmo pitch moment coefficient at =0 - 0.06 Roskam pg 516
Cm Cm_a pitch moment due to angle of attack 1/rad -1.18 Roskam pg 516
Cm Cm_adot pitch moment due to angle of attack rate 1/rad -8.17 Roskam pg 516
Cmq Cm_q pitch moment due to pitch rate 1/rad -22.4 Roskam pg 516
Cme Cm_de pitching moment due to elevator 1/rad -1.73 Roskam pg 516 e positive down
CY CY_beta side force fue to sideslip angle 1/rad -0.883 Roskam pg 517
CYp CY_p side force due to roll rate 1/rad -0.227 Roskam pg 517
CYr CY_r side force due to yaw rate 1/rad 0.448 Roskam pg 517
CYa CY_da side force due to aileron 1/rad 0 Roskam pg 517 a positive
right aileron up
CYr CY_dr side force due to rudder 1/rad 0.2 Roskam pg 517 r positive left
Cl Cl_beta dihedral effect 1/rad -0.1381 Roskam pg 517
Clp Cl_p roll damping 1/rad -0.566 Roskam pg 517
Clr Cl_r roll moment due to yaw rate 1/rad 0.1166 Roskam pg 517
Cla Cl_da roll moment due to aileron 1/rad -0.1776 Roskam pg 517 a positive
right aileron up
Clr Cl_dr roll moment due to rudder 1/rad 0.02 Roskam pg 517 r positive left
Cn Cn_beta weathercock stability 1/rad 0.1739 Roskam pg 517
Cnp Cn_p adverse yaw 1/rad -0.0501 Roskam pg 517
Cnr Cn_r yaw damping 1/rad -0.2 Roskam pg 517
Cna Cn_da yaw moment due to aileron 1/rad 0.0194 Roskam pg 517 a positive
right aileron up
Cnr Cn_dr yaw moment due to rudder 1/rad -0.1054 Roskam pg 517 r positive left

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