Cessna 620 -- Linear Model
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):
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| 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:
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| Variable |
Variable in Code |
Description | Units | Value(s) | Source | Notes |
|---|---|---|---|---|---|---|
| b | bw | wingspan | ft | 55.1 | Roskam pg 515 | |
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cbar | wing mean aerodynamic chord | ft | 6.58 | Roskam pg 515 | |
| S | Sw | wing surface area | ft2 | 340 | Roskam pg 515 | |
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| Variable |
Variable in Code |
Description | Units | Value(s) | Source | Notes |
|---|---|---|---|---|---|---|
 emax
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demax | maximum elevator deflection | deg | +20 | - | guess |
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emin
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demin | minimum elevator deflection | deg | -20 | - | guess |
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amax
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damax | maximum aileron deflection | deg | +20 | - | guess |
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amin
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damin | minimum aileron deflection | deg | -20 | - | guess |
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rmax
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drmax | maximum rudder deflection | deg | +20 | - | guess |
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rmin
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drmin | minimum rudder deflection | deg | -20 | - | guess |
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| 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 | |
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| Variable |
Variable in Code |
Description | Units | Value(s) | Source | Notes |
|---|---|---|---|---|---|---|
| Tmax | simpleSingleMaxThrust | maximum thrust | lb | 1300 | Roskam pg 516 |
estimated from CTx at cruise |
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| Variable |
Variable in Code |
Description | Units | Value(s) | Source | Notes |
|---|---|---|---|---|---|---|
| CD0 | CDo |
drag coefficient at =0
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- | 0.0322 | Roskam pg 516 | |
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CD
|
CD_a | drag curve slope | 1/rad | 0.269 | Roskam pg 516 | |
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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 | |
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CLe
|
CL_de | lift due to elevator | 1/rad | 0.58 | Roskam pg 516 |
e positive down
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| Cm0 | Cmo |
pitch moment coefficient at =0
|
- | 0.06 | Roskam pg 516 | |
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Cm
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Cm_a | pitch moment due to angle of attack | 1/rad | -1.18 | Roskam pg 516 | |
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Cm
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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 | |
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Cme
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Cm_de | pitching moment due to elevator | 1/rad | -1.73 | Roskam pg 516 |
e positive down
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CY
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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 | |
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CYa
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CY_da | side force due to aileron | 1/rad | 0 | Roskam pg 517 |
a positive right aileron up |
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CYr
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CY_dr | side force due to rudder | 1/rad | 0.2 | Roskam pg 517 |
r positive left
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Cl
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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 | |
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Cla
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Cl_da | roll moment due to aileron | 1/rad | -0.1776 | Roskam pg 517 |
a positive right aileron up |
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Clr
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Cl_dr | roll moment due to rudder | 1/rad | 0.02 | Roskam pg 517 |
r positive left
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Cn
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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 | |
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Cna
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Cn_da | yaw moment due to aileron | 1/rad | 0.0194 | Roskam pg 517 |
a positive right aileron up |
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Cnr
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Cn_dr | yaw moment due to rudder | 1/rad | -0.1054 | Roskam pg 517 |
r positive left
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