Where are the sizes of surface areas defined in the FM entries?

[Do335]

I'm wondering about how the data ini entries work. The FM data defines lift/drag coefficients, however I can't seem to find where the surface area sizes are defined. Obviously the size of surface area is needed to compute a lift force, from its lift CL.
 
For example, here is the data section for the F-4 phantom's leftouterwing:
 

[LeftOuterWing]
ParentComponentName=LeftWing
ModelNodeName=wing_left_outer
DestroyedNodeName=DAM_wing_left_outer
ShowFromCockpit=TRUE
DetachWhenDestroyed=TRUE
DamageRating=DISABLED
MassFraction=0.024
HasAeroCoefficients=TRUE
LiftSurface=TRUE
CL0=0.0123
CLa=0.6424
CD0=0.0007
CDL=0.0028
Cmq=-0.7695
Cmad=-0.1863
Clb=-0.0091
Clp=-0.0643
Clr=0.0025
Cnp=-0.0032
Cnr=-0.0041
CL0MachTableNumData=23
CL0MachTableDeltaX=0.10
CL0MachTableStartX=0.00
CL0MachTableData=0.958,0.960,0.968,0.981,1.000,1.026,1.060,1.105,1.162,1.162,1.585,1.329,1.101,0.918,0.789,0.699,0.653,0.594,0.533,0.483,0.445,0.407,0.370
CLaMachTableNumData=23
CLaMachTableDeltaX=0.10
CLaMachTableStartX=0.00
CLaMachTableData=0.958,0.960,0.968,0.981,1.000,1.026,1.060,1.105,1.162,1.162,1.585,1.329,1.101,0.918,0.789,0.699,0.653,0.594,0.533,0.483,0.445,0.407,0.370
CD0MachTableNumData=23
CD0MachTableDeltaX=0.10
CD0MachTableStartX=0.00
CD0MachTableData=2.097,1.223,1.096,1.018,1.000,0.988,0.981,1.001,1.015,1.208,1.215,1.451,1.513,1.495,1.476,1.523,1.571,1.546,1.515,1.463,1.419,1.379,1.343
CDLAlphaTableNumData=15
CDLAlphaTableDeltaX=4.00
CDLAlphaTableStartX=-28.00
CDLAlphaTableData=29.160,21.160,14.440,9.000,4.840,1.960,0.360,0.040,1.000,3.240,6.760,11.560,17.640,25.000,33.640
CmqMachTableNumData=23
CmqMachTableDeltaX=0.10
CmqMachTableStartX=0.00
CmqMachTableData=0.879,0.885,0.906,0.943,1,1.085,1.214,1.426,1.826,1.826,18.842,4.021,5.669,6.594,5.259,3.983,2.172,0.693,0.556,0.494,0.454,0.446,0.47
ClbAlphaTableNumData=37
ClbAlphaTableDeltaX=10.00
ClbAlphaTableStartX=-180.00
ClbAlphaTableData=-0.063,-0.065,-0.07,-0.079,-0.089,-0.1,-0.11,-0.119,-0.124,0.937,1.97,1.883,1.75,1.587,1.413,1.25,1.117,1.03,1,0.477,1.267,0.52,-0.088,2.387,2.35,2.283,2.17,1.874,-0.187,-0.15,-0.11,-0.1,-0.089,-0.079,-0.07,-0.065,-0.063
CnrAlphaTableNumData=37
CnrAlphaTableDeltaX=10.00
CnrAlphaTableStartX=-180.00
CnrAlphaTableData=0.000,0.004,0.015,0.034,0.060,0.094,0.134,0.181,0.234,0.293,0.357,0.426,0.500,0.577,0.658,0.741,0.826,0.913,1.000,0.913,0.826,0.741,0.658,0.577,0.500,0.426,0.357,0.293,0.234,0.181,0.134,0.094,0.060,0.034,0.015,0.004,0.000
XacMachTableNumData=23
XacMachTableDeltaX=0.10
XacMachTableStartX=0.00
XacMachTableData=-1.217,-1.219,-1.225,-1.236,-1.251,-1.271,-1.297,-1.33,-1.375,-1.375,-1.071,-1.257,-1.407,-1.531,-1.563,-1.633,-1.645,-1.639,-1.663,-1.675,-1.672,-1.682,-1.706
CheckStall=TRUE
CLmax=0.1819
AlphaStall=13.50
AlphaMax=24.39
AlphaDepart=35.21
StallMoment=-0.002
StallDrag=0.001
StallLiftTableNumData=37
StallLiftTableDeltaX=10.00
StallLiftTableStartX=-180.00
StallLiftTableData=0.000,-0.013,-0.028,-0.045,-0.062,-0.058,-0.050,-0.034,-0.014,0.000,0.018,0.053,0.100,0.149,0.215,0.261,0.362,0.565,0.961,0.624,0.386,0.282,0.224,0.178,0.126,0.079,0.040,0.000,-0.014,-0.034,-0.050,-0.058,-0.062,-0.045,-0.028,-0.013,0.000
StallDragTableNumData=37
StallDragTableDeltaX=10.00
StallDragTableStartX=-180.00
StallDragTableData=0.001,0.008,0.021,0.043,0.082,0.123,0.171,0.227,0.292,0.367,0.451,0.562,0.689,0.825,0.937,1.018,1.142,1.122,1.000,1.122,1.142,1.018,0.937,0.825,0.689,0.562,0.451,0.367,0.292,0.227,0.171,0.123,0.082,0.043,0.021,0.008,0.001
StallXacShiftTableNumData=37
StallXacShiftTableDeltaX=10.00
StallXacShiftTableStartX=-180.00
StallXacShiftTableData=-0.304,-0.304,-0.259,-0.233,-0.231,-0.222,-0.206,-0.190,-0.168,-0.152,-0.136,-0.114,-0.097,-0.082,-0.073,-0.070,-0.044,0.000,0.000,0.000,-0.044,-0.070,-0.073,-0.082,-0.097,-0.114,-0.136,-0.152,-0.168,-0.190,-0.206,-0.222,-0.231,-0.233,-0.259,-0.304,-0.304
Chord=2.32
Ymac=-4.83
StructuralFactor=1.2
MinExtentPosition=  -5.88,-2.83,-0.68
MaxExtentPosition=  -4.04,-0.19,-0.44
CollisionPoint[001]=-5.88,-1.69,-0.37
CollisionPoint[002]=-5.88,-3.02,-0.37
HasVortexEmitter=TRUE
VortexEmitterName=WingtipVortexEmitter
VortexPosition=-5.84,-1.75,-0.34
VortexG=2.5
SystemName[001]=LeftPositionLight
SystemName[002]=LeftLEFlap
SystemName[003]=LeftOuterSlat 

But... how large is leftouterwing? 2 square meters or 200 square meters... can't seem to know looking at this. Appreciate it if FM gurus can shed some light.
 

Edited August 13, 2014 by Do335

[+acesfakia]

....and also ....how do you find to write all this....number's........

Ok i know that we must write the ini .....but in the export.......ini ....is nothing........inside,,,,...

[Fubar512]

All you're looking there are tables and values that are in part derived from the surface area, the leading edge wing-sweep angle, and the mean-area chord of that specific surface.  The wing area is stated in total under the aircraft data header, as the "reference area".  Each surface is then assigned a fraction of that total value.  In the case of the F-4, let's say that it's 30% of the total for each inner wing, and 20% of the total for each outer wing.

[Do335]

OK... thanks fubar.

[stephenmcparlin]

OK, as an aircraft designer and performance engineer: The reference area for an aircraft will conventionally be given as the Gross Wing Area (it's extrapolated to the symmetry plane). The best open source for these will be Janes' All the World's Aircraft, which is now part of IHS. Standard reference lengths for moments will be mean aerodynamic chord (*not* geometric mean chord) for pitching moment coefficients, and span (not semi-span) for both rolling and yawing moment coefficients.

The conventional way to estimate stability derivatives is to make use of the USAF Stability and Control DATCOM. The digital version is ITAR-controlled and under the care of Bill Blake at AFRL, but the paper version (not updated since 1978) is available through engineering document suppliers. You will note that DATCOM actually source most of these methods from what used to be the Royal Aeronautical Society data sheets, which are now commercially available (at some cost) from IHS ESDU.

*if* you're appropriately qualified, and have computing power available, you can actually calculate/estimate aerodynamic stability and control characteristics to first order using a vortex lattice method or similar. For unswept wings, things like XFLR5 will give you a decent summary of the basic wing characteristics. It's something I'd set undergraduate aerospace engineers to do.

 

Drag estimation is a little trickier. I have a handout I give to my students to allow them to build spreadsheet level performance models of zero-lift and lift-dependent drag for transport aircraft, but it's not really up to doing the more complex stuff you need for separated flow drag estimates on military aircraft, or the transonic/supersonic drag breakdowns you might want to consider. The Harris wave drag program that can be obtained online is a NASA version of a Boeing implementation of an RAE method from the early 1960s (Eminton's method, see ARC R&M 3221). It's reasonably accurate for slender configurations, but is crying out for a proper implementation in C or MATLAB. I'd suggest starting from the UK reports (available online through Cranfield University) rather than try to unravel the Spaghetti Fortran IV of the NASA implementation.

[Do335]

Fubar i think i finally understood what you said

 

http://bbs.thirdwire.com/phpBB3w/viewtopic.php?p=25313#p25313

All coefficients listed in the aircraft data file should use the same reference area and distance regardless of which part...and that set of reference geometry should be listed at near the top of the aircraft data file.

when you have eliminated the impossible, whatever remains, however improbable, must be the truth. my FM needs an overhaul...