how to make aircraft more dull

[kangsan 0]

I want to make Su-27 and varient more dull.

I think Control Surfaces factor is key, and I try to change some factor like

 

CldcAlphaTableDeltaX=4.00

CldcAlphaTableStartX=-28.00

 

and

 

 

CndcAlphaTableDeltaX=4.00

CndcAlphaTableStartX=-28.00

 

but result is dissatisfy.

no one knows how to make aircraft more dull?

What factor is key to change aircraft's movement

[FastCargo 412]

The Flight Models are very complex and based on real world aerodynamics. It is not something easily explained.

 

As an example, something someone else posted and gets brought up every once in a while:

 

OK, here is a list of the various aerodynamic coefficients (the 3 or 4 letter variables

that start w/ the capital C) that are used in the flight model data files. I've also

listed a couple of other variables for the hell of it (Xac and DeltaStallAlpha), but

I'm going to limit this discussion primarily to the aerodynamic coefficients since this

is how the model generates all of the forces and moments on the airplane.

CL0 Lift coefficient at zero

angle of attack (AOA)

CLa Lift coefficient due to AOA

CD0 Zero-lift drag coefficient

CDL Drag coefficient due to lift

(induced drag effect)

Cmq Pitching moment due to pitch rate

(pitch damping)

Cmad Pitching moment due to AOA rate

(aero interaction between wings and horiz tail)

Cyb Side force due to sideslip

Cyp Side force due to roll rate

Cyr Side force due to yaw rate

Clb Roll moment due to sideslip

Clp Roll moment due to roll rate

(roll damping)

Clr Roll moment due to yaw rate

Cnb Yaw moment due to sideslip

Cnp Yaw moment due to roll rate

Cnr Yaw moment due to yaw rate

(yaw damping)

CLiftdc Lift due to control surface deflection

CDdc Drag due to control surface deflection

Cydc Side force due to control surface deflection

Cldc Roll moment due to control surface deflection

Cmdc Pitch moment due to control surface deflection

Cndc Yaw moment due to control surface deflection

DeltaStallAlpha Increase in max angle-of-attack before stall

Xac X-location of aerodynamic center

 

First thing to realize is that the coefficients are normalized by various dimensions of the

aircraft, so they don't represent the absolute value of the force or moment. So for example, for

Cnp, the actual yaw moment due to roll rate is found by mulitplying the coefficient by:

(Dynamic pressure * wing area * span^2) / (2*Velocity)

There is actually a very good reason for this, but I'm not going to go into it. The important

thing to understand is what force or moment is being generated by what.

 

Second thing to understand from a formatting standpoint, is that TK lists the coefficients first

by their 'base' values. Then he lists how the values will vary with either Mach # or angle-of-attack.

So for example, this is extracted from the data file for the F-4E in the section describing

the left outer wing (I've snipped out portions):

 

[LeftOuterWing]

.

.

.

CL0=0.0248

CLa=0.6532

CD0=0.0008

CDL=0.0037

Cmq=-0.2457

Cmad=-0.2229

Clb=0.0137

Clp=-0.0335

Clr=0.0296

Cnb=0.0424

Cnp=0.0011

Cnr=-0.0019

.

.

.

 

Shown above are the 'base' values that I described earlier. Following these are variation with Ma # and angle of attack

tables. Here's a typical table (for the F-4E left outer wing again):

 

.

.

.

CL0MachTableNumData=7

CL0MachTableDeltaX=0.40

CL0MachTableStartX=0.00

CL0MachTableData=0.976,1.000,1.087,1.212,0.858,0.692,0.577

.

.

.

 

The first row (CL0MachTableNumData) shows how many Ma # values the table varies over.

The second row indicates the delta in Ma # between data points.

The third row indicates the starting Ma # in the table.

The fourth row indicates the MULTIPLIER of the base CL0 value.

 

So for example at M=0 (starting takeoff for example), the multiplier of 0.976 is used with

the base value of 0.0248 (I'll let you multiply it out).

 

The same idea applies for the tables that vary with Alpha (angle-of-attack).

 

Finally, listed below is the right outer slat section for the F-4E and I'll go over these items

in detail (use the same basic idea for flaps, etc)

 

[RightOuterSlat]

SystemType=HIGHLIFT_DEVICE

CLiftdc=-0.0443

DeltaStallAlpha=6.00

AreaRatio=1.02

DeploymentMethod=AUTOMATIC_ANGLE_OF_ATTACK

Setting[1].Angle=30.0

Setting[1].DeployValue=13.8

Setting[1].RetractValue=8.7

MaxDeflection=30.0

MinDeflection=0.0

 

CLiftdc is the lift coefficient due to slat deployment (the value of -0.0443 seems questionable BTW).

DeltaStallAlpha is the change in maximum alpha before stall due to slat deployment (6 degrees in this case).

AreaRatio is the increase in wing area due to slat deployment.

DeploymentMethod indicates that the slats deploy automatically based upon the angle of attack.

Setting[1].Angle indicates that when deployed the slats are at 30 degree deflection.

Setting[1].DeployValue indicates that at 13.8 degrees the slats automatically deploy.

Setting[2].RetractValue indicates that at 8.7 degrees the slats automatically retract.

Max and min are self-explanatory

 

FC

[Fubar512 1,350]

Regarding the Su-27, I suggest you try Kreelin's flight model, as at the time it was compiled, it was the most accurate.

 

There's been a host of parameters added to the flight engine since that time (and the various lift and drag tables are now calculated to a higher degree of resolution). Though some of those parameters are automatically applied as "standards" to earlier models that initially lacked them, they are best individually calculated and tailored on an aircraft to aircraft basis. In simple terms, this means that the existing flight models need to be recompiled to SF2 standards.

[frontmann 2]

I had some success strumming MaxDeflection, MinDeflection, ControlRate .

You can reduce the sensitivity of the controls without really altering the "temper" of the plane... every time i can't get a bead on my target due to too sudden response (provided i already reduced the in-game joystick sensitivity) i usually try to mellow it out in this way.

Well, back up the original .Data file and then mess it up.

 

This is MiG-23 MLD.Data file, for example, under --- control surfaces-----

 

 

[LeftFlap]

SystemType=HIGHLIFT_DEVICE

CLiftdc=0.15

CDdc=0.0287

Cmdc=-0.0487

DeltaStallAlpha=-2.44

AreaRatio=1.08

DeploymentMethod=MANUAL_WITH_BLOWBACK

Setting[1].Angle=15.0

Setting[1].DeployValue=113.5

Setting[1].RetractValue=115.9

Setting[2].Angle=50.0

Setting[2].DeployValue=113.5

Setting[2].RetractValue=115.9

MaxDeflection=30.0 --------------------- Fiddle around these

MinDeflection=0.0 --------------------- three parameters, go

ControlRate=0.2 --------------------- in-game and check

ModelNodeName=LeftWingFlap

ReverseModelOrientation=TRUE

 

BACK UP YOUR original .data file!!!

 

Good bye and have fun!!

 

frontmann

[MigBuster 2,861]

I want to make Su-27 and varient more dull.

 

 

Use Photoshop and stick a Volkswagon badge on it - that should cover it

[Streakfalcon 57]

1.21 Gigawatts!