kangsan Posted February 4, 2010 Posted February 4, 2010 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 Quote
+FastCargo Posted February 4, 2010 Posted February 4, 2010 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 Quote
+Fubar512 Posted February 4, 2010 Posted February 4, 2010 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. Quote
frontmann Posted February 4, 2010 Posted February 4, 2010 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 Quote
+MigBuster Posted February 4, 2010 Posted February 4, 2010 I want to make Su-27 and varient more dull. Use Photoshop and stick a Volkswagon badge on it - that should cover it Quote
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