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[4S_Vega]

If you want to do it ok, but please take care of takeoff behaviour after your modifications.

Expecially AI takeoff with heavy loadout.

If you do a nice landing result you should do also a very bad takeoff.

Ah, and first of all start from last FM.

Maybe a Java code is needed.

[Koty]

something is really wrong with this FM...

the landing is very... shaky?

The main problem with AI is that it cannot pitch up soon enough.

[4S_Vega]

As i tell you, Java code is needed

[Koty]

ok, I figured out the things with FM, more or less

what is needed now is effectivness of elevator on ground. I'll try a few things.

[Koty]

now that I am looking at it...

Code: [Select]

[Mass]
  Empty 13396
  TakeOff 19153
  Oil 20.81
  Fuel 5737.2
It's take off weight is listed as just a fueled up plane, no wonder it does not want to take off... Meanwhile the manual lists performance for up to 30 tons... Still cannot take off with some of the load outs without reducing fuel to 70%. But that will be fixed by just changing the T-O mass even more, I am confident.

I will post a fixed FM tomorrow, when I carry over the changes to other models of the plane.

[4S_Vega]

It not depends from that...

[Koty]

I managed to make the AI to lift the nosewheel at the same time as it is possible for player

however

It then begins to constantly pitch the nose lower and lower, until it reaches the speed at which the gear breaks.



So I played around with the FM... now it is fully fixed. It feels nice, it feels like an F-4 and there are no bugs. The takeoff for AI looks strange, but hey, at least it takes off. For a heavy-weight takeoff, if you want it to look nice - cinematic, just set 80% fuel. Beware, it will take you some time to learn to fly it. Also, at high AOA, use rudder for rolling, or wild things will happen. Link to file will follow in about an hour.



EDIT:
and here it is
https://www.mediafire.com/file/3lxb0d1d5o5uast/F4E

[4S_Vega]

Can you post changed strings.

You work only on takeoff/landings I hope.

[Koty]

There is a bit more changes:

1) elevator arm/surface
2) CG position
3) [Params]
4) engine is now angled 5° down as per real plane
5) and then polars, the CL curve has been straightened a bit (only the linear part - climbrates and ceilings should stay unchanged). Then I played a bit with the CL for flaps - the curve was all over the place.


Here F-4E as an example, rest follows the suit.

Code: [Select]

[Aircraft]
  Type 2
  Crew 2
  Wingspan 11.77
  WingspanFolded 9.0
  Length 19.2
  Seaplane 0
  Canard 0
  Jet 1
  JetHiV 1
[Mass]
  Empty 13396
  TakeOff 30000//19153
  Oil 20.81
  Fuel 5737.2
[Controls]
  CAileron 1
  CAileronTrim 1
  CElevator 1
  CElevatorTrim 1
  CRudder 1
  CRudderTrim 1
  CFlap 1
  CFlapPos 3
  CFlapBlown 1
  CDiveBrake 1
  CInterceptor 0
  CEngine 1
  CVectoredThrust 0
  CUndercarriage 1
  CLockTailwheel 0
  CStabilizer 1
  CArrestorHook 1
  CWingFold 1
  WingPeriod 6.0
  CCockpitDoor 2
  CockpitDoorPeriod 2.5
  CRefuel 1
  CAileronThreshold 700.0
  CRudderThreshold 700.0
  CElevatorThreshold 840.0
  DefaultAileronTrim 0.000
  DefaultElevatorTrim 0.000
  DefaultRudderTrim 0.000
[Squares]
  Wing 49.24
  Aileron 2.42
  Flap 2.80
  Stabilizer 0.01//3.20
  Elevator 7//6.075//4.0
  Keel 6.1
  Rudder 0.7
  Wing_In 5.32
  Wing_Mid 12.1
  Wing_Out 7.2
  FuselageCxS 0.001
  AirbrakeCxS 0.06
[Arm]
  Aileron 3.5
  Flap 1.6
  Stabilizer 4.3
  Keel 4.5
  Elevator 7.2//4.8
  Rudder 4.9
  Wing_In 1.1
  Wing_Mid 1.7
  Wing_Out 3.0
  Wing_V 1.5
  GCenter  -0.2//0.0
  GCenterZ 0.2//0.00
  GC_AOA_Shift -0.3
  GC_Flaps_Shift 0.0
  GC_Gear_Shift  0.0
[Toughness]
  AroneL 150
  AroneR 150
  CF 500
  Engine1 200
  Engine2 200
  GearL2 1600
  GearR2 1600
  Keel1 700
  Nose 700
  Oil 100
  Rudder1 200
  Rudder2 200
  StabL 250
  StabR 250
  Tail1 250
  VatorL 200
  VatorR 200
  WingLIn 250
  WingLMid 250
  WingLOut 250
  WingRIn 250
  WingRMid 200
  WingROut 150
  Flap01 250
  Flap02 250
[Engine]
  Engine0Family Jets:F4E
  Engine0SubModel J79GE17
  Engine1Family Jets:F4E
  Engine1SubModel J79GE17
  Position0x 0.0
  Position0y 0.5
  Position0z 0.0
  PropPosition0x 0.0
  PropPosition0y 0.5
  PropPosition0z 0.0
  Vector0x 0.99619469809//1.0
  Vector0y 0.0
  Vector0z 0.08715574274//0.0
  Position1x 0.0
  Position1y -0.5
  Position1z 0.0
  PropPosition1x 0.0
  PropPosition1y -0.5
  PropPosition1z 0.0
  Vector1x 0.99619469809//1.0
  Vector1y 0.0
  Vector1z 0.08715574274//0.0
[Gear]
  H 1.614541
  Pitch -10//11.842
  SinkFactor 200.0
  SpringsStiffness 0.7
  TailStiffness 0.4
[Params]
  CriticalAOA 25.00
  CriticalCy 1.1//00.7
  CxCurvature 1.0
  CxStraightness 00.08
  CriticalAOAFlap 20//22.00
  CriticalCyFlap 1.35//00.93
  SpinTailAlpha 10.00
  SpinCxLoss 0.10
  SpinCyLoss 0.05
  Vmin 280
  Voptimal 900
  Vmax 1400.0
  VmaxAllowed 2500.0
  VmaxH 2550.0
  HofVmax 12190.0
  VminFLAPS 220.0
  VmaxFLAPS 700.0
  Vz_climb 210//150.96134
  V_climb 718.00494
  T_turn 23.715391
  V_turn 618.00494
  K_max 13.0
  Cy0_max 0//0.15
  FlapsMult 0.5//2.0
  FlapsAngSh -5//6.0
  Range 4180.0
  CruiseSpeed 600.0
  G_class_coeff 20.0
  G_class 14.0
  SensYaw 0.2
  SensPitch 0.75//0.3
  SensRoll 0.27
[Polares]
  lineCyCoeff 0.062//0.078
  AOAMinCx_Shift 1.0
  Cy0_0 0.011
  AOACritH_0 25.0
  AOACritL_0 -18.0
  CyCritH_0 1.1
  CyCritL_0 -0.75
  CyBFlap  0.04
  ThrustBFlap 400
  CxMin_0 0.021
  parabCxCoeff_0 21.5E-4
  Cy0_1 0.44//0.55
  AOACritH_1 20.0
  AOACritL_1 18.0
  CyCritH_1 1.35
  CyCritL_1 -0.5//-0.7
  CxMin_1 0.028
  parabCxCoeff_1 9.0E-4
  parabAngle 6.0
  Decline 0.004
  maxDistAng 40.0
  draw_graphs 0
[SOUND]
  Engine he_162
  Prop none
  Start j47_start
[Supersonic]
  VminMach 0.92
  VsoundMach1 0.98
  CfsoundMach1 1.36
  VsoundMach2 1.25
  CfsoundMach2 1.36
  VmaxMach 1.3
  CfmaxMach 1.35

[Koty]

Now, what would definitely help the F-4 with take offs is a complete remodelling.

The front gear leg would be extended for takeoff and this alone would provide the plane with a lot of lift, necessary for heavy-weight take-offs.

[4S_Vega]

first of all modify the parameter "lineCyCoeff 0.062//0.078 " has no influence on the FM, because now in all jets is regulated by Java.

Don't know which effor it give to you, because there is not effort, the parameter lineCyCoeff in JAVA code called "computeLift" is fix till mach 0.9, and then decrease.

Again, "GCenter  -0.2//0.0  GCenterZ 0.2//0.00"

Pls don't touch overall FM parameters to fix Landing/takeoff, because in this way you changed also turn performances, that where already good.

You have these to modify takeoff & landings

GC_Flaps_Shift 0.0
GC_Gear_Shift  0.0

But strangely you don't touch them.

In the F-4 there is a big difference between empty weight and max takeoff weight, and it give problems in flaps lift balancing.

If you give proper lift for takeoff at full weight, you will have too much lift when Landing, and vice versa, if you reduce lift when Landing, you will risk to destroy gear during takeoff run.

It needs a small Java code to fix it, to give different lift between takeoff & landings.

I will do soon, and don't needs FM file changes.

[Koty]

Again, "GCenter  -0.2//0.0  GCenterZ 0.2//0.00"

You are fixing what's not broken. That value is correct. It is supposed to be negative.


if lineCyCoeff is overriden anyways, then there is no change to the turning performance, apart from flaps. Not to mention that 0.07 is highly unrealistic value.

As for which, I had to fix the values, as they were causing bug (critical Cy on the wrong side of the linear part).