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Jug

F-5 "cocked" takeoff

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The F-5E stick actually has a paddle that the pilot pulls when he is lined up with the runway that extends the nose gear oleo strut some 5 inches. This "cocks" the aircraft to the proper angle of attack for takeoff. From the outside it gives the aircraft a "raked" look and appears similar to what I have seen in pictures of the RN F-4K/M series look like on the catapult ready for launch. I have played around with the following in the F-5E_Data.ini file and have not had much success other than losing the front tire into the runway. Can anyone help me?

 

[AircraftData]

EmptyMass=4410.0

EmptyInertia=43106.59,3770.14,46876.72

ReferenceArea=17.30

ReferenceSpan=8.13

ReferenceLength=14.45

CGPosition=0.00,-0.75,0.00

OnGroundPitchAngle=3.0 <-------- Added this

.........

 

 

[NoseGear]

SystemType=LANDING_GEAR

Retractable=TRUE

DeployTime=5.0

AnimationID=1

DragArea=0.25

HideGearNode=TRUE

ModelNodeName=FrontStruct

InsideNodeName=

ShockNodeName=Frontdump

ShockAnimationID=5 <--------Changed to FGRMk2 (F-4M) shock animation

ShockStroke=0.4 <--------Changed to FGRMk2 (F-4M) shock stroke

//ShockAnimationID=2

//ShockStroke=0.25

........

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OnGroundPitchAngle=3.0 <-------- Added this

 

ShockAnimationID=5 <--------Changed to FGRMk2 (F-4M) shock animation

ShockStroke=0.4 <--------Changed to FGRMk2 (F-4M) shock stroke

//ShockAnimationID=2

//ShockStroke=0.25

........

For the OnGroundPitchAngle, i am not sure if this affect something.

Changing the ShockAnimation, doesn´t affect anything, except you see the Animation, when the gear is compressed, with the frame number 5.

I am not sure, what the F-5E has on that animation, let´s say the airbrakes. Now when you land and the gear is compressed, you see the airbrakes

come out 40 cm. (ShockStroke=0.4 means the gear shock length is 40 cm)

Remember, all items, with Animation=X in the data.ini are modeled AND animated in 3ds MAX and are part of the LOD file.

I know, it´s no answer on how to do, but how not to do. :biggrin:

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For the OnGroundPitchAngle, i am not sure if this affect something.

Changing the ShockAnimation, doesn´t affect anything, except you see the Animation, when the gear is compressed, with the frame number 5.

I am not sure, what the F-5E has on that animation, let´s say the airbrakes. Now when you land and the gear is compressed, you see the airbrakes

come out 40 cm. (ShockStroke=0.4 means the gear shock length is 40 cm)

Remember, all items, with Animation=X in the data.ini are modeled AND animated in 3ds MAX and are part of the LOD file.

I know, it´s no answer on how to do, but how not to do. :biggrin:

 

Thanks AmokFloo. I am a beginner at modding the INI files and I know I am nit-picking about the F-5E looking right for takeoff, but she is so cool when she is "cocked and locked". I now know what not to do. Anybody else have any ideas?

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Guest capun

I I remember correctly, OnGroundPitchAngle is used for planes like tail dragger and for planes that normally will sit with the nose up (and down?) due to the nose gear lenght. It's used a lot in FE planes.

 

What does it do? I am not sure, but if TK put them and uses them in the data inis there must be a reason why.

 

One thing you can try with the nose gear is to reverse the model orientation for the shock. I don't know if it will work, but you can try and see if it does.

 

Here's an example

 

ShockNodeName=Shock_F

ShockTravelAxis=Z-AXIS

ReverseShockOrientation=TRUE <- See if this work

ShockStroke=0.25

SpringFactor=1.3

DampingFactor=1.8

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Is this what you are talking about Jug? http://commons.wikimedia.org/wiki/Image:No...F-1234S-069.jpg

 

Also, I hope you don't mind me asking but, what was it like Flying the F-5?

 

Your picture reflects what I am talking about as does this

F_5E_Loading.bmp from Airliners.Net by Karl Drage

You can see the extended nose wheel oleo in the "cocked position".

 

Flying the F-5 was not very different from flying the T-38 other than the feeling of a more sturdy frame and more powerful engines. The jet is relatively simple, quick and reliable. Quick in response to every input, she was small enough to really 'feel' throughout the flight envelope. She is very difficult to see in a dogfight and is about the same size and performance as a MiG-21. That is why the USAF and the USN chose her for adversary training. She fades in comparison to today's fighters, and has always had inadequate (if any) radar, but she is still a shot in the arm to fly and deadly if not treated with respect to adversaries.

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I I remember correctly, OnGroundPitchAngle is used for planes like tail dragger and for planes that normally will sit with the nose up (and down?) due to the nose gear lenght. It's used a lot in FE planes.

 

What does it do? I am not sure, but if TK put them and uses them in the data inis there must be a reason why.

 

One thing you can try with the nose gear is to reverse the model orientation for the shock. I don't know if it will work, but you can try and see if it does.

 

Here's an example

 

ShockNodeName=Shock_F

ShockTravelAxis=Z-AXIS

ReverseShockOrientation=TRUE <- See if this work

ShockStroke=0.25

SpringFactor=1.3

DampingFactor=1.8

 

This did not appear to work either. I am thinking that some sort of animation would be best since it is a pilot initiated action on the runway ready for takeoff. However, an animation is way beyond what I can do now. Thanks for the suggestion anyway.

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Well, the nose wheel strut has a animation assigned to it for the 'shock' action. It's controlled by the following lines:

 

ShockNodeName=LowerNoseGearStrut

ShockAnimationID=4

ShockStroke=0.275

SpringFactor=2.0

DampingFactor=2.0

 

You can pretty much figure out what each line means.

 

Now, to make the nose wheel strut stay near it's maximum extention, you can increase the SpringFactor to a high number...the 'spring strength' as it were.

 

However, I tried this out on the F-5E and the results weren't that great. The nose wheel shock animation simply doesn't have very much travel, so the rake of the aircraft did not change that much (enough to really notice).

 

Another technique I tried was to comment out the above lines and insert the following:

 

[NoseWheelExtend]

SystemType=ANIMATION

InputName=ANIMATION_4

DeploymentMethod=MANUAL

AnimationTime=3.0

AnimationID=4

 

What that did is allow me to take direct control of the extention and retraction of the 'shock' strut of the nose gear.

 

Again, that didn't quite work either...I could get it to extend and retract...but the 'rake' of the aircraft was unchanged. Which looked a little weird (the nose wheel would 'float' off the ground when it was retracted).

 

It seems like something like this would have to be built into the model...you would have to give the nose gear 'shock' animation a very long stroke range so you could affect the 'rake' significantly. Also, it would not be something that could be directly controlled by the pilot...you would have to keep the 'spring strength' very high. The aircraft would ALWAYS have that nose raised attitude while on the ground.

 

FastCargo

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