Aircraft Rolling - Modelling or Config

[M.Evans 10]

I have been working with the Meatball FA-18 and I have noticed that the roll is on a weird axis,

for instance when you do an aileron roll the plane will actually drop quite a way down when rolling it just looks like the axis for the roll is off. Would I be able to fix this through the planes unit Config, or is this something that I would have to remodel, and if so how would I go about doing that,

And I have permission from Meatball to edit this so it is all good,

Thanks for any reply

Edited May 25, 2012 by M.Evans

[max power 21]

Check the centre of gravity in the geometry lod.

[M.Evans 10]

In the video I posted, in the post above, where do you think the center of gravity would sit best so it doesnt use the cockpit as a roll axis, because in the video you can clearly see it,

And I am opening up the p3d file and I do not know where to find center of gravity in the geometry lod, I am a texture guy, modelling is something I want to do but was never good at, so if you could point me to a thread or give me a little more info that would be great :)

Thanks

[max power 21]

Through the aerodynamic centre of the rolling control surfaces.

[[aps]gnat 28]

Select-All in the Geometry Lod, and a little X will appear. That is the models center.

BUT .... I've never always found it that simply for the EXTERNAL VIEW centre.

Other factors to look at, that may well effect the "center" of the fly model.

The "zamerny" point in the MEMORY LOD

The "average" of ALL points in the MEMORY LOD. Select All -> Merge (DO NOT save model after)

The center of the FIRE GEOMETRY

[max power 21]

I was just looking on the nasa website and it was saying that an aircraft rolls around its c of g. I think maybe just putting it through the cenre of the fuselage is probably best, in retrospect.

[Sealife 22]

CofG is the roll point but it is subjective ,

Some people make a small cube and give it weight then move it along the fuselage , this will as you see this will move the Star thats talked about above .

Personally i like to increase the weight of 4 verts on the Geometry model itself till the star moves central :), or you can select all the verts in the the geo lod and gite it one overall weight this can sometimes make the CofG go straight to the center of the plane .

[max power 21]

You can deduce a line the C of G of an aircraft must be in front of by drawing a line from the tip of the rear gear to the bottom surface of the rear of the aircraft, and then draw another line perpendicular to that line back up through the aircraft from the ground contact point. If the C of G was behind that line, the aicraft would stay on its tail if it tipped. Usually it is also on the aircraft's centre line, and as far back as possible on fighters to make them less stable. The appearance of the rolling motion also depends on the aircraft's flight attitude. Some fighters fly at a slight nose-down attitude, but I think this also depends on airspeed.

Looking at some images of hornets in what is probably level flight, it seems like they flight slightly nose up- but who knows at what speed the photos were taken at.

http://www.aerospaceweb.org/aircraft/fighter/f18/f18_38.jpg

I think if the rolling motion is bugging you, I would see how making the c of g on a line drawn from the point of the nose to some place between the engines, maybe near the top, and seeing how that works. If you need to change the flight attitude, I think you must rotate the whole model on all LODs slightly.

[Sealife 22]

The benefit oif the Cube method is that you can alter CofG inflight by using a simple animation , this can be used to develop a "happy place " by recording your section CofG modeltoworld co-ords then setting them permanently or allowing pilot to shift it using an action .

like i say its all subjective , the wider your CofG the less roll , Bis used to make 4 boxes IIRC and place them on all the tips or even further out ( on helicopter models) .

[M.Evans 10]

how do i move that little x for the C og G

[max power 21]

Select the whole model and change its mass to some arbitrary weight, like 100.

Open the model's GeoLOD.

Create 4 cubes at the extents of your model, give them each 1/4 of the mass that you want the whole vehicle to have. Let's say 2000 kg- so each would weight 500. It is not really very important how big these things are. I would make them probably around 10 cm or .25m in length/width/height. Make sure to uncheck the option that will try to keep the total mass of the model the same when you're adding weight. While you make them it might be a good idea to create named selections for them so you can grab them easily if you need to. From the top menu, select structure\topology=> find components.

Now, move the weighted cubes around so they affect the mass distrution of your model. Check your changes in the flight model, come back and retweak, etc etc.

[f2f_bho 10]

Jesus, that got technical real qwik ..... the man already said he's a texture artist..lol

[M.Evans 10]

it seems when I created the new p3d file it did not save with the config, none of the actions of the aircraft work now, any ideas on why that could be?

[max power 21]

Did you save it under a different name? The class in the model.cfg must be the same as the name of the p3d file, and the p3d file name is mentioned in the config.cpp.

[M.Evans 10]

it is exactly the same name, because it overwrote the old one. But the configs are not working still.

[max power 21]

Is this the first time you've tried to pack it?

Do the animations work in buldozer?

[M.Evans 10]

Exactly what I did,

1. Used Debinarizer

turned it into a P3dm

2. Changed the model, (deleted and modified some things)

3. Saved as a P3d file,

4. Reput it in the folder

5. Pbo'ed it on up

repacked the addon and launched,

None of the gear flaps or canopy stuff worked.

[max power 21]

Check and see if the animations are working in buldozer.

I'm getting that it was working as an aircraft in the game?

[Sealife 22]

Used Debinarizer

turned it into a P3dm

I believe that programme will not forward selections so ll your aileron flaps rudder etc , will no longer be defined in the model, think it was designed ffor education purposes , ask your friend Meatball for original Mlod maybe ?

[M.Evans 10]

It was working before I edited it, so somewhere the selections were unnamed and the things need to be renamed, all i need is steps on how to do that. Would it be as easy as renaming the selections?

[Sealife 22]

in a plane probably

depends on your skills , but if Meatball is on this with you as in First post ,then he will have Mlod ?

[M.Evans 10]

This is the problem, I looked it up on dev heaven.

but when it does some of the named selections dont come through at least not fully

so there needs to be certain named selections for the model.cfg

what does this mean, and how do I rename those selections.

(tutorials would be nice)

It was working before I edited it, so somewhere the selections were unnamed and the things need to be renamed, all i need is steps on how to do that. Would it be as easy as renaming the selections?

[Sealife 22]

It means when you open model in O2 and click on a selection name EG aileron or rudder , a part of your model should be highlighted in red.

Because yours now doesnt you need to select the rudder portion of your model only , then right click on the named selection rudder and click redefine , you need to do it for everything that has a named selection in every LOD.

you gonna be busy :).

Like i say best just ask for MLOD.

[M.Evans 10]

Well, I am now using a different model, a lot of work down the tubes, but it will be worth it in the end. New model is an FA18C,

Now it only has about 40 or so selections, so really all I have to do is select the selection, then right click on the name and hit redefine?

(I can do this)

after that do I save it and will it work?

(sorry complete modelling noob, but you gotta learn somehow)

[max power 21]

Who is the author of your new model?