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F-20 development

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F-20 development

Postby Flying toaster » Sun Sep 19, 2010 12:28 pm

Resumed work on the Tigershark (a.k.a great grand son of the T-38)
Image
Image
See if you can spot the livery !
Hint : it is a fictitious one, I intend to make the real ones later on.

Do not expect this to be flyable any time soon since I intend to make the 3d cockpit myself and it may take quite a lot of time.

Cheers
Last edited by Flying toaster on Sat Jan 05, 2013 3:01 pm, edited 4 times in total.
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Re: F-20 teaser

Postby isix » Sun Sep 19, 2010 1:45 pm

Flying toaster, great news!!! I like so much Northrop F-20, a Northrop F-5E evolution, with a amazing GE F-404-100 turbofan. A very important website about F-20 is F-20A Tigershark Home Page at http://www.f20a.com/ . Nice project!!
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Re: F-20 teaser

Postby Flying toaster » Thu Dec 09, 2010 8:03 pm

bump
images back online ;)
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Re: F-20 teaser

Postby MOJO » Fri Dec 10, 2010 4:51 am

I'm guessing 5,4,3,2,1...THUNDERBIRDS
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Re: F-20 teaser

Postby Flying toaster » Fri Dec 10, 2010 5:49 am

We've got a winner here !!! :)

I could not resist this one. I still think the T38 Thunderbirds livery was one of the most fitting ever carried by the squadron, The F-16 livery looks so old-fashioned in comparison ! But then again, maybe it is because the Talon was (and still is) such a slick machine.
Patrouille swiss has also made a good job in making their tigers look good :wink:
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Re: F-20 teaser

Postby Flying toaster » Mon Mar 12, 2012 7:48 pm

Trying afterburner effects ...
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Re: F-20 teaser

Postby DutchPilotMitchell » Wed Mar 14, 2012 2:59 pm

Afterburner looks cool, only a bit too long ;p

Keep up the good work
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Re: F-20 teaser

Postby Ernest1984 » Wed Mar 14, 2012 4:53 pm

DutchPilotMitchell wrote in Wed Mar 14, 2012 2:59 pm:a bit too long


+1
but it looks amazing, colors are nearly perfect, a little bit too pink.
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Re: F-20 teaser

Postby Flying toaster » Thu Mar 15, 2012 5:39 am

Thanks for the comments :-).

I am using particles for this effect and I have a hard time avoiding that the trail gets longer as speed increases. Any suggestion welcome ;-)

Regarding the color, it's difficult to say. The F-404 seems to burn fuel quite well (i.e. as opposed to the F-100 or J-58 with their orange flame) and the flames look bluish/pink on a lot of photos. A lot of night pictures show a plain white flame but my bet is that this is due to overexposure against a dark background. I may tone down the pink a bit though

Thanks again
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Re: F-20 teaser

Postby truthsolo » Fri Mar 16, 2012 10:21 pm

You're probably correct on the overexposure resulting in white flames.. I've seen pink/purple afterburner flames on several occasions, but perhaps just a little bit more orange is in order. Very nice looking, though! Have you tried using a property with factor & offset inside <life-sec>?
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Re: F-20 teaser

Postby Ernest1984 » Fri Mar 16, 2012 11:09 pm

A little bit orange, like truth said, and it will be perfect :)
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Re: F-20 teaser

Postby Flying toaster » Sun Dec 09, 2012 5:54 pm

OK so I am out of possibilities I guess.
With the particles effect, the plume will bend right out of the nozzle when pulling g's and lengthens when speed increases.
I am almost resolved to get a few tens of billboarded polygons with the same texture, apply the same alpha/color trick, but do the animations trough Nasal.
If anybody could point me a better way to do, that would relieve me from a serious pain in the neck + a CPU killer :)

Cheers

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Re: F-20 teaser

Postby Thorsten » Mon Dec 10, 2012 7:34 am

I am using particles for this effect and I have a hard time avoiding that the trail gets longer as speed increases. Any suggestion welcome


I don't know how your particle code looks like, but probably the issue is that you're shooting the particles 'at rest in world space' from a moving plane, so both the length and the spacing of the AB effect particles depend on airplane velocity. What you want to do instead is to shoot particles relative to your moving model, such that spacing and length remain independent of the airplane state of motion. The thing to do according to the Wiki seems to use

<attach>local</attach>

but if that doesn't do the trick, it seems the shooter speed can also be property-controlled, so you could use that to compensate if the shooter speed is a function of the airspeed.

With the particles effect, the plume will bend right out of the nozzle when pulling g's


Would it not do so in reality? I'm a hard time understanding why a volume of burning exhaust gas should not continue on a straight line trajectory and 'know' somehow that the plane changes trajectory. The curvature of the plume is just a function of exhaust velocity vs. airplane turning velocity, and that can be done in the particle system correctly with fast-moving particles with a short lifetime.

The particle system has a lot of physics in which begs to be used - it has probably better physics in than any Nasal you can come up with :-)

(Not that I'm an expert in the particle system, I've just done a few waterfalls, but all you need seems to be there).
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Re: F-20 teaser

Postby Flying toaster » Mon Dec 10, 2012 12:44 pm

Thorsten wrote:but if that doesn't do the trick, it seems the shooter speed can also be property-controlled, so you could use that to compensate if the shooter speed is a function of the airspeed.


Alas I tried that to no avail. Actually I tried a lot of combinations for speed, number of particles, lifetime ... I also tried to correct the angle of emission and apply a rotation to the particle object... Still not doing it

Would it not do so in reality? I'm a hard time understanding why a volume of burning exhaust gas should not continue on a straight line trajectory and 'know' somehow that the plane changes trajectory. The curvature of the plume is just a function of exhaust velocity vs. airplane turning velocity, and that can be done in the particle system correctly with fast-moving particles with a short lifetime.

The particle system has a lot of physics in which begs to be used - it has probably better physics in than any Nasal you can come up with :-)

(Not that I'm an expert in the particle system, I've just done a few waterfalls, but all you need seems to be there).


The fact is that the plume speed is HUGE (vastly supersonic). So yes there must be some curvature, but some distance off the nozzle and gently curving, not just bending. From a physical perspective, I wouldn't bet a lot that the dynamics of a superhot supersonic jet with a cross-wind are the same than that of a chimney plume in the same conditions. I have not made the theoretical derivations though, so this is largely speculations.

It would be nice to find somebody who has seen a flight demonstration in full after burner in proper light conditions to tell if they observed the deformation of the plume or not

I still appreciate the feedback ;)

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Re: F-20 teaser

Postby Philosopher » Mon Dec 10, 2012 2:40 pm

First of all, my opinion is that the particles should be emmitted at the exhaust speed, which will be really high, which means it must have a very small life to get the right length. This should make it look the most realistic, especially if you could control the speed of the particles by speed of the engine exhaust. I do agree with Thorsten, the particles should curve; however, this effect will be smaller than you might expect because of the (very) high velocities and (very) short lifetimes (if you take my suggestion).

Also, these nodes in the file do not get loaded into the property tree, they just are read by the particle system during initialization. They also don't support aliasing an "unloaded" (non-property tree) node to a property in the property tree, which would be quite nice IMO. I would suggest filing a feature request for support for an alias="" attribute for the entries in the particle subsystem (and maybe any generic <PropertyList> file that isn't put in the tree) that changes the node to represent/point to the node in the property tree. Then it could be controlled externally via Nasal, since it could be a fixed value:
Code: Select all
<tag>352</tag>

Or "bound" to a property:
Code: Select all
<tag alias="/engines/engine[0]/exhaust-speed"/>


I do think this effect has a lot of promise! I'm looking forward to what comes out of this project.
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