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F-20 development

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Re: F-20 development

Postby Flying toaster » Tue Apr 15, 2014 6:03 am

OK found the issue...
V2.8 of canvas somehow required me to do an updateCenter on each SVG object before making a rotation, whereas v3.0 does not.
The question is, should I keep two pieces of code in the HSI definition file to make the aircraft backward compatible ?
If so, I guess there is a property in the property tree mentioning the version of FG that I could use for this purpose. Any pointers ?

All that being said, with the tremendous performance improvement I would definitely advise migration to 3.0 :)
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Re: F-20 development

Postby Hooray » Tue Apr 15, 2014 3:05 pm

this is true, you can search the canvas forum for "updateCenter", Gijs and TheTom were discussing that a while back IIRC.
Personally, I would simply target 3.0 given that 3.2 is upcoming soon. But it is up to you obviously - backward compatibility is obviously a great thing, and it would not seem too difficult, in fact api.nas already handles version checking for compatibility purposes, so if you want to do something like that, check the end of the that file
Please don't send support requests by PM, instead post your questions on the forum so that all users can contribute and benefit
Thanks & all the best,
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Re: F-20 development

Postby Philosopher » Wed Nov 26, 2014 10:32 pm

Hello Enrique,

I got the urge today (on my day off) to fly FG, so I re-downloaded and flew my favorite aircraft :D ;). I got an error in HSI, something about props.setDouble getting a NaN, which crashed the HUD update loop. So I looked, and when I called f20.rose.getCenter(), the second element was -0e-00 (which is a NaN, usually from division by zero ... although I didn't see any division leading up to that result). Anyways, my suspicion was that you didn't need to call .updateCenter() each frame, so I moved it outside of the loop, and it worked!

Here's the relevant part of the file, could you make sure it doesn't mess with anything and apply it when you get a chance? I'm using the latest GIT version, I'm not sure if you have the issue in releases.
Code: Select all
rose.updateCenter();
E_label.updateCenter();
W_label.updateCenter();
S_label.updateCenter();
N_label.updateCenter();
label_3.updateCenter();
label_6.updateCenter();
label_12.updateCenter();
label_15.updateCenter();
label_21.updateCenter();
label_24.updateCenter();
label_30.updateCenter();
label_33.updateCenter();
compass_labels.updateCenter();
var updateHSI = func ()

  #compass
  var heading_rad = heading * 3.1416 / 180.0;
   
  rose.setRotation (-heading_rad);
  E_label.setRotation (heading_rad);
  W_label.setRotation (heading_rad);
  S_label.setRotation (heading_rad);
  N_label.setRotation (heading_rad);
  label_3.setRotation (heading_rad);
  label_6.setRotation (heading_rad);
  label_12.setRotation (heading_rad);
  label_15.setRotation (heading_rad);
  label_21.setRotation (heading_rad);
  label_24.setRotation (heading_rad);
  label_30.setRotation (heading_rad);
  label_33.setRotation (heading_rad);
  compass_labels.setRotation (-heading_rad);
}


Time to mess around some more :)

EDIT: I just read what you said above... I would recommend you leave it, but just don't put it in the loop, because that gave me errors.
Thanks,
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Re: F-20 development

Postby Flying toaster » Fri Nov 28, 2014 6:47 am

Hi Philosopher

I am working on a few fixes.
Right now I have an issue with 3D model. Version 3.2 is proving to be very buggy for me on windows with lots of visual glitches and outright crashes to desktop, so I may roll back to 3.0 or resume development on Linux for the time being.
I fixed the HSI some time ago but have been busy making textures (which I am not proficient at) so I did not release new stuff for quite some time. I have resorted to freezing work on new liveries and started working on finishing what is essential (like systems simulation and complete cockpits ;) ). There release package now is defined as :
- 3 variants (prototypes as built, and fictitious A and C versions)
- 9 liveries
I will try to make weekly / bi-weekly updates for people to go beta testing.
First release expected sometime this week end.

Cheers

Enrique
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Re: F-20 development

Postby Flying toaster » Sat Nov 29, 2014 3:38 pm

Time for a fisrt update.
Lots of minor visual improvements (and still a lot to do), but noticeable :
- Fixed the gains for the yaw damper, you can now hit 700kts IAS without the yaw damper becoming insane. As it stands I would claim the FCS is 90% complete
- The speed brakes are now functionnal. E to extend, R to retract (uh, need to animate the thumb switch on the throttle for that one). You can place them at any intermediate position
- Functional flares (only A and C models, even though the C has half the load due to the presence of a Jet Fuel Starter)
To use the flares you need to select a release mode. In order to do that use the mouse wheel on the flare knob ahead of the throttle :
Image
and set either single or program.
To release flares, press ctrl-F (the red button on the throttle *will* animate ;), but the interesting things will happen outside )

The versions are
F-20 (with hot rod and air superiority grey liveries)
F-20bmw (one of the prototypes painted in a dark metal gray used on BMWs in the early 80's)
F-20A (with Thunderbirds, compass ghost and F-16 like liveries)
F-20-dutchdemo ( A fictitious F-20A with a demo scheme worn by the dutch F-16 solo demo some time ago ... and my personal favorite)
F-20C (With patrouille suisse and have glass V liveries)

I have not been using rembrandt for quite some time now so expect the textures to look oversaturated on that renderer

There's a new link now (the old one went dead) : F-20 download link

Enjoy

Enrique

Caveat : If you use ALS, the F-20 dutch demo variant will look fairly dull because you will lose the reflection shader
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Re: F-20 development

Postby abassign » Sun Nov 30, 2014 8:24 pm

Image

I want to congratulate the author of 'F20, the plane is very pleasant to drive and has a very good effect after-burner that should be integrated in many other aircraft of FGFs. The only thing I do not understand is that the plane is extremely easy to fly, is it real ? Or is a feature of the current FDM ?

Image

At night the effect post burner is very cute, but if the afterburner is turned off, you can not see the effect of red, varying with the regime, due to the combustion engine. I think that would be very nice to also insert this effect.
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Re: F-20 development

Postby Flying toaster » Mon Dec 01, 2014 6:37 am

abassign wrote in Sun Nov 30, 2014 8:24 pm:I want to congratulate the author of 'F20, the plane is very pleasant to drive and has a very good effect after-burner that should be integrated in many other aircraft of FGFs. The only thing I do not understand is that the plane is extremely easy to fly, is it real ? Or is a feature of the current FDM ?

Thank you ;) As a matter of fact it is hard to say if the real thing was that easy to fly given the few people having actually flown it and the unlikelyhood of them hanging around in these forums. I designed the FCS around what is available in terms of documentation (flight manual ...).
I could have made it even easier to fly if I went to full fly by wire (I did it at first but changed the FDM to mix direct input and flight augmentation system as advertised). Once the aircraft is complete, you will have the opportunity to disconnect the FCS (the aircraft feels less wooden but is much more demanding not to over-g/stall it).
As it stands you can still get it outside the flight enveloppe by making a tailslide and letting it turn into a spin (force the rudder towards any direction it may be willing to take).... And ... Good luck with the recovery. Actually the spin behaviour without stores is pretty crappy, need to fine tune that.

BTW, the afterburner effect I designed for the F-20 *has* been used on other aircraft for quite some time ;)

At night the effect post burner is very cute, but if the afterburner is turned off, you can not see the effect of red, varying with the regime, due to the combustion engine. I think that would be very nice to also insert this effect.

Actually, this is my view of how it should look like. The combustion chamber is hidden by the turbine stages and the after burner flame holders, so I guess that even if you could see past that, you will see the low pressure turbine which may not be warm enough to glow red. But then again first hand experience with night operations of F/A-18 may be more relevant than my educated guess.

Cheers

Enrique
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Re: F-20 development

Postby abassign » Mon Dec 01, 2014 1:38 pm

From a study NASA on F404 is possible to know the temperature of the outlet gas (page 29):

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19880010923.pdf

So I think you could color the outlet nozzle with a pattern similar to what I've added to the image:

Image

This is the table that I have taken as a reference, pointing out that the color does not depend so much the type of material, but mainly by the radiant coefficient of the material. I used the iron because I think it is a good approximation.

Image
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Re: F-20 development

Postby daveculp » Mon Dec 01, 2014 3:48 pm

I've looked in the back of a J-85 engine at night in formation, and the color is a dull blue. I read a pilot report of flying the F-84 (by Richard Bach, I think) and he reports a blue color. With only those two data points I decided to use a faint blue in my models for all engines.
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Re: F-20 development

Postby Flying toaster » Mon Dec 01, 2014 6:32 pm

daveculp wrote in Mon Dec 01, 2014 3:48 pm:I've looked in the back of a J-85 engine at night in formation, and the color is a dull blue. I read a pilot report of flying the F-84 (by Richard Bach, I think) and he reports a blue color. With only those two data points I decided to use a faint blue in my models for all engines.

Uh oh, that's weird since it implies a somewhat high temperature ... Guess some of the hot gases from the combustor might have leaked all the way back... Or the rotating blades left a clearance with the stator to see all the way through the flame
Anyway I am working on a way to have a rotating and glowing turbine showing through the flame holders ... We can then decide what color it should glow once we have that up and running

Thanks for the info :)
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Re: F-20 development

Postby Necolatis » Tue Dec 02, 2014 7:01 am

When the human eye sees a bright white colour, it looks as though it is a bit blueish. That's due the sun colour being a bit orange after it has passed through the atmosphere, and the brain uses that as a reference for white. That might explain why it looks a bit blue, but in reality might be pure white. Just an idea..
Last edited by Necolatis on Tue Dec 02, 2014 9:44 am, edited 1 time in total.
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Re: F-20 development

Postby Thorsten » Tue Dec 02, 2014 9:37 am

Uh oh, that's weird since it implies a somewhat high temperature ...


Did you consider the possibility that you're not seeing anything glow at all, and that the blue is just the light of the flame from the combustion process further in which leaks partially out?

I would be seriously suspicious about tensile strength of materials which glow white...
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Re: F-20 development

Postby abassign » Tue Dec 02, 2014 5:03 pm

Image

This example shows (A) do you see the output of a turbojet military, certainly we are at a very high speed, but certainly not after burning! So this confirms what I said earlier. Not only but (B) shows the red color of the outer wall of the combustion chamber. So I think it would be interesting to reproduce the effect because the F20 has cooling vents rear similar to this. Are small details, but they are beautiful to see especially at night or dusk.
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Re: F-20 development

Postby Flying toaster » Tue Dec 02, 2014 5:50 pm

Thorsten wrote in Tue Dec 02, 2014 9:37 am:Did you consider the possibility that you're not seeing anything glow at all, and that the blue is just the light of the flame from the combustion process further in which leaks partially out?



Actually I also hypothesise that in my previous post that
Or the rotating blades left a clearance with the stator to see all the way through the flame

meaning the same thing

Thorsten wrote in Tue Dec 02, 2014 9:37 am:I would be seriously suspicious about tensile strength of materials which glow white...

I second that, if it is white, it is about to fail ;) Even though the after burner which only bears aerodynamic loads can be *somewhat* hot as is the case in the J-58 test
Image
(note that the F-404 is not likely to glow that much as the bypass air is actually meant to cool the afterburner duct)

So here is a proposal for the glow :
Image
Darker ? Brighter ?

@ abassign
The afterburner liner actually already looks like that
Image

So that's OK for A. Even though the open nozzle indicates afterburner in use for this Grippen ... In bright daylight you are less likely to see the flame ;)

As for B, what you point out are chaff/flares dispensers and not intakes/exhausts. The red color is the cover of the rounds ;) On the F-20 as I made it, it is blue and below the side fairings.
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Re: F-20 development

Postby abassign » Tue Dec 02, 2014 10:44 pm

It would perhaps be better to put a dark red as a base on which to affix a transparent orange 100% when the system is low and it becomes less and less transparent regime higher. I made an example to understand, I think it should not be difficult to make a multiplication table that as a function of engine speed increases or decreases the rate of orange.

Consider then that night the eye perceive it differently, the pupil enlarges, so the colors of hot elements are lighter, I see it clearly when working with thermally material based on nickel in my lab.

Image
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