The T-50 (PAK-FA) Thread

[tflash]

Which part of 'aligned edges, unexposed rivets, lack of corner reflectors, and lack of right angles reduce rcs' is difficult for you to understand? :D

At the same time, which part of 'visible engine fan blades produce a large RCS, as does the radar dish when pointed at the right angle' happens to cause issues with comprehension?

 

There are basic rules, we can make gross judgements by rules of thumb that are known. If they did something new and sneaky, that'll be something interesting to learn! :D

 

As for the F-104 vs. the F-35, I'm not sure what makes it difficult to determine at a glance that one was designed for stealth, and the other not - we're not looking at a (visibly) new generation of stealth here, like B-2/F-22/F-35 vs. the F-117.

 

I guess you know perfectly well that the stealth properties of the surface alignment of even the F-117 does not just amount to the canted surfaces, aligned egdes and other visible clues. Any airplane has canted surfaces when it evolves through the air. It is the massive calculations of which reflections actually happen, in such a way that there are dissipation and cancellation effects that are at the core of stealth. And yes, some simple measures can already help but they don't make the aircraft LO.

 

This means indeed conversely that an aircraft that at first looks is not stealthy in reality could have a rather good RCS.

 

If the F-35 were shown to you experts in the timeframe of the F-117, you would all have said it isn't stealthy since it has curved lines and we had just learned that you needed facetted lines a la F-117 to be stealthy.

 

With the B-2, it was proved you could yield the same deflection results with a curved form. Sorry, but NONE of you "knew" this beforehand. In reality, F-117 era computers didn't even allow to make the necessary calculations for that.

 

It is also possible to yield cancellation results from opposing surfaces that are cleverly mounted, as is the case in the inlet ducts of Super Hornet.

 

In any scenario, it is calculation and modelling that counts.

 

And "visible fan blades produce a higher RCS" is indeed a good rule of thumb but it is not really a correct statement. It is a gross simplification for saying that the fan blades usually generate high radar returns. That is, before some designers knew how you can calculate what exactly happens with these returns at certain frequencies. And can act upon that knowledge.

[GGTharos]

The part where these simplifications actually came from people in the know, rather than the discovery channel.

 

What part of "those are just simplifications for the Discovery Channel" don't you understand? :)

[nscode]

And the study of flight originated with the French and the Dutch.

 

 

 

If only it was the first...

 

 

And space exploration originated in Russia.

 

 

You had to be first in something about the space. And how's that reusable space vehicle white and black thingy doing? Good, yes?

 

I like this game :)

 

I do too, but I think it should end here, we don't want mods mad for too long ;)

 

I resent that comment - I guarantee you that I'm far more qualified to comment on subjects of radar and stealth features than you will ever be.

 

Come on! Other forums at least have long threads with pretty lines drawn on pictures and whatnot. :doh:

[nscode]

The part where these simplifications actually came from people in the know, rather than the discovery channel.

 

I did say for the dc :)

[GGTharos]

This means indeed conversely that an aircraft that at first looks is not stealthy in reality could have a rather good RCS.

 

Non-argument. Again, we're talking about a similar generation of stealth.

 

If the F-35 were shown to you experts in the timeframe of the F-117, you would all have said it isn't stealthy since it has curved lines and we had just learned that you needed facetted lines a la F-117 to be stealthy.

As above, but I'll add: Sure, you bet. So what? Are you complaining about people gaining knowledge, or are you making unfounded implications that Russia is now implementing magical stealth that we know nothing about ?

 

I mean it's one thing if they had claimed advancement, but they didn't - in fact, they flat out even said that aircraft was more of a competitor to the F-35 than to the F-22 - but, that's just IIRC.

 

With the B-2, it was proved you could yield the same deflection results with a curved form. Sorry, but NONE of you "knew" this beforehand. In reality, F-117 era computers didn't even allow to make the necessary calculations for that.

Again, so what? Do you have a problem with people having knowledge now that they didn't have before? You want to try being correct by telling people that they don't know, when you don't know? Ok, there's a chance you might be proven correct, but your chances aren't that good.

 

It is also possible to yield cancellation results from opposing surfaces that are cleverly mounted, as is the case in the inlet ducts of Super Hornet.

... did you just say what I think you said?

 

In any scenario, it is calculation and modelling that counts.

 

And "visible fan blades produce a higher RCS" is indeed a good rule of thumb but it is not really a correct statement. It is a gross simplification for saying that the fan blades usually generate high radar returns. That is, before some designers knew how you can calculate what exactly happens with these returns at certain frequencies. And can act upon that knowledge.

 

Your mind is writing cheques that your body can't cash - in money, or physics. Visible fan blades are a problem. Now, whether you take care of the problem by turning slightly, installing radar blockers, or whatever else - you aren't taking care of it by wishing. Even older aircraft could reduce some rcs by taking the fan blades out of the equation. The T-50 would just happen to make itself more or less vanish, instead.

 

I can't see how you'd presume to claim that they've come up with magical radio interference from a source that doesn't radiate back to the attacking radar ( ... which just might defeat the purpose of stealth).

Edited August 30, 2011 by GGTharos

[GGTharos]

Fair enough. And I say the rules of thumb are there because they apply. :)

 

I did say for the dc :)

[nscode]

As in

 

What he doth, he doth by rule of Thumb, and not by Art.

[aaron886]

You had to be first in something about the space.

 

What kind of poor logic is this? You just took the flaws in his logic and made them your own. Next a German will arrive and make fun of you for thinking you had some kind of primacy in rocket technology. Absolutely ridiculous. If you're going to continue trolling for nationalistic arguments, do it right. (And maybe for your own country... that's how nationalism is supposed to work, isn't it?)

 

And how's that reusable space vehicle white and black thingy doing? Good, yes?

 

It was doing just great... there's a reason the US has remained at the forefront of space exploration and technology for years.

[RIPTIDE]

The T-50 would just happen to make itself more or less vanish, instead.

 

I can't see how you'd presume to claim that they've come up with magical radio interference from a source that doesn't radiate back to the attacking radar ( ... which just might defeat the purpose of stealth).

 

lolol... caught you again.

 

tflash never mentioned T-50, yet you seem to be responding as if he said 'T-50 is bestest in teh werld'.

 

BTW, I agree with his premise. You seem to be, out of blindness, misrepresenting what his assertions were. Or intentional. U mad, bro? lulz

[GGTharos]

Have you looked at the thread topic?

[combatace]

lolol... caught you again.

 

tflash never mentioned T-50, yet you seem to be responding as if he said 'T-50 is bestest in teh werld'.

 

BTW, I agree with his premise. You seem to be, out of blindness, misrepresenting what his assertions were. Or intentional. U mad, bro? lulz

 

+1

[4c Hajduk Veljko]

I resent that comment - I guarantee you that I'm far more qualified to comment on subjects of radar and stealth features than you will ever be.

O yeah? So you publish your work in scientific magazines and write books on radars and stealth design? What is your name and what is your published work on radar and stealth design?

 

I've never claimed that I am qualified in any way to discuss stealth and radar design.

[GGTharos]

He has secret clearance and he works with the equipment. He can both easily be much better qualified than you are, and not be able to write any books about it at the same time (or not being willing to, or being qualified to tell you what happens but to be unable to design or write the math. Plenty of people fall into such categories on a variety of subjects, and you know that.)

 

O yeah? So you publish your work in scientific magazines and write books on radars and stealth design? What is your name and what is your published work on radar and stealth design?

 

I've never claimed that I am qualified in any way to discuss stealth and radar design.

[4c Hajduk Veljko]

I am sure we have more experience and probably some advantage over other stealth designs. The reason being is a simple fact that we, by far, invested the most money into it.

 

Reminder: SAM = Stealth STOP!

 

I'm certain the science doesn't escape them, but I don't think their level of expertise is at the same level as that of the US, who have been building stealth aircraft and weapons for decades now.

[Case]

Engine fan blades are the single most obvious reflector of radar energy from the front and rear aspects of an aircraft. Due to the fact that radar waves bounce you can get some feedback at angles off of them too.

 

Could you explain this statement a bit further? Why is something that is hidden inside the aircraft the most obvious reflector of radar energy? Yes it is rotating rapidly, but due to the ducts it is rotating in a plane perpendicular to the emitter/receiver.

[GGTharos]

The rotation is important for NCTR IIRC, not so much for RCS. The three traditional big RCS contributors are the fan faces, the radar dish (and potentially surrounding equipment), and elements of the cockpit.

[Cali]

I am sure we have more experience and probably some advantage over other stealth designs. The reason being is a simple fact that we, by far, invested the most money into it.

 

Reminder: SAM = Stealth STOP!

 

Why haven't they made a stealth jet until now? maybe they have and we don't know about it, that's how stealthy it is :D

[mikoyan]

It all boils down to this; the t-50 is not American ergo; it is not as good as the raptor.

For God sake this is a prototype; the russians are working on this thing on incremental stages instead of building the thing on its final stage to find out that they to redesign something that was already designed. You guys make the argument of the money; perhaps the russians are more efficient administrating budget and their people make less money. Look at most military projects on the US most of them are over budget and this without mentioning stupid research projects that don't produce any significant benefit for the taxpayers. I really like american aircraft manufactures but lately y get the feeling that they are squeezing the people for more money without a second thought. Reading the black bird book; I saw the Lockheed Martin; actually started working on the U2 by their own incentive and money; and once the government got interested; they promised to build the airplane on 7 months! and true to their words they did it; I don't see this type of work this days; why companies are not held accountable when they don't deliver or keep their promises?

Don't believe me; look at the yf-32; why Did boeing had to change the wing of the airplane once it was already designed? why the stealthy intake never really worked? something as fundamental of the wing; changed once the prototype was completed?

[Cali]

It boils down to this, why are we arguing over something that we don't know everything about. We only know what they allow or want to to think we know. Who gives a rats butt if the Russians had the first stealth jet. Who cares if the F-14 was a very good jet, it's retired and stealth has been out for a while. We don't know everything involved in this stuff, we are just saying what we know or think we know.

[nscode]

He has secret clearance and he works with the equipment. He can both easily be much better qualified than you are, and not be able to write any books about it at the same time (or not being willing to, or being qualified to tell you what happens but to be unable to design or write the math. Plenty of people fall into such categories on a variety of subjects, and you know that.)

 

Yeah... um.. those people tend to live by this mantra:

 

 

 

I am perfectly OK with people making educated guesses. As long as it's clear they are doing just that - guessing.

[Case]

The rotation is important for NCTR IIRC, not so much for RCS. The three traditional big RCS contributors are the fan faces, the radar dish (and potentially surrounding equipment), and elements of the cockpit.

 

I'm sorry, but this is hardly an explanation. What is the physics behind fan blades being the most obvious reflector?

[aaron886]

We don't know everything involved in this stuff, we are just saying what we know or think we know.

 

Suggest this be revised to "We don't know anything involved in this stuff..."

 

That's closer to the truth. :D

[Pilotasso]

I have a documentary where reflectivity of aircraft parts is described.

 

basically light will reflect off in the same but opposite angle as the original emmission. therefore metalic round surfaces, overall are not the biggest RCS features but will always reflect in any direction to the emitter/reciever no matter where it is placed.

 

Blades are rounded, and on top of this do not have any coating to conceal its metallic nature. Since you have dozens of them packed in a small space they will be good reflectors for the wavelength the airborne radars operate at (i.e. <= antenna size and that is inversly proportional to frequency).

 

Also flat surfaces in different aircraft parts should be of same angles so that all reflected energy is concentrated in one direction. Even if a radar reciever is at propper direction to pick this energy up, it will do so only for a fraction of a second (as a blink of light) as the aircraft is moving along the sky. That is insufficient to keep tracking it, and so it remains stealthy.

 

Again, blades are not flat, and are radial mounted which means stable reflection energy levels anywhere you look at it from, of crourse only limited to the nacelle restraints. But then again the T50's nacelles are straight intead of S shaped, and are themselves reflective to the entire 180 degrees from the bottom aspect.

Edited August 31, 2011 by Pilotasso

[Cali]

Suggest this be revised to "We don't know anything involved in this stuff..."

 

That's closer to the truth. :D

 

That's a good one :)

[sobek]

LOL, this thread reminds me of the futurama episode on the theory of evolution.