Russian Fifth-Generation Fighter to Exceed Rivals

[Tang0]

ChinaOwnsEverything..

A couple of years ago (2003 maybe?) the AIAA ( American Institute of Aeronautics and Astronautics) did a design competition for a low cost alternative to the F-22 with equivalent stealth to an F-117. It was an undergraduate level competition... I had a friend who completed it. It took a team of 7 undergraduates 2 weeks to come up with the conceptual design for an aerodynamically stable (At least in pitch and yaw) aircraft with equivalent stealth to the F-117 using commercially available CAD software, and an RCS software called POFACETS.

These were aerospace engineers, experts in fluid dynamics who know next to nothing about EE or ECE beyond freshman electrodynamics.

You know how they could do in a couple of weeks what took professional engineers in the late 70's months/years? FASTER COMPUTERS. Read the POFACETS description if you care, no secret sauce meta-materials there, just faceted classical optics.

http://www.google.com/url?sa=t&sour...sg=AFQjCNEfwmgEWtIewP9XbQcs2uO0has10g&cad=rja

By the way, all of the stuff that is equally important, but hard to quantify that Gambit. et al. were talking about? This code does not include.
IE: No Creeping, surface waves, no multiple second order reflection or diffractions, no shadowing....
And still, it does not take long to beat the design of the F-117....

Might I recommend something from the sources on that paper?

Jenn, Radar and Laser Cross Section Engineering, AIAA Education Series, June 1995.
It might enlighten you, so you can come back and not sound like a moron.

 

[Tang0]

And here is a bunch of excellent sources from the Author of that book, which should further enlighten you. Of course, he is an employee of the USN, so maybe it is all just imperialist western propaganda from the military-industrial complex....
Dr. David C. Jenn

 

[below_freezing]

I know that it is conical, but in reality that cone is extremely large compared to the object that it is locating. So relative to the object the waves will be straight lines. Just like how relative to the size of a human the face of the earth is flat.



Attacking strawman again are we? I never claimed that creeping wave only existed on spherical bodies.

Creeping wave only applies to surface waves, they are not independent of each other

Again you don't seem to realize how radars work, the radar only sees the waves that comes back to it. I have stated before that when a surface wave creeps around the object that it loses most of its energy, this energy is conserved by leaky waves. These leaky waves will never make it back to the receptor due to low energy and wrong orientation.

I already explained to you in my nicely drawn pictures why creeping wave appears to come from behind the actual object. Because the wave that ends up making it back to the receptor due to having the proper orientation having traversed around the object and thus reversing its direction the lower energy signature that it carries implies that the object is further away.



I found plenty of resources that disproved ALL OF YOUR POSTS. The only things that you have disproved were set up strawmen

Valid scientific evidence that you just ignored?

F-117 vs F-22 RCS? IGNORED

RCS of slightly curved plate vs spherical plate? IGNORED

Saying that Stealth ships had angled plates because of RADAR DOESN'T WORK UNDERWATER when I pointed out that every experimental stealth helicopter design look similar to stealth ships and F-117?

I have debunked all of your arguments, while you spout gibberish to waste my time digging through sources to disprove you and making nice little MS paint diagrams to try and educate you. And ignoring the arguments that you can't disprove.


Not once have you posted a source, this entire conversation has been one sided. You make CRAZY CLAIM, I pull up a paper telling you wrong. You ignore it, strawman by stating things and claiming that I said them just to debunk them yourself (most of the time getting many theories completely wrong).

According to your crazy pseudoscience theories (WITHOUT ANY SOURCES) stealth helicopters and stealth ships should all be spherical. Obviously you know more than all the engineers at Raytheon,Northrop etc...

And this is why some people in life work designing machines while others (similar to you) are working cleaning toilets. I bet that you are one of those scum that go around telling girls that they are engineers when really they are "sanitation engineers"

forget it. these people know jack s* about engineering. you're wasting your degree. it's like me arguing with the fake "doctor" (who is actually something like an army associate paramedic trainee) a few months back about biochemistry.

 

[ptldM3]

Explain then why recently developed stealth ships look more like the F-117 than the F-22?

While I was going to college I got lucky enough to get hired on at a company that built ships, I understand the construction methods inside and out. I have worked with or closely collaborated with engineers, project managers, foremen, and most departments ex: mechanics, shipwrights...ect.

A ship has 'flat plane surfaces' because it comes natural with the design. Remember a typical hull flares outwards, main deck cabin sides although often flat can be angled, ones that are angled fit into the 'flat plane surfaces' criteria. The only parts of a ship that typically come cylindrical is the rear comeing.


There are many 'stealth' ships, some designs are radical while most are traditional, what you see in most 'stealth' ships is simply an increase in slopes on already sloped surfaces. The rest is just refinement.

A 'stealth' ship that would come in cylindrical form would be inefficient if it was curved, for example, like the B-2's fuselage.

Clearly the F-117 has the superior stealth design since the F-117 is almost 3 times as big as the F-22 yet the RCS does not differ significantly, if the F-22 was optimized for stealth the design would look similar to the F-117 as it would have an even smaller cross section.

The F-22 and F-117 are almost identical in regards to length and wingspan. In fact, the F-22 has more wing areas and has a larger height.

The F-117 is not a superior design, it is a inferior design. The F-117 was the first true 'stealth' aircraft. The designers at the time only knew one way to design the F-117 and that was in the form of the trapezoid. The f-117's design was terribly inefficient, looking at the geometry of the F-117 it's clear that the designers added extra and unnecessary (back then necessary) surface area's, while the F-22 and all other 'stealth' aircraft have clean surfaces areas, the less surface areas, the less emissions.

The F-22 uses the same principles as the F-117 minus needles surface areas such as the nose and all the bagage it carries.

Smooth surfaces do give better aerodynamics, but this should not be used as the only reason for the F-22's and all other 'stealth' aircraft designs. Remember, the F-22 is not the only stealth design, The B-2, F-35, pak-fa, Mitsubishi ATD-X, and countless drones developed in the UK, Russia, France and the USA all have smooth curves.

So why do aircrafts such as drones and the B-2 all come with smooth curves? After all aerodynamics in these aircraft aren’t as important as in fighter designs. High speed and maneuverability aren't even considered in these aircraft.

The F-22 was built more for aerodynamics rather than pure stealth as a shrunken F-117 to the size of the F-22 would have a smaller cross section.

Again aircraft such as B-2, F-35, pak-fa, and countless drones didn't come with smooth curves by coincidence.

Now if you still do not believe that angled plate is better look at some of these designs for stealth helicopters

How strange they look like stealth ships! apparently according to gambit, stealth ships only look angled because of water! and that spherical designs give ultimate stealth!

Why are these helicopters shaped like this? because it gives better stealth.

Those helicopters aren’t real, but the Comanche is.



As you can see everything from the nose to the tail, to the rotor hub is smooth and curved.

Why is F-22 spherical? because it provides a little bit of stealth and a lot of speed and maneuverability

No it's spherical because the trapezoid method is outdated.

I can say that I have PHD friends who worked on the F-22? Saying my friend told me as an argument just shows that you have lost.

If it makes any difference, Gambit has, in other threads, stated that the F-22 uses less composites and less coats of RAM, I believe he knows this because he knows technicians that have worked on both aircraft.

 

[Tang0]

forget it. these people know jack s* about engineering. you're wasting your degree. it's like me arguing with the fake "doctor" (who is actually something like an army associate paramedic trainee) a few months back about biochemistry.

Good sir, would you then enlighten this engineer on how ChinaOwnsEverythings views hold weight?
__
Self Delete, Off topic
__

 

[below_freezing]

so you're a US bachelor's in engineering? know how many PHDs are out there? what do you want, a medal or something?

 

[Brotherhood]

so you're a US bachelor's in engineering? know how many PHDs are out there? what do you want, a medal or something?

Its best to ignore those self-proclaim west this, west that, its nothing more than someone you can smell them from miles away.

 

[amalakas]

Its best to ignore those self-proclaim west this, west that, its nothing more than someone you can smell them from miles away.

hey, this is not about starting a cultural war here.

There were some comments made on how specific planes were designed, and some people (myself included) don't agree or share your "friend's" chineowneseverything thoughts on cetrain technical areas.

I am a professional and I don't happen to agree with him, I outright say he is wrong. Plus he is showing poor professionalism in this forum as he is publishing papers that are copyrighted by authors and institutions. What does that tell you?

 

[Jigs]

"copyrighted by authors and institutions"


Look at his flags. Those things don't exist in his world.

 

[gowthamraj]

"copyrighted by authors and institutions"


Look at his flags. Those things don't exist in his world.

Nothing to say more than there

 

[gambit]

ChinaOwnsEverything..

A couple of years ago (2003 maybe?) the AIAA ( American Institute of Aeronautics and Astronautics) did a design competition for a low cost alternative to the F-22 with equivalent stealth to an F-117. It was an undergraduate level competition... I had a friend who completed it. It took a team of 7 undergraduates 2 weeks to come up with the conceptual design for an aerodynamically stable (At least in pitch and yaw) aircraft with equivalent stealth to the F-117 using commercially available CAD software, and an RCS software called POFACETS.

These were aerospace engineers, experts in fluid dynamics who know next to nothing about EE or ECE beyond freshman electrodynamics.

You know how they could do in a couple of weeks what took professional engineers in the late 70's months/years? FASTER COMPUTERS. Read the POFACETS description if you care, no secret sauce meta-materials there, just faceted classical optics.

http://www.google.com/url?sa=t&sour...sg=AFQjCNEfwmgEWtIewP9XbQcs2uO0has10g&cad=rja

By the way, all of the stuff that is equally important, but hard to quantify that Gambit. et al. were talking about? This code does not include.
IE: No Creeping, surface waves, no multiple second order reflection or diffractions, no shadowing....
And still, it does not take long to beat the design of the F-117....

Might I recommend something from the sources on that paper?

Jenn, Radar and Laser Cross Section Engineering, AIAA Education Series, June 1995.
It might enlighten you, so you can come back and not sound like a moron.

When I enlisted back in 1983, there were four Training Instructors (TI) in Lackland AFB that knew of the F-117. When they eased off their verbal abuse of recruits, as TIs and DIs usually do, and act a little humane, the most they could do was hint about it. One guy told us that the future of combat aviation is rapidly changing and we, the next generation, is going to be in the thick of it. Today, I do not like the word 'invisible' but that was what they used to describe what they saw but could not speak of. The F-117 was designed with sliderulers. Only senior project engineer leads have access to something exotic called a 'computer' and machine time was expensive. The Matlab code you presented excluded edge diffraction, which is unusual in that edge diffractions made life hell for the F-117 engineers after they include items like engine exhausts, vents, and a cockpit.

This fool and his lack of military experience amplified his foolishness. Tactically speaking, top RCS is irrelevant. Underside RCS is slightly less irrelevant only because most radars are ground based and despite the fact that all aircrafts have relatively somewhat 'flat' underside, the odds of having a radar directly below the F-117 is extremely remote, leaving the bi-static configuration the best odds of a ground based system to pick up an F-117 and no one has a functional bi-static air defense radar system. The fool's argument regarding side RCS is also irrelevant in that radars sweeps and in their motions, if an F-117 or F-22 happens to be within that sweep in an ideal position, the 'stealth' aircraft's detection would be so fleeting that it would be dismissed as an anomaly, not likely a valid target.

But when an aircraft, 'stealth' or not, is in a head- or tail-on radar collision, then that sweeping motion is dangerous for the aircraft because the aircraft would be heading directly towards the radar, or a valuable target, or exiting an area after it dropped its bombs, and that head- or tail-on position would be constant, not transient like an aircraft flying across one's vision. So the F-117 designers focused more on how to reduce head- or tail-on RCS than they did for side-on RCS. The result is the signature 'bow-tie' radar reflective graph so popular among US 'stealth' aircraft critics who do not know what the hell they are talking about.

Back to edge diffractions...

For the F-117, aerodynamic necessities demanded that no matter what, the angled facets must allow airflow in certain paths over the body. So the engineers created multiple triangular facets to accommodate aerodynamic laws. But facets, or panels, must meet and when they do, their joints created edges and the edge diffraction effects contributed to the RCS figure. The solution was to reorient these edges, no matter their lengths, so that none would be perpendicular to a radar signal in a head- or tail-on radar collision.

It is not difficult to imagine.

In the above B-2 head-on radar collision, the wavefront will never be perpendicular to the aircraft's wing leading edges. The wave will travel over the body and when it meet the trailing edges, edge diffraction effects result. That is why the B-2's have precisely calculated 'sawtooth' trailing edges, to reduce the odds of any edge diffracted energy going back to the seeking radar.

Now mentally rotate the aircraft, in any direction, until the wavefront impact one wing straight on. The wing now is the greatest RCS contributors. But that would also make the B-2 in an off-angle to the radar's scan direction, effectively making the bomber crossing the radar's scan 'face'. Not only that, the radar is also sweeping and as it sweeps, that angle will increase. At several hundreds km/h, that ideal wavefront-to-wing position will be too short in duration for most air defense radars to trigger an alert. This is also why, for the F-22 and F-35, the wings and other leading edges have absorbers and not the rest of the bodies.

The man is already a 'moron' several times over. He is too stupid to realize it.

 

[siegecrossbow]

so you're a US bachelor's in engineering? know how many PHDs are out there? what do you want, a medal or something?

More precisely just how many PhDs are Chinese . In the research center that I worked during the summer Chinese was the second most commonly spoken language, after Chinglish.

 

[gambit]

...he is showing poor professionalism in this forum as he is publishing papers that are copyrighted by authors and institutions. What does that tell you?

It tells us that he is dishonest.

Very seldom do I ever post paywalled sources and whenever I did, I only posted the summary teaser and made sure it contains keywords relevant to the discussion. If the reader has access to paywalled contents, he can verify my argument for himself. If the reader does not have access, at the very least, he can see that there are reputable professional and educational institutions that touched the subject, and that he can use the keywords to research further on his own.

NEVER have I posted parts of the paid contents themselves. It raises too many questions -- legal and ethical. The legal issue is obvious for places like this forum. The ethical issue is that if you control the paywalled sources, you can selectively post passages that appears to support your argument when it is always possible that the authors have caveats or cautions regarding the passages that you screen captured and posted.

 

[aj_tech123]

russian equiment isn't trash. but its not going to allow us to match china in my opinion.

if you think about 2020-25 timeframe, if pak-fa doesn't deliver good enough stealth but j-xx does, that won't be good news for us.

maneuverability, which is the russian strength doesn't mean much anymore. plus american / euro bvraams are going to be much better than russian ones too.

the jsf program is looking for more commitment of orders afaik.

Wow wen did china learn to make aircraft better than russians????
but chinese have made a cheapest fighter aircraft..which u could get at $15million..

 

[aj_tech123]

the chinese defense budget is already 2x russia and will get to 3x or more within 5 years.

russia is the wrong bet in the long term.

do u think increased budget will also increase aircraft technology?????