J-20 5th Gen Fighter Thread V

[plawolf]

No I base my opinion on the stated scenario which was the argument in WVR.
As a matter a fact if u read my previous posting I was the one who stated that a j20 pilot engaging in gun range against say a typhoon etc meant something may have gone awry because the J20 would not be able to utilize the advantages it has at that point.

Within a couple of miles stealth is basically useless. The mk1 eyeball and maybe IRST will be the primary determinant aside from good energy management and turn radius.

You can be within a couple hundred metres of a target aircraft and still remain undetected if you approach from the right vector. Stealth fighters have the advantage of being able to slip past a conventional enemy fighter while still beyond the detection range of said fighter, and then reapproach to attack from a direction neither the fighter's sensors or pilot is going to be able to cover.

As such, things could be going absolutely perfectly as far as the J20 pilot is concerned if an opponent pilot gets a view like the CGI/PS photo that started this entire line of discussion, if he is looking back behind him, and is thus likely seconds away from having to pull the ejection handle, if he is lucky.

In a similar vain, things could be going exactly as planned for the J20s even if they do end up in a real dogfight, if said dogfight started with a flight of J20s mauling a similar sized formation of enemy fighters by coming up from the rear, and then proceeded to mop up the few remaining survivors by expoilting their numerical superiority caused by the 'free' open salvo shoot downs of unsuspecting enemies.

 

[FORBIN]

J-20 probably won't be the greatest dogfighter in the current config. It lacks WS-15 with TVC. The thrust gap is pretty severe.

P&W F135 - 190 kN
P&W F119 - 156 kN (officially),
Saturn 117 (142 kN /147 kN in emergency mode).

WS-15 I see 160 kn also mentionned eventualy ? up to 180 kn
For T-50 i have futur reactor to 175/180 kn, 20 t.
Both for 2020 about normaly.

 

[taxiya]

......The J-20 has "distant coupled canards", in other words the canards are designed to be able to exert MORE force, by virtue of their longer moment arm, the Eurofighters have close coupled canards, and more "mass centralized", which means they require less force due to the "closer coupling" with the main wing, but have to move less mass, and are able to do it marginally "quicker".
......

Eurofighter Typhoon is distantly coupled just like J20. Actually it is more distantly coupled than J20 by proportion as it is almost in front of the cockpit.
Rafale is close coupled, the canards overlap the main wings.

It is the distantly coupled canards gives Eurofighter an edge over Rafale of otherwise "same" design. J20 shares that same design.

I can't be sure about the mass centralized subject though. Although J20 is longer than Typhoon, it also has all it's weapon load concentrated in between the engines and canards, while Typhoon has quite some loads close to the rear (wing tip racks). Doesn't this make J20 "more" mass centralized?

Also I am not sure mass centralization is always good for maneuverability. Take Typhoon for example again, mass closer to the rear will actually benefits nose lifting move, but then makes a dive difficult.

 

[Quickie]

Actually the more distant coupled canard has a longer moment arm which means that the force acting on the canard would be smaller than that of the closer coupled canard to produce the same moment. (Think of lever action.)

Short coupled canards like those of the Rafale, J-15 have the function of controlling the airflow over the wing surface and have too short of a moment arm for effective pitch control. Instead, the Rafale uses its elevon and the J-15 its horizontal stabilizers for pitch control.

 

[siegecrossbow]

Keep in mind that even dogfights these days most frequently occur at ranges of several miles or more. Don't bring a gun to a missile fight.

 

[Air Force Brat]

Have you been "engaged" inside the F-22 or J-20 to make any assessable comparison or do you just take those "experts" word for it? Seems like they tell what you wanted to hear regardless of objective view points. Really? As if only Americans have great researchers and insight into aerodynamics engineering? Are you Trump boys that desperate to "Make America Great Again" that you can't see anyone else being better than you at anything? And please don't say because you believe in "God" and the Bible....blah.....blah...blah...therefore are better.

Now, NOW, NOW! little brother?? I was married nearly fifteen years the first time, picked a MO better one that takes care of ME!, and I guarantee, that if I brought you home for dinner, she would have you eating out of her hand and asking the AFB if she has a sister??? she does, and she is divorced and has three boys... but both very sweet girls, and smart. In addition I have 7 daughters and as many granddaughters, and I worked in a DD Adult Rehab facility for 21.5 years, and was Hospice Chaplain for nearly five years, only other guy on staff was our Medical Director? so I do know a little bit about women!

I was "conceived while my Daddy was studying his Dash 1 for the C130-A, no doubt flying/aircraft where on his mind even as the AFB was conceived. Mr. Forbin offered me the outstanding complement of stating he felt like he was in a flight simulator seeing it, as I detailed the 360 overhead break?? nice complement and thanks Mr. Forbin. I am currently flying a 1946 Erco Ercoupe Model 415C, I have about 15 hours right seat time in an MU-2 Marquise Turbo-prop, and lots of time, in lots of different gen aviation aircraft, and am currently flying my old Cessna 172 that taught me more than ANY expert or textbook ever could, "remember" guys are "visual" learners.

That last fact is key here, we know lots and lots and lots about the J-20, and its predecessors, yes I have been up close and personal with the F-22, MIG-29, MIG 15, MIG 17, there is LOTS of information out there if you know what to look for, and I have read full PIREPS on the F-22, and MIG-29. OF course I trust the Pilots and Engineers, they are published and peer reviewed here in the West. Why do you think you were able to see what the F-35 jockey had to say about the F-35, although that info was likely classified, he was POed that he couldn't put it one that F-16.

I never stated anything like you suggested I have said, I give Dr. Song, and the Chinese J-20 team and pilots lots of credit, check out my ancient posts, I also give the Russians lots of credit for the T-50. But the reality is the F-22 is far and away the most capable A2A bird on the planet! does it matter whether or not you agree with that? or whether I agree with that???? not one whit, it is true.

Finally the next to the last thing I would want to do is offend you my brother, I do trust you as well, I would absolutely bet my last dime that you have never posted anything that you believe is "untrue"! We just happen to have a very inconsequential disagreement here about the truth.

Finally, I am not a Trump guy, I am a Cruz guy, Mr. Trump comes up with the most "off the wall Krap" I have ever heard, but he has won the GOP nomination, I pray that he picks a true conservative as his running mate, and to serve on the supreme court, and I believe he will do that if we the people respectfully make our wishes known

Finally my God is able to "stand up" for Himself, I on the other hand will continue to depend on Him to watch over me and mine, as well as you and your's, and I know I was "tweaking you" a little bit, but remember, the AFB has been "tweaked" as much as any other poster??? its made me a better man, much more able to defend my science, and my faith?? LOVE YOU Brother, and thank you for your service to your many friends and fans on the Sino Defense Forum. I would NEVER question your integrity, NEVER!

 

[Engineer]

Traditionally, long coupled canard provides higher moment but less lift enhancement, whereas short coupled canard is the opposite. The simplified explanation is that wing-tip vortex takes longer to travel from canard to the wing, during which energy dissipates. This is no longer the case. On the Tyhpoon, there is a pair of strakes beside the cockpit to re-energize the vortices. On J-20, the LERX serves a similar purpose.

 

[Air Force Brat]

Traditionally, long coupled canard provides higher moment but less lift enhancement, whereas short coupled canard is the opposite. The simplified explanation is that wing-tip vortex takes longer to travel from canard to the wing, during which energy dissipates. This is no longer the case. On the Tyhpoon, there is a pair of strakes beside the cockpit to re-energize the vortices. On J-20, the LERX serves a similar purpose.

I agree with Eng, he's never steered us wrong, and is about aerodynamic purity, with out the Engs patient and kind explanation, I would have never understood the J-20s aeros?? I was very confused initially, and because I did NOT understand it, I was very discouraged as I began to study this aircraft, overlooking much of its design and engineering brilliance, I did NOT like canards, but the Eng's reading my posts, enabled him to see where I was "missing the connection", and very patiently explain what I was missing.

I also agree with the Eng that the WS-15 will come along sooner or later, but that it will not include OVT, as it is unnecessary for the J-20, those distant coupled canards and ruddervators adding considerably to the quick pitch transitions of the J-20.

 

[taxiya]

Actually the more distant coupled canard has a longer moment arm which means that the force acting on the canard would be smaller than that of the closer coupled canard to produce the same moment. (Think of lever action.)

Short coupled canards like those of the Rafale, J-15 have the function of controlling the airflow over the wing surface and have too short of a moment arm for effective pitch control. Instead, the Rafale uses its elevon and the J-15 its horizontal stabilizers for pitch control.

Not necessarily, it is the function of three: positions of center of gravity, center of the lift of the wings and location of the canards.
Plus, the center of lift moves to the rear along with the increase of the air speed making it even more complicated to tell.
I think these have been repeatedly talked about in this forum, now we are doing it again.

 

[Quickie]

Not necessarily, it is the function of three: positions of center of gravity, center of the lift of the wings and location of the canards.
Plus, the center of lift moves to the rear along with the increase of the air speed making it even more complicated to tell.
I think these have been repeatedly talked about in this forum, now we are doing it again.

The shifting of the center of lift with respect to the CG would change the effort needed for pitch control but it does not change the fact that longer moment arm would require less effort than the shorter moment arm during pitch control.