Oddities of the China J-20 External Fuel Tank Test Report

The Chinese Air Force conducted new tests of a new generation J-20 fighter with external-mounted fuel tanks. The main purpose of these tests was to find out the maneuverability parameters of the combat vehicle in the presence of additional fuel tanks, to identify the percentage of increase in the radius of use, and also to evaluate the characteristics of “stealth” under such flight conditions.

It is noted that the test of the J-20 with additional fuel tanks was carried out for the first time after putting such a fighter into service with the PLA Air Force. Previously, tests were carried out with prototypes of a combat vehicle. Moreover, 4 additional tanks were installed immediately on the external suspension.

During the flight, it was revealed that "the invisibility of a fighter under these conditions ceases to be its main quality." Translated into the public language, this means that the additional fuel tanks nullify all those J-20 stealth characteristics that are often flaunted in China.

At the same time, the PLA Air Force notes that it is not planned to fly with additional fuel tanks in a situation that provides for the possibility of a battle. It is stated that such a flight may be in demand for fighters if they are transferred from one air base to another - remote. If so, then the test narrative sounds strange. Why, in this case, was initially reported to study the parameters of "stealth" when using tanks on an external sling.

In a statement from the Chinese department, it was reported that when using additional tanks, the J-20 fighter “nevertheless showed high maneuverability and excellent dynamics, including when changing selected flight modes”. And again, a strange statement. If the Chinese Air Force considers equipping a fighter with additional tanks solely for a flight from one of its airbases to another, then what kind of flight is this, during which the pilot will need to use super-maneuverability and lay turns? ..

Comments

[knn54]

Who bought at least ... units of hanging tanks as a gift.

[Thrifty]

Kpp54 - to a buyer of Chinese letak as a gift noodles about his invisibility in flight

[Revolver]

Quote: Thrifty

Kpp54 - to a buyer of Chinese letak as a gift noodles about his invisibility in flight

on the ears

[Shurik70]

The article is stupid. The author is trying to belittle the achievements of the Chinese. What for?
Obviously, the outboard additional tanks are not for battle.
But it is also obvious that for Chinese radars it is necessary to know the signatures of their fighters (as well as those of others) in all aspects and modifications. So if for the first time they test with such tanks, then all the characteristics must be removed.

[Shurik_2]

The author is right when he noticed the strangeness of testing the Chinese, hanging tanks on over maneuverability. Many of you have not considered why this is done. China will not fight with the United States on the continent, but in the sea and ocean, for the islands. Those islands and reefs that they have washed are poorly protected. And those airfields that they built are easy to bomb. Therefore, holding stealth aircraft is dangerous. They will fly from the mainland and the distances there are not close, and we must take into account that the radius of the Chinese aircraft is much smaller than ours. And when the author wrote about the test of two or even four hanging tanks, it was not casual. Indeed, in addition to flying, you need fuel and to fight, as well as to return, we will take into account that the approach airfields can be destroyed. The author does not belittle but analyzes. What for???

[Bad_gr]

Quote: Shurik_2

After all, in addition to flying, you need fuel and to fight, and also to return,

The point is then to use a stealth aircraft for these tasks if it will be seen with tanks as an ordinary aircraft.
PS
It is strange that the Chinese did not say that the tanks, too, "stealth"

[Vladimir_2U]

Quote: knn54

Who bought at least ... units of hanging tanks as a gift.

There will be a gift, you just need to correctly compose an application! Like this:
"Air flying car for a fight, multi size. Free shipping." And there they will either give the tanks or a compass on a strap. )))

[Thrifty]

That is, the Chinese have no technology for making comfortable fuel tanks, otherwise they would not have been tormented with ordinary hanging fuel tanks.

[donavi49]

So one does not interfere with the other. For example, both.

[Thrifty]

Donavi 49 - just the usual fuel tanks will increase, and significantly the RCS of the fighter's stealth. That is, conventional PTBs are "contraindicated" for such an aircraft!

[DVR]

Not a specialist, but a moot point. If PTB increase including and the combat radius (conditionally by 30-40%), then the aircraft can drop the PTB at a fairly decent distance from a collision with the enemy (a couple of hundred kilometers).

fuel tanks will increase and substantially the EPR of the stealth fighter

And what is the technical difficulty, given the aerodynamic shape of the tank, to make it with an EPR comparable to the EPR of cruise or ballistic missiles, the size of which is measured in hundredths and thousandths of a sq. m. Is that the cost will be high. It would be interesting to hear the opinion of experts.

[ancient]

Quote: DVR

If PTB increase including and the combat radius (conditionally by 30-40%), then the aircraft can drop the PTB at a fairly decent distance from a collision with the enemy

You quote "the procedure for maintaining the database of various types of aviation" according to the UBD.
But in fact - this is the "article" itself ... "STRANGE", and not .. the Chinese conclusions from the report.

That at the latest, articles on VO began to appear ... "one cooler than the other," ... then let's make "UDC's pepelats" out of the Su-57 ... now this one ...
Dear administration ... on the crisis in materials?

[DVR]

You quote "the procedure for maintaining the database of various types of aviation" according to the UBD.

Very far from aviation, just logic in my understanding. Frequent stay (thanks to baht) as a child in the military unit, especially in the fuel and energy sector, left an interest in military aviation. Golden days were)

[mvg]

A rare case, I completely agree with the "ancient": the "newsman" is terrified, how bad ...

[dauria]

And what’s the technical difficulty, given the aerodynamic shape of the tank, to make it with an EPR comparable to the EPR of cruise or ballistic missiles,

Two "invisibles", adding reflections can give "visible" ...
Even a "shiny point" visible in a wide range of azimuths.
After all, "invisibility" is achieved not so much by absorption, but by reflection into "milk" (that is, anywhere, but not back to the locator). Hence the predominance of sharp edges and straight non-scattering panels, no large radii and domes, no panels at right angles (corner reflectors).
Of course, you can also get out of the tank and provide a small EPR. But is it worth it? Dumped and fight.
By the way, a simple example. From a flat glass, a sunny bunny rarely gets into your eye. But from the sphere of the church dome - always from any azimuth. There is always a plot on it that reflects the light exactly in the eye, no matter how long you walk past.

[DVR]

Thanks for answers.
When writing a comment, I thought about the fact that the aircraft and the PTB combined can significantly increase the EPR. I did not mention, because suggested that getting around this point is also technically not the most difficult task.

[lego2]

And the fact that tanks are usually suspended instead of missiles, is that not what?

[DVR]

So I kind of wrote about that in response to the comment above Lean.

[ancient]

Quote: lego2

And the fact that tanks are usually suspended instead of missiles, is that not what?

And for information ... in all aviation, this is either fuel or ammunition (G max. Take-off is determined mainly from 3 main criteria (weights) - empty-fuel and second-hand, well, since the weight of an empty (equipped) is different at a not very large value, the main one as I wrote is fuel and b / c).

[opus]

Quote: donavi49

So one does not interfere with the other. For example, both.

Quote: Thrifty

That is, the Chinese manufacturing technology of comfortable tanks is completely absent

1.Comfortable fuel tanks - DO NOT RESET. And for a long time, tedious and expensive, they are demonized.
in flight from dump it is IMPOSSIBLE.
2. Conformal fuel tanks (CFTs, ​​KTB (usually mounted on those machines that have been manufactured for a long time, and it is necessary to increase the combat radius or range)

3. Suspended: took off over his territory (or loitering in the distance), reached the frontier, dropped and again "stealth".
Different things

Quote: Thrifty

That is, conventional PTBs are "contraindicated" for such an aircraft!

F-35 and CONTRAINDICATIONS

Lockheed Martin is considering what it will take to give the F-35A Joint Strike Fighter and, accordingly, the Israeli sub-option F-35I, the ability to carry two 600-gallon landing tanks under their wings as part of a larger study of range extension. This will increase their total fuel capacity by about 40 percent, although it will negate the stealth quality of the aircraft.

For Israel, the theater of operations (air defense and news agency: Syria, Lebanon, Iran) is tolerable.
For others and yourself
Lockheed Martin is considering could an improved version of the Pratt & Whitney F135 engine for a stealth fighter offer additional range.


The Growth Option 2.0 update for the F135 engine, launched in June 2018, includes an advanced traction and temperature control system that can be used to help the F-35 add new weapons (ammunition mass) and sensors (electronic mass of entrails).

Growth Option 2.0 includes new compressor and turbine technologies, which provide more traction and fuel economy, which was part of the Growth Option 1.0 concept, introduced in 2017.

Pratt tested the early version of the Growth Option 2017 engine in 1.0. which was called the demonstration engine for reducing fuel consumption, that demonstrated that modernization can improve traction by up to 10 percent and reduce fuel consumption by up to 6 percent.

[Avior]

for fuel tanks you have a picture of 2008, then there were such plans. But then there was a rumor that in the end all the same they decided not to do it yet.

[poquello]

useful activity, in general, how it flies if something hangs there

[Break through]

Let it fly without tanks

[Revolver]

Quote: Break through

Let it fly without tanks

Far away he will fly away.

[kjhg]

During the flight, it was revealed that "the invisibility of a fighter under these conditions ceases to be its main quality." Translated into the public language, this means that the additional fuel tanks nullify all those J-20 stealth characteristics that are often flaunted in China.

I do not see any problem in using stealth fighter fuel tanks on the external sling. For example, purely hypothetically, Israeli F-35s, taking off with such tanks from their airfields, can fly over the territories of Jordan, Iraq, where no one will shoot them down, and before entering Iranian airspace they drop these tanks, becoming again hardly noticeable, and, calmly solving their problems, return to base.

[Shurik_2]

This is stupid, given that Iran is cooperating with China and Russia and probably has long had radars that are hundreds or even thousands of kilometers away, they will be known and met about them before they arrive. So additional tanks are not for Israel.

[Alex_You]

Oddities of the China J-20 External Fuel Tank Test Report

Search for a black cat in a dark room where she is not.

[Vitaly Tsymbal]

If the Chinese Air Force considers equipping a fighter with additional tanks solely for a flight from one of its airbases to another, then what kind of flight is this, during which the pilot will need to use extra maneuverability and lay turns? ..

If you fly high - to maneuver between the peaks of Tibet and the Himalayas, if low - from the JI towers - 5, etc. ... But seriously, it is quite possible that aircraft on their territory "glow" with tanks, and when approaching In the air defense zone, the enemy, having dropped their tanks, becomes invisible. This is the development of tactical tasks, in the understanding of the Chinese generals.

[svp67]

Why, in this case, was initially reported to study the parameters of "stealth" when using tanks on an external sling.

but what if....

If the Chinese Air Force considers equipping a fighter with additional tanks solely for a flight from one of its airbases to another, then what kind of flight is this, during which the pilot will need to use extra maneuverability and lay turns? ..

, but what if...

[Revolver]

Quote: svp67

Why, in this case, was initially reported to study the parameters of "stealth" when using tanks on an external sling.

but what if....

If the Chinese Air Force considers equipping a fighter with additional tanks solely for a flight from one of its airbases to another, then what kind of flight is this, during which the pilot will need to use extra maneuverability and lay turns? ..

, but what if...

The doorbell rings a friend, he opens and it is clear that all that he is wearing underpants and a tie (option - only a tie).
- What are you in this form?
- But who will see?
- why tie?
- Well, you never know who will see!

[Krasnoyarsk]

= It is stated that such a flight may be in demand for fighters if they are transferred from one air base to another - remote. =
The length of China from North to South is -5.500 km., From West to East - 5.200 km.
The flight range of I-20 is 5.500km.
Where to fly with ext. tanks? To Africa!

[Bad_gr]

Quote: Krasnoyarsk

The flight range of I-20 is 5.500km.

About - 5500km on internal tanks lie.

Su-35
maximum take-off weight: 34500 kg
Fuel capacity kg: ------- 11200
Range of flight
with maximum fueling, km:
H = 0, M = 0,7 ---------------- 1580
NKR, MKR -------------------- 3600 (according to other sources 4000km)
Ferry range
with 2 x PTB-2000, km -------- 4500

J-20
Weight:
maximum take-off weight: 36 300 kg
Fuel mass: -------------- 11 100 kg
Range: ------------------ 5500 km

It turns out that a heavier J-20, with less sophisticated engines, with the same amount of fuel flies one and a half times farther than our S-35? this is from the realm of fiction.

[Chetbor]

I don’t see any oddities - as you know, there are PTBs that can be reset in flight, so there are PTBs that can not be reset in flight, so to speak, are screwed and unscrewed on the ground ...
It is clear for sure that the discharged PTBs have a lower value of normal and especially lateral overload
What they actually experience - only they know.
For some reason, no one is considering the option of barging an airplane on duty and studying this issue

[rotkiv04]

Well, they clung to the papalats, let it be already the best

[Vasyan1971]

Why, in this case, was initially reported to study the parameters of "stealth" when using tanks on an external sling.

And suddenly ... But it did not grow together.

[opus]

Quote: author

. If the Chinese Air Force considers equipping a fighter with additional tanks solely for a flight from one of its airbases to another, then what kind of flight is this, during which the pilot will need to use extra maneuverability and lay turns? ..

Why the author scoffs is not very clear ...
1. Depending on the flight mode and the shape of the tank, certain components of aerodynamic drag will prevail. For example, for blunt bodies of revolution moving at a high supersonic speed, the resistance is wave-like.
For well streamlined bodies moving at low speed, friction resistance and vortex loss prevail.

The rarefaction that occurs on the rear end surface of the streamlined body also leads to the appearance of a resultant force directed opposite to the speed of the body.
2. Fuel is consumed - the mass and position of the CM changes. EVERYTHING IS EQUAL to calculate and verify.

3. The fluid is considered as a concentrated decreasing mass with reduced dispersion and stiffness

4. Dumping suspension tanks after fuel consumption is dumped tsame as aerial bombs from locks of bomb rackson which they are suspended. Toko they will be more bombs + hollow (very low density)

You can’t just take the canister and screw it on.
Shl.
after the war, in the Vietnamese jungle, they began to find many fuel tanks dumped by American planes.

The peasants saw the tanks along and get two boats. Such a boat does not rust, weighs little, and thanks to the aerodynamic shape it is very easy to row on it

[voyaka uh]

Additional tanks - a thing useful for any fighter.
And stealth, and ordinary.
Stealth flies with extra tanks for a long distance, on approach to the enemy -
resets them and switches to stealth mode.
The same thing is with weapons on external suspensions.
Long-range shot from afar, and continue to fly with weapons in the internal
compartments.
----
Israel designed and manufactured such tanks before receiving their first F-35s.

[Avior]

Americans did not seem to do this.
Either hoping for refueling, or for other types of aircraft.

[bk0010]

And what would the stelt tanks not do? In shape like F-35, close to the wing (so that the corner reflector does not work out).

[agoran]

Hm. This is an interesting thing.
You can put an additional tank in the trunk of the car.
But you can not screw the PTB to the plane. Need a beam. Well, if roughly, an adapter with a valve.
Assume that the beam is discarded from the PTB, this c-t loses the suspension points.

[75 Sergey]

And what, flew to the zone, threw them so that they would not shine, did things and quietly screwed them back.

[slipped]

The Su-57 has something like this

[Marconi41]

Quote: slipped

The Su-57 has something like this

Of course it is! For the transfer of the aircraft from the Far East to the European part of the country, this will not be enough.

[Klingon]

and his nozzles are not flat therefore, I don’t understand why the Chinese drove away so many times and poked a finger about the absence of these at the Su-57 and Hunter

[Shurik_2]

The author is right when he noticed the strangeness of testing the Chinese, hanging tanks on over maneuverability. Many of you have not considered why this is done. China will not fight with the United States on the continent, but in the sea and ocean, for the islands. Those islands and reefs that they have washed are poorly protected. And those airfields that they built are easy to bomb. Therefore, holding stealth aircraft is dangerous. They will fly from the mainland and the distances there are not close, and we must take into account that the radius of the Chinese aircraft is much smaller than ours. And when the author wrote about the test of two or even four hanging tanks, it was not casual. Indeed, in addition to flying, you need fuel and to fight, as well as to return, we will take into account that the approach airfields can be destroyed.

[Evil 55]

A transparent hint that when approaching the AUG, the outboard tanks will be dropped, the aircraft will lower the ESR and have a chance to drown one of the Arly Berks or slap the Big Galoshes on the runway ..

[strelokmira]

Does an author make an idiot out of himself? Well, since the thing is useful for the fighter, and by the way, before the clash, no one bothers to drop the tanks, remove the pylons in the hull

[Dmitry Vladimirovich]

If the Chinese Air Force considers equipping a fighter with additional tanks solely for a flight from one of its airbases to another, then what kind of flight is this, during which the pilot will need to use extra maneuverability and lay turns? ..

What kind of amateurish questions - why do you even decide to write about something that gentlemen have no idea?

Suspension units and suspension equipment / armament is designed for certain overloads, and the purpose of the tests is to confirm the parameters laid down during the design.
If for someone this is not clear - do not write about something that you do not understand!

[iouris]

... but what would the adversary be able to unravel and contrast!