Chengdu J-20 5th Generation Aircraft News & Discussions

[Asoka]

1.) Just as I thought I was done with figuring out the length and width of J-20, I have a persistent urge to verify and confirm, whether the actual wingspan of J-20 is: 13.47m, as stated in the blurry low resolution satellite picture.

2.) To improve the possibility of a better estimate, I took the blurry picture, which was only about 300 pixels across, and resized it to 800%.

3.) This would allow me to view the resultant picture, across my 27 Inch screen, in its new size, and apply the thinnest red lines, that the iMac Preview would allow.

4.) Using the J-15's wingspan of 14.7m as scale, I resized the Metric meter, so the 14.7m falls exactly between the redlines of J-25's wingspan.

5.) I then copied the metric meter image and applied it to the J-20 wingspan.

6.) It yielded the new wingspan value of 14.0m for J-20, which is about 58cm longer than the old value of 13.47m.

7.) I noticed that J-20 was not parked exactly parallel to J-15, but slightly tilted to the left. So I used the Pythagorean theorem to adjust the value to 14.05m.

8.) J-15's wingspan is indeed longer than J-20's wingspan, but its only 0.42m longer, not 1.10m.

9.) The new wingspan values still have rooms for doubts or improvement, since the estimate is based on original low resolution satellite picture, that is extremely blurry.

 

[Figaro]

看到了，你确定这个董玉玺就是航展接受采访的那个董工吗？
下面这些话是这个董工的采访记录，这是一个航发工程师能说出来的话？

tp://www.ycwb.com/ePaper/ycwb/html/2014-11/13/content_579814.htm?div=-1

记者：12000KGF-14000KGF有什么含义？
老董：这是说明太行发展了很多种机型，我们最好的发动机已经达到14000公斤的推力。（苏35的发动机推力为14500公斤）
记者：达到这样的推力，就是说太行发动机与苏35的发动机推力大致相当了？
老董：是的，而且我们还在向前发展，这几年一直在完善和发展。这是最新的涡扇10发动机，已经定型了。
记者：它已经量产了吗？
老董：已经大批量装上歼10B、歼11B和运20。
记者：为什么歼10，比如八一飞行表演队的歼10用的还是俄罗斯的发动机呢？
老董：中国购买了那么多俄罗斯的发动机，还有已经装上的俄罗斯发动机还没到寿命，当然还要用呵。
记者：涡扇10在发动机寿命和稳定性方面与俄罗斯、美国三代机上的发动机比怎么样？
老董：这方面我们差一些，也可以说有较大的发展空间，比如说有些材料在科研单位的数据是不错的，但在实际应用时，还是不尽如人意，这就是研究航空发动机的难处，一个发动机要在相当长的时间内逐步完善它的稳定性，就算是美国也要十来年，而且还不算他们的预研阶段。
记者：网上有人质疑中国发动机不行，说太行发动机只有300小时的寿命，这是否属实？
老董：这个错大了，我们太行的寿命是1500小时，按照设计要求，300小时是定期维护。（林丹）
http://www.ycwb.com/ePaper/ycwb/html/2014-11/13/content_579813.htm?div=-1

Do you guys remember this interview with an employee working on the WS-10 in late 2014? Back then, the highest thrust (presumably the WS-10B or WS-10G) was already at 14,000 kgf. This was 3 years ago. I think that the J-20's WS-10X thrust is at least 14 tonnes (in line with what Pupu said) at this point, maybe even more to 14.5 tonnes given the large improvements over the past 3 years. It wouldn't surprise me if this WS-10B was indeed the IPE ... and we just don't know it yet.

 

[Asoka]

1.) By using the new wingspan estimate of 14.05m for J-20, I applied the same method to find the length as before.

2.) This yielded the following:

a.) Overall Length, J-20: 22.8m, F-22: 18.8m, Difference: 4.0m, or 21.3% longer
b.) Nose to Nozzle length, J-20: 21.7m, F-22: 16.7m, Difference: 5.0m, or 29.94% longer

That is from nose to nozzle J-20 is 5 meters, or nearly 30% longer than F-22.

Those extra 5 meters long fuselage could give J-20 enormous volume to store extra internal fuel.

The F-111's length is similar to J-20, but probably has wider fuselage, it has "Fuel tanks were distributed through the fuselage and in the wings, providing a total fuel load of over 19,000 liters (5,000 US gallons) or 18.56 tons." --http://www.airvectors.net/avf111.html

Like F-22, F-111 and J-20 also have a large internal weapon bay, so the amount of space taken up for such purpose should be similar.

J-20 definitely has a much greater internal fuel capacity than F-22's 8 tons. It's internal fuel capacity is probably in the range of 12-15 tons, or 50-87.5% more than F-22's 8 tons.

This is not yet including the 4 external fuel tanks, which could add another 8 tons of fuel.

This is totally astounding and mind boggling.

Note the Combat Range of F-111 is 2,140km, and Ferry range is: 6,760 km, Max. Speed is: Mach 2.5 . J-20's performance should be no less than that.

F-111 Performance

• Maximum speed: Mach 2.5 (1,650 mph, 2,655 km/h)
• Combat radius: 1,330 mi (1,160 nmi, 2,140 km)
• Ferry range: 4,200 mi (3,700 nmi, 6,760 km)
• Service ceiling: 66,000 ft (20,100 m)
• Rate of climb: 25,890 ft/min (131.5 m/s)
• Wing loading: ** Spread: 126.0 lb/ft² (615.2 kg/m²)
  • Swept: 158 lb/ft² (771 kg/m²)
• Thrust/weight: 0.61
  
• Lift-to-drag ratio: 15.8

Powerplant: 2 × Pratt & Whitney TF30-P-100
Lat turbofans

• Dry thrust: 17,900 lbf (79.6 kN) each
• Thrust with afterburner: 25,100 lbf (112 kN) each

J-20 will be powered by two an amazingly powerful engines, WS-15, capable of, at least 210kN, of Maximum thrust, which is 100kN more than F-111's PW TF30-P-100's 112 kN.

I would bet J-20 and F-22 (because of their powerful engines, and highly aerodynamic airframes, with high lift-to-drag ratio) will be able to fly a lot faster's F-111's top speed of Mach 2.5 (F-111's highly swept back wings, allow it to have this kind of super fast performance).

Because of it long and slender shape, J-20 could possibly capable of cruising, beyond Mach 3.0, with its afterburner turned on.

 

[Deino]

OMG .. Asoka again at his best.

+210 kN minimum thrust... Mach 3....

OMG

 

[Asoka]

OMG .. Asoka again at his best.

+210 kN minimum thrust... Mach 3....

OMG

Cruising near Mach 2.0, w/o AB, and cruising near or above Mach 3, with AB on.

There is a very good reason, why USAF won't disclose, the maximum speed of F-22, and keep it classified, because the top speed of F-22, could be shockingly high. If a F-15 and F-111 could do Mach 2.5, over 4-5 decades ago, F-22 could definitely go much faster, if it could supercruise, w/o AB, at Mach 1.6+.

 

[Ultima Thule]

Cruising near Mach 2.0, w/o AB, and cruising near or above Mach 3, with AB on.

There is a very good reason, why USAF won't disclose, the maximum speed of F-22, and keep it classified, because the top speed of F-22, could be shockingly high. If a F-15 and F-111 could do Mach 2.5, over 4-5 decades ago, F-22 could definitely go faster.

@Asoka as per your theory both F-22 and J-20 can't maneuver at the top speed because increase in speed reduced capability of agility and maneuverability remember the SR-71 which had cruised at MACH-3 and its had a excess IR signature at this speed lost of purpose of stealth and you're just assuming that if you have valid source please provide us,your F-15 and F-111 theory is valid that doesn't mean F-22 and J-20's top speed is above mach 2.5 and not to forget at above mach 2.5 jet engine have turbine and compressor problems starting within the engine like MIG-31 have

 

[Figaro]

OMG .. Asoka again at his best.

+210 kN minimum thrust... Mach 3....

OMG

I regrettably ignored him ... since then, this thread has seemed to calm down

@Asoka as per your theory both F-22 and J-20 can't maneuver at the top speed because increase in speed reduced capability of agility and maneuverability remember the SR-71 which had cruised at MACH-3 and its had a excess IR signature at this speed lost of purpose of stealth and you're just assuming that if you have valid source please provide us,your F-15 and F-111 theory is valid that doesn't mean F-22 and J-20's top speed is above mach 2.5 and not to forget at above mach 2.5 jet engine have turbine and compressor problems starting within the engine like MIG-31 have

You’re wasting your time here ... he ain’t gonna listen to you at all.

 

[Ultima Thule]

You’re wasting your time here ... he ain’t gonna listen to you at all.

i'm trying to correct him from his falsehood

 

[Figaro]

i'm trying to correct him from his falsehood

How can you correct him if he refuses to believe?

 

[Asoka]

Someone has said stealth plane can't fly at Mach 3?

I guess some people never heard of "High Temperature Ceramic Based Radar Absorbing materials."

I already posted this on Jan 7, 2017.

https://defence.pk/pdf/threads/chen...news-discussions.111471/page-499#post-9078781

High Temperature Ceramic Based Radar Absorbing materials.
高温吸波材料基体的研究
http://mmwqz.com/960261163/

This new class of Ceramic Based Radar Absorbing Materials is High Temperature heat resistance, anti-oxidation, high strength and fracture resistant.

In contrast to polymer based materials, this class of materials must be baked in high temperature oven. This is different from the applied (涂覆型 ) absorbing polymer rubbery materials, which could be easily damaged by rain, heat, sands, or even just by stepping on it.

This over come the heat problem that prevents radar absorbing materials to be use on missiles, inside the jet engine nozzle, and high speed aircrafts.

This class highly heat resistant materials could also forms a barrier to prevent high heat from entering the skin of the aircraft and damage the internal structure or delicate electronics equipments inside it.

http://www.yhclgy.com/ch/reader/view_abstract.aspx?file_no=2276&flag=1
Current Study of High Temperature Radar Absorbing Materials
高温吸波材料研究现状

http://www.hgxx.org/News_View.aspx?id=415
高温吸波材料研究新进展与趋势

One of the paper I read said those High Temperature Ceramic Based Radar Absorbing Material could withstand 600C degree celsius, which is more than enough for cruising at Mach 3.

https://www.space.com/16666-sr-71-blackbird.html:

"The aircraft (SR-71, Blackbird) was also covered with a special black paint to absorb radar, radiate excess heat and to camouflage the aircraft against dark skies — a feature that inspired Air Force to give it the official "Blackbird" name.

Titanium skin helped protect the aircraft's aluminum airframe from the intense heat of supersonic flight. Temperatures ranged from 450 degrees F (232 C) near the back part of the aircraft to 950 degrees F (510 C) near the engine exhaust.

 

[grey boy 2]

Nice

 

[Figaro]

Nice

J-20B? Too bad no backside ...

 

[Michael Corleone]

basically, carbon titanium based composites?

 

[leapx]

J-20B? Too bad no backside ...

probably just different angle or a new painting

 

[leapx]

basically, carbon titanium based composites?

I dont know what carbon titanium based composites is.
there was some discussion about material used in J-20
20% titanium，29% composites.