J-20... The New Generation Fighter III

latenlazy said:

You should also keep in mind that roughly speaking the average height for people above the age of 30 is shorter than below the age of 30 for historical demographic reasons, and there is a noticeable geographic difference. I feel pathetically average height wise when I'm in Tianjin, but magnificently tall in Shanghai. Whether these differences really translate to significant differences in a picture or not is ambiguous, but I did say the landing gear height was an important factor

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what does age have anything to do with it??? I was responding to your explanation for the small size of the people relative to the plane. You obviously did not talk about the age of the people, but only ethnicity.

With regard to whether human eyes can pick up the height difference from this distance, the answer is no. First of all, no one can tell how tall those people are without a reference. this means, unless you have someone with known height standing next to those guys, you simply cannot tell how tall they are . For all we know, they could be a bunch of basketball players that are well above 6'. Without a reference, no one can tell. Our eyes don't have the kind of resolution to pick up the difference without the reference in the same photo. If you don't believe me, try to estimate the height of the pilot in the photo I posted in Post 1269. Also, our eyes play tricks with us all the time in terms of size of objects. Simply look at how they made the "hobbit effects" in the "lord of the rings"...

vesicles said:

what does age have anything to do with it??? I was responding to your explanation for the small size of the people relative to the plane. You obviously did not talk about the age of the people, but only ethnicity.

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Well, age does have a story to tell. Most of the people in that picture are probably around or passed middle age, meaning they grew up in a period of time when nutrition wasn't so good in China, and to my knowledge this reflects in the demographic data.

With regard to whether human eyes can pick up the height difference from this distance, the answer is no. First of all, no one can tell how tall those people are without a reference. this means, unless you have someone with known height standing next to those guys, you simply cannot tell how tall they are . For all we know, they could be a bunch of basketball players that are well above 6'. Without a reference, no one can tell. Our eyes don't have the kind of resolution to pick up the difference without the reference in the same photo. If you don't believe me, try to estimate the height of the pilot in the photo I posted in Post 1269. Also, our eyes play tricks with us all the time in terms of size of objects. Simply look at how they made the "hobbit effects" in the "lord of the rings"...

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Relax, the height comment was a more of a joke than a committed point of analysis. I'm not disagreeing with you.

Let's leave the height for somewhere else.

i'm interested on hotdog's comment in keypub, the serration on J-20 appears to be smaller than the ones on F-22 and T-50

would that imply that J-20 is optimized for shorter wavelength RF LO?

which also reminds me on quellish's comment on secretprojects, that J-20 canopy is tailored to different wavelengths compared with the F-22

an edit on previous J-20 pic

paintgun said:

i'm interested on hotdog's comment in keypub, the serration on J-20 appears to be smaller than the ones on F-22 and T-50

would that imply that J-20 is optimized for shorter wavelength RF LO?

which also reminds me on quellish's comment on secretprojects, that J-20 canopy is tailored to different wavelengths compared with the F-22

an edit on previous J-20 pic
View attachment 5518

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Here's the tricky part. Quellish made the argument that the J-20 was optimized for longer wavelengths, but the smaller sawtoothing indicates optimization against shorter wavelengths. What this tells us is that no one really knows how the J-20 is optimized.

well, it is more probable that he/she does not exactly know which wavelengths the J-20 is optimized on, the assumption for longer wavelength might stem from the previous idea that the J-20 is a long-range interceptor/striker

the serrations on J-20 is indeed much smaller, which hints on optimization against enemy fighter radars and missiles

someone in Chengdu really wants to clear the sky off the F-22s

J-20... FC-1... J-10B... Take-off... a little flying... landing... taxi... Best quality video yet!

If anyone finds this on Youtube... please post. My realplayer download only capture 7mins.

From 5:30mins onwards...

"News of J-20 flying demo received positive comments... J-18 VTOL-Stealth jet leaked out, carrying out intense experiments now."

Reports from Pheonix TV

[video=youtube;OjEquYz61V4]http://www.youtube.com/watch?v=OjEquYz61V4[/video]

Not sure about the J-18 though as reports said that the plane is now in Chengdu as well. Programme is in Chinese.

Depends if the serration is a band stop or high pass measure(effective for blocking a band of frequencies vs being effective for frequencies below a certain threshold).

It could be that the smaller serration is designed for shorter wavelengths but also equally effective for longer wavelengths. Just like the wire mesh on your microwave oven is designed to block around 2.4 GHz but will also stop lower frequencies although it is not designed to. It however won't block higher frequencies which is why you can still see your food inside. If the wire mesh is made fine enough eventually you will not even be able to see your food.

In these type of structures to be effective they have to be smaller or close to comparable size for the wavelength they are trying to affect. Higher frequency -> smaller wavelength and hence you need finer structures.

Lion said:

The plane is simply huge. Did you see how smAll the guy standing on top of the plane?

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Somewhat off-topic but the guy is probably standing on the other wing and has most of his legs cut off from view, so he appears to be small. The guys standing on the ground might be a better indicator.

You can just remove the landing gear then compare with one of the guys on the ground, then the plane won't look nearly as big, just slim and long. J-10 is actually taller than it due to the chin intake.