Chinese Stealth Plane Sucks

[W.E.B. Du Bois]

When the Chinese stealth plane came out, I forget my reaction. I don't know if I thought the design was decent or a bad one. I do think my outlook on the plane is a lot different now, a lot worse for the plane. The plane is not stealthy. The J-20 has canards, or foreplanes, or small wings in front of the main wing in order to provide balance and lift to the midsection of the plane, since its wings are situated further back.

It also has two stabilizing fins in the back. In my opinion, the US F-22 set the standard for stealth planes and the Russian T-50, Chinese J-20 and J-21 have similar designs. The F-22 does not have the shortcomings of the Russian (exposed engine nozzles) and Chinese planes (exposed engine nozzles, canards and stabilizing fins). All of these things are radar reflectors (and in the case of the engines uncovered heat sources for infrared to track) and thus unstealthy.

http://www.documentingreality.com/forum/attachments/f181/251749d1299306116-so-im-interested-russian-military-pictures-s27j20t50f22.jpg

The J-20:

http://www.defenceaviation.com/wp-content/gallery/j-20-maiden-flight/tshdc.jpg

Just to be clear to people with a passing interest in this stuff, what I don't like about J-20 is the two small wings at the front of the plane, and the two tiny wings under the plane near the engines. The two small wings are called canards and they tilt on the vertical axis, considerably decreasing the plane's stealth.

I can only guess why China went with such an unstealthy design when they know it is an inferior design. The J-21, China's answer to the US F-35 fighter (think of a mini-F-22 that has a strong ground attack capability) also looks like a mini-F-22.

Pictured below: the even more newly revealed Chinese J-21 multirole fighter (this is the little brother to the J-20, just like the F-35 is the little brother to the F-22).

http://cnair.top81.cn/fighter/J-21_model.jpg

Why did China go with this piece of shit design for the J-20, which is a heavy weight fighter?

Possible answers:

* For some reason the bad design is necessary and China has just accepted it due to some kind of technology constraint
* It's just a technology demonstrator which will test out technologies for the real thing

I posed this question to the Chinese Defense Forum, which is a fairly nationalist but also fairly knowledgeable website on the Chinese military. It's also the most credible English-speaking website on the Chinese military.

I'll be posting up the replies which are not insults (I dared question the great J-20, so I expect to be insulted).


WEB

[W.E.B. Du Bois]

Here's the reply I got back:

Canards are neither inherently stealthy or unstealthy. They are just another surface (like wings or vertical stabilizers) that you have to shape and account for. The general principle is that the fewer surfaces you have the better, but it's about the net result of the entire air frame and not the individual features. In short it means we don't know how stealthy or unstealthy a design is unless we're signal engineers who have the right model and tools to test. In the end RCS is a number, not a collection of features.

As for the rear fins, I imagine the engineers thought the aerodynamic benefits were worth the trade off. Some speculate that the fins will be deleted when the J-20 is installed with TVC, but the way I see it the rear stealth is already compromised anyways, and what it has in added signal returns from the fins, it makes up for with a smaller vertical tail. Furthermore, the rear fins are probably no worse than tail planes. They're surfaces behind the wing whose shaping and signals returns need to be accounted for, just like tailplanes.

As for your first question about what role we expect the J-20 to play...everything we've heard from the PLA seems to indicate that they intend this to fulfill air superiority as one of its roles. There's no sense in putting canards on a design if it's simply going to be a pure interceptor. Furthermore, we've never seen China actually do a demonstrator, so the design is probably intended for mass production, though not without revisions to the air frame I imagine, as they're still doing tests.

I think this is a foolish reply, though I did not say so on that forum. I did not reply at all, since it would likely escalate, and I would lose since I don't tolerate insults well and I'm arguing in favor of reason against the pro-nationalist circle-jerk position on a forum with many Chinese nationalists.

In any case, I reject this argument because the idea behind stealth is to minimize the radar cross section (RCS). Quibbling about the word choice between "unstealthy" and higher "RCS" is just the nationalist circle-jerk. It's the same thing by a different name.

I think that as a plane with canards moves, its canards will move at a greater angle than the ailerons would on a plane without canards, thereby increasing the RCS more than a design without canards.

A plane with canards has the advantages of carrying a heavier payload while keeping excellent manueverability. However, why build a stealth plane that compromise stealth even more than it already compromised stealth with its exposed engines and fins on the underside of the plane? This comes to my tentative conclusion: that the Chinese military (the PLA) has basically made a mistake in its fighter design. It is a mistake to create a stealth plane that makes considerable reductions in stealth to achieve more maneuverability and lift. Maybe what China really wants from the canard-delta configuration is to increase lift and thereby increase range.

Maybe they should have ditched the canards and gone with a bigger plane instead, or invent drop tanks for a stealth aircraft.