J-20 5th Gen Fighter Thread IV (Closed to posting)

[Totoro]

I don't know, i've been looking at images and the hinge is more or less the same length. it *may* be slightly lenghtened towards the MLG, but the different angles in different images make it hard to asses. And even if the hinge is lenghtened towards MLG, it wouldn't appear it's more than several cm worth. None of that is really proof of actual weapon bay wall being moved aft, in comparison to earlier prototypes. because the overhang of the serrated edges is now bigger, making the whole door longer, it may've been decided it requires slightly longer hinge to support the added weight.

what would've been immensely more benefitial than hypothetically lengthening the bay by several cm is making the underbelly structure stronger and devising some system (probably complicated, but then so is the side weapon ejection system) to support the weapon bay doors while closed - so the whole separator wall between the weapon bays is removed.

but i'm guessing there's a good reason why both f22 and j20 went with such a wall. maybe the added weight penalty of having such an unitary weapon bay is just too much. i'm guessing it'd require either much thicker and heavier doors with accompanying actuators or some sort of discreetly foldable yet heavy duty braces to move in place when doors are closed and to get out of the way when doors open.

 

[latenlazy]

I don't know, i've been looking at images and the hinge is more or less the same length. it *may* be slightly lenghtened towards the MLG, but the different angles in different images make it hard to asses. And even if the hinge is lenghtened towards MLG, it wouldn't appear it's more than several cm worth. None of that is really proof of actual weapon bay wall being moved aft, in comparison to earlier prototypes. because the overhang of the serrated edges is now bigger, making the whole door longer, it may've been decided it requires slightly longer hinge to support the added weight.

what would've been immensely more benefitial than hypothetically lengthening the bay by several cm is making the underbelly structure stronger and devising some system (probably complicated, but then so is the side weapon ejection system) to support the weapon bay doors while closed - so the whole separator wall between the weapon bays is removed.

but i'm guessing there's a good reason why both f22 and j20 went with such a wall. maybe the added weight penalty of having such an unitary weapon bay is just too much. i'm guessing it'd require either much thicker and heavier doors with accompanying actuators or some sort of discreetly foldable yet heavy duty braces to move in place when doors are closed and to get out of the way when doors open.

What sold it for me was the photos of the belly. It's the hinge from that angle compared to 2001/2. The serrations add a bit of length, but the hinge ends further back.

I don't think the increase is more than several centimeters either, but several cms worth of length probably enables a staggered arrangement with those mystery AAMs without having to crop the fins more, and might allow it to carry PL-21 sized missiles in a staggered arrangement too.

EDIT: This one. Note how the weapons bay doors end halfway past the MLG doors? In 2001/2 it ended at the start of the MLG doors.

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[Munir]

The middle wall is handy cause if you open the bay there is less room that can reflect radar. Besides that the different room can provide protection when damage is done by foreign objects. Whether it is slightly bigger is very difficult to see yet. But it does have logic. If you want some extra range in BVR you need slightly more length. I see the F22 more as air dominance fighter for medium range (due to AMRAAM capabilities) but the J20 is for me more the real long range in flight distance but also in BVR capabilities. Just mu 2 cents.

 

[Totoro]

we'll see. i just fear it may be years until we get images of open weapon bays. previous prototypes' images with open bays may've been an abberation that won't be repeated. unless PLA wants to send a message.

 

[latenlazy]

we'll see. i just fear it may be years until we get images of open weapon bays. previous prototypes' images with open bays may've been an abberation that won't be repeated. unless PLA wants to send a message.

It may well be years before we get a picture of the bay...but that's only one more thing stacked on the bundle of other mysteries, like the radar, or the role of the vents along the intake, or the WS-15, or the aerodynamic and RCS performance of the plane. To be honest I don't think the design has even been frozen yet. I don't think 2011 will be the final design iteration either. We're going to have to do a lot more spotting over the years...so now it just doesn't bother me that much that we don't have answers...

 

[Deino]

Maybe helpful ....

 

[yanyan25]

Left and right main landing gear wheel fairings are different.

 

[Air Force Brat]

Maybe helpful ....

Very much so, also shows the clipped inside relief cut on the port flapperon, as to the weapons bay, my own "limited insight" would suggest that the weapons bay remains largely the same in volume. The reason for my supposition is that internal weapons bays usually butt up against a forward and an aft bulkhead, to move either of those bulkheads further forward, or further aft is a major redesign, and might affect weight and balance etc, etc. Now, I know all about fuselage plugs etc, and it can be done, but I would suspect that the whole aircrafts initial design was/is centered around that weapons bay and its standard dimensions to carry available/proposed weapons/systems. That's just the way it is done, and you build the aircraft around those weapons, not saying you can't gain something here or there, by tweaking this or that, but you try NOT to have to change internal structure, but we shall see some day in the future????

As for that central longitudinal stringer separating the right and left weapons bays, that is necessary for the structural integrity of the whole aircraft, it ties it all together, and those doors are also very strong, but those center latches add immeasurably more strength when you begin to pull pos or neg gs on the airframe.

 

[delft]

Very much so, also shows the clipped inside relief cut on the port flapperon, as to the weapons bay, my own "limited insight" would suggest that the weapons bay remains largely the same in volume. The reason for my supposition is that internal weapons bays usually butt up against a forward and an aft bulkhead, to move either of those bulkheads further forward, or further aft is a major redesign, and might affect weight and balance etc, etc. Now, I know all about fuselage plugs etc, and it can be done, but I would suspect that the whole aircrafts initial design was/is centered around that weapons bay and its standard dimensions to carry available/proposed weapons/systems. That's just the way it is done, and you build the aircraft around those weapons, not saying you can't gain something here or there, by tweaking this or that, but you try NOT to have to change internal structure, but we shall see some day in the future????

As for that central longitudinal stringer separating the right and left weapons bays, that is necessary for the structural integrity of the whole aircraft, it ties it all together, and those doors are also very strong, but those center latches add immeasurably more strength when you begin to pull pos or neg gs on the airframe.

The bulkhead aft of the weapons bays carries the main landing gear. If the main landing gear isn't moved than the bulkhead remained in the same place.

 

[Hyperwarp]

I PSed the landing gear off this image - link