Chengdu J-20 5th Generation Aircraft News & Discussions

[sweetgrape]

Just see the pictures!

 

[gambit]

gr8 stuff this mechanism solves the problem of weapons bay creating a lot of rcs when opened. ...awsome stuff frm china

An overly complex solution for a problem that is not a problem to start.

 

[sms]

Just see the pictures!

Solution Looks too complicated, they could have done better!!
Any way kudos to Chinese engineers for doing something unique!!

 

[S-A-B-E-R->]

An overly complex solution for a problem that is not a problem to start.

mate comon i am not haitng on f22 it is a problem that many pilots and engnears talked abt in the US i think in the documantery abt futur air warfare the same problem is discussed.side weapons bay mostly house IR guided missles that need borsight locking and this method maked the j20 stealthy wile doing that but same canot happen in f22 because until an ir lock is achieved u canot close your bay doors and the radar reflicitivity from the bay makes the f22 visible to some level.

 

[gambit]

mate comon i am not haitng on f22 it is a problem that many pilots and engnears talked abt in the US i think in the documantery abt futur air warfare the same problem is discussed.side weapons bay mostly house IR guided missles that need borsight locking and this method maked the j20 stealthy wile doing that but same canot happen in f22 because until an ir lock is achieved u canot close your bay doors and the radar reflicitivity from the bay makes the f22 visible to some level.

You talk as if this issue was never considered during the design phase of the F-22. It was. And the fear was unfounded.

The difference between an opened weapons bay and an intake is -- PERSISTENCE. Meaning a jet engine intake is always there, always opened. But a weapons bay is not persistent. Doors opened and doors closed. In order for the weapons bay to be seen, a radar must look at it and here is where you are wrong. When a radar is looking at an aircraft, it sees only the aircraft side that is facing the radar, so if the weapons bay on the other side opens, it does not know.

This is an imaginary problem.

 

[S-A-B-E-R->]

You talk as if this issue was never considered during the design phase of the F-22. It was. And the fear was unfounded.

The difference between an opened weapons bay and an intake is -- PERSISTENCE. Meaning a jet engine intake is always there, always opened. But a weapons bay is not persistent. Doors opened and doors closed. In order for the weapons bay to be seen, a radar must look at it and here is where you are wrong. When a radar is looking at an aircraft, it sees only the aircraft side that is facing the radar, so if the weapons bay on the other side opens, it does not know.

This is an imaginary problem.

you r 100% rite but in a war where 10000 variables r in play u cant have a open wound and think that u ll just point it away from the enemy. yes the weapons bay opens and closes bur while it is trying to get a lock on enemy it has to stay open and in that time a second aircraft or a sam can not only detect the ac but also fire at it now i know the possibility of hitting the f22 like that r low but they r there and contengency theory states even the smallest variable can cause a lot of problems.

 

[sancho]

Now this is miles ahead of what F-22 has for firing side-bay missiles。

Hey，we might as well use the mechanism to air-luanch our beloved rockets。

It's indeed kind of interesting, but also more complicated than really needed. For example, you could have attached the raillauncher to the baydoor itself, so when it opens up, it directly extracts the missile as well. Like this:

So it opens (1), launches the missile (2) and closes again(3)
While this system in the J20 opens the doors (1), extracts the missile (2), closes the doors (3), launches the missile (4), opens the doors again (5), retracts the raillauncher (6) and close the door again (7).

Which should make the F35 sytem simpler and faster right?


Can you tell me what these 3 yellow parts are that are build in the airframe and extracts with the missile?

 

[gambit]

It's indeed kind of interesting, but also more complicated than really needed. For example, you could have attached the raillauncher to the baydoor itself, so when it opens up, it directly extracts the missile as well. Like this:

So it opens (1), launches the missile (2) and closes again(3)
While this system in the J20 opens the doors (1), extracts the missile (2), closes the doors (3), launches the missile (4), opens the doors again (5), retracts the raillauncher (6) and close the door again (7).

Which should make the F35 sytem simpler and faster right?


Can you tell me what these 3 yellow parts are that are build in the airframe and extracts with the missile?

The mentality is that if it is more complex, it must be more 'advanced', so in order to have the J-20 more 'advanced' than the American fighters, things must be more complex at the expense of engineering common sense.

 

[SQ8]

An overly complex solution for a problem that is not a problem to start.

I think the intention was to avoid Aerodynamic drag(and strain) arising from those bay doors opening and still allow the seeker of the missile to pop out and scan away.
Yet, it still does seem a complicated solution to a problem that does not seem to be obvious here.

The F-22 leaves its side bay's open in sidewinder employment(with its pylon pushing(canting) the missile but those bays are a snug fit.

 

[gambit]

I think the intention was to avoid Aerodynamic drag(and strain) arising from those bay doors opening and still allow the seeker of the missile to pop out and scan away.
Yet, it still does seem a complicated solution to a problem that does not seem to be obvious here.

The F-22 leaves its side bay's open in sidewinder employment(with its pylon pushing(canting) the missile but those bays are a snug fit.

The denial of the missile's ability to have its own sensor acquiring the target because of its enclosure is indeed a technical hurdle to overcome but not an insurmountable one. Lock-on-after-launch (LOAL) is not a new technology but its advancement was somewhat ignored because of the current configuration of the weapons' sensors being exposed, but now that is changing because of the need to prevent the weapons from contributing to the fighter's RCS. Aerodynamic drag from weapons bay doors is not a significant issue and even the flight control system of my -111 days was able to compensate for that.

 

[siegecrossbow]

It's indeed kind of interesting, but also more complicated than really needed. For example, you could have attached the raillauncher to the baydoor itself, so when it opens up, it directly extracts the missile as well. Like this:

So it opens (1), launches the missile (2) and closes again(3)
While this system in the J20 opens the doors (1), extracts the missile (2), closes the doors (3), launches the missile (4), opens the doors again (5), retracts the raillauncher (6) and close the door again (7).

Which should make the F35 sytem simpler and faster right?


Can you tell me what these 3 yellow parts are that are build in the airframe and extracts with the missile?

The yellow parts fill up the "gap", so to speak, when the weapons bay closes. I guess this is done as an RCS reduction measure, but I could be wrong.

 

[SQ8]

The denial of the missile's ability to have its own sensor acquiring the target because of its enclosure is indeed a technical hurdle to overcome but not an insurmountable one. Lock-on-after-launch (LOAL) is not a new technology but its advancement was somewhat ignored because of the current configuration of the weapons' sensors being exposed, but now that is changing because of the need to prevent the weapons from contributing to the fighter's RCS. Aerodynamic drag from weapons bay doors is not a significant issue and even the flight control system of my -111 days was able to compensate for that.

In my view, the actual complication here is not the trapeze that takes the missile out, its the need to close the doors.
Definitely has ZERO value in RCS reduction. So apart from reasons pertaining to drag I see no other as to why the door would need to be closed. Considering that you have already come that close that you need a WVR weapon, chances are you have exposed yourself and there is no need to try and stave off RCS spikes now.
Moreover, Chinese missiles such as the PL-5E-II already have LoAL slaved to the radar or IRST if need be.
Unless the Chinese want to ensure an uncaged mode as well.
I dont see the mechanism that complicated if its simply a rotating pylon as a trapeze like the one in the F-22's larger bays is surely more complicated But I do see unnecessary need to close the doors everytime you pop that heat-seeker out.

 

[gambit]

In my view, the actual complication here is not the trapeze that takes the missile out, its the need to close the doors.
Definitely has ZERO value in RCS reduction. So apart from reasons pertaining to drag I see no other as to why the door would need to be closed. Considering that you have already come that close that you need a WVR weapon, chances are you have exposed yourself and there is no need to try and stave off RCS spikes now.
Moreover, Chinese missiles such as the PL-5E-II already have LoAL slaved to the radar or IRST if need be.
Unless the Chinese want to ensure an uncaged mode as well.
I dont see the mechanism that complicated if its simply a rotating pylon as a trapeze like the one in the F-22's larger bays is surely more complicated But I do see unnecessary need to close the doors everytime you pop that heat-seeker out.

The weapons bay contributorship to RCS and aerodynamics issues are -- imaginary problems.

Incorporating an additional step and mechanism to compensate for them is certainly technically viable, but is it really worth it? To me, what I have seen so far is more about one-upmanship to the Americans than it is to solve a genuine problem.

 

[hk299792458]

The weapons bay contributorship to RCS and aerodynamics issues are -- imaginary problems.

Incorporating an additional step and mechanism to compensate for them is certainly technically viable, but is it really worth it? To me, what I have seen so far is more about one-upmanship to the Americans than it is to solve a genuine problem.

Aerodynamics issues are not imaginary, but not "upsetting".

The additional strain applied to the structure, is an another issue to be simulated and solved.

Henri K.

 

[gambit]

Aerodynamics issues are not imaginary, but not "upsetting".

The additional strain applied to the structure, is an another issue to be simulated and solved.

Henri K.

In this case -- it is.

The release of a bomb from a wing is structurally and aerodynamically more serious than the opening of a weapons bay. You are looking at a major structure that is present on one side of the aircraft but not on the other -- asymmetric drag or wing loading. You can lose as much as 2g on maneuver limits with such a condition. With external fuel tanks, an empty on one wing and a partial/full on the other wing will produce the same issues as with asymmetric aerodynamics.

When opened and present in the air stream, weapons bay doors present minimal profile and they are usually close to centerline/center-of-gravity. Their effects -- brief duration as it is -- have no noticeable effects on flight handling.