J-20 5th Gen Fighter Thread IV (Closed to posting)
- Thread starter siegecrossbow
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usaf0314
Junior Member
An alternative depiction on how the rail system works.
Tags: China; Imgur; J-20; SRAAM rail; animation; missile rail; operation; side weapon bay;
nice model. Although, i think there are too many sequences in the simulation.
Instead of Open>toggle>close>fire>open>toggle>close, it should be Open>toggle>fire>toggle>close. the longer the bay and the missiles are exposed, the more the aircraft is exposed to conventional radar.
SteelBird
Colonel
An alternative depiction on how the rail system works.
Tags: China; Imgur; J-20; SRAAM rail; animation; missile rail; operation; side weapon bay;
Does that mean it can carry only one missile at a time?
It's designed to, yes. F-22's side bays only hold one sidewinder each. Same for T-50 with its dedicated SRAAM "pods"
superdog
Junior Member
As someone has pointed out earlier, not all short range AAM is capable of lock-on after launch (LOAL), which means they need to stay outside during a dog fight to be prepared to acquire target. A F-22 equipped with AIM-9M will have to open its side bay to acquire a lock, it can't just open and launch immediately. Even for AAM missiles that are capable of lock-on after launch (e.g. AIM-9X, ASRAAM), the launch sequence from internal bay will take a bit of extra time and locking performance may be affected.
When opening a side bay, radar reflection may not be the biggest concern because side bay is usually used at visual or near visual range, IR signature is more relevant to weapons used at this range. When he is in range to use that short range AAM, a J-20 pilot probably won't worry too much about having a missile sticking out increases his radar signature. A bigger drawback could be the impact to aerodynamics when the door opens, as well as the time it takes to open that door if you want to fire in a small time window (for LOAL missile). The J-20 design seems to have found the solution in bringing it out early yet minimize aerodynamic impact, even though the missile sticking out still adds a little bit of drag. The F-22 design appears to rely on the LOAL ability of the AIM-9X upgrade to minimize time that the bay door has to open, even though at time of launch there will still be a small delay. If it is only "Open>toggle>fire>toggle>close" for the J-20, it defeats the purpose of using that design.
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plawolf
Lieutenant General
I agree with superdog, I think the J20 is designed to be able to go into 'dogfight mode' if so desired, whereby the SRAAMs are deployed from the weapons bays with the weapons bay closed behind them just before entering WVR combat instead of waiting till just before weapons launch to open.
This will mean some aerodynamics and RCS penalties, but if you are deploying SRAAMs, chances are the enemy are close enough to see you on radar even if you were flying 'clean'/close enough to eyeball you, or that you had used your stealth to get on their six for an easy kill, so the RCS hit shouldn't mean much.
What you gain from this is a much shorter response time between lock-on and missile launch, and a much smaller aerodynamics penalty than if you were trying to digfight with weapons bays open. In addition, you shouldn't get any aerodynamic surprises, in that I mean that if you were doing extreme manoeuvres and open your weapons bay, the extra drag could be similar to deploying air brakes and cause your plane to behave unexpectedly, which might be enough to spoil a shot if you are unlucky.
You can mitigate this with training, but its something else the pilot needs to keep in mind, so there is always the potential that he might forget in the heat of the moment when he is almost blacking out from the Gees and is under enormous mental pressure and strain.
Something else to consider is I have always wondered just how much an AAM sticking out of the Raptors bay can see on the other side of the plane since the seeker head is pointing away from the nose of the plane. So, if a Raptor fired his left AIM9, for example, how much more would he have to point the nose to get a tone on another target on his left with the right bay missile? It should not be much, but when you are in a dogfight, every small fraction of an advantage can make all the difference. Again, this would be less of a problem with the J20's approach.
The main downside to the J20 approach is that the sides of the plane would be exposed to a lot of heat and jet blast from the missile engine, and we all know how delicate stealth coatings can be, so there is a risk that high intensity use might result in degradation to the stealth coatings on the sides on the plane, which is something ground crews would need to look out for. But since the bays only carry one missiles, they should be able to make sure the coatings can take at least one more launch before each mission. Worst case scenario, they design easy peal patches of coating for the affected areas and strip and re-apply those patches every 1, or 5 or however many launches those patches are proven to be able to withstand. That might drive up operating costs, but considering these measures would only kick in during war time, a few extra millions on maintenance would be the least of anyone's worries.
This will mean some aerodynamics and RCS penalties, but if you are deploying SRAAMs, chances are the enemy are close enough to see you on radar even if you were flying 'clean'/close enough to eyeball you, or that you had used your stealth to get on their six for an easy kill, so the RCS hit shouldn't mean much.
What you gain from this is a much shorter response time between lock-on and missile launch, and a much smaller aerodynamics penalty than if you were trying to digfight with weapons bays open. In addition, you shouldn't get any aerodynamic surprises, in that I mean that if you were doing extreme manoeuvres and open your weapons bay, the extra drag could be similar to deploying air brakes and cause your plane to behave unexpectedly, which might be enough to spoil a shot if you are unlucky.
You can mitigate this with training, but its something else the pilot needs to keep in mind, so there is always the potential that he might forget in the heat of the moment when he is almost blacking out from the Gees and is under enormous mental pressure and strain.
Something else to consider is I have always wondered just how much an AAM sticking out of the Raptors bay can see on the other side of the plane since the seeker head is pointing away from the nose of the plane. So, if a Raptor fired his left AIM9, for example, how much more would he have to point the nose to get a tone on another target on his left with the right bay missile? It should not be much, but when you are in a dogfight, every small fraction of an advantage can make all the difference. Again, this would be less of a problem with the J20's approach.
The main downside to the J20 approach is that the sides of the plane would be exposed to a lot of heat and jet blast from the missile engine, and we all know how delicate stealth coatings can be, so there is a risk that high intensity use might result in degradation to the stealth coatings on the sides on the plane, which is something ground crews would need to look out for. But since the bays only carry one missiles, they should be able to make sure the coatings can take at least one more launch before each mission. Worst case scenario, they design easy peal patches of coating for the affected areas and strip and re-apply those patches every 1, or 5 or however many launches those patches are proven to be able to withstand. That might drive up operating costs, but considering these measures would only kick in during war time, a few extra millions on maintenance would be the least of anyone's worries.
plawolf
Lieutenant General
Just to add, them deploying the missile rail is the first step to weapons integration trials. We are still a while off, but I would not be surprised if the next time we sell these rails, they got AAM dummies attached.
I also wonder if leaving the rail out on landing was intentional or not. It seems like an unnecessary thing to do/test, and even if they wanted to test the aerodynamics, surely they would start with both rails deployed instead of just one. The only reason to land with one rail deployed would be to test how the plane would handle in the event one of the rails jam/fail and cannot be retracted.
Maybe that was what they were testing, but it just seem like such a minor detail to test at this early stage of development.
Right now, I am leaning more on the possibility the test pilot simply forgot the rail was deployed after tests, which would indicated that the aerodynamics impact on deploying the rails are very minimal.
I also wonder if leaving the rail out on landing was intentional or not. It seems like an unnecessary thing to do/test, and even if they wanted to test the aerodynamics, surely they would start with both rails deployed instead of just one. The only reason to land with one rail deployed would be to test how the plane would handle in the event one of the rails jam/fail and cannot be retracted.
Maybe that was what they were testing, but it just seem like such a minor detail to test at this early stage of development.
Right now, I am leaning more on the possibility the test pilot simply forgot the rail was deployed after tests, which would indicated that the aerodynamics impact on deploying the rails are very minimal.
Speaking on behalf of the many here that are neither professional or enthusiasts regarding Aero Engineering and Project Development, would those of you that are, be so kind as to help the rest of us understand the general arguments by producing a schedule of the development process by which a modern Military Aircraft is produced and tested and the typical time scale of each phase.
Thanks
Thanks
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