MiG-29
Banned Idiot
Do you have a link for that paper?
J-20... The New Generation Fighter III
- Thread starter siegecrossbow
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Do you have a link for that paper?
It does seem that there are yet many questions about the stealthy coatings of all our birds, but the fact remains that the use of those materials will in some manner reduce the absolute top speed. All of which is interesting, but when talking about a fifth generation aircraft the airframes have all been optimized for stealth which involves the use of these super duper composite coatings. Long story short even paint increases weight as well as drag, the ability to operate within a hostile environment with a relatively low risk of being observed increases the odds of mission success and survivability. For my money, thats the best game in town.
Oh, I'm certainly not questioning that, but composites are not a bunch of materials that all share the same general properties. By the nature of their identity (or rather lack thereof) they're varied, and new ones are constantly invented that exhibit new and different properties, so I'm a bit suspicious if someone just goes out there and says "composites limit an airframe to x speed". The first question that comes to mind in response to that is "which/what composites are you referring to."
Quickie
Colonel
Source of that info? I'm sure if the engine prototype had not passed the required MTBO in the early design stage, the WS-10 wouldn't have passed the prototype stage and proceeded to LRIP. The previously reported WS-10 problem had more to do with production which had to do with production equipment and training and skills of factory personnel. I believe most of the problems have already been solved judging by the number of flying WS-10As. Even the slower spooling has been solved - there's a video showing a J-10B with WS-10x taking off with a very quick spool up.
plawolf
Lieutenant General
With the new evidence of the flameholders, I am starting to be turn around in thinking that the J20 prototype might be running on some sort of AL31 derivative.
I also do not see why it would be so hard to accept that the AL31 is at present, a more reliable choice in the sense that it is much more mature and well-known, by both pilots and ground crews.
The WS10A may well be a more reliable design compared to the AL31FN in that it has much better MTBO and operating life, but it is only just entering service with the J11Bs.
Testing, no matter how exhaustive, cannot truly simulate for large scale operational deployment, and many of the world's best and most famous jet engines had teething problems after they entered service even though they have all been cleared by testing.
When you are dealing with a brand new prototype, that is one problem you could do without.
Another reason for using AL31s could be pure power. There is no denying that the latest AL31 models offer more thrust compared to the WS10A, and since the J20 is designed to flying with the far more powerful WS15, having more power would allow them to get to a better job of testing it now.
Hell, let us all not forget that the first pictures of the J20 did indeed show it with the distinctive AL31 nozzle. It could be that that was a second prototype, or that they changed engines, but it is also possible they just changed or painted the nozzles.
The obvious question we need an answer to if we suppose the J20 is flying with AL31s with different/painted nozzles is why the different nozzles?
Detractors would claim vanity, but I do wonder if it could be because AL31 versions not officially cleared for export had been transfered on the side by Saturn, possibly as a 'sweetener' to entice CAC to sign the latest 123 AL31FN engine order.
If such a deal was struck, Saturn is not going to be bragging about it (I cannot think of why they would not tell everyone and their dog that the J20 was using their engines otherwise as a marketing tool if it really was using AL31 variants), and may have requested the cosmetic changes to avoid Rosoboronexport officials from asking them awkward questions.
I also do not see why it would be so hard to accept that the AL31 is at present, a more reliable choice in the sense that it is much more mature and well-known, by both pilots and ground crews.
The WS10A may well be a more reliable design compared to the AL31FN in that it has much better MTBO and operating life, but it is only just entering service with the J11Bs.
Testing, no matter how exhaustive, cannot truly simulate for large scale operational deployment, and many of the world's best and most famous jet engines had teething problems after they entered service even though they have all been cleared by testing.
When you are dealing with a brand new prototype, that is one problem you could do without.
Another reason for using AL31s could be pure power. There is no denying that the latest AL31 models offer more thrust compared to the WS10A, and since the J20 is designed to flying with the far more powerful WS15, having more power would allow them to get to a better job of testing it now.
Hell, let us all not forget that the first pictures of the J20 did indeed show it with the distinctive AL31 nozzle. It could be that that was a second prototype, or that they changed engines, but it is also possible they just changed or painted the nozzles.
The obvious question we need an answer to if we suppose the J20 is flying with AL31s with different/painted nozzles is why the different nozzles?
Detractors would claim vanity, but I do wonder if it could be because AL31 versions not officially cleared for export had been transfered on the side by Saturn, possibly as a 'sweetener' to entice CAC to sign the latest 123 AL31FN engine order.
If such a deal was struck, Saturn is not going to be bragging about it (I cannot think of why they would not tell everyone and their dog that the J20 was using their engines otherwise as a marketing tool if it really was using AL31 variants), and may have requested the cosmetic changes to avoid Rosoboronexport officials from asking them awkward questions.
Quickie
Colonel
IMO, I think the reason for sticking to AL-31FNs for exsiting J-10s is just that modifying and messing around the structure of the aircraft to accomodate a new engine is time consuming, costly and may affect the integrity of the aircraft's structure.
once more, paper refers to methodology of choosing composite construction materials for 'prospective frontline fighter' which is euphemism used for PAK FA here, and talk of speed limits vs. reasonable efforts implementing various composites refers to specific aircraft types (i.e. fighters)
Doesn't really address the point...
Engineer
Major
So your own reference shows Al-31 caused J-10 to crashed then. Thank you for proving my point! Don't forget that there are also "success stories" of how pilots guide unpowered planes back to the airport -- unpowered because of lubricant issues in the Al-31FN.
As for that first crash listed by Wikipedia, it is a rumor at best and has been denied by China and CAC.
How long ago 'one' became 'numerous' in your world and how this make you convinced that it makes your statement right? 'Numerous crashes caused by engine failure' you said. Proof? List?
Regarding 'success stories' - any proof of 'numerous', again?
Proceed...
P.S. I do not bother was first reported crash is myth or not as engine not mentioned.
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