i.e.Everybody saw the huge J-20 take off without afterburner after a short run…
The engine cannot be a regular AL-31FN which cannot support such high dry thrust.’
logic is off.
you don’t know what weight this thing took off in.
i.e.Oh God when would people ever learn.
PLAAF and PLAN paid for and specificed those MKKs with specific operational requirements in mind. as far as I can tell they filled those requirements.
hopefully so did IAF with those MKI.
but IAF’s requirements and PLAAF and PLAN’s requirements were different.
DIFFERENT.
the USAF analogue would be F-15E vs an operational F-15 STOL/MTD.
how in the ******* can you compare them two?!
i.e.Hi … and nice to have You back !
But don’t You think that such a “movement” would have been noticed ?
… so then it’s simply a “special treated” AL-31F/FN !!?? 🙁
Deino
me too
if they take off in the night I don’t think any one would notice.
besides. yanliang is not the only 10,000 ft runway in china where flight tests are done.
again, people like them are known to be off the mark sometimes. especially if they want to put up smoke screens. 😀
i.e.trainers are all about structure hours.
being cheap enough $ / hour for the pilots to hon their flying skills.
for tejas to be a advance trainer they have to redesign the structures from bottom up. keeping prob only the outer mold line.
Chengdu ran into the same issue when they proposed to turn FC-1/JF-17’s two seater into a trainer to compete in the same niche as L-15.
seeing how ADA has trouble nailing their structure weight in the first place. I would be skeptical of the basic aero of Tejas to take on more structure weight.
i.e.I remember hearing an old joke from some douglas guys that they would gladly sell their mother for 5 knots of stall speed… and their grandmas for 1 knots
this is the magnitude of numbers people inside of industry play with… and that’s civil.
i.e.Its nonsense because you’re using wildly wrong figures just to suit your argument. And the diddly fancy FCS will not allow you to pull more Gs than has been tested during test flights, pure and simple. Only small over-ride values are allowed (from Saab test pilot Ola Ringell’s seminar).
Because the Tejas’s empty weight is confirmed to be 6560 kgs from AI-11. That is higher than what the design goal was, but it is still well within the range of other similar fighters. The T-50 Golden Eagle is 6500 kgs, JF-17 is around 6600 kgs and Gripen C/D are around the same figure. Of these, the T-50, JF-17 are also supposed to be +8G/-3G fighters only.
As and when more of the envelope is opened up and FCS modified accordingly, the Tejas will get to 8Gs. Just as it was done on the Gripen.
I am aware that in any self respecting G-command flight control law, G-limiting is a relatively simple thing to do. there is no point to lecture others. I am simple stating that the natural aircraft (minus the control law) may not be able to achieve what your control law is commanding.
also. please be aware that weight is only half of the equation, the other half is lift. if your aircraft’s wing is designed to generate 9 Gs worth of lift given a certain weight… key word is given a weight… any pointing to similar aircraft’s weight is rather pointless. as their aerodynamic surfaces are sized to generate lift given these weight to generate specified Gs. while the over-weight Tejas’s may not. that’s assuming the Tejas can generate the amount of lift.
like quadbike’s link indicated… missing sustained turn and AoA indicate to not hitting the required lift/drag curve slope.
this is more serious than reseting some limit in control law. no tweaking with control law can fix your basic aero-performance…that much
i.e.clearly indicates its not an issue with G limit expansion.
Performance specifications that the Aeronautical Development Agency (ADA) has not been able to attain include sustained turn rate, speed at low altitude, angle of attack and certain weapon delivery profiles. Exactly how far off the performance is from the specification remains classified.
Looks like the basic lift/drag curve slope.
i.e.nonsense. you pull lower Gs because you have not yet fully explored the entire flight envelope. As and when that is opened up further, the FCS will allow more Gs to be pulled.
Or do I need to post links to Gripen flight tests where it was shown that a Gripen B was limited to 7Gs till it’s FCS allowed it to go to 9Gs AFTER testing was complete and software changes were made ? :rolleyes:
why non-sense?
you think your diddly fancy FCSs system would allow you to pull more Gs than your natural aircraft is capable?
My suspicion is Tejas’s aerodynamics and structure can not achieve its designed capability.
or look at it from pure physics. example:
you have a 10 ton aircraft that is designed to generated 90 tons of lift. thus achieving 9 Gs.
if you are 3 ton overweight. assume you can still generate 90 tons of lift. you can only physically achieve 6.9 gs with same margins.
this is simple physics folks.
i.e.Could also speak for the fact that changing the design and integrating canards properly into the FCS is still a major task not to be underestimated. They certainly have other priorities. As long as the aircraft meets its requirements they are just fine. Won’t change the obvious benefits of canards vs a tail and canardless raw delta winged design.
.
integrating the FCS is the least of your problems.
Your basic main wing has to be redesigned… at least relooked at in the tunnels and cfd. if you stick a sizable canard infront.
judging from the program’s performance, their process and tools and methodologies aren’t that good in terms of giving good predictions.
If I was in charge of Mk2 program, the process and tools and methodologies is where I would start.
i.e.read my post above regarding pulling 9Gs and 6Gs and how much of a difference that makes. If you have a science background then you must have studied centrifugal forces and then you SHOULD how as the radius of the turn has to be decreased (meaning a tighter turn), the centrifugal forces will increase leading to higher G forces on the airframe?
You must think a little before going into all these very very generic statements that you make.
agreed that lack of power is not the only issue, drag is also an issue. But, there are remedies for these issues and the Tejas Mk2 aims to address that specific issue through increase in fine-ness ratio of the airframe.
Regarding AoA, the Gripen’s limits are +26 deg /-10 deg. The Tejas when it will reach FOC will be at around that same figure.
Since spin tests are yet to be conducted, pilots will not be allowed to go anywhere beyond 22 deg AoA which the Tejas has achieved as of date. And no pilot would want to go beyond that either, without the anti-spin chute to pull him out of a spin should he enter one.
I really feel you need to educate yourself a bit more before going into all these comparisons without getting the full picture clear.
pulling a lower Gs means either your lift curve prediction is wrong or your structure strength is off. either way shows bit of incompetence.
It is not amount of AoA that can be pulled that matters… I can design a wing with nice leading edge devices that can pull gobbles of AoA. …
It is amount of lift generated that matters.
also remember your lateral-directional stability goes to s**t when you are at these angles too.
my opinion: don’t matter how much you tune the basic Tejas airframe. if the performance number is that much off, it means who ever designed the basic planeform has got it wrong., and no matter how much fixes you put in Mk2. it is extremely limited in how much improvement you can make… especially if it is the same bunch that made the mistakes in the first place.
if they want to fix all the problems, they need bigger changes. bigger changes means a new plane…Mk2 or not.
i.e.Would it be cost effective?
eg.I dont want to fire a 68000 $$ hellfire missile [say to kill a few terrorists/enemy soldiers] when a few bursts of the GAU 12 does the job.
there is laser guided 70mm rockets.
i.e.Hi, long time no see…
couple of observations:
1) quality of this thread has gone to the sink, especially after throwing in the Indian’s chief’s ACM comment.
2) Chengdu is definitely busy. chinese new year holiday is over. J-20 should be in their flight test center in Yanliang now.
3) apparently US spy sat saw J-20, but like they said they don’t think it would made 1st flight so early.
4) I would believe “Maya” more than any… ANY…speculative western babble w.r.t. J-20’s engine.
i.e.The J10B and any future incremental improved versions (maybe with the new WS10G engine used on the J20 for example) should be up to the job of holding their own against Eurocanards and any ‘slient’ whatevers.
And would the PLAAF really need any additional 800+ fighters for air superiority on top of 200-400 J20s?
I would rather the PLAAF not repeat the mistakes of the USAF. Instead of going for huge numbers of a less-than-your-best Fifth gen fighter for the sake of having a fully fifth gen fighter force, I would rather they kept the bulk of their strength conventional and just use the money saved to buy as many J20s as they could afford.
With a healthy number of J20s, J10Bs and J11Bs forming the tip of the spear and the cutting edge, it would be perfectly reasonable to use a few hundred cheap JF17s to replace the likes of the J7, J8 and Q5.
I always believe quantity is a quality by itself.
the key is per unit yuan/dollar fighting power.
a mid sized fighter with a healthy focus on air2air may do 80% of what J-20 does and cost 50%. that’s more per unit yuan/dollar fighting power.
china don’t have global comittments of us. but it does have alot of well-armed neighbors on all of its sides. it can’t take its time and concentrate its resources. so quantity must come into play. or rather there must be enough quantity as a baseline. because I don’t foreseen in a two fronted crisis china can shift its limited top of the line assets around fast enough to garantee a minimum level of deterent.
i.e.Whether F-16.net have “a lot” of F-16 pilots I don’t know but they do have several F-16 pilots, and also some mechanics. Some very good discussions to be found there. A bit US-sentric of course, as you would expect.
Just like here there are several fanboys but overall the F-16.net site has a very high level on the discussions.
why did everyone took it the wrong way?
i.e.I think you have a pretty optimistic notion about how fast an F-16 can fly when it isn’t clean. It’ll never fly at M2 with any stores on it. Even an F-15 would be lucky to exceed M1.8 with 8 AAMs. I hope you’re beginning to see the picture why the F-35 was optimized for the M1.6-1.8 range, for top combat speeds.
well, couple obserbvations.
1) you seem to think that sticking missiles inside is so much less draggy than sticking missiles outside. just like sticking your hands out of a car right? well, wrong.
2) for the record I think F-16’s MMO with 2 missiles is much > M1.6. again, I am not going to breakout flightenvelopes and its up to you to take my word for it.
3) go back and read up on my comments on F35A and F35C. and what does the big wing gets and limits F35’s basic flight science performance. and why USAF chooses the smaller wing for A.
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