Question is more of IAF crying wolf because of something missing..ks_sachin wrote:Indranil wrote:Don’t worry Sachin sahab. At the very worst, they will end up with maintenance friendlier MK1 with an AESA radar and an SPJ.
Thanks Sir. I've slightly different understanding.ramana wrote:My understanding:
Current LCA line will call it Assy -1 is 8/year.
Second line call it Assy-2 was funded in March 2017 and also 8/year. Most reports say its Hawk hanger. I dont know if its the same as Kiran hanger bldg. Funds were Rs. 1331 crores. Delay raised price from Rs. 1231 stated last year in HAL chairman Raju interviews.
Now once SP-5 et al fly the second line is qualified.
Sachin chill. Weight reduction takes time because it is like a chain. If you save 15 kg on the undercarriage you can then make the wing spar and undercarriage supports a little "thinner/lighter". If those become lighter, then the spar attachment to the fuselage can be made thinner/lighter. If that is smaller something else higher up the stress/G force chain can become lighter.For 15 kg saved on undercarriage total weight saving may be 100 kg as structural components higher on the weight bearing chain also get lighter. All have to be made with new specs.ks_sachin wrote:
I am worried...
Shiv Saar,shiv wrote:Sachin chill. Weight reduction takes time because it is like a chain. If you save 15 kg on the undercarriage you can then make the wing spar and undercarriage supports a little "thinner/lighter". If those become lighter, then the spar attachment to the fuselage can be made thinner/lighter. If that is smaller something else higher up the stress/G force chain can become lighter.For 15 kg saved on undercarriage total weight saving may be 100 kg as structural components higher on the weight bearing chain also get lighter. All have to be made with new specs.ks_sachin wrote:
I am worried...
Now if you already have manufactured items of old specs and 4 are already at different stages on the assembly line, then the new mods can only be implemented AFTER those 4 are done and delivered.
Old Kiran hanger you mean..? The line 1 prime. Line 2 which was recently approved is coming up in Hawk hanger isnt it..?Indranil wrote:Ramana sir, SP5, SP 9, SP 10 are from line 2. Not only is this line in the same space as the Hawk line, it is run by the same people. Even on the Hawk line, there were initial hiccups. But after a while, they not only made up for lost time, but delivered the last few ahead of schedule
JayS wrote:
Currently there are two lines with 8/yr each.
1. Original Line in LCA hanger - 8/yr as [planned]. Since it was laggarding at 5/yr, HAL went ahead with an extension of this with a secondary line in Kiran hanger with 3/yr. So total 8/yr (I had confirmed these numbers with AKN over twitter once).
2. The new line sanctioned by GOI recently. Its coming up in Hawk hanger replacing hawk line. This has 8/yr.
My understanding initially was that the outsourcing is for all the lines including the very 1st one. But in recent multiple interviews TSRaju is repeatedly saying that HAL has established 16/yr capacity and whatever the Tier1 companies can provide will add to this. And with that the rate can go to 24-25/yr. So what I understand from this is that HAL has established manufacturing capability of 16/yr now including sub-assemblies for them. So even if they do not get anything from vendors, they can still make 16/yr. Whatever the vendors supply, HAL will integrate adding to this capacity that it over and above 16. I think HAL will off-load the subassemblies from these 16 as well eventually. But as of now I sense that HAL has inhouse capacity to churn out 16/yr even without the Tier-1 vendors supplying anything. ( structural subassemblies I meant here)
Given that original line was designed at 8/yr but was functioning at 5/yr due to bottlenecks in assembly and the secondary line is augmenting it, its not too much stretch of imagination that once the assembly process is streamlined the 5+3 could become 8+3 or 8+4 in future.
I have always been of the opinion that the production rate of LCA can be easily hiked to 25/yr or even 32/yr in short time frame. From all the indications it looks like that's the case afterall and HAL is well on its way to achieve it if need be.
They didnt create 5/yr line. It was 8/yr only. But equipment stage was taking too long to reach that rate so they opened up a partial secondary line to argument, rather than waiting to streamline otiginal line.ramana wrote:JayS,
Each in is right Line 1 is 5+3.
Line 2 will be 8.
Now what moron will create a Line eith just 5 over all the 17 years since LCA TD started.
Program was on IV all these years.
It was Parrikar who sanctioned the Line 2 at 8/ year. And it cost measly Rs1351 crores. Chimp change.
Idiots all conspiring to kill it.
I wrote a long response and I deleted it. Because it is useless to give you the facts. It has been given to multiple times.Philip wrote:This is the point that the good Prof.Das has been labouring for quite some time.Inadequate aero- engineering design expertise to streamline the architecture within the fuselage,etc.We are still- with the weight saving exercise, trying a hit or miss attitude.The AMCA policy spelt out in that td. shows that some lessons have been learnt and that the option of a firang partner in a JV , plus engine majors listed for the power plant,will significantly reduce design/dev. time.This the LCA has not benefited from, why as mentioned by some experts/IAF brass, every prototype was different from the other why manuals, etc. had not been passed on to the end user. I think that it is with the first LSP aircraft that some standardisation is taking place.
Here too quality is essential.Remember the remarks by an AM about no two canopies could be interchanged with similar aircraft without adjustments.Difficult to understand as surely in this day and age the use of precisely machined templates must be standard practice.Is this aspect why Rafale refused to guarantee the quality of Indian built aircraft?
Good to hear that the second line is humming and that the same folk are monitoring both lines.What about space in the JAG line? Are we still building Jags or has work on upgrades begun.
Philip you make me wonder sometimes!!!!Philip wrote:This is the point that the good Prof.Das has been labouring for quite some time.Inadequate aero- engineering design expertise to streamline the architecture within the fuselage,etc.We are still- with the weight saving exercise, trying a hit or miss attitude.The AMCA policy spelt out in that td. shows that some lessons have been learnt and that the option of a firang partner in a JV , plus engine majors listed for the power plant,will significantly reduce design/dev. time.This the LCA has not benefited from, why as mentioned by some experts/IAF brass, every prototype was different from the other why manuals, etc. had not been passed on to the end user. I think that it is with the first LSP aircraft that some standardisation is taking place.
Here too quality is essential.Remember the remarks by an AM about no two canopies could be interchanged with similar aircraft without adjustments.Difficult to understand as surely in this day and age the use of precisely machined templates must be standard practice.Is this aspect why Rafale refused to guarantee the quality of Indian built aircraft?
Good to hear that the second line is humming and that the same folk are monitoring both lines.What about space in the JAG line? Are we still building Jags or has work on upgrades begun.
JayS wrote:They didnt create 5/yr line. It was 8/yr only. But equipment stage was taking too long to reach that rate so they opened up a partial secondary line to argument, rather than waiting to streamline otiginal line.ramana wrote:JayS,
Each in is right Line 1 is 5+3.
Line 2 will be 8.
Now what moron will create a Line eith just 5 over all the 17 years since LCA TD started.
Program was on IV all these years.
It was Parrikar who sanctioned the Line 2 at 8/ year. And it cost measly Rs1351 crores. Chimp change.
Idiots all conspiring to kill it.
I am a little confused on the cost of 2nd line due to DDM. Some reports say its 1300 odd Cr total out of which HAL pays 50%. While some others say, HAL's 50% itself = 1300Cr means total cost is 2500-2600Cr. Also slightly varying numbers to add to confusion. Need to have some authoratative ref such as MoD report or ADA report or CAG report.
PS - OK. MP in Aero India presser said second line at govt investment of 1359Cr. So thats total cost. Half from HAL. Work should have started by May 17 and actual production expected in 2-2.5yrs. That is mid 2019 or 2020 early.
https://youtu.be/fHXZTuw8rFo
At 2.00min
IR, your earlier post mentioned that they have NOW started to burn the midnight oil for the Tejas AF Mk2..does that mean that whatever had caused the work on the Mk2 to stall was on ADA's end and not the IAF or MoD? Is the program now gathering pace with the full backing of all the stakeholders? If so, I'd be extremely happy to hear that, given that I fervently believe that the Mk2 will be the ultimate fighter evolution of the Tejas and if they put their heads to it, can serve the IAF well for another 35 years, well into the 2050s.Indranil wrote:Jay,
I think they are thinking on similar lines. I don't know the length of plug that they are going to add. But if they go for a 1 mtr or longer plug, then a close coupled canard makes a lot of sense. I don't know what would differentiate the Gripen NG from the LCA Mk2 then.I was thinking that they would go with an active extended levcon like the PAKFA. But, they are considering an MKI kind of layout (-the tailplane).
Sachin sahab,
That is why they are trying to limit the scope. We will know in 6 months for sure. AESA/avionics/SPJ/EW is okay. They have experience and HAL is a very good systems integrator. Those can be ironed out with time as well. Just get the airframes out first. And to do that they have to complete the re-layout, and freeze the design. And that is my biggest worry. I don't have a lot of confidence in HAL's fixed wing aero department. If they manage this part, I am not worrried of the others.
Close-coupled canard
Wing wake and its downwash diminish horizontal tail's control effectiveness. However, canard is located in wing's upwash, meaning that its influence is magnified, which results in the center of the lift being moved forward more than canard size would suggest. This destabilizing effect has in past meant that a very forward Cg position was required, but has proven beneficial with advent of unstable fly-by-wire aircraft.
Since aircraft with close-coupled canard are dynamically unstable, they typically show better pitch rate through the angle of attack range than non-canard aircraft of the same configuration. Additionally, large momentary enhancement in lift is observed when canard pitches up rapidly to high angle of attack (this assumes that canards are used for pitch control), thus improving pitch onset/turn onset rate.
Canard's own downwash can impede lift generation of the parent wing at low angles of attack, but this effect can be countered by proper horizontal and vertical positioning of the foreplane. This is to say that canard has to be high in relation to the wing, as can be seen in Saab's Viggen and Dassault's Rafale. Additional consideration is wing sweep angle, with 45* being ideal as at that sweep angle canard has relatively little influence on the lift generation. At higher angles of attack, downwash can suppress the flow separation on the wing, thus improving lift and reducing drag.
Aircraft with close-coupled canard does not have to have as large amount of statical instability as one with long-arm canard or tail, since close-coupled canard naturally creates an area of low pressure on forward part of the wing. This results in center of lift being moved forward, increasing aircraft's instability to levels beyond what would be expected by taking lift from the wing on its own.
Both canard and wing producing two sets of vortices - one from tip and another from root. In close coupled-configuration, canard tip, canard root and wing root vortices all help increase lift at high angles of attack. Mutual influence of canard and parent wing means that free-roling vortices are stabilized and vortex bursting is delayed, especially at high angles of attack; an additional vortex may be formed on the wing where canard downwash suddenly decreases effective angle of attack. Wing vortex also moves canard wortex inward. As a result, wing's trailling-edge control surfaces remain effective at far higher angles of attack than in a long-arm or tailless delta configuration, as vortices allow air flow to remain attached for longer and vortex bursting point reaches wing trailling edge at a higher angle of attack than it would without presence of a canard (vortex breakdown is delayed for both wing and canard vortices, increasing effectiveness of both surfaces at high angles of attack). Necessary wing twist is also reduced, as outboard vortices help prevent the wing tip stall, while inboard vortices increase body lift in addition to improving wing lift. Effects of outboard vortices on wing tip also result in improved roll rate and roll response, especially at high angles of attack.
This also results in improvement in the maximum lift, which can be as much as 20-30% greater than what is achieved by surfaces in isolation, as well as improved lift for most, if not all, angles of attack (all close-coupled canard configurations discussed in various documents I have read experience lift increase at AoA above 20 degrees, and many experience lift increase at AoA as low as 10 degrees, albeit at low AoA lift enhancement is so minor so as to be insiginificant. At 20 degrees AoA, lift increase in one case was 34% compared to the sum of lift produced by wing and canard on their own. Angle of attack for maximum lift is also increased). Enhancement is largest for canard above and just in front of the wing, and wing camber and twist have no effect on the lift increase; lift improvement is maximized when canard area is 25% of the wing area, and best relation between lift and L/D ratio was achieved in 45*-swept canard. Canard trailling edge and wing leading edge should be as close as possible, but should never overlap else a loss of lift occurs. Beyond Mach 0,9 however, close-coupled canard has little effect on lift.
As a result, aircraft with close-coupled canard configuration tend to have better air field characteristics and maneuvering performance than they would if canard was removed. A series of tests with F-4 that had canard mounted on the upper forward portion of the air inlets revealed that addition of canard would allow the aircraft to pull a full g more at 470 kph and 9.000 m, and would also lower the approach speed by 14 kph. Israeli Kfir, a modification of Mirage 2000, used close coupled canards to improve airfield performance, as did Saab Viggen. Thanks to favorable canard-wing vortex interactions, Viggen achieved 65% greater lift coefficient at approach than a pure delta wing, reducing takeoff and landing speeds for STOL capability. Use of close coupled canard gave Viggen much greater trim control, and allowed it to use elevons to enhance lift at takeoff, where tailless delta's elevons would subtract from lift.
Aside from increase in lift, close-coupled canards help reduce drag in maneuvers at all angles of attack but lowest (10* AoA or less) ones, and reduce drag for the same turn rate compared to the canard-off configuration. There are three primary causes for this. First, since increase in lift is apparent even at low angles of attack, close-coupled canard configuration needs lower angle of attack for the same wing size, or less wing size for the same angle of attack, to achieve same lift-to-weight ratio; this results in the same turn rate being achieved with less drag penalty. Second, close-coupled canard supresses flow separation. Flow separation (stall) is a major source of drag, and in delta wing configurations without close coupled canard, first stall can happen at angles of attack well below those required for maximum lift. Third, close-coupled canard configuration requires less control surface deflection (trim) to maintain same angle of attack, thus reducing trim drag.
All these factors combine to reduce drag for given lift. In fact, lift/drag ratio for close-coupled canard configuration can be 10% greater than for canard-off configuration.
Additional factor is the design influence. Strongest wing vortices are produced by sharp-edge, highly-swept planforms which have low L/Dmax and thus poor range and endurance, and high approach speed. Thus a selection of a more adequate planform requires an additional mechanism to produce and/or energize vortices.
Canard is set at neutral AoA during subsonic cruise, producing no lift and causing minor drag penalty. Position of canard ahead of wing also helps move center of pressure forward relative to the center of mass, creating a naturally unstable configuration.
At supersonic speeds, close coupled canard configurations experience less center of lift shift, reducing induced and trimmed drag compared to tailless delta and long-arm canard aircraft. This is partly offset by comparably minor drag from the canard itself. There is little effect on lift or drag during supersonic maneuvers, and close coupled canard combined with ventral intake actually increases supersonic drag. At transonic speeds, benefits are same as on subsonic speeds.
Close coupled canard also delays buffet onset and reduces buffet intensity. Additional benefit is controllability at post-stall angles of attack, which is important mostly for safety considerations - close-coupled canard configurations remain controllable at angles of attack up to 100-110*, with no risk of getting trapped in superstall. Further, if FCS is properly developed, close-coupled canard can help dampen roll and yaw oscillations, thus guarding against the wing roll and sideslip; but if FCS is not properly developed, these problems can be magnified. Close coupled canard configurations also have acceptable spin behavior. In emergency, canards can be feathered, rendering aircraft stable or neutral.
While high canard (canard is above the wing) has been discussed here, most of these effects are true for coplanar canard as well, albeit coplanar canard is significantly less effective, and does not increase aircraft's instability level beyond effect of the canard itself (which, for control canard, is zero at subsonic speeds). Low canard, on the other hand, creates low pressure area at wing's lower surface, causing pitch down moment. Additionally, low canard prevents formation of wing leading edge vortices; both these effects reduce lift compared to the wing alone, coplanar or high canard configuration. Another possibility is an oscillating canard, which would significantly enhance wing pitch response.
Overengineering is a safe and standard route to take. Under engineering and getting a much lighter aircraft would have been a risky gamble - because if a component failure had brought a plane down no one would have known what exactly had failed.Philip wrote:This is the point that the good Prof.Das has been labouring for quite some time.Inadequate aero- engineering design expertise to streamline the architecture within the fuselage,etc.We are still- with the weight saving exercise, trying a hit or miss attitude.
There is no genius there. It is just experience and time. Unless we give them a chance, inefficiencies and all without verbally beating the shit out of them because we all know all this much better than them - nothing will ever come fruition. The HF 24 went down the same way. We were to damn clever for ourselves.Philip wrote:The genius lies in knowing where and how to pare off weight without failure.
So now they know where they can pare off weight.Philip wrote:Was there are any benefit in performance seen with the NLCA's "Lerxes"? Amazingly this same debate was going on in BRF in Nov.2010! Vina asked whether Levcons in the LCA were the equiv of the Euro- canards? Back to Das and over- engineering.Yes, OE may be safe but comes with penalties! The genius lies in knowing where and how to pare off weight without failure. Even in the JSF programme some wing spars failed/cracks appeared, but there is no substitute for design knowledge and experience .The LCA appears to still be on the learning curve.
What happened to the SU-47 Berkut or MIG 1.41 or numerous such aircrafts designed and developedby Soviet Union/USA/Canada etc?Philip wrote:Same 2 u2! This canard debate in 7 yrs old.Over engineering, playing it safe adds weight.I've asked the Q whether the NLCA lerxes as did Vina 7 yrs ago, was found to be equiv. to the eurocanards.What's objectionable about That? We're still attempting to refine the LCA after 30 years.Does it not show some lack of engineering experience?The IAF ( not moi) has categorically stated that only MK-2 will meet thier performance reqs.MK1/1A are interim solutions.When will the refining of the bird end? Does anyone at the ADA or HAL know or have given a finite deadline? At some point the design/dev. stage must end and production begin if the aircraft is to be built in sufficient numbers on time and be a useful addition to the IAF's fleet.Please read the archives and LCA debate from the yr. 2000 , you may understand better what I'm saying now.
Who, when and where from IAF said "catagorically" that only MK2 meet IAF's requirement..?Philip wrote:Same 2 u2! This canard debate in 7 yrs old.Over engineering, playing it safe adds weight.I've asked the Q whether the NLCA lerxes as did Vina 7 yrs ago, was found to be equiv. to the eurocanards.What's objectionable about That? We're still attempting to refine the LCA after 30 years.Does it not show some lack of engineering experience?The IAF ( not moi) has categorically stated that only MK-2 will meet thier performance reqs.MK1/1A are interim solutions.When will the refining of the bird end? Does anyone at the ADA or HAL know or have given a finite deadline? At some point the design/dev. stage must end and production begin if the aircraft is to be built in sufficient numbers on time and be a useful addition to the IAF's fleet.Please read the archives and LCA debate from the yr. 2000 , you may understand better what I'm saying now.
As compared to the awesome service record of fulcrums in Naval service. Or R-77. Or trying to assess the cost of Gorshkov.Philip wrote:The LCA appears to still be on the learning curve.
You are right Ramana sir. My point though was that there are enough facts available. Anyway I shall cease and desist.ramana wrote:OK, enough backbiting.
Philip, You don't know till you do it.
Dr Das Bless his heart is a side observer. No doubt more informed as he teaches but still an observer.
To me now he is like an ox let off in the village main street making a nuisance of himself by saying "Ambaa!' now and then.
Folks people got upset when I created the Whine thread where people can post whatever is worrying them.
Right now I see too many whines without any information.
Sachin you are leading the pack. I see you doing this in quite a few threads.
Why not start the New Year on an optimistic note informed by facts?
Philip no more quoting the dear Doc Das.
Why just the navy? the original Fulcrum had given the IAF an awfully severe period of "learning" while all its teething issues were being resolved. But then, that is what product design is all about. It is an iterative process and refining continues with time. The more experienced one gets, the likelier that the refinements work, since they've already experienced for themselves as to what works and what doesn't. But Product Design is all about trying out various configurations and fixes, so they'll look at it from every angle if they can.Thakur_B wrote:As compared to the awesome service record of fulcrums in Naval service. Or R-77. Or trying to assess the cost of Gorshkov.Philip wrote:The LCA appears to still be on the learning curve.
And, that is a very good thing. Nobody us going to share their wares with you. Books can only teach you so much. Models can do a bit better. It is the actual stuff that is the best and many times the only teacher. Failures are real good indicators of progress. And, if one looks at the stuff from the past, luck is a huge factor.The LCA appears to still be on the learning curve.