ADA Tejas Mark-II/Medium Weight Fighter

[DivineHeretic]

Find this poster on tejas mk-2 the net. Are the specs correct?

The current Mk1 has a top speed of Mach-1.6, not sure if the mk2 will have higher speed. It should be possible with the increased thrust though.

However, the dimensions of the internal fuel tank is not up for change in mk2. As such there is no way the range of mk2 can reach 3000km. Most likely the poster meant ferry range and not effective range. 3000km is closer to the mammoth SU-30MKI, and sure as hell the Tejas does not have equivalent fuel capacity.
Most likely it will be around 1800Km, which is the standard for a MMRCA.

Btw, the current G limitations is +8/-3.5g, and without any major structural strengthening, I'm not sure if it will handle +9g.
And just to remind you, most of the terms/names are plain wrong. Weight=4.6m. Makes me wonder, if the guy actually is in primary school?
I would point out that traction is grip or friction, but seeing the above error, its really not worth it.

 

[ersakthivel]

The current Mk1 has a top speed of Mach-1.6, not sure if the mk2 will have higher speed. It should be possible with the increased thrust though.

However, the dimensions of the internal fuel tank is not up for change in mk2. As such there is no way the range of mk2 can reach 3000km. Most likely the poster meant ferry range and not effective range. 3000km is closer to the mammoth SU-30MKI, and sure as hell the Tejas does not have equivalent fuel capacity.
Most likely it will be around 1800Km, which is the standard for a MMRCA.

Btw, the current G limitations is +8/-3.5g, and without any major structural strengthening, I'm not sure if it will handle +9g.
And just to remind you, most of the terms/names are plain wrong. Weight=4.6m. Makes me wonder, if the guy actually is in primary school?
I would point out that traction is grip or friction, but seeing the above error, its really not worth it.

The weight is dead wrong.

Demonstrated top speed of mk-1 till IOC is mach-1.6. So there is no way you can say that this mach 1.6 is the ultimate top speed of mk-1. For that we should wait till FOC.

Internal fuel capacity is going to be substantially increased in mk-2 with an additional new fuel tank and the enlargement of all the other tanks because the dia of fuselage is going to increase.So the range will definitely increase for atleast the IAF version , but 3000 km looks far fetched.

But you should know when comparing a bigger fighter with a smaller fighter for range, you should look at the FUEL FRACTION to determine the range, not the fuel in litres alone. That is the amount of fuel divided by/weight of the fighter. Because bigger fighters like SU-30 will lug a total of close to 28 tons compared to 14 tons for tejas.

And 9G is confirmed for tejas mk-2 by ADA.

Well all the published lit says that Ge-414- IN S6 is going to have 98 kn wet thrust. But a 10 percent increase in wet thrust is possible without much further certification cost and time is what the boeing chief has stressed in interviews, And there are reports that the Grippen -NG is looking at the option of higher than 98 kn thrust Ge-414- variant for their powerplant needs.

 

[DivineHeretic]

The weight is dead wrong.

Demonstrated top speed of mk-1 till IOC is mach-1.6. So there is no way you can say that this mach 1.6 is the ultimate top speed of mk-1. For that we should wait till FOC.

Internal fuel capacity is going to be substantially increased in mk-2 with an additional new fuel tank and the enlargement of all the other tanks because the dia of fuselage is going to increase.So the range will definitely increase for atleast the IAF version , but 3000 km looks far fetched.

But you should know when comparing a bigger fighter with a smaller fighter for range, you should look at the FUEL FRACTION to determine the range, not the fuel in litres alone. That is the amount of fuel divided by/weight of the fighter. Because bigger fighters like SU-30 will lug a total of close to 28 tons compared to 14 tons for tejas.

And 9G is confirmed for tejas mk-2 by ADA.

Well all the published lit says that Ge-414- IN S6 is going to have 98 kn wet thrust. But a 10 percent increase in wet thrust is possible without much further certification cost and time is what the boeing chief has stressed in interviews, And there are reports that the Grippen -NG is looking at the option of higher than 98 kn thrust Ge-414- variant for their powerplant needs.

To be honest, it wouldn't really matter much whether speed is M1.6 or M1.8. Of course, higher speed wouldn't hurt.

Are you sure about the increased fuel storage? The increase in size of the fuselage is to accomodate the GE-414, in any case, the increase is quite modest, at only. 5 m length and about. 2 m width. I'm not sure how they'll place a larger fueltank in the fuselage. In any case we are looking at 17-1800 km combat range, which is comparable to Rafale (2100Km), enough in my opinion.

When I'd compare the fuel capacity of the Tejas to the Mki, I really did mean the fuel fraction. Thats why I used the "equivalent fuel", wrong choice of words.

About the engine, well 98KN should be good enough. Of course, if higher rating is possible at same price, we will go for it!, especially since the main proponents of MK2 were the IN, and they'd want the most powerful engine they can get.

 

[ersakthivel]

To be honest, it wouldn't really matter much whether speed is M1.6 or M1.8. Of course, higher speed wouldn't hurt.

Are you sure about the increased fuel storage? The increase in size of the fuselage is to accomodate the GE-414, in any case, the increase is quite modest, at only. 5 m length and about. 2 m width. I'm not sure how they'll place a larger fueltank in the fuselage. In any case we are looking at 17-1800 km combat range, which is comparable to Rafale (2100Km), enough in my opinion.

When I'd compare the fuel capacity of the Tejas to the Mki, I really did mean the fuel fraction. Thats why I used the "equivalent fuel", wrong choice of words.

About the engine, well 98KN should be good enough. Of course, if higher rating is possible at same price, we will go for it!, especially since the main proponents of MK2 were the IN, and they'd want the most powerful engine they can get.

the lengthening is happening just behind the cockpit and a new fuel tank is being placed there.The modifications for GE-414 is largely in fuselage diameter.

you can understand that lot of internal space will be there if the diameter of fuselage is increased through out it's 13.7 meter length. That will free up lot of space for fuel and other things.

 

[ersakthivel]

What I have heard is a pure/crancked delta form finds it difficult to maintain sustainable turn rate something for which IAF have been yelling ADA wrt LCA some thing for which LCA was not designed for (initially designed to be a light weight interceptor 'only', while current projection is for a capable multirole platform). Pure delta form have its own advantages but not known as a all round, heavy duty performer for a multirole platform, or am I missing something?

The movable leading edge vortex lift aka LEVCON for Tejas seems as a rescue package if things do not get too complicated but it is no more a pure/cranked delta form then on.

Beauty depends upon the eyes of the viewer.

It is a strange cocktail of accusations you throw at a cranked delta wing form. The crank in delta does the same job of inducing vortex generation which delays the onset of stall in high AOA regime , which has been proven in CFD analysis and wind tunnel model even before a single piece of metal was cut for Tejas!!!!!!!!!!!!!

It follows on the much acclaimed F-16 XL design which was viewed very favourably for a single engine fighter design by the Aviation community as the next evolution of F-16!!!!!!!!!!!

LEVCONS are primarily being developed for carrier landing requirement of Indian navy, and it is a further development of cranked delta wing form , not a rejection, the LEVCONS will give additional lift during critical moments on the deck. It was the primary purpose of their design. If they are found to help in other flight envelopes it will of course be used for that purpose as well. But adding LEVCONS won't change the cranked delta wing form

So only posters are yelling across each other in various forums about this so called revulsion of IAF over the LCA. In reality IAF voluntarily increased the order from 20 to 0 for Even the Tejas mk-1 itself.

So some uncorraborated yelling noway reduces the Cranked delta design's utility,

Infact canrds were added to this cranked delta to see whether they will significantly improve the Tejas mk-1 performance for the weight it is going to add. And found out to be of no use, since the crank and the twist at the wing root does the same job of canrds, the canards were found to be redundant. In TYPHOON and RAfaLE there is no crank or twist at the wing root, So a canard complements the simple swept back delta wing. In tejs it is not the case.

 

[ersakthivel]

It takes 30 years for a failed ADA project and still no results, who has 50 years to wait for AMCA? Rafale is the clear winner here.

For that to happen first the RAFALE deal will have to be signed!!!!!!!!!! . We don't know what commission mongering expose is going to hit the deal , and whether it is going to be signed or not. or your information the RAFALE and AMCA have nothing in common, They belong to different league of fighters. So your contention that RAFALE can fulfill the AMCA numbers is just a wishfull thinking.

Also this so called 30 years time and 50 years time frame is a stupid claim made by people who know nothing about aviation.

RAFALE and TYPHOON took 16 and 17 years respectively to enter into service from first metal cut and Tejas took 20 years for mk-1 to enter into serial production,

Both RAFALE and TYPHOON entered production without finishing all their developmental goals and are being updated in tranches,TYPHOON is yet to demonstarate it's stand alone ground bombing ability , but that hasn't precluded it from entering in 100s in service, Because it can be upgraded after induction. The same goes for Tejas,

For Tejas funding for two prototypes were released only in 1993 , it finished IOC in 2012, entered series production in HAL with orders for 40. So just 4 or five years delay when compared to RAFALE and TYPHOON. The above words are not mine, They are HAL chief retired Airmarshal MSD WOOLEn's words.

 

[ersakthivel]

I have always been amused by the design philosophy of creating an unstable ac and than adding more and more contol surfaces to just to make it fly. Addition of these control surfaces add weight and consequently results in degradation of performance besides making the ac heavier. All you aerodynamics experts must remember the qudraple rule for designing an ac and need to know few basic facts about aerodynamics.

The vetted area of an ac and its wings matters the most for high speed ac as skin friction drag increases with increase in size and speed.
The design of airfoil (wing Planform) has direct bearing on the overall weight of the ac as the weight of the undercart increases and can be anywhere from 2.5% of MTOW to 4.5% of MTOW of the ac. This is what made LCA go beyond the design OEW. Infact the weight of undercart for a carrier based ac is 25% higher than a shore based ac. The CLmax of an airfoil is directly proportional to its sweep angle.
Now, we started LCA project with an aim to have a small light fighter. We used F-16XL as a baseline. The net result is that we have an ac which flies better than M2K but has control surfaces much bigger than that of M2k resulting in overall degradation of load carrying ability and also problems with C of P control. The control deflection for a tail less RSS delta has these problems.
Using movable LEVCONS in LCA will only add to these problems. My best suggestion is to make LCA positively stable design with maneuover margins kept between 5% to 1% like F-16 blk-52. AND ADD CRUCIFORM TAIL TO IT AS IT ALREADY HAS A FLAT RUDDER.

What made the LCA go beyond the targeted empty weight is not the large wing, but the later insistence from IAF for the deployment of higher launch stress inducing, higher weight longer range BVR missiles on all the pylons, which led to the strengthening of the wing and the consequent weight increase and the sudden increase in cross section from x=5000 mm to x=6000 mm along the fuselage axis.

Even with this weight increase and some drag issues related to the sudden fuselage cross section increase needed to strengthen the section there to attach the higher weight wing, (due to the revised IAF BVR missile needs) the LCA mk-1 still managed to clear many of the targets set for it.MK-2 will be in the grippen NG class.

Since the design phase of LCA all the fighters be it RAFALE, TYPYHOON, F-22, J-20, J-31,FGFA(T-50) all followed the Relaxed static stability Fly by wire based, low wing loading massive wing area delta type design of Tejas, thereby vindicating the wing design.

The benefit of lower wing loading obviously offsets the higher drag of higher wetted area resulting in superior lift to drag performance in all flight envelopes is the reason for this continued adherence to the low wing loading theory.

Any positive static stability fighter will have it's center of gravity ahead of the center of lift in subsonic and trans sonic flight regime , where maneuvering at corner speeds and all other close combat maneuvers will be performed.

The CoG positioned in front of the CoP will act against the center of the lift by nose down momentum thereby delaying the fighter from attain higher bank angles quickly and reach higher Gs quickly.

Even Mirage-2000 has it's wings positioned far below the CG, meaning it's thrust line is well below the CG, But still it is supposed to be RSS fighter. If this lower thrust line alone makes the fighter nimble, then why Dassault went in for Analogue FBW based RSS aerodynamic layout for this fighter?

Having the thrust line right below the Cg will remedy this problem to some extent, But will it completely solve it? Only detailed wind tunnel modelling will clarify these things.

In the same way bigger control surfaces only increase the maneuverability, not decrease it. Now with the advent of 60 G plus BVR and WVR missiles the emphasis is on agile maneuvers to avoid these mssiles as much as possible, opposed to the low drag, positive static stability,higher STR fighters of the previous era.

That is the reason for RSS fighters with larger and more in number control surfaces to attain this goal. Rather than having smaller control surfaces and the low drag configuration.

Having the thrust line right below the Cg will remedy this problem to some extent, But will it completely solve it?

Only detailed wind tunnel modelling will clarify these things.

Even though it may result in a force couple to lift the fighter, the continued presence of CG in front of the CP will give a nose down momentum which will act against the pilot's effort to obtain higher AOAs quickly.

In RSS fighters the presence of CG behind the Center of Lift or pressure will aid the pilot's effort to attain higher AOA in all flight profiles.

More in number controlling surfaces assist in maneuvering quickly coupled with the higher agility of the RSS airframe.

The mirage-200 has low enough thrust line, still it's designers went for RSS. WHY?

Mirage-2000 is the fighter that started the original RSS , low wing loading airframe design concepts of the tailless large wing weight , wing area delta.

The Mirage 2000 features a low-set thin delta wing with cambered section, 58 degrees leading-edge sweep and moderately blended root; area-ruled; two small canard wings, fixed, placed just behind the air intakes. The flight controls on the wings are: four elevons (+15/−30°), four slats.

In the 1982 summer, at the Farnborough Airshow, this machine displayed not only excellent handling capabilities, but also a full control at 204 km/h and 26 degree angle of attack.

This was totally unexpected in a delta-wing fighter, and proved how CCD controls were capable of overcoming the delta wing shortcomings related to poor low-speed control, while retaining the advantages, such as low-drag, low radar cross section, ideal high speed aerodynamics and simplicity, provided by the absence of horizontal tail surfaces


Its neutral point is in front of its center of gravity, giving the fighter relaxed stability to enhance maneuverability. It incorporated negative stability and fly-by-wire controls with four analog computers. An airbrake is fitted above and below each wing in an arrangement very similar to that of the Mirage III. A noticeably taller tailfin allows the pilot to retain control at higher angles of attack, assisted by the small strakes mounted along each air intake.

The mirage-2000 has low enough thrust line compared to CG., still it's designers went for RSS. WHY?

Doing away with the tail also results in a reduction of control surfaces and associated hydraulic loads for it.

F-16 blk 52 onwards became-------- maneuover margins kept between 5% to 1%----- as it bulged with repeated additions of hardware after every upgrades. So it may not be a good solution for tejas as it faces no such restrictions.

 

[ersakthivel]

@ersakthivel, There is a huge difference in having a low thrustline and a thrustline which passes below the CG of the ac. Just to explain you better,
have you ever played pool? What happens when you hit the ball on the centre, when you hit it on top and when you hit it on bottom?
Please explain and than I won't need to explain anything to you.

All low thrust lines simply has to pass below the Cg is my opinion.
There is no way for the thrust line of Mirage -2000 to pass on or above the CG.
It has to go below the CG.
Still Mirage went for CG behind CL RSS config. Why?

Well , when the ball is hit at the bottom the force passes through different vector. It is quite a simple thing.And the ball has the tendency to move in upward direction.


But that does not prevent the Cg which is in front of the Center of lift(in non- RSS configuration) from applying a nose down momentum opposing the effort of having a thrust line below CG config alone.



But Mirage also has a thrust line below the CG in the same way as F-16 XL is my opinion.

Is it right or wrong?

if it is right then why it went for the same RSS airframe opposed to simple thrust line which passes below the CG arrangement?

 

[ersakthivel]

You go into combat with full bore. If you have CG ahead of the CP for a stable ac, the thrustline below the CG adds to the pitch up movement of the nose and gives you same kind of pitch up rate which you get in a RSS ac. Just calculate what will be the pitch up thrust added to the tail plane authority for an engine generating 98KN thrust with a downward tilt of its thrustline of 3*.
You will need to multiply the Sin3* with the thrust available.

The amount of lift produced is directly proportional to the wing area, and the engine thrust available for the weight of the fighter,
It won't change with thrust line arrangement alone.

The calculation you use is used to get the distance, The lift force won't change by SIn3* multiples is my opinion.

The 98 Kn thrust will generate only a fixed amount of lift, whatever be the position of thrust line with respect to CG.

Unless we have Cg behind the CL there (i.e RSS )is no way a simple Thrust line below the CG arrangement alone will counteract the nose down momentum of CG infront.

What is more important is the position of CL wrt to Cg not just that of thrust line.

You are yet to answer the question whether the Mirage-2000 's thrust line lies below the Cg or not?

Why I am asking it is the older mirage -lll were positive static stability platforms with the same thrust line below CG arrangement you are referring to. The Mirage-2000(RSS fighter with Cg behind the CL) evolved from the older mirage-lll for reasons of better maneuverability.

The following is the picture of MIRAGE-III , it certainly has thrustline below the CG as much as F-16XL has, you can't deny that . it is obvious. But it has positive static stability meaning the CL is behind the CG leading to nose down momentum ,

But Mirage-2000 below is an improvement over the MIRAGE-lll with the same wing arrangement resulting in lower thrust line below the CG, but with one major difference RSS(CL infront of the CG , giving a nose up momentum, same as that of tejas)

 

[ersakthivel]

I rest my case as you seem to have bcum dogmatic with hardly any knowledge of ac design stability. You are stuck on RSS without realising that the trend now has gone back to stable design as the need for ITR and STR are no more a factor with advent of all aspect missiles which like MICA can shoot down a target 180* behind while the ac is flying straight without the need to turn. You probably have not even heard of HMD guidance wherein the ac need not even use its ITR or STR.
Buddy, you are still in 2013 BC while the aircombat has moved to 2013 AD.

I know all about high offboresight HMDS-DASH air to air missiles that doesnot need fancy STRs any more , as I myself has posted it moths before you became a member here.

If you want to discuss stuff about LCA do it in that thread.Or if you want to discuss Why Relaxed Static Stability airframe fighters are not needed any more and a waste of tax payer money , please open another thread dedicated to that.We will discuss it.

DOn't discuss RSS and LCA in AMCA thread. As other posters are feeling suffocated.

Thanks.

You must learn to answer questions as you love to throw them up. Please reply to my last query.

thrust is a physical force which generates lift. But Sin3* multiples relate to distance not force. How do you mingle both up?

Bro please do not teach me all about stability. I have flown ac which was not a RSS ac but an ac which used to transition from a basic stable to neutral to completely negative called the SEA HARRIER. Keep all this stupidity of M2K to yourself.

The sea harrier is a sub sonic carrier based positive stability platform, What is it going to contribute to a discussion on thrust line and RSS airframe?
So you are not going to answer any questions regarding MIRAGE-lll vs MIRAGE-2000 and F-16 XL.
Doesn't matter.
When does Sea harrier achieve negative stability?

The moment you rotate the nozzles for take off, the ac bcums negatively stable and also when you rotate nozzles to come for landing the ac is negatively stable. We take off and land with negative stability in all configurations except normal take off and landing which we very rarely do. I ejected from IN-619 seaharrier on 6Th june 1993 as the reaction control system failed during a 100/65 T/O. The ac departed completely.

Are these flight profiles simply near stall or relaxed static stability?

RSS fighters pitch up with negative stability while their wings are fully aerodynamically efficient,
in close combat maneuvers at corner speeds, not while flying backwards.
Generating pitch up rates using nozzles(or just with thrust line below the Cg) is one thing ,
and sustaining it in close combat using the RSS enabled instability with CG behind the CL and all the while maintaining corner speeds is another thing.

 

[ersakthivel]

I don't care. Basically, you're saying that the entire forum has to be your personal bully-pulpit for defending the LCA (which I don't find that interesting), allowing you to hijack any thread without regard to staying on topic.

Not sure why Kunal Biswas actively approves your conduct. BAD MODERATOR... BAD!!

don't you find it odd that in AMCA forum people are dragging LCA needlessly?

That too with stupid aeronautical theories like Relaxed stability fighter is a repeatedly Sold Shit, and a tactic used by US to dumb costly stuff on other country's airforces.The guys who are gunning here for LCA in AMCA thread have no proof other than their wild imaginative spurious claim to back it.

Why is that?

In a forum every person is entitled his views as long as one guy doesnot abuses other with foul language and backs his claim with authentic source.

When people post what they feel about LCA , I post what I feel quoting source.That's why Kunal Biswas approves it. If I am throwing unsubstantiated statements and wishful thinking to bolster prejudiced view points like Tejas is an unmitigated disaster He wouldn't approve of it. So he Looks like a good MOD to me.

Report to MODs to stop discussing LCA in AMCA thread. And I am too glad to comply with it , if all other so called defence pros adhere to it.

 

[ersakthivel]

Let me answer your query now.
Even a blind man can make out where the CG of M3 is w.r.t its CP in vertical plane.

The same blind man can make out that the inability of the Positive Static Stability config's low thrust line and CG above CP combination alone to give high AOA , highly agile,high alpha performance at close combat maneuvering corner speeds, which are typically well below 0.95 mach ,

That's why the same blind men of Dassault went for RSS that is CG behind CL in mirage -2000 to achieve exceptional handling at low speeds , and quick nose pointing ability at corner speeds , which will enhance the use of HMDS-DASH High offboresight dual seeker missiles.Note that Mirage-2000 was controllable with an AOA of 28 deg at airspeeds at the intro airshow.

That was due to CG behind CL RSS set up. NOT DUE TO CG BELOW CL STABLE FLIGHT PROFILE SETUP.

In a low wing airplane the CG is above CP. One of the reasons for F-16XL to supercruise was its upward canted tail and downward engine nose. even in the case of Typhoon, it has been found that by tilting the thrustline by use of TVC in cruise will reduce the fuel consumption and provide better lift.

And the same blindman can also easily comprehend that that the reason for the exceptional handling of F-16 XL is not just due to the upward canted tail and downward engine alone.

F-16 XL is an evolution of Relaxed Static Stability- F-16 high agility airframe design.With a much bigger exceptionally lower wing loading CRANKED DELTA wing form as Tejas , weighing twice more ,



This beneficial Lift to drag ratio provided by the low wing loading ,huge wing delta wing like the LCA (accused by you for high drag due to high wetted area of the huge delta wing.) also the reason that it can deliver 40 percent more weapon loads at twice the distance of normal F-16 with improvement in every performance spec.

And that is the reason for it's exceptional buffet free performance , impressive low speed handling ability and it's impressive ability to pull more Gs with less time needed than the F-16 A/B.

It was primarily due to the impressive Highly beneficial LIFT to DRAG ratio , provided by the huge wings, which resulted in better performance in all flight envelopes regardless of the higher so called drag all you guys are stressing about.
[/B]

Sin3* for 98Kn thrust will provide a lift componant of approx 5KN and that too as part of nose pitch up. I hope you know how to resolve a parallelogram of vectors. Now at slow speeds the AOA is higher and CP lies close to CG in a stable ac. As the AOA reduces and speed increases, The CP moves back,

Of course your point that CP moves back in at higher speed supersonic flight ,is explained in the official website of RSS fighter TYPHOON in a much simpler manner.

That is why it become less maneuverable at high supersonic speeds, the reason exactly being their transition into Positive static stability config from the highly agile Relaxed static Stability config.

The reason why every fighter after Mirage is an RSS is the need for high AOA , high ITR at CORNER SPEEDS which are well below the 0.95 mach, where most of the critical close combat maneuvers are effected.



You and may hold the view that MICA and DASH has made close combat corner speeds is extinct. But the very name FIGHTER PLANE implies it should have the ability to give a good account of itself at the 0.5 to 0.95 mach close combat speeds. Otherwise it will be called a simple interceptor which flies from A to B delivering just Missiles.

You may have known that 90 percent of the time a fighter flies is in this 0.5 to 0.95 mach speeds where the RSS -negative stability airframe excels in close combat maneuver.IF it continuously fly in supersonic speeds alone it's range and manuevering ability will be drastically curtailed.-

And 200 deg temp of the airframe of the Fighter in continuous Supersonic Flight is a magnet for Passive heat seeking missiles, opposed to 40 to 60 deg airframe temp of the fighter flying continuously in subsonic speeds, which won't advertise it's presence to enemy's passive infra red seeker faraway attracting counter measures like a magnet.

the moment arm between the CG & CP increases and the drag rise due to higher speed needs higher thrust to overcome this drag rise. Which means that more and more thrust is available to overcome the nose down effect due to backward movement of CP. This obviates the need for use of stabilisers which add to trim drag to keep the nose up thereby reducing overall drag of the ac.


At the same time the ac is able to accelarate much faster and can have higher mach speeds for same elevator authority.
In a RSS ac, the CG lies behind the CP, as the speed increases, the CP starts moving back and stage comes when it goes behind the CG making the ac stable. This is normally done at 0.9-0.95 mach.

After that, a further increase in speed and lowering the AOA results in further back movement of CP giving a pronounced nose down movement to ac. This is particularly true about highly swept Talless Delta or cranked delta designs. To overcome this nose down movement, the elevons must move upwards to add to pitch up force to keep nose up.

THIS nose down momentum will be twice more in Static Stability Fighter is the point(since their CG is much in front of RSS fighter) , you conveniently ignore.

You should note that only CL moves back at supersonic speeds, NOT CG.

So you can calculate the extra nose down momentum penalty in Positive Static Stability fighter (which have their Cg much further in front than the highly swept Talless Delta or cranked delta design RSS fighter, due to much higher moment arm between the CG & CP increase resulting in a much bigger nose down momentum.)

This reduces the overall lift as effective AOA due to this upward deflection of elevons, reduces the CL. A RSS ac must have either canards or tailplane or TVC to control this movement of CP by use of thrustline but in a stable ac as the nose up force required is directly proportional to the moment arm between CG & CP ,

Due to the CG situated much further in front the moment arm between Cg and CL will be much much higher in Positive Static Stability fighter than the RSS huge cranked delta wing fighter like Tejas.

So when you talk about the so called 5kn lift advantage for Positive Static stability low thrust line fighter , You should equate it with the much higher nose down moment arm between CG & CP penalty of the low thrust line -Positive Static Stability Fighter

which is directly proportional to AOA and which is directly proportional to drag and that in turn is directly proportional to the thrust required. So for a stable ac using thrustline as a control surface, the vertical componant of the thrust at any stage of flight

But a stable ac using thrustline as a control surface, has a much, much bigger nose down moment arm between CG & CP penalty all the time,more so at supersonic flight

provides a pitch up force which is needed at that stage of flight. This remains true even when ac is loaded as the loading of stores adds to weight requiring higher AOA consequently higher thrust even though the moment arm of CG & CP in such a case is small due to higher AOA.
I will not like to answer any of your questions regarding the thrustline here anymore as you need to first study aerodynamics properly and also understand it in detail. I suggest that you buy,"Aerodynamics for Naval Aviators" and study it in detail. If you can understand it properly.

----------------------------

http://www.airforcemag.com/MagazineArchive/Pages/1983/November 1983/1183f16xl.aspx

F-16 XL too seems to have the same mid mounted wing arrangement of tejas, Where is the proof of it's low thrust line?
http://www.airforcemag.com/MagazineArchive/Pages/1983/November 1983/1183f16xl.aspx


You need not answer any questions regarding Thrust line here any more , as I have no doubts about it, While it may be beneficial at some flight envelope, it cannot replace the RSS config is my idea.
SO We can discuss all these things in a separate RSS(negative Static Stability) vs LOW thrust line Positive Static Stability thread without suffocating other posters.

http://www.airforcemag.com/MagazineArchive/Pages/1983/November 1983/1183f16xl.aspx

For a decade and a half, many fighter tacticians have stressed the paramount importance of being able to sustain a high turn rate at high Gs. The rationale was that with such a capability, enemy aircraft that cannot equal or better the sustained turn rate at high Gs could not get off a killing shot with guns or missiles.


With developments in missiles that can engage at all aspects, and as a result of having evaluated Israeli successes in combat, the tacticians are now leaning toward the driving need for quick, high-G turns to get a "first-shot, quick-kill" capability before the adversary is able to launch his missiles. This the F-16XL can do. Harry Hillaker says it can attain five Gs in 0.8 seconds, on the way to nine Gs in just a bit more time. That's half the time required for the F-16A, which in turn is less than half the time required for the F-4. The speed loss to achieve five Gs is likewise half that of the F-16A.


All of these apparent miracles seem to violate the laws of aerodynamics by achieving greater range, payload, maneuverability, and survivability. Instead, they are achieved by inspired design, much wind-tunnel testing of shapes, exploitation of advanced technologies, and freedom from the normal contract constraints.


The inspired design mates a "cranked-arrow" wing to a fifty-six inch longer fuselage. The cranked-arrow design retains the advantages of delta wings for high-speed flight, but overcomes all of the disadvantages by having its aft portion less highly swept than the forward section. It thus retains excellent low-speed characteristics and minimizes the trim drag penalties of a tailless delta.


Although the wing area is more than double that of the standard F-16 (633square feet vs. 300 square feet), the drag is actually reduced. The skin friction drag that is a function of the increased wetted (skin surface) area is increased, but the other components of drag (wave, interference, and trim) that are a function of the configuration shape and arrangement are lower so that the "clean airplane" drag is slightly lower during level flight, and forty percent lower when bombs and missiles are added. And although the thrust-to-weight (T/W) ratio is lower due to the increased weight, the excess thrust is greater because the drag is lower – and excess thrust is what counts.


The larger yet more efficient wing provides a larger area for external stores carriage. At the same time, the wing's internal volume and the lengthened fuselage enable the XL to carry more than eighty percent more fuel internally. That permits an advantageous tradeoff between weapons carried and external fuel tanks.

Where does it say the F-16XL's magical handling abilities are due to Positive Static Stability , Low thrust line config, as you are repeatedly implying?

It only says that all the performance of F-16XL is due to the fact that it had an inspired cranked arrow delta design which was followed in tejas, and not due to any Positive Static Stability , Low thrust line config.

F-16 XL too has no canards and no thrust vectoring . You insisted that to get the most of the tail less delta design a fighter should have a Canard or TVC, but F-16 XL has none of these.

 

[ersakthivel]

@ersakthivel,
You have no idea of what you are posting here and you have absolutely no idea of what is the meaning of CG being above CP or use of thrustline.
Will you shut the bloody F**K if I give you the proof of F-16xl thrustline?

The language you used here shows the kind of dumbass you are faking to be a know all.Who the f**k is needed to show proof about F-16 Xl's thrust line . A troll like you or me?

Who advanced the spurious argument that F-16 Xl's low thrust line and not the fantastic low wing loading cranked delta RSS airframe being the reason behind it's stupendous performance?

It is you.NOT ME. Before asking me to show proof about F-16 XL thrust line get it into your air tight head that you are the one who advanced this F**King argument. Not me.

I just quoted that what the designer of the F-16 XL saying that,","F-16 Xl's fantastic low wing loading cranked delta RSS airframe being the reason behind it's stupendous performance and not the low thrust line"".

This is the accepted norm for posting in open forum.Know the damned rule first.If you cannot quote any credible web site for your defense, Don't lunge on the person doing exactly that like a rabis infested dog.

There are legions of retards roaming the net sprouting foolish theory. I don't have time to argue with proficient BS posters.

You are novice to this world and you are harping on things you have no clue about. Power or thrust can also have a destabilizing effect in that an increase of power may tend to make the nose rise. The aircraft designer can offset this by establishing a "high thrust line" wherein the line of thrust passes above the CG as power or thrust is increased a moment is produced to counteract the down load on the tail. On the other hand, a very "low thrust line" would tend to add to the nose-up effect of the horizontal tail surface. This is what was applied in M3 and M2K. wherein the partial pitch moment of RSS was offset by thrustline use.

yeah, I have seen it all being explained with three figures of a prop driven aircraft with three illustrations, with three vector lines indicating center of lift,center of gravity and a down load on the tail. it is no rocket science beyond my comprehension.

Just think about whether those three illustrations on which you place your entire faith have any relation to the cranked delta tail less RSS layout. Those illustrations are done to explain the pros and cons of wing arrangement of classic positive static stability fighters of yore.

Don't imagine yourself to be Newton and Einsteen combined after explaining these mundane class -I lessons to me.

Aircraft designing is a holistic science, not faking a few useless argument.All forces that act on the F**king thrust line should act through the center of lift or pressure which is the cumulative point which focus's the lift force which is planned in front of the CG in RSS airframe.That is what the difference between Mirage-III and Mirage-2000, and not any other BS you expound here.

It is not stated by something a hothead like you who posts BS clothed as knowledge. this. It is the authoritative science called Aerodynamcis.

The CG of an aircraft exists in three dimensions. It's position not only effects the balance of the aircraft, but how the aircraft reacts when power is applied or reduced. A thrust line above or below the longitudinal axis creates different behavior during power changes, mostly in the pitching moment about the lateral axis.

A simple application of Newtons Law (which ignores some other effects) says the if the thrust line is above the CG, the nose will pitch down when power is added, and up when power is reduced. If the thrust line is below the CG, the effect is opposite.

The basic postulate of aerodynamics is that any thrust on the thrust line is to act through the center of LIFT or center of pressure and nothing else. RSS airframe deals with this theory and fixes the position of the CG behind the CP or CL in subsonic and trans sonic flight to achieve super agility. Rest of the BS like TYPHOON has lower thrust line , mirage has lower thrust line is known to any kid.

Only a hero like you can dodge accepting simple facts like and go on posting your own fancy BS like F-16 XL's lower thrust line is the sole reason for it's superlative performance.

And finally when proved otherwise brazenly asking the other guy for proof of F-16 XL's thrust line!!!!!!!!!!!!!!!!!!!

Think of it like a rope being around your neck, your waist, or your feet and what would happen to your balance when it is suddenly tugged by someone in front of you. If around your neck, you'd pitch forward and fall face down. If your feet, you'd pitch face up and land on your back. If around your waist, you'd maintain your balance. Same basic effect in an airplane.

These rope trick and tugging are based on the premise that a person is planted on the ground with his feet and the rope is tied in a fixed point on the pole . But a fighter is a free body floating in the air with force couple between the CG , CP and the act of all the control surfaces to configure all these into useful flight.No one drives a nail through the Cg of the fighter so you can tug with your thrust line on it.

If lift force produces an upward moment . the Cg produces a downward moment that's all. By placing CG behind the CL a nose up momentum is produced and maintained. As simple as that.

All the force that acts on the thrust line should act through the cumulative point called center of lift.

If this center of lift is placed behind the CG (in a positive static stability config ) there is no F***king way to avoid a downward momentum that will certainly be caused by the CG which lies in front of CP or CL.

It is actually quite a bit more complicated than that. First is the issue of whether the center of thrust (different from the centerline of thrust) is ahead or behind the CG.

DOES THE FORCE ALONG THE THRUST LINE ACT THROUGH THE CENTER OF LIFT (which is the point of focus of cumulative lift produced by all the control and lifting surfaces )OR NOT?
Contemplate it and you will have all the answers to yourself.

There is also the issue of whether the thrust line is parallel to the longitudinal axis, or if it is slightly offset, above, below, or to one side. Designers vary these things to obtain the desired handling characteristics or to serve other more important needs. If you set a centre line, then set the elevator to 0 degrees, then for positive stability, you need the wing to have a positive incidence, with a lifting air foil, the CG below the wing, and if the thrust line is on the same line, you need down thrust. If you set the engine to 0 degrees, when you open the throttle, the airframe will tend to loop. With down thrust, it wil pull the nose down when power is increased, so you will stay in level flight. If the thrust line is above the CG, the engine needs less down thrust. If the thrust line is below the CG, the engine needs more down thrust. The relation between the thrust line and the CG depends on the nose moment, which is the distance between the CG location and the point at which the thrust acts.

What is the relation between the center of lift and the thrust line?

If the forces along the thrust line act through center of LIFT or NOT?

If they act then the logic of RSS is unbreaable. No amount of waffling will change that.

The longer the nose moment is, the longer the effective lever is, and the less shift in thrust line is needed.

You have learnt just three letters about stability and design of an aircraft

Just learn that wherever the thrust line is all the force along the line should act through the center of lift. And you will get it easy.

That is why all modern multi role high agility fighters like M2K,TYPHOON, RAFALE, F-16 ,tejas,grippen, F-22,F-16 Xl are all low wing loading tail less delta either with a CRANK or COMPOUND or LREX or CANARD or Diamond shaped wing RSS airframe irrespective of the fact where the hell their thrust line is. The objective of the crank or canard or lrex or compound delta is to create lift inducing vortices and delay the onset of stall to increase the aerodynamic efficiency of the wing at close combat corner speed High AOA dog fight maneuvers.

R S S and you think that you have mastered it all. Can please explain to me as to how RSS helps in SUSTAINING high AOA? What use are vortex generators or LERX if RSS cud do it all for F-16? I suggest that you read something more than wiki and more advanced rather than rely on articles which you can't even understand. All this while I have been discussing about higher and lower thrustline while you are hung on RSS.

That's enough of an explanation I suppose.

 

[ersakthivel]

The Revolutionary Evolution of the F-16XL

All of these apparent miracles seem to violate the laws of aerodynamics by achieving greater range, payload, maneuverability, and survivability. Instead, they are achieved by inspired design, much wind-tunnel testing of shapes, exploitation of advanced technologies, and freedom from the normal contract constraints.


The inspired design mates a "cranked-arrow" wing to a fifty-six inch longer fuselage. The cranked-arrow design retains the advantages of delta wings for high-speed flight, but overcomes all of the disadvantages by having its aft portion less highly swept than the forward section. It thus retains excellent low-speed characteristics and minimizes the trim drag penalties of a tailless delta.

The above is the reason for the superlative performance of the F-16 Xl. Not any freaking thrust line!!!!!!!!!!!!!!!

Although the wing area is more than double that of the standard F-16 (633square feet vs. 300 square feet), the drag is actually reduced. The skin friction drag that is a function of the increased wetted (skin surface) area is increased, but the other components of drag (wave, interference, and trim) that are a function of the configuration shape and arrangement are lower so that the "clean airplane" drag is slightly lower during level flight, and forty percent lower when bombs and missiles are added. And although the thrust-to-weight (T/W) ratio is lower due to the increased weight, the excess thrust is greater because the drag is lower – and excess thrust is what counts.

You lack very basic knowledge has further been proven by what you have posted. Let me ask you what will be the diff in flying charactersticks of a non delta design with lesser sweep back having similar wing area as F-16xl when compared to your famous design of cranked delta?

The leading edge of the delta wing will not contact the shock wave cone that has to be encountered by the normal simple swept back wings. This ensures that delta wing has a laminar airflow available to it to generate lift and function with high aerodynamic efficiency which cannot be done by simple swept back wings that has to encounter the turbulent airflow at trans sonic shock waves.


The high rearward sweep back angle lowers the airspeed normal to the leading edge of the wing, which ensures that the wing remains aerodynamically efficient at at high subsonic, transonic, or supersonic speed, because the speed of air perpendicular to leading edge will be lower than the speed of sound ensuring laminar air flow bereft of shock wave while the over wing speed of the lifting air is kept to less than the speed of sound.

The delta plan form gives the largest total wing area for the wing shape, with very low wing loading, giving high maneuverability and beneficial lift to drag ratio to a fighter , remember the F-16 XL.


the leading edge of the wing produces stall delaying , lift inducing vortices at high angle of attack(ev)

it also gives large internal volume and sturdy wing design.


The problem in the plain tailless delta designs, is loss of total available lift caused by turning up the wing trailing edge or the control surfaces (as required to achieve a sufficient stability) and the high induced drag of this low-aspect ratio type of wing.


This causes plain delta-winged aircraft to 'bleed off' energy very rapidly in turns, a disadvantage in aerial maneuver combat and dogfighting.

It also causes a reduction in lift at takeoff and landing until the correct angle of attack is achieved, this means that the rear undercarriage must be more strongly built than with a conventional wing.

Pure delta-wings faced these problems like flow separation at high angles of attack (swept wings have similar problems), and high drag at low altitudes, due to denser air..

what is it that cranked delta overcomes when compared to with other delta designs?

compound delta,or double delta or cranked delta ,with two different sweep back angles , makes the creation of stall delaying high-lift inducing vortex in a more controlled fashion, countering the effect of the high drag typical of old plain deltas, giving the cranked delta acceptable slow speed specs and more control at slow speeds..

These vortices cancel out the bleed off in energy typical of the old plain deltas, because they increase lift and gives it a
highly beneficial lift to drag ratio cancelling out the higher drag of low aspect ratio plain deltas.

l Also it retains these large vortices in high AOA delaying the formation of flow separation ad postpones the onset of stall.

Which wing plan form will have more internal fuel volume, a cranked delta or normal swept back wing for similar wing area?

cranked delta has a bit lesser wing area than full delta ,for having better flying specs. But it will still do better than normal swept back wing.

Was their any comparision made of the flying qualities of F-16xl w.r.t anyother ac other than that of F-16?

F-16 XL was an evolution of F-16 design, which did much much better than the plain vanilla F-16 proving the superiority of cranked or compound delta wing form.The results paved the way for compound delta (like a diamond) wing form of the F-22. If yo still have any doubt look at the difference between SU-30 MKI wing form and FGFA wing form.

Why is it that no such ac has been built by US companies till date while after F-16xl testing they had made atleast ten more ac prototypes and non of them had cranked delta design?

At that time the F-15 which was a much bigger twin engine fighter with lot higher TWR , and higher powered RADAR and weapon load was also available to USAF. The non induction of F-16 XL was due to these factors clearly explained in the link I posted, and not due to the cranked delta design.

Why did HAL change from original cranked delta to compound delta design?

the much larger fighter that F-16 was enabled it to carry double crank of the delta wing form (cranked arrow) which allowed it to have a large area of vortice generation at two separate places in the wing.

And F-16 XL was just the expansion of the cropped delta of F-16 which had LREX at wing root. Not a new design So they converted the LREX to crank and added another bigger crank at the wing tip.

SInce Tejas was a new design it does not have to go thorough the contortions of double crank and straight away went with the big crank with a twist at wing root to enable large vortices generations at wing root passsing over the large delta wing area energizing lift over the entire wing.

What are the short comings of cranked delta w.r.t air combat?

Your turn to expound on that.

Regarding RSS, you need to explain other than higher pitch up rate, what other benefit does RSS offer especially when compared to canard designs? You also need to explain as to how does RSS help in maintaining high AOA?

i have explained it all along .better nose pointing authority, higher instantaneous turn rate vital for nose up lock ons with DASH-HMDS , high off boresight missiles. overall beneficial high lift to drag ratio.RSS exploits the naturally better ITR of delta wing forms even further.

Can you pls elaborate that between 0.5m to 0.95m wherein most ac are negatively stable, what happens to the fuel burn and what design penalties come into effect?

Most of the time a fighter flies at the air speed optimized for lower fuel burn and low drag according to it's design. But when it comes to close combat the better agility of the RSS cranked or compound delta wing form gives more chances to the pilot with high ITR and exceptionally low wing loading leading to better lift for high AOA , high alpha maneuvers which is further sharpened by RSS airframe.

What use does ITR have in todays aircombat wherein you have missiles like Python-5 and also targetting system like SPECTRA which have shot down targets flying behind them without the need to turn at all?

A fighter needs to be a fighter at first in it's clean config with super agility. using Pythons come much later.

What role does ITR play a in true BVR launch? Does RSS have any use their? Why was F-16 made and what were the reasons that it was given RSS?

ITR gives the quick nose pointing ability for python type WVR missiles. of course if missile has duel seeker infra head this ITR is not needed. But infra seeker is supplemented with radar seeker or guidance from mother craft to ensure better kill rates. That's where the high ITR comes into play.

Lastly can you fly any RSS ac once its FBW fails for any reason?

If you clarify whether you can fly a conventional plane after the loss of all hydraulic fluids I will also clarify.

 

[ersakthivel]

RSS ac with pure delta design of any combination has more problems than solutions. It is for this reason that F-22 and F-35 both have tailplane. Typhoon and Rafale have Canards. To sustain high AOA you need control input even in RSS ac as it might just do a flip. But in a pure delta RSS ac, it requires abnormally high control inputs. The high AOA of F-16 & F-18 is due to vortices generated by LERX and in F-35 by the chin and this ability has nothing to do with RSS.

for your information trapezoidal and cranked delta are one and the same.Not really different to each other in the aerodynamic layout.The F-22 and F-35 both are much larger planes , so they need tail planes. In tejas by having bigger after wing control surfaces the same is achieved.

Every one knows that having tail planes just after the huge wings reduce their efficiency by a large margin as a result of wing wash on the tail planes.

canards or LREX or also does the same job of crank in the delta, that is producing lift inducing stall delaying energizing vortices. Nothing more. nothing less.

A canard was added to Tejas and tested in wing tunnel and found out to give so significant efficiency increase for the weight and power penalty it provides.

Also if you see the canard deltas the control surfaces like elevons attached to the wing are small for (ex- Grippen ) compared to tejas.
So in the sum totl all it matters is having sufficient area on control surfaces. that's all.

canard config also has the undesirable element of canard tip wash on the wing and lead to pilot induced oscilations leading to crash in certain circumstances.Also the charecteristics of large aspect canards and the peculiarities of their charecteristics must be taken into account.

Wings are also deprived of fresh air laminar undisturbed stream in many flight profiles of the canard delta config imposing significant limitations on canard operations.And the inevitable canard wash over the wing reduces the wing's aerodynamic effficiency in certain critical flight profiles.

But on the other hand the cranked delta performs as part of the wing eliminating all the above mentioned complexities and at the same time providing the lift inducing vortices ensuring fresh airstream for high wing efficiency all the times.

diamond , trapedoizal, cranked delta may be different in geometrical sense but their aerodynamic purpose are all the same i.e generate vortices give better lift to drag ratio enhance low speed specs, ensure high alpha high AOA performance at corner speeds. thats all.

The cranked delta design only provided solution to poor slow speed handling of delta designs and nothing else. The planform of YF-23 and F-22, F-35 is called Trapezoidal design and not a delta design. The lightest, strongest and max volume wing form is a trapezoidal planform. It also has far lower drag as has been proven by the excellent kinematic performance of these wings.

As I said earlier trapezoidal,crank , or compound delta a;; serve the same purpose, they may look different in geometry but aerodynamically they do the same job of vortice generation.

They do not produce lower drag . All of them produce better lift to drag ratio countering the higher drag of plain delta wing form
.

The effective sweep angle of a trapezoidal wing is the algebric sum of its back and fwd sweep. YF-23 was far superior to F-22 as it had a wing which was swept fwd and back at same angle of 40* giving it an effective sweep angle of zero like a straight wing while still having all the benefits of a sweepback wing.

These algebras will be taken care of in design phase in any cranked delta fighter aimed at providing the best combination for the weight , wing loading and ASR req of the fighter. SO there is no need to discuss that.The shock cone of YF-23is much larger than the Tejas , so you can place that kind of wing form and still have low enough wing loading along with tail planes due to the bigger plane the YF-23 was compared to LCA TEJAS.

The mach cone is a well defined for each speed and the problem of keeping wings can be overcome in many more simpler ways than using delta design like reducing the span, AR, Increasing the length of the nose, placing wings well aft etc.

The mach cone is also well defined for the size of the fighter dictating optimum wing shape suited to it like Trapezoidal or cranked delta.

In fact, A NASA study had found that lightest fighter can be made which uses trapezoidal wing in a tailless design and not delta planform. I have not been able to locate that file as many NASA files have been removed from net after the chinese cyber activities.

So nothing really changes wrt to canards or cranks or trapezoidal wing form as all the variation of the pure deltas are aimed at vortice generation to energize the wing and nothing more..

 

[ersakthivel]

An RSS delta design ac must make use of elevons thruout its flight while being negatively stable which adds much higher drag to it than a conventional stable desig or a canard design.

It is to counter this undesirable property of pure delta form the cranked delta is used to provide better lift to drag ratio energizing the wing and reducing trim drag effort.The higher natural lift of the low wing loading added with energizing cranked delta can take care of that.

It also has problem in its roll rates for this very reason. A cranked delta has excellent gust riding qualities but poor dogfighting ability as the vortices add to drag

VORTICES ON THE CRANKED DELTA WING FORM,INCREASE LIFT TO PROVIDE BETTER LIFT TO DRAG RATIO AND CANCELLING OUT THE INHERENT DRAG OF THE PLAIN DELTA WING FORM,which forms the basis of best dog fighting skills.
Where in the world do you find vortices increasing drag!!!!!!!!!!! they reduce it in fact by providing better lift to drag ratio in cranked delta tailess fighters.

and larger the sweep angle of a delta, larger is the drag which you too have agreed.

tHE SWEEP ANGLES ARE OPTIMIZED FOR LESSER DRAG TRANSSONIC FLIGHT UNDERTAKEN BY CRANKED DELTAS MOST OF THE TIME. WHERE DID I AGREE LARGER SWEEP ANGLE MEANS LARGER DRAG?

This requires higher power settings to sustain turns so whatever ITR advantage RSS gave you by way of higher pitch up is undone by the poor STR which results for the same reason.

WHAT IS MORE IMPORTANT IN TODAYS COMBAT IS ITR AND BETTER NOSE POINTING ABILITY TO FIRE HIGH OFFBORESIGNT HMDS -DASH WVR MISSILES, NOT STR. I HAVE POSTED IT MORE THAN HUNDRED TIMES.

Reagrding ac being able to fly without hyd power, B-737-1/2/3/4/5/6/7/8/9 have complete manual reversion and can be flown by just the muscle power of a pilot. I have over 2500 hrs on them in command. all fighters flown by IAF barring Mig-29, Su-30MKI, M2k have hydro-mechanical controls and can be flown with speed restrictions down to zero speed. They all can do dead stick landing. I have flown Hunters which also had this feature. But in case of a failure of FBW, pilots have no option but to eject as ac departs. We have already lost three fully fit Su-30s due to FBW malfunction, two Gripen prototypes were lost and many such cases keep happening all over the world with RSS FBW ac.

The age of all electrical control is dawning.And you are talking of piloting a few old IAF planes being flown by pilot's muscle power!!!!!
No one is going to make fighters like that any more.

 

[Ganesh2691]

First LCA Tejas Mk.2 Prototype Next Year?

As the LCA Tejas Mk.1 fights through its crucial final stretch, it has been revealed that the first Mk.2 prototype is likely to be rolled out next year. As part of its effort to identify and certify LRUs for the improved combat jet, HAL has declared on April 9 to prospective development partners/suppliers of a hydraulic pump: "HAL-ARDC is taking up for development and qualification of certain LRUs required for catering to LCA-Mark 2 version. The first prototype aircraft is slated for built during 2013-14, while series production(s) are planned for inducting to fleet which is stated to be taken up in two phases commencing from 2016 onwards." (sic)

HAL suggests here that series production of the Mk.2 commences in 2016 -- that'll be bare months after the Mk.1 enters squadron service with the IAF, so I'm inclined see this as typical HAL/DRDO optimism, especially given that there's substantial work that needs doing on the Mk.2, not least airframe/fuselage changes to house and operate the new F414-GE-INS6 turbofan and allow higher performance requirements.

Livefist: First LCA Tejas Mk.2 Prototype Next Year?

 

[The Fox]

Re: ADA LCA Tejas - IV

so when will the Tejas MK II production will begin........ if the FOC for MK I is going to be by 2014

 

[p2prada]

Re: ADA LCA Tejas - IV

so when will the Tejas MK II production will begin........ if the FOC for MK I is going to be by 2014

Mk1s IOC and FOC schedule won't be related to Tejas Mk2.

Mk2s first flight is supposed to be late next year or even in early 2015. IOC is expected two years later. These are the only official dates. The rest are speculations.

IOC in 2016 would mean production starts from that year. A more optimistic schedule would be between 2018 and 2020. More die hard observers are expecting production to begin after 2020. Some are expecting FOC in 2024, giving it a 9 year testing cycle instead of 3 or 4 that ADA must be expecting.

According to P Rajkumar, it should be inducted sometime in 2020.

 

[ersakthivel]

12 years was the total time from the first flight of a totally new design TD-1 to the IOC date of mk-1.

that too with no separate serial production line and with a significantly more time consuming FSED-phase -2 along with so many design changes and cautious approach to thousands of test points due to very limited availability of LSPs and PVS with very slow production rate.

All this was done and all the test points were proved in 12 years. Mk-2 will share most of the design and performance features of mk-1 along with a dedicated serial production line to roll out PVs and LSPs , with no sanctions impact.

other than areas where performance is increased most of the test points of MK-2 are already validated by the grueling trials of mk-1.

So mk-2 can get into service at less than half the time taken for Mk-1 to get IOC is my guess.

In mk-2