ADA Tejas (LCA) News and Discussions

[ersakthivel]

One engine has always equated to greater risks in aviation.

The F-16 and Mirage-2000 have the same problem. But this is really a question of cost vs capability. This Soviet Union did not take such a risk and instead went ahead with the two engine Mig-29.

Two engines reduce the risk of crashing due to engine failure, but at the same time, the maintenance on two engines will be more expensive than if we built an aircraft on one engine. So, an air force would want something affordable as long as the crash rate is acceptable.

F-35 followed suit with a single engine primarily because of the requirement for vertical landing, where two engines don't benefit the design.

This is not a naive question at all.

Welcome back.Then why did US built thousands and thousands of F-16s?
They don't have the money I suppose.

 

[ersakthivel]

Vayu have flaws in reporting regarding National defense Projects, earlier same was repeated in Arjun report..

Anyways Still a great insight of past and its relation with present and future evolution for LCA ..

These are not errors kunal. These are motivated news like the paid news undertaken by the political parties in election with vested interests. For example the author could have walked into ADA office and got all his doubts clarified.

The real standard journalists will always do that. They will put their point of view and then post questions to the designers regarding these issues. ANd then publish the view of ADA along side .That is real journalism.
You woul have known RADIA tape affair and how reputed journalista push the agendas of vested interest. It is not a crime though. It is an accepted slimy practice.People can not eat their reputation, they have to make money as well.

 

[Daredevil]

ADA LCA Tejas

New LCA Tejas thread as the last thread has become huge.

Link to Previous thread

http://defenceforumindia.com/forum/indian-air-force/18521-ada-tejas-lca-iii-246.html#post610186

Post away..

 

[Daredevil]

Thread Closed as it has become huge. Please continue in this thread

http://defenceforumindia.com/forum/indian-air-force/43717-ada-lca-tejas-iv.html

 

[Kunal Biswas]

re: ADA Light Combat Aircraft Tejas

 

[Kunal Biswas]

re: ADA Light Combat Aircraft Tejas

 

[Kunal Biswas]

re: ADA Light Combat Aircraft Tejas

 

[Kunal Biswas]

re: ADA Light Combat Aircraft Tejas

It has no audio

 

[Kunal Biswas]

re: ADA Light Combat Aircraft Tejas

Flying in formation, EW installed..

 

[Kunal Biswas]

re: ADA Light Combat Aircraft Tejas

Some Links and Post have added to new thread, Continue posting.. :thumb:

 

[ersakthivel]

Re: ADA Tejas (LCA) - III

LCA is actually a compound delta. But yeah, as you said, we need Canards, Horizontal Tails, LERX or Chines along with the delta because of more stringent maneuverability requirements.

Anyway the Mk1's turn performance(STR) is somewhere between a Mirage III at 15-16deg/s and a Mirage-2000 at 18-19deg/sec, obviously at speeds of 300-400 Knots and sea level altitude. According to ACM Naik in his media comments and Air Marshal Wollen's article the turn performance of the LCA is 17deg/s which actually makes sense.

Tejas - Feature - The Light Combat Aircraft Story by Air Marshal MSD Wollen (Retd)

The author, Air Marshal M.S.D. Wollen (Retd) was the chairman of Hindustan Aeronautics Limited from September 1984 to March 1988

From this link.

Delay in commencement of Project Definition (PD) gave ADA time to marshal national resources (80 work centers spread over the country); to construct buildings, recruit personnel and create infra-structure; and to get a clearer perspective of the advanced technologies that could be indigenously developed and those that would need to be imported. The IAF's Air Staff Requirement, finalized in October 1985 is the base document for development.
THe IAF's Air Staff Requirement, finalized in October 1985, is posted here with the authentic link.

The LCA is tailless with a double-sweep delta wing. Its wing span is 8.2 m, length 13.2 m, height 4.4 m. TOW clean 8.500 kg, MTOW 12500kg. It will be super-sonic at all altitudes, max speed of M 1.5 at the tropopause. Specific excess power and g-over load data has not been published. Maximum sustained rate of turn will be 17 deg per sec and maximum attainable 30 deg per sec.

So this is the actual document provided to ADA on 1993 as ASR.

Now the LCA has 14 ton mtow.

It has crossed 22 degree AOA within 85 percent of it's potential capacity with an underpowered 70plus kn engine.

It's present targeted top speed is 1.2 mach at sea level.This has been achieved only in 4 km deep dive as the present 70 plus kn engine is insufficient to reach this speed in level flight.

Another important consideration is because SPIN RECOVERY TEST HAS NOT BEEN COMPLETED , The aircraft is flying within 85 percent of it's original potential.

Because reaching the max AOA is getting close to stall speeds ,The spin recovery test validates the performance of tejas in post stall recovery.SO only after finishing this test will tejas clear it's max AOA.

So the max AOA will be increased only after the conducting of the test.

In all programs this is the norm.




At ceiling limit it is 1.8 mach.

With 90 kn GE-INS6 engine LCA will ahieve much better STR than the so called 17 degree.
This engine will be fitted only on the Serial production aircraft.
SO comparing it with ASR of 1983 with a planned 80 kn engine is basically wrong.

The mk-2 is slated to have 100kn engine.
5ton weapon load .And another 30 percent in crease in range.

Once the JV with snecma produces 90 kn engine, almost all subsystems on it will be indegenised.

SO this achievement is far and above the original specs mandated in the original ASR.

It will have substantially more top speed,more fuel load,more range,more MTOW, more STR,higher AOA,and asea radar and long range BVRs in the mk-2 version ,which won't need as much time consuming flight tests as mk-1.

It would have one of the least RCS fighters in IAF as well.

So this is a signifiant indicator of the basic aerodynamic potential of the design.

If ADA chose some long fuselage ,with high wingloading short wing design in place of the cranked delta,fully relaxed stability,carefree handling FBW,and composite materials(which is chosen by all 5th gens),

all the above specs would have been pipe dreams.

So the LCA that now flies is a completely different aircraft than the mig-21 replacement it was touted to be.
Now it's specs are near grippen C/D if the flight envelope is opened fully with lesser wing loading than grippen.

The mk-2 specs will be even more close to the NG specs.


The author, Air Marshal M.S.D. Wollen (Retd) was the chairman of Hindustan Aeronautics Limited from September 1984 to March 1988. He entered the Indian Air Force in 1947 and was awarded the Param Vishisht Seva Medal (PVSM) for his exemplary role in the 1971 Indo-Pak War. It was during his tenure at HAL that the design and development of the Advanced Light Helicopter and Light Combat Aircraft (LCA) was undertaken. He is considered an authority on LCA, and MIGs in particular. Air Marshal Wollen has authored several papers on aviation and here he talks about Tejas and the reason why it is so important.

The following is the actual timeline of LCA

1983 ADA was formed.


The IAF's Air Staff Requirement, finalized in October 1985 is the base document for development.

Project definition (PD) commenced in October 1987 and was completed in September I988

A Review Committee was formed in May 1989. Experts from outside the aviation industry were included. The general view was that infrastructure, facilities and technology had advanced in most areas to undertake the project. As a precaution, Full Scale Engineering Development would proceed in two phases. Phase 1: design, construction and flight test of two Technology Demonstrator aircraft (TDI & 2); construction of a Structural Test Specimen; construction of two Prototype Vehicles (PVI &2); creation of infrastructure and test facilities. Phase 2: construction of three more PV '5, the last PV5, being a trainer; construction of a Fatigue Test Specimen; creation of facilities at various work centres. Cost of Phase I - 2188 crores, of Phase II - 2,340 crores. Phase I commenced in 1990. However, due to a financial crunch, sanction was accorded in April 1993 and was marked by an upsurge in work.

As a point of interest, a second series of in-flight simulation tests of flight control software took place in July 1996 at Calspan USA on an F-16D VISTA (variable in-flight stability aircraft); 33 test flights were carried out. Another reason for delay was the sanction imposed after Pokhran II in May 1999. Scientists working at Lockheed Martin, USA were sent back; equipment, software and documents were impounded. Herculean efforts brought the FCS software to a standard where the FCS performed flawlessly over 50 hours of testing on TD 1 by pilots, resulting in the aircraft being cleared for flight in early 2001.

The LCA is tailless with a double-sweep delta wing. Its wing span is 8.2 m, length 13.2 m, height 4.4 m. TOW clean 8.500 kg, MTOW 12500kg. It will be super-sonic at all altitudes, max speed of M 1.5 at the tropopause. Specific excess power and g-over load data has not been published. Maximum sustained rate of turn will be 17 deg per sec and maximum attainable 30 deg per sec.
The fighter that was in the works in 1970 was MARUT.Not LCA.
The first funding for the aircraft TD-1 came in 1993 due to severe Financial crunch in the early nineties.

Previously 500 cr was given on 1989 ,which went into establishment of infra and testing facilities and labs for ADA.

SO saying LCA program started in 1970s and it's designers are working on it for 45 years is a motivated lie.

TD-1 won't walk out of the ADA labs with it's own legs in 1995 , just because these 500 cr worth of labs and infra was set up in 1989.
Phase -1 commenced in 1990 with 2180 cr is the official statement .But it was only peper work because due to severe financial crisis in the i990-93 period funds for construction of TD-1 was not released.

The first funding of the prototype TD-1 was received in 1993.

In 7 years the TD-1 flew on 2001 with complete fly by wire software.



I have repeated it more than 10 times in this forum.
But the same absurd cock and bull story that LCA is in the works for 45 years and it is 30 years late is being repeated again and again.


again from the samw article.

In the late eighties India's aircraft Industry was not as advanced as Sweden's; and yet India follows a more arduous design/development route for its LCA, compared to Sweden for its JAS-39 Gripen. The Gripen embodied a far higher percentage of foreign, off-the-shelf technology, including its RM-12 engine (improved GE F404). France (Dassault Aviation) built and exhaustively flew a demonstrator aircraft (Rafale-A) before embarking on construction of Rafale prototypes. Over 2,000 flights were completed by September 1994 when first Flight of a production Rafale was still 20 months away. At that point of time, Dassault Aviation had built or flown 93 prototypes, of which at least fifteen went into production after sixteen years elapsed from 'first-metal-cut' of the Rafale demonstrator to entry into service.

It is unlikely that the LCA will attain initial operational clearance (IOC) before 2010.When it is achieved, it will be an industrial success of magnificent proportion, and is sure to receive the acclaim it deserves.

It achieved IOC with much higher specs than the original ASR.

Tejas - India's Light Combat Aircraft - Official Website

 

[ersakthivel]

Tejas - Feature - The Light Combat Aircraft Story by Air Marshal MSD Wollen (Retd)

THE ABOVE LINK IS A MUST READ FOR ANYONE TO UNDERSTAND THE TIMELINES, MAGNITUDE OF THE TECH CHALLENGES FACED AND WHAT WAS ACHIEVED IN TEJAS PROGRAM

Most of the misconception regarding tejas can be cleared by the through read of the above article by AIR MARSHAL ASD WOOLLEN WHO WAS THE HAL CHAIRMAN DURING THE CRITICAL PERIOD OF 1984 to 89 when the lca program was conceptualized.

The LCA is tailless with a double-sweep delta wing. Its wing span is 8.2 m, length 13.2 m, height 4.4 m. TOW clean 8.500 kg, MTOW 12500kg. It will be super-sonic at all altitudes, max speed of M 1.5 at the tropopause. Specific excess power and g-over load data has not been published. Maximum sustained rate of turn will be 17 deg per sec and maximum attainable 30 deg per sec.
According to him the above is the original ASR.
G loads,excess power data was not there even in this link.

During early flight development, the TD aircraft will be powered by a single GE F404 F2J3 engine (7,250 kg reheat thrust).

Then specs of lca now is
Tow clean -9 ton ,
Mtow-14.5 ton,
top speed-1.8 mach at altitudes,1.2 at sea level,
AoA-28 degree,

SO these specs cannot be achieved by the lower powered GE engine that is currently onLCA LSPs,
It needs a higher powered engine for achieving the specs.

From 1983 to 1993 nothing much happene on the TEJAS,
The 500 cr released before 1993 was used for infra set up and Project definition,(all defined specs changed later)
Only after Funding of Tds started in 1990s did any practical work commenced on the project.

Salient engine features include the 3 stage fan; 6 stage HP compressor with variable geometry IGV, I and II stators; annular combustion chamber; cooled single stage HP and LP turbines; modulated after-burner; fully variable, convergent-divergent nozzle; length 3490 mm; max diameter 910 mm; dry thrust 52 kN; reheat thrust 81 kN; thrust weight ratio 7.8. The 'Achilles heel; in the successful development of the LCA, in the opinion of this author, is the Kaveri engine.

The above is the specs of kaveri engine.

Around 75 kn thrust is now achieved with thrust weight ratio of around 7 in 20 years ,typical of any engine developmental program.So what was refered to as achilies heels of tejas has been solved.The problem is tejas specs have gone well past the specs of the engine due to developments in modern fighter design.

Tweaking the engine for 80 plus kn is not impossible.But tejas needs 90 pluskn engine in it's current avathar.That's why JV with snecma is proposed.

Note the AL-31 FP has the same thrust to weight ratio of 7.8 (it is on the sukhoi,I think but I am not sure)that was aimed for GTRE KAVERI
And more or less it has been achieved.
The chinese WS engines also has the same thrust to weight ratio of 7.8 .

So india is not not lagging behind even in engine techlevel,once all the small niggling problems with K-9 are solved.

the blind thrust figure doesnot say anything regarding tech level of engines.It is the TWR figure that determines the engine tech level.In which now we have advanced to a significant extent.That's why the PRATT &WHITNEY team which examined the engine said it was a world class engine and further improvements in thrust level is possible.

Also the SNECMA team too studied the engines and said it can be uprated to 90 plu KN.

In the late eighties India's aircraft Industry was not as advanced as Sweden's; and yet India follows a more arduous design/development route for its LCA, compared to Sweden for its JAS-39 Gripen. The Gripen embodied a far higher percentage of foreign, off-the-shelf technology, including its RM-12 engine (improved GE F404). France (Dassault Aviation) built and exhaustively flew a demonstrator aircraft (Rafale-A) before embarking on construction of Rafale prototypes.


Over 2,000 flights were completed by September 1994 when first Flight of a production Rafale was still 20 months away. At that point of time, Dassault Aviation had built or flown 93 prototypes, of which at least fifteen went into production after sixteen years elapsed from 'first-metal-cut' of the Rafale demonstrator to entry into service. Current plans for the LCA is ten years. And what of India's past record?

It is unlikely that the LCA will attain initial operational clearance (IOC) before 2010.When it is achieved, it will be an industrial success of magnificent proportion, and is sure to receive the acclaim it deserves.

this is the prophetic conclusion of the author who was the chairman of HAl at that time and it was proved conclusively right.
Note his words--When it is achieved, it will be an industrial success of magnificent proportion, and is sure to receive the acclaim it deserves.

But the spin recovery test on tejas has not been completed ,That is one of the reason why it has not reached high AOA level as without validating the parameters of near stall behaviour and post stall recovery of the aircraft MAX AOA and MAX G can't be reached with confidence, SO FBW is restricted to 6g is and flight envelope is opened only till 85 percent.

To conduct this SPIN RECOVERY test ADA is taking consultancy from EADS, not to reduce weight as implied by some members.The weight reduction consultancy was taken for N LCA's landing gear not for air force version.

So it will clear most of the misconception regarding tejas programs time lines, capabilities.
This is as authentic as it gets.

 

[ersakthivel]

Re: ADA Tejas (LCA) - III

http://defenceforumindia.com/forum/...d-working-third-stealth-fighter-report-2.html

Post no-16 by weg

The concept seems to be, build an ultra stealthy, low cost UAV which can work autonomously or in squadron (possible with a Eurofighter or Rafael in command). Low cost comes from the Rolls-Royce Adour engine as used in the BAe Hawk and Jaguar.

The aircraft will probably cost 1/5 the price (~$20m) of a EF or Rafael and less than half the hourly cost to operate. Being unmanned you could have two aircraft on point, with their radar shining on approaching stealth aircraft to receive reflections from the side aspect, while others could use their all aspect, ultra stealth (better than any manned aircraft). The manned fighter could loiter behind with its radar switched off (stealth aircraft cannot use their Radar..) ready to pick off whatever makes it past the drones.
For anbody interested in how stealth UCAVs like AURA or EW aircrafts working in combination with 4th gen fighters like tejas,rafale,eurofighter ,against 5th gen stealth this will give some clarifiction

 

[ersakthivel]

Re: ADA Tejas (LCA) - III

Designers insist Tejas will belie all sceptical questioning

In an exclusive interview with Business Standard, P Subramanyam, director of the Aeronautical Development Agency (ADA), which is developing the LCA and the AMCA, responded to IAF criticism that the Tejas was not yet a world-class fighter. He said the Tejas Mark-I, still being flight-tested, had been flown to just 85 per cent of its full capability.

The Tejas Mark-II -- in which a more powerful GE-414 engine will replace the current GE-404 engine -- would perform another 15 per cent better.

"The Tejas Mark-I will expand its performance envelope to its full capability by end-2012. And, a major performance boost will come from the Tejas Mark-II's new GE-414 engine, for which we have signed a $700-million (Rs 3,135 crore) contract to build here in India.

The Mark-II will outperform the Mark-I by about 15 per cent in the key aspects of take-off run, rate of climb, acceleration, and turn rate. Most of this would come from the higher thrust of the GE-414 engine. Another two-three per cent benefit would come from better aerodynamics"¦ since we will re-engineer the fighter to accommodate the new engine.

That overall 35-40 per cent improvement would make the LCA the world's premier light fighter," says Subramanyam.[/QUOTE]

 

[ersakthivel]

In aerodynamics, wing loading is the loaded weight of the aircraft divided by the area of the wing The faster an aircraft flies, the more lift is produced by each unit area of wing, so a smaller wing can carry the same weight in level flight, operating at a higher wing loading.

Correspondingly, the landing and take-off speeds will be higher. The high wing loading also decreases maneuverability. The same constraints apply to winged biological organisms.

Effect on performance

Wing loading is a useful measure of the general maneuvering performance of an aircraft. Wings generate lift owing to the motion of air over the wing surface. Larger wings move more air, so an aircraft with a large wing area relative to its mass (i.e., low wing loading) will have more lift available at any given speed.

Therefore, an aircraft with lower wing loading will be able to take-off and land at a lower speed (or be able to take off with a greater load). It will also be able to turn faster.

Effect on take-off and landing speeds

As a consequence, aircraft with the same CL at take-off under the same atmospheric conditions will have take off speeds proportional to . So if an aircraft's wing area is increased by 10% and nothing else changed, the take-off speed will fall by about 5%. Likewise, if an aircraft designed to take off at 150 mph grows in weight during development by 40%, its take-off speed increases to mph.



Effect on climb rate and cruise performance

Wing loading has an effect on an aircraft's climb rate. A lighter loaded wing will have a superior rate of climb compared to a heavier loaded wing as less airspeed is required to generate the additional lift to increase altitude.

A lightly loaded wing has a more efficient cruising performance because less thrust is required to maintain lift for level flight. However, a heavily loaded wing is more suited for higher speed flight because smaller wings offer less drag.


The wing loading is important in determining how rapidly the climb is established. If the pilot increases the speed to vc the aircraft will begin to rise with vertical acceleration ac because the lift force is now greater than the weight.



Effect on turning performance

To turn, an aircraft must roll in the direction of the turn, increasing the aircraft's bank angle. Turning flight lowers the wing's lift component against gravity and hence causes a descent. To compensate, the lift force must be increased by increasing the angle of attack by use of up elevator deflection which increases drag.


Turning can be described as 'climbing around a circle' (wing lift is diverted to turning the aircraft) so the increase in wing angle of attack creates even more drag. The tighter the turn radius attempted, the more drag induced, this requires that power (thrust) be added to overcome the drag. The maximum rate of turn possible for a given aircraft design is limited by its wing size and available engine power: the maximum turn the aircraft can achieve and hold is its sustained turn performance.

As the bank angle increases so does the g-force applied to the aircraft, this has the effect of increasing the wing loading and also the stalling speed. This effect is also experienced during level pitching maneuvers.

Aircraft with low wing loadings tend to have superior sustained turn performance because they can generate more lift for a given quantity of engine thrust. The immediate bank angle an aircraft can achieve before drag seriously bleeds off airspeed is known as its instantaneous turn performance. An aircraft with a small, highly loaded wing may have superior instantaneous turn performance, but poor sustained turn performance: it reacts quickly to control input, but its ability to sustain a tight turn is limited.

A classic example is the F-104 Starfighter, which has a very small wing and high wing loading. At the opposite end of the spectrum was the gigantic Convair B-36. Its large wings resulted in a low wing loading, and there are disputed claims[who?] that this made the bomber more agile than contemporary jet fighters (the slightly later Hawker Hunter had a similar wing loading of 250 kg/m2) at high altitude. Whatever the truth of that, the delta winged Avro Vulcan bomber, with a wing loading of 260 kg/m2 could certainly be rolled at low altitudes.

Like any body in circular motion, an aircraft that is fast and strong enough to maintain level flight at speed v in a circle of radius R accelerates towards the centre at . That acceleration is caused by the inward horizontal component of the lift, , where is the banking angle. Then from Newton's second law,

Tidying up gives

The smaller the wing loading, the tighter the turn.

Gliders designed to exploit thermals need a small turning circle in order to stay within the rising air column, and the same is true for soaring birds.

Other birds, for example those that catch insects on the wing also need high maneuverability. All need low wing loadings.

Effect on stability

Wing loading also affects gust response, the degree to which the aircraft is affected by turbulence and variations in air density. A small wing has less area on which a gust can act, both of which serve to smooth the ride. For high-speed, low-level flight (such as a fast low-level bombing run in an attack aircraft), a small, thin, highly loaded wing is preferable: aircraft with a low wing loading are often subject to a rough, punishing ride in this flight regime.

Effect of development

A further complication with wing loading is that it is difficult to substantially alter the wing area of an existing aircraft design (although modest improvements are possible). As aircraft are developed they are prone to "weight growth" -- the addition of equipment and features that substantially increase the operating mass of the aircraft. An aircraft whose wing loading is moderate in its original design may end up with very high wing loading as new equipment is added. Although engines can be replaced or upgraded for additional thrust, the effects on turning and take-off performance resulting from higher wing loading are not so easily reconciled.

to sum it up

1.The smaller the wing loading, the tighter the turn.

2. For high-speed, low-level flight (such as a fast low-level bombing run in an attack aircraft), a small, thin, highly loaded wing is preferable[/U]: aircraft with a low wing loading are often subject to a rough, punishing ride in this flight regime.It is to compensate for this problem, the LCA has cranked delta which improves handling at low altitude.LEVCONS are planned to aid more in this regard..

3The maximum rate of turn possible for a given aircraft design is limited by its wing size and available engine power, the maximum turn the aircraft can achieve and hold is its sustained turn performance

4. Wing loading is a useful measure of the general maneuvering performance of an aircraft

5. Larger wings move more air, so an aircraft with a large wing area relative to its mass (i.e., low wing loading) will have more lift available at any given speed.

6.Wing loading has an effect on an aircraft's climb rate. A lighter loaded wing will have a superior rate of climb compared to a heavier loaded wing as less airspeed is required to generate the additional lift to increase altitude.

7. A lightly loaded wing has a more efficient cruising performance because less thrust is required to maintain lift for level flight. However, a heavily loaded wing is more suited for higher speed flight because smaller wings offer less drag.

That is why from mirage onwards to LCA,TYPHOON,RAFALE,GRIPPEN,F-22,F-35,PAKFA ARE ALL GOING FOR LOW WING LOADING DELAT DESIGN.THE LCA TEJAS HAS THE LOWEST WING LOADING OF ALL.IT IS NOT SOME INSIGNIFICAT STUFF.

LCA integerates the functionality of canards in the shape of the lesser swept angle crank in the wing itself.
The crank with twist at wingroot performs the same role of canards,i.e delaying theonset of flow seperation vortices to delay the wing stalling .
The pitch control can be done by the elevons in much better way,if they are big enough.

With no additional drag ,and avoiding a lot of minus points of the canards,
1.force coupling resulting in uncontrollable spin,
2.extra hydraulics weight ,
3.DRAG in supersonic flight,
4.complexities of managing two center of lifts in fbw(grippen prototype crashed especially on this issue and force coupling)
5.The lesser effeciveness of wing in certain modes of flight due to canard wash effect.
6.The placement of canards also present challenges to the whitcomb area rule,

infact a canarded model was put into wind tunnel testing for LCA and found to have no significant improvement in performance


It is not a herculean job to add a tail plane to the 1 or more meter proposed fuselage length increase for mk-2.the point is they are superfluous.

The levcons and cranked delta wing shape with lesser sweep and twist in the wing root in combination will perform the same job as that of canards, without subjecting wing to adverse canard wash in some critical flight envelopes there by limiting the fighters maneuverability in critical points.

the mirage has a long fuselage and much higher weighty plane than lca,the makers deemed there is no need for tailplanes or big canards.

Strakes near the nose and small cat mush like minute canards do the job and still it is contemproary.
And IAf preferrred 126 extra mirages even with the lower TWR ,over the option of mig-29s despite the mig-29 having all the bells and whistles in the form of tailplanes.
Lca has a much better TWR and much lower wing loading than mirage.

The sustained turn rate is the combination of
1.Thrust to wight ratio
2.low wing loading
2.Angle of attack.

It is not the function of tailplanes or canards..

 

[ersakthivel]

More regarding the F-16 xl cranked delta

Less noticeable is that the fuselage was lengthened by 56 in (1.4 m) by the addition of 2 sections at the joints of the main fuselage sub-assemblies.
With the new wing design, the tail section had to be canted up 3°, and the ventral fins removed, to prevent them from striking the pavement during takeoff and landing.

However, as the F-16XL exhibits greater stability than the native F-16, these changes were not detrimental to the handling of the aircraft.

These changes resulted in a 25% improvement in maximum lift-to-drag ratio in supersonic flight and 11% in subsonic flight, and a plane that reportedly handled much smoother at high speeds and low altitudes.

The enlargements increased fuel capacity by 82%. The F-16XL could carry twice the ordnance of the F-16 and deliver it 40% further. The enlarged wing allowed a total of 27 hardpoints:

The Revolutionary Evolution of the F-16XL

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.

The aircraft was loaded with twelve Mk 82 50-pound general-purpose bombs, four dummy AMRAAM missiles, and two AIM-9 Sidewinder missiles. Internal fuel was 10,200 pounds (full fuel for the prototype is 10,600 pounds). Allowing for fuel consumption for engine start and taxi, gross takeoff weight was 43,500 pounds. Jim estimated the takeoff roll at a bit more than 3,000 feet.



Of particular interest were the control surfaces on the aft edge of the cranked-arrow wing. The F-16XL does not have a horizontal tail. Thus, the control surfaces for both pitch and roll are on the rear edge of the wing. The inboard surfaces are mainly for pitch control, while the out board surfaces take care of roll control. However, thanks to the automatic flight control system, when performance requires it, all four surfaces can act in either pitch or roll.


Supersonic in Seconds


Takeoff from Edwards AFB's Runway 22 with maximum power at gross weight of 43,500 pounds was achieved in les than 3,000 feet. Jim eased back the power to climb away from the Edwards traffic pattern and take up a northerly heading for the test airspace assigned to us.


Even with the heavy bomb load aboard, the aircraft went supersonic without a tremble. Handling characteristics at mach 1.2 with the heavy ordnance load were remarkably similar to those of the standard F-16 without bombs.



Next, we maneuvered at slow flight speeds and high angles of attack, demonstrating the F-16XL's agile handling in that corner of the performance envelope. We accelerated back to more than 400 knots and I tried more 360° rolls. Once I was accustomed to the correct control stick pressures, the roll rate was fast and the controls crisp. The same feelings were apparent at 500 knots – quick, sure response, with no feeling of carrying the heavy bomb load.


Next, Jim demonstrated the F110 engine's ability to accelerate from idle to max afterburner by slamming the throttle forward. Engine response was smooth with no coughing or stalling, thanks to General Electric's advanced electronic engine controls.


Then we descended to low level for penetration at high speed. Jim set up the aircraft at 600 knots indicated airspeed at 100 feet above ground level. The ride quality on a very hot day was smooth. The G-indicator on the head-up display (HUD) showed excursions of less than 0.2 above the below 1.0, but they were undetectable in the body. On similar flights with an F-4 as the chase aircraft, its G excursions were as high as 2.0, making for an uncomfortable ride and heavy concentration on flight controls.


In the loaded configuration, the F-16XL can penetrate at low level at airspeeds fifty-to-ninety knots faster than the basic F-6 when similarly configured. In fact, at every corner of the performance envelope, the aircraft has power in reserve, according to members of the Combined Test Force at Edwards.

Attack maneuvers resulted in G forces ranging to +7.0. With the heavy bomb load aboard, the F-16XL is cleared for maneuvers up to +7.2 Gs, compared with 5.58 Gs in the F-16A. This demonstrates how the designers were able to increase the aircraft weight while maintaining structural integrity and mission performance.

For people who want to know the basic purpose of cranked delta wing and the misconception that higher wing area of LCA tejas provides more drag and reduces performance .IT IS A MUST READ.

Especially for the author of flight global magazine's 2009 piecec on lca and the PRODYUT DAS types who write on VAYU.

 

[Kunal Biswas]

LCA Tejas with Payload flight, Includes fuel tanks, Laser Guided Bombs, Lighting Pod and R-73RD Short range Heat seeking Missile..

 

[Kunal Biswas]

Future Squadrons of LCA for Indian Air Force..

 

[Kunal Biswas]

There are 6 x NLCA planed for INS Vikramaditya

 

[roma]

i would like to thank (a little belatedly) Admin for the previous thread ( now appropriately closed and merged with this one ) for letting us continue to have a great discussion on the LCA-Kaveri ... by keeping the discussion on-track, at a good professional and technical level avoiding flaming and all that ....many thanks to Mr Kunal and our colleagues in admin ...ive learned many an interesting fact and view the LCA project and all the dedicated officers and technologists with a lot more renewed respect thanks to all your inputs ....will continue to read this lively discussion, keep it up !