ADA Tejas (LCA) News and Discussions

[ersakthivel]

2000 hours of incident free flight tests

 

[Sridhar]

2000 hours of incident free flight tests

You need to upload the image to Image Hosting site and the use the Link here.

 

[ersakthivel]

We can clearly see, how the fuselage is pinched near wing root to obey the whitcomb's area rule for a coke bottle like shape to reduce supersonic wave drag.
And the wingroot twist as a cranked delta.

 

[ersakthivel]

We can clearly see, how the fuselage is pinched near wing root to obey the whitcomb's area rule for a coke bottle like shape to reduce supersonic wave drag.
And the wingroot twist as a cranked delta.

 

[ersakthivel]

we can clearly see the two different wing sweep angles on the leading edge.The lesser swept wing near the root along with twist at wing root ,to improve low altitude performance and to delay the flow separation vortices formation on the wing root,and higher swept angle after for excellent low drag high altitude supersonic dash , bestowing the tejas with lowest wing loading of all single engined fighters, resulting in agility in the vertical plane.


The lesser swept angle at the front is designed to perform the job of canards,with out the drag penalty ,rcs reflections,., and canard wash disadvantages, so that wings can always get the fresh airstrean at any angle of attack without turbulence from canards.

This frees tejas from ,force coupling issues resulting in uncontorallable flat spin ,and loss of control of the fighter, if certain parameters are exceeded, capping the agility of canard-deltas at some portions of flight envelopes

These features in combination is not seen on any other in production fighters before, so this is a original design endeavor from ada, not a copy of mirage as persistently advocated in many forums.The mirage is a plain vanilla delta with none of the above features with way lower twr and way lower wing loading figures.

 

[ersakthivel]

LCA Tejas is a lightweight multi-role fighter developed by India. It is a tailless, compound delta-wing design powered by a single engine. It came from the Light Combat Aircraft (LCA) programme, which began in the 1980s to replace India's aging MiG-21 fighters. Later, the LCA was officially named "Tejas", meaning "Radiance" .

The Tejas has the delta wing configuration, with no tailplanes or foreplanes, and features a single vertical fin. It integrates technologies such as relaxed static stability, fly-by-wire flight control system, advanced digital cockpit, multi-mode radar, integrated digital avionics system, advanced composite material structures and a flat rated engine. The IAF is reported to have a requirement for 200 single-seat and 20 two-seat conversion trainers, while the Indian Navy may order up to 40 single-seaters to replace its Sea Harrier FRS.51 and Harrier T.60.

The Tejas achieved a speed of over 1,350 kilometres per hour (840 mph) during its sea level flight trials, thus becoming the second supersonic fighter developed indigenously by Hindustan Aeronautics Limited after the HAL Marut. The Tejas achieved Initial Operational Clearance (IOC) in January 2011 for use by Indian Air Force pilots. Final operational clearance (FOC) is scheduled to be in early 2013.

We can clearly see the two different wing sweep angles on leading edge on the LCA.The lesser swept wing near the root along with twist at wing root ,to improve low altitude performance and to delay the flow separation vortices formation on the wing root,and higher swept angle after for excellent low drag high altitude supersonic dash , bestowing the tejas with lowest wing loading of all single engined fighters, resulting in agility in the vertical plane.


The lesser swept angle at the front is designed to perform the job of canards,with out the drag penalty ,rcs reflections,., and canard wash disadvantages, so that wings can always get the fresh airstrean at any angle of attack without turbulence from canards.

This frees tejas from ,force coupling issues resulting in uncontorallable flat spin ,and loss of control of the fighter, if certain parameters are exceeded, capping the agility of canard-deltas at some portions of flight envelopes

These features in combination is not seen on any other in production fighters before, so this is a original design endeavor from ada, not a copy of mirage as persistently advocated in many forums.The mirage is a plain vanilla delta with none of the above features with way lower twr and way lower wing loading figures.

 

[ersakthivel]

The smooth upper wing body blending is shown in this photograph , typical of lifting body designs of later generation fighters from sukhoi, rafale,eurofighter typhoon, F-22,PAKFA,J-20.

This high wing body blending is the hall mark of even the fifth gen fighters, reducing the corner reflections from the awacs radars searching from above resulting in lower RCS with missiles and extenal sores hidden under the wing. (as there are no corners formed when the flat wings get attached to cigar like fuselage in old fighters designs like mig-21, jf-17,j-10,grippen,and mirages)

Mote this high wing body blending feature is absent in J-10,jf-17, so these two designs are not as contemproary as tejas.

That's why I get livid and blow out, when people compare second generation all aluminum birds like vintage upgraded mig-21 bisons(consistently saying they are 4th gen) and jags, resulting in vituperative rebuttals.

 

[ersakthivel]

Re: ADA Tejas (LCA) - III

The smooth upper wing body blending is shown in this photograph , typical of lifting body designs of later generation fighters from sukhoi, rafale,eurofighter typhoon, F-22,PAKFA,J-20.

This high wing body blending is the hall mark of even the fifth gen fighters, reducing the corner reflections from the awacs radars searching from above resulting in lower RCS with missiles and extenal sores hidden under the wing. (as there are no corners formed when the flat wings get attached to cigar like fuselage in old fighters designs like mig-21, jf-17,j-10,grippen,and mirages)

Mote this high wing body blending feature is absent in J-10,jf-17, so these two designs are not as contemproary as tejas.

That's why I get livid and blow out, when people compare second generation all aluminum birds like vintage upgraded mig-21 bisons(consistently saying they are 4th gen) and jags, resulting in vituperative rebuttals.

 

[ersakthivel]

We can clearly see, how the fuselage is pinched near wing root after the air intake , to obey the whitcomb's area rule for a coke bottle like shape to reduce supersonic wave drag.

We can clearly see the fuselage gradually reducing in cross section , just after the air intake , to compensate for the increased total cross section, resulting from increased wing area cross section.

This is what is called following the WHITCOMB'S AREA RULE.

Harping on the CEMILAC report by S.K.JEBAKUMAR, which suggests some improvements by smoothening this adherence further to reduce drag by 3.7 (units for drag) should not be cited to imply that tejas violated the WHITCOMB's area rule in principle from the design phase itself, as implied by some members in his thread as unresolvable drag issue.

So the increased requirement by IAF which resulted in the all up weight of tejas increasing by 2 tons as implied by GTRE chief himself in the aeroseminar press conference 2011,is the reason for tejas yet to achieve it's level speed of 1.2 mach at sea level.which too will be esolved with higher power engine.


when viewed from bottom it is more easily visible to eye.

 

[ersakthivel]

Re: ADA Tejas (LCA) - III

We can clearly see, how the fuselage is pinched near wing root after the air intake , to obey the whitcomb's area rule for a coke bottle like shape to reduce supersonic wave drag.

We can clearly see the fuselage gradually reducing in cross section , just after the air intake , to compensate for the increased total cross section, resulting from increased wing area cross section.

This is what is called following the WHITCOMB'S AREA RULE.

Harping on the CEMILAC report by S.K.JEBAKUMAR, which suggests some improvements by smoothening this adherence further to reduce drag by 3.7 (units for drag) should not be cited to imply that tejas violated the WHITCOMB's area rule in principle from the design phase itself, as implied by some members in his thread as unresolvable drag issue.

So the increased requirement by IAF which resulted in the all up weight of tejas increasing by 2 tons as implied by GTRE chief himself in the aeroseminar press conference 2011,is the reason for tejas yet to achieve it's level speed of 1.2 mach at sea level.which too will be esolved with higher power engine.


when viewed from bottom it is more easily visible to eye.

 

[ersakthivel]

You need to upload the image to Image Hosting site and the use the Link here.

sorry I am uploading images for the first time in this forum ..Am I doing it right or not?
please inform me, so that I will correct it.

 

[ersakthivel]

Taking off with two air to air missiles and two drop tanks is the proof of this lowest wingloading design, where only one of the famed MMRCA contenders passed the IAF specification.

The same will hold true for performance in high altitude himalayas, where fighters like J-10 with far higher wing loading won't be able to give a good account vis a vis the low wing loading tejas purely in airframe consideration.

However bigger the canards may be, it won't help as much in increasing the lift co efficient of the fighter ,compared to lower wing loading of tejas.

so the ability to maneuver in vertical plane with agility ,provided a higher power engine is mated with it, is a function of tejas's low wing loading design due to cranked delta wing form.

So you can imagine how effective tejas will be in himalayas region .but some people are persisting with the view that it 's first base in sulur is an advertisement of it's inferiority!!!!

All these features are there, because it is made with varied geographic conditions and climate conditions of india, in mind exclusively for the IAF.So that it can excel in hot humid conditions in peninsular south india's sea level flights and rarefied high altitude conditions of HIMALAYAs

The advertised top level thrust and speed figures of western fighters too will be a bit less if it is tested in hot,humid,arid conditions of peninsular india's sea level altitudes.

A squadron of SUKHOI is going to be based in tanjore in tamil nadu near the sulur airbase. Does that mwean sukhois are worthless?

 

[ersakthivel]

smooth sexy curves from behind , highlighting how high wing body fuselage blending is implemented from behind,resulting in smooth bouncing off of searching radar waves whether they are x band or l band or asea or mechanical it does not natter.


So efforts were taken to deflect the radar waves away from the source in every possible way from the design phase itself resulting in one of the best rcs figures of all 4th gens.If it flies low hiding it's stores no airbourne radar will detect it from beyond 120 kms due to 0.3 sq meter rcs (clarification needed), when it flies in the home airspace in point defence interception mode.

Ofcourse sideways rcs won't be great as it has vertical stabilizer.But it's frontal rcs would hold good, it seems.

So even in deep penetration roles over enemy territory if it manages to fly a path away from ground based radar ,no awcas can light up it's worser RCS emitting external stores.So even in deep penetration over enemy aispace it ies more suitable due to this feature.
If people have anything to contradict , please post, as I am interested in knowing more about this feature of tejas amd whether it will be able to do deep penetration mission in enemy territory remaining undetected beyond 100 kms. Is this correct?

That's why ADA is saying it is designed with high lift, high controllable,low rcs , wing body fuselage blending aspect in mind from the design phase.

I can categorically say no other 4th gens other than RAFALE and EUROFIGHTER have this feature, which avoids the plain joining of plate like wings with cigar like fuselage, with some smoothing of curvature near the joining point,for all other fighters that are designed before tejas. This modern feature is carried forward in all 5th gens, please note,

 

[ersakthivel]

SO tejas is optimized for stealth from all angles as much as possible.

Another view of the coke bottle shaped fuselage illustrating adherence to whitcomb's area rule and the beautiful cranked delta wing form..

 

[ersakthivel]

Right side profile illustration view of the HAL Tejas multirole fighter - Military Aircraft Pictures

http://www.flying-wings.com/2011/aero-india-2011.html?vsig172_4=8
http://www.flying-wings.com/2011/aero-india-2011.html?vsig172_4=8
http://www.flying-wings.com/2011/aero-india-2011.html?vsig172_4=8
http://www.flying-wings.com/2011/aero-india-2011.html?vsig172_4=8
http://www.flying-wings.com/2011/aero-india-2011.html?vsig172_4=8
http://www.flying-wings.com/2011/aero-india-2011.html
http://www.flying-wings.com/2011/aero-india-2011.html?vsig172_4=2

http://www.google.co.in/imgres?q=lc...18&start=15&ndsp=20&ved=1t:429,r:15,s:0,i:141
http://www.google.co.in/imgres?q=lc...7&start=61&ndsp=25&ved=1t:429,r:62,s:20,i:346


Another superb view of tejas is available in this site. Truly stunning. which illustrates the beautifully curved wing

 

[ersakthivel]

Fighter Combat: Tactics and Maneuvering - Robert L. Shaw - Google Books
http://www.wisegeek.com/what-is-wing-loading.htm

Basically wingloading usually defines the aircraft's stall speed (a least in combat, without lift assisting devices such as slats and flaps), and through it, how slow the aircraft can get in turn, and thus the turning circle.

Simply to put, planes with low wingloading are usually having smaller turning circles.

Low wingloading on the other hand is not so pronounced as far as turn rate, or in other words, turn times go. Turn times are basically defined by how high G the aircraft can hold up in a sustained manner

some tactics in a fight between low wing loading fighter and hight twr fighter is discusse here.
But tejas has a decent twr and will only increase with suitable engines.
people who promise low wing loading is meant for passenger aircraft only can read the above link and learn something useful.


http://www.foinikas.org/ftp/public/Docs/Fighter Combat - Tactics and Maneuvering.pdf

http://forums.ubi.com/showthread.php/487786-Myth-Bustng-The-advantages-of-low-Wing-Loading/page2?

this is the pdf format of the same robert .l.Shaw's book,A detailed reading will clear many doubts.

An aircraft with higher wing loadings tend to be faster but less manoeuvrable. Since speed is life, this was always the priority.. However, once top speeds become supersonic it is superfluous due to the operational, aerodynamic and thermodynamic issues associated with supersonic flight.


As a result of this, current fighters are no faster than 1960s fighters, but generally they have lower wing loadings, since if you can't go faster the next wise thing is to turn harder

.Low wing loadings are necessary for high supersonic L/D and therefore help towards supercruise.

 

[Kunal Biswas]

Finally i made the poster on the topic..

 

[ersakthivel]

Wing configuration - Wikipedia, the free encyclopedia

An excellent read, butpity people don't trust wiki.

 

[Payeng]

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/crancked delta form then on.

Beauty depends upon the eyes of the viewer.

 

[Payeng]

Re: ADA Tejas (LCA) - III

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/crancked delta form then on.

Beauty depends upon the eyes of the viewer.