ADA Tejas (LCA) News and Discussions

[tsunami]

From Prof. Prodyut Das's Blog:
Tejas MK I's Wingloading->242

ID/T -------->0.35
TWR ------>0.52/ 0.84​

First twr is with full military weight. I dont know whether it is same as maximum takeoff. Some count MTOW as empty weight+fuel and ignore stores and armaments. Anycase 0.52 is lower than Mig-21's(0.64).
Induced drag quotient is as high Mig-21's, affecting corner speed and tends to stall aircraft easily.
The only positive feature in Tejas MK 1 is its lower wing loading of 242 which is why it is able to pull up vertically for a few seconds after a full throttle horizontal push.
Mediocre engine power can be set right with induction of GE 414-IN, but high induced drag point to less than optimum aerodynamics of Airframe.
http://profprodyutdas.blogspot.in/2014/12/the-ada-lca-2014-open-source-review.html?m=1

​

First TWR is military thrust, which is thrust to weight ratio on dry thrust w/o after burner.

 

[sasum]

First TWR is military thrust, which is thrust to weight ratio on dry thrust w/o after burner.

Right. Then I presume, during take off A/B is used to take care of full load. Also during high maneuver, A/B is used. That drains out much fuel; hence Tejas's over-dependence on drop tanks, mid-air refuelling etc.
After-burner adds to thrust but it also desires a lot of fuel. The additional fuel-load in turn nullifies some of the thrust.

 

[Chinmoy]

@ersakthivel has responded to that blog in kind in the comment section.

@ersakthivel and Mr Mukut Pathak did used a combo of Surf, RIN et.al on Mr Prodyut......

 

[HariPrasad-1]

Weight of A2A missiles not counted or considered as external load?

No, 2 short range missile weight is not counted in external load. Pilot weight, its equipment such as oxygen bottles, Gun and its ammunition and two short range missiles are not counted in external weight.

 

[Rahul Singh]

Right. Then I presume, during take off A/B is used to take care of full load. Also during high maneuver, A/B is used. That drains out much fuel; hence Tejas's over-dependence on drop tanks, mid-air refuelling etc.

Name us a Fighter jet which does not uses AB during take off and dog fight? I hope you have seen videos of two new jet fighters with powerful and new engines performing at recently concluded air show? Rafale is one. Do check the video.

 

[Rahul Singh]

No, 2 short range missile weight is not counted in external load. Pilot weight, its equipment such as oxygen bottles, Gun and its ammunition and two short range missiles are not counted in external weight.

No its not. Anything attached to wing fugelage with a pylon, adaptor or rails is counted as external weight.

 

[HariPrasad-1]

Well scope of development is there. I never discounted that. What i did said and will again say is that Gripen pulls more than Tejas at this point. That is at MK-1 pre FOC stage.

Again nothing was said with respect to Naval LCA. It's a different aircraft. It's performance is definitely better than Tejas MK-1. But unknown so far. It is however other thing that there no such thing as Naval Tejas. It's Naval LCA. Tejas is name of only the airforce version. Naval version is till yet unnamed.

Weight of A2A missiles not counted or considered as external load? Anything of this sort is illogical. It's better to wait and see them correct the figures instead of finding out, 'out of the world' reasons. I seriously feel that loaded weight figure of 9800 is out of date, old figure hence incorrect.
It's not just about fuel load. But also at what thrust your aircraft handles it. In other words how much of thrust goes into managing extra drag that is there in case Tejas MK-1.

Besides Gripen is about 1.2 m longer than Tejas Mk-1 and thats extra volume for you. Gripen does uses same or even less powerful engine than Tejas. But its body is aerodynamically more efficient than Tejas Mk-1 hence it uses less fuel and because of it goes longer. Testimony to it is Naval LCA MK-2, which is 14.56 m long or some 1.25 m longer. Mind you engine in both are identical by length.

In end i make myself clear. LCA does not matches Gripen in range vs payload domain, in ACM it does. For that it was just conceived as mig-21 replacement not as Mirage -2000. Gripen C was always close to Mirage 2000 in performance albeit with less powerful engine.

It is not that Tejas is a badly designed aircraft. Just that it was never build to match Gripen in range vs payload performance. Tejas was always meant to be interceptor and a dog fighter in addition to conducting shallow strike missions and which will be based at FOBs. But it's not what happened. Tejas today is true multirole hence overweight by 1 ton hence compromises. MK-1A will also carry part of this weight, so not much increase in range and endurance. But it's ACM and BVRAAM performance will be class apart. MK-2 will be however different story considering IAF chooses to join NLCA MK-2 program.

Talk ith facts and figures like I did. Most of your post is meaningless. Pilots flying Tejas has said that it handles better than mirage. Yes, tejas is bit more draggy and issue is getting addressed in MK1+ in which drag and wave drag issue are taken care of and it will have atleast 8% aerodynamic improvement. However this can not have much difference in range and payload. Actually tejas carries 4.5 ton in addition to its 6.5 ton weight and 2.5 ton fuel. MTOW is 13.5 tons. However 800 KG is not considered as external fuel. It includes following as per Ersakthievel

pilot-75 Kg, gun-100 Kg, ammo-300 kg, 6 pylons-200 kg, 2 WVR-210 .

 

[HariPrasad-1]

No its not. Anything attached to wing fugelage with a pylon, adaptor or rails is counted as external weight.

No it is not. Please read following from the post of ERSAKtheivel

_________________________________________________________
LCA weight is 6500 kgkg with pilot-75 Kg, gun-100 Kg, ammo-300 kg, 6 pylons-200 kg, 2 WVR-210 kg, =7385 Kg+ 1250 kg of internal fuel(half fuel weight)=8635 Kg
So TWR at half fuel weight with pylons and two WVr missiles is =0.97

This combined with the lowest possible wing loading of 242 Kg per square meter give tejas a very good combo of wing loading and TWR.

other fighters like f-16 may have more TWR, but they have higher wing loading. it means the area from which they generate lift for sudden turns is lesser for them compared to tejas mk1.

the reason tejas has lower TWR than F-16 is it has to support much larger wing area than f-16.

SO when we take these two factors into combo we can see the effectiveness. because mirage-2000 with much lower TWR than tejas and much higher wing loading than tejas has been favored by none other than greek airforce chief for even close combat , because the higher Instantaneous turn rate and higher G on set rate given by the combo of low wing loading and high TWR gives the first shoot advantage for mirage-2000 in dog fight over F-16.

With tejas mk1 comfortably ahead of mirage-2000 in both the specs there should be no worry for tejas at all in close combat with even the famed f-16s of PAF.

So how the prof rates tejas mk1 between Gnat and Mig-21 is a mystery to me!!!

I have not even included terms like high alpha and Relaxed Static Stability air frames here. because the RSS airframe of tejas mk1 is said to give negative stability to tejas mk1 through out its flight envelope according to a research paper , (even in super sonic flight is the assumption).

This factor also adds to better agility of tejas.

regarding mig-21s, Please give us the break up as I have stated above for a real comparison.

http://profprodyutdas.blogspot.in/2014/12/the-ada-lca-2014-open-source-review.html?m=1

If what you say is right than give the explaination of 800 KG weight

Plane weight 6560 KG
Fuel weight 2450 KG
MTOW 13500 KG
External weight 3700 KG

Now 13500-3700-2450-6560= 800 KG.

What is the explaination of this 800 KG. Pl read.

By ersakthievel.

LCA weight is 6500 kgkg with pilot-75 Kg, gun-100 Kg, ammo-300 kg, 6 pylons-200 kg, 2 WVR-210 kg,

 

[Rahul Singh]

Talk ith facts and figures like I did. Most of your post is meaningless.

Ever heard something called " Take off clean" ? Least you can try is understand why Tejas website site says: Tejas's Take off clean weight is 9800. Mind you ' clean'. Now if you still think that Take off clean means everything plus two wvraam with pylon and rails mounted externally, post with something from a credible source. I will take it open heartedly.

Pilots flying Tejas has said that it handles better than mirage. Yes, tejas is bit more draggy and issue is getting addressed in MK1+ in which drag and wave drag issue are taken care of and it will have atleast 8% aerodynamic improvement. However this can not have much difference in range and payload. Actually tejas carries 4.5 ton in addition to its 6.5 ton weight and 2.5 ton fuel. MTOW is 13.5 tons. However 800 KG is not considered as external fuel. It includes following as per Ersakthievel

pilot-75 Kg, gun-100 Kg, ammo-300 kg, 6 pylons-200 kg, 2 WVR-210 .

Wow wow wow. Sir which post of mine is talking about hadling quality of Tejas? From where did handling of Tejas vs Mirage came into discussion?

And i am very well aware of projected performance of MK-1A. Thanks for reiterating it.

BTW do you know GSH-23 weights only 50.5 kg. That's good enough for you to start thinking. Source is below. It's official.

http://ofbindia.gov.in/products/data/weapons/wmc/3.htm

 

[HariPrasad-1]

Ever heard something called " Take off clean" ? Least you can try is understand why Tejas website site says: Tejas's Take off clean weight is 9800. Mind you ' clean'. Now if you still think that Take off clean means everything plus two wvraam with pylon and rails mounted externally, post with something from a credible source. I will take it open heartedly.

Wow wow wow. Sir which post of mine is talking about hadling quality of Tejas? From where did handling of Tejas vs Mirage came into discussion?

And i am very well aware of projected performance of MK-1A. Thanks for reiterating it.

BTW do you know GSH-23 weights only 50.5 kg. That's good enough for you to start thinking. Source is below. It's official.

http://ofbindia.gov.in/products/data/weapons/wmc/3.htm

I have already explained the justification of that 800 KG weight. Now if you do not believe, it for you to explain tht difference of 800 KG which you failed to explain and you are again and again asking me the questions which I have already answered as per my understanding and I have quoted the most authenticated poster of this thread mr. @ersakthivel in my support.

Now please prove me wrong. I am very happy to learn couple of things if you can teach me new.

 

[HariPrasad-1]

Yes and gun is not hanged in air. Gun means gun and its fixing assembly. Like radar means not only its array but also its stearing device (In case of Non AESA Radara) and processing computer.

 

[Rahul Singh]

Yes and gun is not hanged in air. Gun means gun and its fixing assembly. Like radar means not only its array but also its stearing device (In case of Non AESA Radara) and processing computer.

It's not a podded gun. It's internally mounted gun. Airframe has prerequisite for this system in form of what is called a gun bay. It's like internal weapon bays of 5 th gen fighters.

 

[sasum]

It's not a podded gun. It's internally mounted gun. Airframe has prerequisite for this system in form of what is called a gun bay. It's like internal weapon bays of 5 th gen fighters.

Internally mounted gun, radar assembly are part of empty weight..since they can not be detached from aircraft for a particular mission. Any kind of missile should be considered add-on weight. However, total stealth aircrafts like Raptor do away with external stations and instead have weapons bay concealing missiles, bombs to reduce RCS as also conformal tanks.

 

[sasum]

the reason tejas has lower TWR than F-16 is it has to support much larger wing area than f-16.

Larger wing area also affords lower wing-loading and helps the aircraft to gain lift within a short distance, provided the wings are made of light composite material.

 

[Rahul Singh]

I have already explained the justification of that 800 KG weight. Now if you do not believe, it for you to explain tht difference of 800 KG which you failed to explain and you are again and again asking me the questions which I have already answered as per my understanding and I have quoted the most authenticated poster of this thread mr. @ersakthivel in my support.

No, not me. I don't have anything left to explain. In very first post in this particular matter i have posted three different possiblity. I never said one of these is true and rest are false. I only picked one as my preferred possibility.

Now please prove me wrong. I am very happy to learn couple of things if you can teach me new.

I am not making claims without source. It is fortunate that you are living in today's tolerant world of DFI. In good old days a claim with source would be treated like.....never mind

No it is not. Please read following from the post of ERSAKtheivel

_________________________________________________________
LCA weight is 6500 kgkg with pilot-75 Kg, gun-100 Kg, ammo-300 kg, 6 pylons-200 kg, 2 WVR-210 kg, =7385 Kg+ 1250 kg of internal fuel(half fuel weight)=8635 Kg
So TWR at half fuel weight with pylons and two WVr missiles is =0.97

This combined with the lowest possible wing loading of 242 Kg per square meter give tejas a very good combo of wing loading and TWR.

other fighters like f-16 may have more TWR, but they have higher wing loading. it means the area from which they generate lift for sudden turns is lesser for them compared to tejas mk1.

the reason tejas has lower TWR than F-16 is it has to support much larger wing area than f-16.

SO when we take these two factors into combo we can see the effectiveness. because mirage-2000 with much lower TWR than tejas and much higher wing loading than tejas has been favored by none other than greek airforce chief for even close combat , because the higher Instantaneous turn rate and higher G on set rate given by the combo of low wing loading and high TWR gives the first shoot advantage for mirage-2000 in dog fight over F-16.

With tejas mk1 comfortably ahead of mirage-2000 in both the specs there should be no worry for tejas at all in close combat with even the famed f-16s of PAF.

So how the prof rates tejas mk1 between Gnat and Mig-21 is a mystery to me!!!

I have not even included terms like high alpha and Relaxed Static Stability air frames here. because the RSS airframe of tejas mk1 is said to give negative stability to tejas mk1 through out its flight envelope according to a research paper , (even in super sonic flight is the assumption).

This factor also adds to better agility of tejas.

regarding mig-21s, Please give us the break up as I have stated above for a real comparison.

http://profprodyutdas.blogspot.in/2014/12/the-ada-lca-2014-open-source-review.html?m=1

If what you say is right than give the explaination of 800 KG weight

Plane weight 6560 KG
Fuel weight 2450 KG
MTOW 13500 KG
External weight 3700 KG

Now 13500-3700-2450-6560= 800 KG.

What is the explaination of this 800 KG. Pl read.

By ersakthievel.

LCA weight is 6500 kgkg with pilot-75 Kg, gun-100 Kg, ammo-300 kg, 6 pylons-200 kg, 2 WVR-210 kg,

Kindly help me locate where in entire post ersakthievel mentions 'Loaded weight' or 'Take off clean '.

 

[HariPrasad-1]

With regards to MTOW. Do anyone has a source which says 13.5 tons. Or people here are deducing MTOW by adding take off weight in clean configuration with maximum external pyload..

Below is spec sheet of Gripen. It says MTOW of 16.5 tons. But if you add empty weight (7.2 tons) + internal fuel (3.3 tons) + payload (9 tons). Sum total 19.5 tons. Same may be the case in LCA. 9.8 tons of max take off weight in clean configuration. Max external armament load 3.5 tons. But MTOW is not what is being said here i.e 13.5 tons. Atleast official site does not say so. But Tejas may be able to carry extra load internally which could be fuel, avionics as part of upgradation, internal SPJ anything.

Pl Check HAL source for 13.5 MTOW.

Now look how gripen has derived that 9 ton payload. It is simply by deducting the Empty weight of plane from MTOW. i.e 16.5 ton less 7.2 tons. If we apply same criterion for tejas, it will be 13.5 tons- 6.5 tons = 7 tons i.e 2 tons less than Gripen.

Now considering the way We calculate the MTOW.

16.5-7.3(Empty weight) =9.2-3.3(Fuel) =6.1 tons- Weight of pilot and support equipements+gun+ ammunition+ WWR missiles+ Pylon etc (1 ton) Shall left gripen with external payload of 5.1 tons for gripen E which is equal to what we have planned for Tejas MK2.


http://www.militaryfactory.com/aircraft/detail.asp?aircraft_id=861

http://www.militaryfactory.com/airc...ft1=861&aircraft2=758&Submit=Compare+Aircraft

http://www.business-standard.com/ar...he-tejas-get-foreign-help-115071401389_1.html

http://*****************/threads/for-lca-tejas-its-now-about-months-not-decades.54234/page-7
http://daily.bhaskar.com/news/NAT-T...-skies-4348828-PHO.html?seq=12&corder=popular

Look at the above sources for 13500 KG MTOW.

 

[tejas warrior]

First Tejas Squadron to fly on July 1, HTT-40 waiting in wings

SOURCE: UNI

Two high profile events one after another are set to take place next month with the first squadron of India’s own Light Combat Aircraft-Tejas starting its flight on July 1 and indigenously developed basic trainer HTT-40 will have its maiden flight the same month.

The first squadron comprising four aircraft, including a trainer, will be raised at Bangalore, sources in the IAF today told UNI. The IAF is already flying two of the home grown Tejas while a trainer and the forth aircraft will be handed over before the formal raising of the squadron.

Chief of Air Staff Air Chief Marshal Arup Raha is likely to present on the historic occasion, as it is for the first time an indigenous squadron is being inducted in the 83 year old IAF. The Air Chief himself had his first sortie in the LCA last month, giving it a thumbs up. “It is my first sortie in Tejas, it is a good aircraft for induction into IAF operations,” he said after a 30 minute flight, which involved manoeuvres in the entire flying envelope of the aircraft. Coinciding with the event, Hindustan Aeronautics Limited (HAL) was trying to have the inaugural flight of its basic trainer HTT-40. The historic event is likely to be witnessed by Defence Minister Manohar Parrikar, a strong votary of indigenous aircraft. The trial sortie of the trainer was carried out last week, with the aircraft landing back in flying colours. HAL’s chief test pilot, Group Capt Subramaniam, who flew the HTT-40 for about 30 minutes, expressed his satisfaction after at the performance aircraft.

http://idrw.org/first-tejas-squadron-fly-july-1-htt-40-waiting-wings/#more-97908

Is this news Authentic ? Had heard First Tejas squadron will be formed with 4 fighter.. and now they are making it with SP1, SP2, SP3(was planned to be coming in June) + Trainer !!

 

[Rahul Singh]

.

Pl Check HAL source for 13.5 MTOW.

Thanks for pointing. I agree HAL source clearly mentions 13.5 tons MTOW.

Now look how gripen has derived that 9 ton payload. It is simply by deducting the Empty weight of plane from MTOW. i.e 16.5 ton less 7.2 tons. If we apply same criterion for tejas, it will be 13.5 tons- 6.5 tons = 7 tons i.e 2 tons less than Gripen.

HAL page on LCA,says, LCA had payload of 5.1 tons. So if calculate they way you did. Then it is like 13.5 tons (MTOW) minus 5.3 tons (payload) should equals to 8.2 tons (Empty weight). But as per Tejas.gov.in Empty weight of LCA is 6.55 tons. This difference of of 1.65 tons is intriguing.

Now considering the way We calculate the MTOW.

16.5-7.3(Empty weight) =9.2-3.3(Fuel) =6.1 tons- Weight of pilot and support equipements+gun+ ammunition+ WWR missiles+ Pylon etc (1 ton) Shall left gripen with external payload of 5.1 tons for gripen E which is equal to what we have planned for Tejas MK2.

13.5 - 6.5 = 7 (payload as per your definition) - 2.4 ( internal fuel load) = 4.6. Now you are saying that this extra 1 ton weight is from pilot. Ok then take 100 kg for pilot + for gun take 100 Kg(GSH-23 weights only 50.5 kg) + Ammo 230x 0.5 kg = 115 kg and weight of clip or belt make it 200 kgs together + oxygen cylinder take 20 kgs. Total equals to 420, ha ha make it 500 kgs.

Now you say even WVRAAMs and all pylons are also included in this weight. With complete disregard to the fact that these are externally mounted object. And weight of pylons varies with type of associated system it carries. So how you can restrict weight of all 7 pylons to all up weight of 200 kgs?

Fact is Tejas not only carries 2x wvraams on out board stations but practice bombs also on same station. Will it also form part of loaded weight? And payload in SLVs and Ballistic Missiles is the extra load which is Crew module and crew/ satellites and warhead(s) respectively that it needs to take it to somewhere and no it does not includes fuel load or of any other system that makes delivery system work.

And again no, i do not know what is the justification for that extra weight. So i won't claim one of many possibilities as fact. And won't accept hilarious explanation like WVRAAMs weight is included into Loaded Weight or Take of clean weight.

http://www.militaryfactory.com/aircraft/detail.asp?aircraft_id=861

http://www.militaryfactory.com/airc...ft1=861&aircraft2=758&Submit=Compare+Aircraft

http://www.business-standard.com/ar...he-tejas-get-foreign-help-115071401389_1.html

http://*****************/threads/for-lca-tejas-its-now-about-months-not-decades.54234/page-7
http://daily.bhaskar.com/news/NAT-T...-skies-4348828-PHO.html?seq=12&corder=popular

Look at the above sources for 13500 KG MTOW.

Thanks for this many links. Catch is HAL site says ceiling of 16k. Broadsword says 15,000 m. Which one is correct?

 

[HariPrasad-1]

HAL page on LCA,says, LCA had payload of 5.1 tons. So if calculate they way you did. Then it is like 13.5 tons (MTOW) minus 5.3 tons (payload) should equals to 8.2 tons (Empty weight). But as per Tejas.gov.in Empty weight of LCA is 6.55 tons. This difference of of 1.65 tons is intriguing.

Some times payload is mentioned at half fuel load. That me be the reason though I am not very sure.

13.5 - 6.5 = 7 (payload as per your definition) - 2.4 ( internal fuel load) = 4.6. Now you are saying that this extra 1 ton weight is from pilot. Ok then take 100 kg for pilot + for gun take 100 Kg(GSH-23 weights only 50.5 kg) + Ammo 230x 0.5 kg = 115 kg and weight of clip or belt make it 200 kgs together + oxygen cylinder take 20 kgs. Total equals to 420, ha ha make it 500 kgs.

You forgot 2 WVR missles of around 100 KG + Pylon weight. That shoul make the figure near 800 to 900 KG.

 

[tejas warrior]

From Tejas - LCA Facebook page

Saurav Chordia is a young Boy from Basugaon in Assam. Only 19 years old, he currently studies in Delhi, his dream is to become a Defence Analyst. Besides studies he is an Aviation Enthusiast and is up to date with the Current Aviation Affairs in India.

This inspired him to try his hand in Aviation Art and design different types of aircrafts when he was in the 7th Standard in School. It took him more than a year to Master 3D Software to render High Quality Images. He learnt everything on his own and last year the Makers of the Indian Air Force Game ‘Guardians of the Galaxy’ discovered his Talent and invited him to do a 3 Month Internship with them.

He also designs art for Retired Veterans. He does war reenactments like Dogfights, Bombing Ground Targets and much more. He has designed these for the likes of Marshal Arjan Singh (Spitfire), Retd Naval Chief Arun Prakash (Sea Harrier), Retd. Chief of Air Staff N.C Suri (Hurricane), Flt. Lt. Alfred Cooke VRC 1965 war (Hunter Shooting Down Sabres)

Before starting any work, he collects references with proper dimensions. He uses multiple tools like Blender for designing, Cinema 4D for Rendering and for tweaking and filtering Adobe Photoshop.