ADA Tejas (LCA) News and Discussions

[Kunal Biswas]

In that case please go through Tejas aerobatic maneuvers in excersie IRON FIST 2013 as well as recent exercise, I am sure you will find your answer there ..

But even in dogfight A to A missiles are needed, along with canon. Besides, the aircraft needs other load augmenting paraphernalia like towed decoy, jammer pod etc....all necessary tools in interception/ dogfight.

 

[Rahul Singh]

During Bahrain Airshow, Tejas was without the load of armaments and drop-tanks.

Air Show displays is about displaying ACM capability of performing fighter. And before entering into any dog fight it is mandatory for fighter to jettison its heavy load and all non esential loads like drop tanks, bombs and any a2g load. So ersakthivel assessment is correct considering Tejas at BIAS was carrying two smoke generators roughly of the dimension of WVRAAM.

 

[sasum]

So ersakthivel assessment is correct considering Tejas at BIAS was carrying two smoke generators roughly of the dimension of WVRAAM.

Smoke generators are of much smaller weight and dimension than SRAAM. I have not mentioned A2G missiles and two drop-tanks as dog-fight requisites. But A2A missiles, targetting pod/ jammer and towed decoy radar are essentials for interception, dogfight. T/W ratio of bare-bones Tejas is 1.07. Just enough for vertical climb. With those additional weights for dog-fight, T/W will go down and in the absence of thrust-vectoring, Tejas will not be able to do vertical climb and other intense gravity-defying maneuvers.
Situation may change with Mark II when 414IN engine is integrated.

 

[Chinmoy]

Smoke generators are of much smaller weight and dimension than SRAAM. I have not mentioned A2G missiles and two drop-tanks as dog-fight requisites. But A2A missiles, targetting pod/ jammer and towed decoy radar are essentials for interception, dogfight. T/W ratio of bare-bones Tejas is 1.07. Just enough for vertical climb. With those additional weights for dog-fight, T/W will go down and in the absence of thrust-vectoring, Tejas will not be able to do vertical climb and other intense gravity-defying maneuvers.
Situation may change with Mark II when 414IN engine is integrated.

You concerns are true on their respective place. But lets take one scenarion for our kind consideration.

Lets assume that India had gone to war with its western neighbour. Then what role would you assign to Tejas in the presence of Su30, Mirage and jaguar. Lets not consider Mig's for now. Obviously the ground attack role would be given to Jaguar prominently among the top three. Mirage would be there to provide a 50 50 role of ATG and ATA role. For deep strike ATG role you have to rely on Su30, but it would be possible only when you take care of the periphery first.

Now where to fit Tejas in all of these. We know that Tejas don't posses the range of Su30 for deep strike mission. It would have to depend on drop tanks to penetrate deep. But in that case you need to provide ATA cover for it. Leave alone Tejas, for any deep penetration mission, you have to provide ATA cover for Su30 also.

So obviously for deep penetration attack with drop tanks, you don't need to worry about ATA dog fight as you would have Mirage and Su30 to look after your tail. You only have to take a couple of BVRAAM and WVRAAM to assist them.

Second role for Tejas would be to provide Air cover to Su30 or Mirage. For this purpose you would obviously take off from forward base instead of deep territorial bases. For this you don't have a need of drop tanks as 500 km range is enough. Then too if a need of drop tanks occurred, you could jettison them after 300 km.

Talking about onboard weapon, if you have a couple of BVRAAM and WVRAAM, you would sure be using the BVRAAMs first to take down any adversary which shows up in your RADAR. Then you would go for WVRAAM befor trying to engage them in a close quarter canon battle.

So with all these in mind, I think a TWR of 1 is good enough for Tejas. But your comment that 414 would give it more venom wins hands down. So cheers buddy.

 

[tsunami]

^^^ For our western neighbour we will not have any role like deep penetration. When you have a country like Pakistan who is just 300 KM wide and who's most of the assets are in with 100 KM range from our border why we will ever need deep penetration attack fighters.

 

[Rahul Singh]

Smoke generators are of much smaller weight and dimension than SRAAM. I have not mentioned A2G missiles and two drop-tanks as dog-fight requisites. But A2A missiles, targetting pod/ jammer and towed decoy radar are essentials for interception, dogfight. T/W ratio of bare-bones Tejas is 1.07. Just enough for vertical climb. With those additional weights for dog-fight, T/W will go down and in the absence of thrust-vectoring, Tejas will not be able to do vertical climb and other intense gravity-defying maneuvers.
Situation may change with Mark II when 414IN engine is integrated.

4x Derby (each = ~ 165 kg) and 2x Python 5 ( each = 105 Kg) and 1x EL\O 8212 ( ~ 100 kg) thats about 1200 Kg considering weight of adaptors and pylons. Empty weight of Tejas is 6500 and it's loaded weight is 9500 kg ( internal cannon and its ammo and max load of internal fuel) or 25794 lb. F-404 at full thrust delivers 20200 lbf. Divide it and you get TWR of 0.78. That doesn't sound much. But when compared with Mirage 2000 which has TWR of 0.7 and Gripen C with TWR of 0.97, both calculated at 'loaded weight', not at their MTOW ( meaning not with any external armament). And when you know that both of these two jets can perform vertical charlie ( check photos below) when loaded with external armaments the point becomes or should become amply clear.

Need to mention that for a object to move vertically upwards, and which is in stationary state, a TWR of more than one is required. And that object will keep going vertically upwards until it runs out of power or reaches its max altitude or ceiling. That however is not the case with a Jet fighter. For a jet fighter to climb vertically upwards it's not necessary to have a TWR of more than 1. They build speed in horizontal and then go vertical and until it bleeds of its energy entirely, it keeps going vertical. And in any dog fight you don't need to touch ceiling every time you pull up. A good dog fighter is all about good energy management. When you need to build energy or bleed one, he knows all, may be she as well. It's about time after all.

 

[rohit b3]

4x Derby (each = ~ 165 kg) and 2x Python 5 ( each = 105 Kg) and 1x EL\O 8212 ( ~ 100 kg) thats about 1200 Kg considering weight of adaptors and pylons. Empty weight of Tejas is 6500 and it's loaded weight is 9500 kg ( internal cannon and its ammo and max load of internal fuel) or 25794 lb. F-404 at full thrust delivers 20200 lbf. Divide it and you get TWR of 0.78. That doesn't sound much. But when compared with Mirage 2000 which has TWR of 0.7 and Gripen C with TWR of 0.97, both calculated at 'loaded weight', not at their MTOW ( meaning not with any external armament). And when you know that both of these two jets can perform vertical charlie ( check photos below) when loaded with external armaments the point becomes or should become amply clear.

Need to mention that for a object to move vertically upwards, and which is in stationary state, a TWR of more than one is required. And that object will keep going vertically upwards until it runs out of power or reaches its max altitude or ceiling. That however is not the case with a Jet fighter. For a jet fighter to climb vertically upwards it's not necessary to have a TWR of more than 1. They build speed in horizontal and then go vertical and until it bleeds of its energy entirely, it keeps going vertical. And in any dog fight you don't need to touch ceiling every time you pull up. A good dog fighter is all about good energy management. When you need to build energy or bleed one, he knows all, may be she as well. It's about time after all.

Offtopic, but Actually Gripen C's TWR at 100% loaded fuel is 0.90, not 0.97. The loaded weight on Wiki is inaccurate. Empty weight of Gripen C is 6800 kgs, add 2200 kgs of fuel and about 100 kgs of pilot and other accessories.
9100 kgs or about 20,000 lb divided by 18,100 lbf.

Tejas's loaded weight is 9800 kgs according to Tejas's official site and thus a TWR of almost 0.94.

 

[Rahul Singh]

Offtopic, but Actually Gripen C's TWR at 100% loaded fuel is 0.90, not 0.97. The loaded weight on Wiki is inaccurate. Empty weight of Gripen C is 6800 kgs, add 2200 kgs of fuel and about 100 kgs of pilot and other accessories.
9100 kgs or about 20,000 lb divided by 18,100 lbf.

Tejas's loaded weight is 9800 kgs according to Tejas's official site and thus a TWR of almost 0.94.

I took rough estimates from wiki.

BTW Tejas loaded weight of 9800 may be incorrect or old one. It has been widely reported that Tejas MK-1 is 1 ton overweight over tageted weight of 5.5 tons. Earlier it was like 1.5 ton overweight but during PV stage. Since then a lot of weight has been shelved and LSP 7&8 are way lighter. So with 6.56 tons of empty weight ( it includes GSH-30 gun) plus 2.4 tons of fuel plus 100 kg pilot. Thats only ~9 ton. Now intriguing question is, where does that extra 800 kgs come from? Does it means that 130 rounds of GSH-23 cannon weights 800 kg? Can it be? Or does Tejas carries about 3 tons of fuel internally? That's way too much for a fighter which has been blamed for having low endurence. Or empty weight of Tejas is around 7.3 tons. Official website says ~6.56 tons. So which one is correct and which one incorrect? I say the figure on loaded weight.

Anyway in case of Tejas, present TWR is gonna get better in MK-1A beacause of reduction in empty weight. And since MK-1A will be the aircraft that will go to war it's logical to take it as baseline. So don't take Tejas TWR figure as hard one. It's flexible and will change for better.

 

[tejas warrior]

@Rahul Singh @rohit b3 : Thanks for your analysis..
http://defenceforumindia.com/forum/members/rahul-singh.211/
To summarize, Tejas mk1 is awesome fighter better than Gripen/Mirage2K..
http://defenceforumindia.com/forum/members/rahul-singh.211/
AND mk1-A is going to be a beast !!

 

[Rahul Singh]

@Rahul Singh @rohit b3 : Thanks for your analysis..
To summarize, Tejas mk1 is awesome fighter better than Gripen/Mirage2K..
AND mk1-A is going to be a beast !!

I can't say so without reservation. Gripen has longer range. Its weapon or combat load is greater. And it's a certified 9g puller. In contrast Tejas MK-1 can't carry as much as Gripen C, neither it can go as deep as Gripen C. It has been reported that Tejas MK-1 has pulled +8 g, but no mention of 9 g yet. All in all Tejas lacks in certain aspects of performance with Gripen C. But most of it is due lesser volume in Tejas, but that's because Tejas MK-1 is only 13.2 m long when Gripen C is 14 m. Naturally there got to be shortfalls. And are, indeed.

MK-1A will however be different story, if HAL manages to cut weight to targeted level. Also, it has been said that MK-1A will see 6-7 % reduction in drag.

Performance of Tejas MK-1A may not improve much vis-i-vis Gripen C in range vs payload domain. But certainly it will be on par with Gripen C in ACM or dog fight because of much better TWR in MK-1A.

 

[HariPrasad-1]

Offtopic, but Actually Gripen C's TWR at 100% loaded fuel is 0.90, not 0.97. The loaded weight on Wiki is inaccurate. Empty weight of Gripen C is 6800 kgs, add 2200 kgs of fuel and about 100 kgs of pilot and other accessories.
9100 kgs or about 20,000 lb divided by 18,100 lbf.

Tejas's loaded weight is 9800 kgs according to Tejas's official site and thus a TWR of almost 0.94.

Here the question is how can the lower weight tejas loaded weight can be 700 KG higher than loaded weight of 300 KG heavier Gripen. People while comparing the plane close their eyes as well as mind. Tejas 6500 KG+2500KG (Fuel)+100 KG pilot is also equal to 9100 KG. From where does those extra 700 KG comes from?

If it is some other stuff than it should also be added in gripen C/D.

 

[HariPrasad-1]

I can't say so without reservation. Gripen has longer range. Its weapon or combat load is greater. And it's a certified 9g puller. In contrast Tejas MK-1 can't carry as much as Gripen C, neither it can go as deep as Gripen C. It has been reported that Tejas MK-1 has pulled +8 g, but no mention of 9 g yet. All in all Tejas lacks in certain aspects of performance with Gripen C. But most of it is due lesser volume in Tejas, but that's because Tejas MK-1 is only 13.2 m long when Gripen C is 14 m. Naturally there got to be shortfalls. And are, indeed.

MK-1A will however be different story, if HAL manages to cut weight to targeted level. Also, it has been said that MK-1A will see 6-7 % reduction in drag.

Performance of Tejas MK-1A may not improve much vis-i-vis Gripen C in range vs payload domain. But certainly it will be on par with Gripen C in ACM or dog fight because of much better TWR in MK-1A.

No

Look at the MTOW of tejas. It is 13500 KG. which is 135000-9800 Kg =3700 KG. However empty weight is 6560 KG + 2450 KG of fuel. which is 9000 KG. However it is mentioned at 9800 KG. The 800 KG of additional weight of air to air missile and pilot and may be something else which they do not consider as the part of external load which gripen consider extra load.

Working that way tejas' external load is 13500 KG -9000 KG is 4500 Kg but that extra wight of missile and pilot is not considered as additional pay load. Tejas also has same engine with 250 KG additional fuel so the range of gripen can not be much higher than the range of Tejas. The ranges depends on the height at which the plane travels. It may be as much as as 100% difference depending of height of travel. So gripen having a very high range with same engine and lower fuel and higher weight compared to Tejas is also something very difficult to digest.

 

[HariPrasad-1]

The main drawback of tejas what I perceive is the lower highest speed and little bit lower timing in STR. People say that it is optimized for transsonic performance so we can not expect it to be as faster as F 16 and gripen. However new aerodynamic changes re going to increase transsonic acceleration by 20% and top speed at sea level by 2%. Drag shall reduce by 8% which is significant. Along with 500 KG weight reduction and aerodynamic changes, MK1+ must be beat better than Gripen C. It will have higher range and better payload , speed and acceleration and other timing.

 

[HariPrasad-1]

t has been reported that Tejas MK-1 has pulled +8 g, but no mention of 9 g yet.

No gripen is 8.5 g air craft and how much it actually does ???? Nobody knows. On other hand Tejas has done 8+g repeatedly before foc. AOA is yet to be opened fully and I am very very sure that it will go beyond 8.5 by FOC. We have witnessed a great improvement in STR timing bellow 22 second for Horizantal loop which is faster by atleast 4 second than anything we saw previously by tejas. Vertical loop timing of just 17 to 18 second is best compared to anything , i believe. Marginal improvement in these parameter will make them best and comparable to anything we saw anywhere. And that improvement is going to come certainly with opening of flight envelope and weight reduction. As declared at the time of pulling 8 g, it t was declared that Tejas pulled 8+g and aircraft beheaved nicely. This means that it is still left with a great scope of doing more gs compared to 8g.

It is also said that Naval tejas behaves better than airforce tejas. It lands at much lower speed compared to airforce tejas. It has a great climb ratio as well. So let all goodies of other variant may come into Airforce variant and vis a versa. Looking to the present status of tejas, it seems that plane offers a great scope of improvement and perhaps to be recognized as the best in its class leaving F 16 and Gripen behind in a decade to come.

 

[rohit b3]

Actually, Im confused too. I agree with both @HariPrasad-1 and @Rahul Singh ,though i believe the GSH-23 is not counted in the Empty weight of 6.56 tons.
The loaded weight with the fuel,gun,pilot and accessories should be around 9100 kgs.
Or are we calculating the weight of the interal fuel wrong??

An article from Business standard says "Currently, its internal tanks carry just 2,300 litres of fuel, with another 2,400 litres carried in external pods."
I guess 2300 liters is around 2300 kgs, however i dont take that seriously cause the "2400 liters in external pods" isnt right.
We know externally Tejas can carry 1200+1200+800 kgs of Fuel.

So I dont trust the Internal fuel capacity either , of that article.

If anyone has any better source, feel free to share.

 

[HariPrasad-1]

Actually, Im confused too. I agree with both @HariPrasad-1 and @Rahul Singh ,though i believe the GSH-23 is not counted in the Empty weight of 6.56 tons.
The loaded weight with the fuel,gun,pilot and accessories should be around 9100 kgs.
Or are we calculating the weight of the interal fuel wrong??

An article from Business standard says "Currently, its internal tanks carry just 2,300 litres of fuel, with another 2,400 litres carried in external pods."
I guess 2300 liters is around 2300 kgs, however i dont take that seriously cause the "2400 liters in external pods" isnt right.
We know externally Tejas can carry 1200+1200+800 kgs of Fuel.

So I dont trust the Internal fuel capacity either , of that article.

If anyone has any better source, feel free to share.

No it is 2458 KG internal fuel which is 3034 Liters. 2300 liters turns out to be 1863 KG only which will left tejas to carry 6773 kg of other weight to carry.

 

[Rahul Singh]

No gripen is 8.5 g air craft and how much it actually does ???? Nobody knows. On other hand Tejas has done 8+g repeatedly before foc. AOA is yet to be opened fully and I am very very sure that it will go beyond 8.5 by FOC. We have witnessed a great improvement in STR timing bellow 22 second for Horizantal loop which is faster by atleast 4 second than anything we saw previously by tejas. Vertical loop timing of just 17 to 18 second is best compared to anything , i believe. Marginal improvement in these parameter will make them best and comparable to anything we saw anywhere. And that improvement is going to come certainly with opening of flight envelope and weight reduction. As declared at the time of pulling 8 g, it t was declared that Tejas pulled 8+g and aircraft beheaved nicely. This means that it is still left with a great scope of doing more gs compared to 8g.

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.

It is also said that Naval tejas behaves better than airforce tejas. It lands at much lower speed compared to airforce tejas. It has a great climb ratio as well. So let all goodies of other variant may come into Airforce variant and vis a versa. Looking to the present status of tejas, it seems that plane offers a great scope of improvement and perhaps to be recognized as the best in its class leaving F 16 and Gripen behind in a decade to come.

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.

No

Look at the MTOW of tejas. It is 13500 KG. which is 135000-9800 Kg =3700 KG. However empty weight is 6560 KG + 2450 KG of fuel. which is 9000 KG. However it is mentioned at 9800 KG. The 800 KG of additional weight of air to air missile and pilot and may be something else which they do not consider as the part of external load which gripen consider extra load. Working that way tejas' external load is 13500 KG -9000 KG is 4500 Kg but that extra wight of missile and pilot is not considered as additional pay load.

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.

Tejas also has same engine with 250 KG additional fuel so the range of gripen can not be much higher than the range of Tejas. The ranges depends on the height at which the plane travels. It may be as much as as 100% difference depending of height of travel. So gripen having a very high range with same engine and lower fuel and higher weight compared to Tejas is also something very difficult to digest.

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.

 

[Rahul Singh]

Actually, Im confused too. I agree with both @HariPrasad-1 and @Rahul Singh ,though i believe the GSH-23 is not counted in the Empty weight of 6.56 tons.
The loaded weight with the fuel,gun,pilot and accessories should be around 9100 kgs.
Or are we calculating the weight of the interal fuel wrong??

An article from Business standard says "Currently, its internal tanks carry just 2,300 litres of fuel, with another 2,400 litres carried in external pods."
I guess 2300 liters is around 2300 kgs, however i dont take that seriously cause the "2400 liters in external pods" isnt right.
We know externally Tejas can carry 1200+1200+800 kgs of Fuel.

So I dont trust the Internal fuel capacity either , of that article.

If anyone has any better source, feel free to share.

Cannon and internal fuel tanks are part of empty weight. When loaded with their complement that is ammo and fuel, the weight that you get then is called loaded weight.

So no its not. Weight of internal gun/cannon and its full compliment of ammo is included in loaded weight. It is regular and standard practice.

So it's like that, the loaded weight figure is either wrong or ADA has increased fuel capacity by 800 kg. Latter looks highly unlikely.

 

[sasum]

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

​

 

[cannonfodder]

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

​

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