ADA Tejas (LCA) News and Discussions

[Kshithij]

I too did Engineering in college.

Removing 150 kg ballast & adding a heavy cooling unit for ASEA radar(which could roughly weigh the same ) should hv no effect on CG.

I too studied Engineering only.

Have they changed the laws of physics?

Isn't the ballast being used due to lack of AESA radar? So, shouldn't the weight of AESA radar be subtracted from the ballast to find the remaining weight for cooling?.

 

[TPFscopes]

I too did Engineering in college.

Removing 150 kg ballast & adding a heavy cooling unit for ASEA radar(which could roughly weigh the same ) should hv no effect on CG.

I too studied Engineering only.

Have they changed the laws of physics?

Developers are not that much fool as you are expecting. They will not waste their time in redesigning the cooling system, if they can shift the Ballast weight. Ballast weight is placed in such a way that it become the part of the airframe and mostly covers the unused space of the truss.

A solid weight can't be replaced with a AESA with same volume and weight and its a basic physics.

Good to hear that you are an engineer

I noticed

O noticed that you hv been posting for eons that,.Being a ,"short ranged" ,"light" fighter tejas need not hv Sub sonic or super sonic cruise missiles,

That's why I quoted you.

Again you are comparing my post related to Radar with the missiles

Ballast weight need not be ,"removed".

It just needs to be replaced with heavier ASEA cooling unit.

Replacing the ballast weight with ASEA heavier cooling unit , which also sits at the same place won't change CG.

For your info tejas is a relaxed static stability fly by wire fighter,
For minor variations in CG tweaking the control laws are good enough.

CG of tejas keep changing dynamically & computer calculates it every fraction of the second & flies it accordingly.

Add heavy fuel tanks, bombs, BVR missiles, fire them .

All will impact CG.

Fly by wire software of tejas good in dealing with it.

Besides ASEA cooling unit sits at the same place where ballast sits. So no big changes.

Besides naval tejas which has significant airframe modifications than tejas mk1 is flying with no issues with tweaked fly by wire software.

So do trainers which have entirely different s cockpit, fuselage design.

I don't know how good or bad you are in teaching.

But I certainly don't need ,"this kind" of wisdom from you.

So in our long conversation we found out,

That Tejas has the second biggest radar in IAF(so much for the ,"light" fighter, ) with the lowest frontal RCS , a deadly combination in air to air mode,

With most modern air to air BVR missiles & a validated R73E & Python close combat missiles available.

It has a state of the art DRFM based ASEA jammer.

Without centerline fuel tank in IOC 2 config

It has 500 km combat radius & more than 1700 km ferry range.

DRDO is developing a brahma version for ir.

Good day mate.

As previously said..
Can't replace a solid metallic weight which mostly use waste space can't be replaced by anything which has low weight but high volume.
I might be wrong if it is no according to physics.


A personal suggestion: please visit LCA production line if you can manage how? or please surely go for Aero India 2018 and analyse your facts related to physical structure and appearance of LCA . You will also find uninstalled radar on one of the stall. You may also ask the same with developers and users directly.

Good Day

 

[ersakthivel]

Isn't the ballast being used due to lack of AESA radar? So, shouldn't the weight of AESA radar be subtracted from the ballast to find the remaining weight for cooling?.

Ballast is used to maintain over all CG.

ASEA cooling unit weight is certainly not going to exceed th ballast weight.

Plus there are three versions of tejas , the IAF, naval, trainer are flying simultaneously.

Naval tejas has canards, and actuators operating it .

Tejas Trainer is a two seated .

All hv different CGs than IAF version & flying well.

 

[ersakthivel]

Developers are not that much fool as you are expecting. They will not waste their time in redesigning the cooling system, if they can shift the Ballast weight. Ballast weight is placed in such a way that it become the part of the airframe and mostly covers the unused space of the truss.

A solid weight can't be replaced with a AESA with same volume and weight and its a basic physics.

Good to hear that you are an engineer



Again you are comparing my post related to Radar with the missiles


As previously said..
Can't replace a solid metallic weight which mostly use waste space can't be replaced by anything which has low weight but high volume.
I might be wrong if it is no according to physics.


A personal suggestion: please visit LCA production line if you can manage how? or please surely go for Aero India 2018 and analyse your facts related to physical structure and appearance of LCA . You will also find uninstalled radar on one of the stall. You may also ask the same with developers and users directly.

Good Day

I hv real that ballast is a solid steel plate , & not some unused part .

I told you naval , trainers with far different CGs are flying at the same time.
ASEA cooling unit weight is certainly not going to exceed th ballast weight.

Plus there are three versions of tejas , the IAF, naval, trainer are flying simultaneously.

Naval tejas has canards, and actuators operating it .

Tejas Trainer is a two seated .

All hv different CGs than IAF version & flying well.
So don't make heavy weather out of a simple cooling unit about which no public info is available.

Plus the entire old radar with its back end processing unit & mechanical steering unit is replaced with ASEA & its cooling unit.




ASEA is coming for mk1A not mk1.

 

[TPFscopes]

I hv real that ballast is a solid steel plate , & not some unused part .

I told you naval , trainers with far different CGs are flying at the same time.

So don't make heavy weather out of a simple cooling unit about which no public info is available.

ASEA is coming for mk1A not mk1.

Did you know that NLCA , LCA and LCA-Trainers required to get their FOC individually.
Do you know why?
= Due to different configs and designs.

Please don't made any irrelevant comparison.

@Kunal Biswas
Take some necessary action. You can ban me if there is anything wrong. This guys is sharing irrelevant data and comparisons not as query but as a claim..

 

[ersakthivel]

Did you know that NLCA , LCA and LCA-Trainers required to get their FOC individually.
Do you know why?
= Due to different configs and designs.

Please don't made any irrelevant comparison.

@Kunal Biswas
Take some necessary action. You can ban me if there is anything wrong. This guys is sharing irrelevant data and comparisons not as query but as a claim..

I damn well know that

So will mk1A get its FOC with minor changes in weight distribution for ASEA radars
Okay just a simple question for you,
.Both gripen & rafale flew with older mechanically steered radar, & PESA radars

They replaced those old radars with same sized ASEA radar , with no drastic changes in airframe.

Please explain how it was possible for them. But not possible for tejas mk1A.

I will accept your explanation & won't bother you.

 

[TPFscopes]

Okay just a simple question for you,
.Both gripen & raffle flew with older mechanically steered radar,

They replaced those old radars with same sized ASEA radar , with no drastic changes in airframe.

Please explain how it was possible for them. But not possible for tejas.

I will accept your explanation & won't bother you.

It will be pretty similar like that all mk1 will be upgraded to mk1a and MMR to AESA upgraded will be the part of upgrade.

 

[ersakthivel]

Did you know that NLCA , LCA and LCA-Trainers required to get their FOC individually.
Do you know why?
= Due to different configs and designs.

Please don't made any irrelevant comparison.

@Kunal Biswas
Take some necessary action. You can ban me if there is anything wrong. This guys is sharing irrelevant data and comparisons not as query but as a claim..

This is RBE2 ASEA

Below is 2032 & 52

What are the space constraints & weight constraints in replacing 2032 with RBE2.
Please explain

 

[TPFscopes]

View attachment 21820
This is RBE2 ASEA

Below is 2032 & 52

What are the space constraints & weight constraints in replacing 2032 with RBE2.
Please explain

View attachment 21821

Please carefully check out your source, there is no EL/M-2052 anywhere.


Rough idea of radar placement on LCA

Highlighted portion is the almost space available for Radar. Rest is occupied with other equipments.

Also checkout the radome design which shows size limitations for Radar.

As per the official website of Thales RBE AESA designed for LCA is smaller and lighter than RBE2-AA , it means Thales found their available Radar not suitable as per RFQ released by HAL.Hence they modified it as per the specifications mentioned in RFQ.

Link for RFQ: http://hal-india.com/Common/Uploads/TenderDoc/10364_TenderPDF1_RFQ_AESA.zip

Unable to find the links for Annexures mentioned in RFQ.


Hence, I can say, Rafale's RBE2-AA (in original form) as in quoted image can be a suitable contender for LCA.

Extra stuff:
EL/M-2052 showing the two module architecture of the new system, designed to fit into compact spaces like the LCA nose cone

ELM-2032 with LCA's cone on a testbed

 

[Vorschlaghammer]

About the "compact" RBE2, does it retain the OSF system ?

 

[TPFscopes]

About the "compact" RBE2, does it retain the OSF system ?

Possibly No, because HAL didn't ask for that in their RFQ and Thales will try their best to make their offer cheaper than why they add more goodies.

But wait for detailed official data, as it us still in testing as per Thales, France.

 

[G10]

When did tejas fly with uttam? I think integration still in process though its happening from a year now. I didnt hear any flight test.

 

[no smoking]

The Kaveri engine is not being given by french as ToT. India is simply taking consultation which could be avoided by using trial and error. It will waste 2-3 years, but will get things done

You still don't understand: in the engineering field, the trial and error you are trying to avoid is a part of critical knowledge and experience.

 

[ersakthivel]

Please carefully check out your source, there is no EL/M-2052 anywhere.


Rough idea of radar placement on LCA

Highlighted portion is the almost space available for Radar. Rest is occupied with other equipments.
View attachment 21823

Also checkout the radome design which shows size limitations for Radar.

As per the official website of Thales RBE AESA designed for LCA is smaller and lighter than RBE2-AA , it means Thales found their available Radar not suitable as per RFQ released by HAL.Hence they modified it as per the specifications mentioned in RFQ.

Link for RFQ: http://hal-india.com/Common/Uploads/TenderDoc/10364_TenderPDF1_RFQ_AESA.zip

Unable to find the links for Annexures mentioned in RFQ.


Hence, I can say, Rafale's RBE2-AA (in original form) as in quoted image can be a suitable contender for LCA.

Extra stuff:
EL/M-2052 showing the two module architecture of the new system, designed to fit into compact spaces like the LCA nose cone

ELM-2032 with LCA's cone on a testbed

The red rectangle you marked shows the space for just the front end(antenna) og tejas radar, not the entire radar unit space,

From the diagram below it is obvious that the space for radar back end(cooling unit) extends much further than the area marked by your red rectangle.

We need to wait for reasons for Thales resizing, whether it is lack of space or cost, or power needed for cooling unit, or RFI from HAL

 

[TPFscopes]

The red rectangle you marked shows the space for just the front end(antenna) og tejas radar, not the entire radar unit space,

From the diagram below it is obvious that the space for radar back end(cooling unit) extends much further than the area marked by your red rectangle.


View attachment 21831



We need to wait for reasons for Thales resizing, whether it is lack of space or cost, or power needed for cooling unit, or RFI from HAL

I also share much more data other than that.. flying testbed of MMR, Cone design, 2052 mock-up. If you really want to skip all that for your convenience, I can't help it..

 

[ersakthivel]

I also share much more data other than that.. flying testbed of MMR, Cone design, 2052 mock-up. If you really want to skip all that for your convenience, I can't help it..

Just beating around the bush won't help any one's cause.

What is the

1. length,
2. diameter,
3.weight
4.volume
5.antena dia,
6.cooling power requirements, cooling unit volume

Of the RBE2 ASEA ob rafale?
What is the

1. length,
2. diameter,
3.weight
4.volume
5.antena dia,
6.cooling power requirements, cooling unit volume

Available in Tejas for ASEA radar

Answer to the questions alone would give a compete picture.

Your claim that excess ballast weight is distributed in ,"unused truss" is also without any basis.

So even of the entire RBE2 ASEA unit weighs 150 kg more than 2032 back end, HAL antenna combo radar of Tejas,

Removal of the ballast will eliminate any weight complications.

RBE2 ASEA is a long cylinder (with varying dia) .

Tejas radar back end is not a fully packed cylindrical unit like rafale.

Let's wait for full data. Or further development before jumping the gun.

 

[pmaitra]

Of course you are talking about stuff you don't know again.

Tejas carries close to 200 kg ballast weight behind radome.

I do hope that this occupies sonme space in fuselage.

Because I haven't seen the weight being carried by pilot in his lap,

So as usual you are making another not so credible claim ,
because of the unavailability of space , tejas can not have bigger or the same sized ASEA radar.

I normally don't make such claims.
Dassault rafale having 1.5 times space, means doesn't mean it can allot all to a cooling unit , for an ASEA , whose radius is way lesser than that of Tejas,,

To justify its 150 million dollar price tag & 1000s & 1000s of kilometer range dassault has to give that space to fuel tanks, I think.

Besides as I don't expect you to have any knowledge of geometry, you obviously don't know that space behind a radome 30 cm bigger dia will always be bigger than space behind radome which is 30 cm lower in radius.

@Kunal Biswas
Beg your efforts to tell him about the importance of "center of gravity" in the aviation design. If you can't than suggest someone who can share that...
Bcoz I'm an engineer by education but I'm very bad in teaching..


AFAIK, according to the design issued earlier have no issues with CG but with the extensive design changes and heavier landing gears shifts the CG of jets behind the expected place. So, to retain the CG at its expected place developers added a solid Ballast/Dead weight just infront of the cockpit.
To remove, the Ballast weight, Designer have to redesign the airframe extensively which will again required to have IOC and FOC for its own.

I don't know how to convince the guy one who has a already placed perception of not to get convinced.

This is also one of the reason behind the delay in UTTAM AESA delays.specially for cooling system development.

I have a question regarding the ballast.

Was this ballast added to all LCAs or was it added only to the Naval-LCA? From my understanding, it was the Naval-LCA that required strengthening of the landing gear. Was there anything else that contributed to more weight being added to the rear of the aircraft?

 

[ersakthivel]

I have a question regarding the ballast.

Was this ballast added to all LCAs or was it added only to the Naval-LCA? From my understanding, it was the Naval-LCA that required strengthening of the landing gear. Was there anything else that contributed to more weight being added to the rear of the aircraft?

I've read that ballast is present on IAF Tejas.

Don't know about ballast on naval tejas,

Even the air force version's landingbgear was overweight.

So HAL has many times claimed that they can reducec300 kg weight from landing gear & other areas even in mk1.

In the initial phases tejas was designed in a very cautious conservative manner, leading to excess weight as precaution.

Now with all parameters validated & stress on all areas known optimization will happen.

The naval tejas landing gear is even more over weight is what I read. That too will be addressed based on consultation from foreign defence majors as sanctions are no more in force now.

All these info is based on what I read from interviews of HAL & ADA personalities.

That's one of the reason ADA claims that Tejas mk1 despite 0.5 meter fuselage plug in , won't weigh much heavier, because these weight reductions will equal extra weight .

These weight optimization is going to happen in mk1A is HAL's claim. That's why HAL says that IAF mk1A itself will cater to IAF needs , however we will hv to wait for clarity to emerge on mk1A final spec

To know how much weight reductions are gonna happen in mk1A.

 

[TPFscopes]

I have a question regarding the ballast.

Was this ballast added to all LCAs or was it added only to the Naval-LCA? From my understanding, it was the Naval-LCA that required strengthening of the landing gear. Was there anything else that contributed to more weight being added to the rear of the aircraft?

Anyways, All three variant have Ballast weight and the lowest is in LCA trainer.
In LCA (AF) , the landing gears preferred during design are too light comparable to the present one. Maybe because of precautions for crash landings. Tho who have no experience in jet aviation may compare it with other heavier class fighter
LCA

F-35 (much heavier jet than LCA)

Rafale:

You can even compare gears with JF-17 which has almost half Weight gears.

Problem is that we can't replace these landing gears with lighter one because it will need major modification which further require all certifications again. And IAF,ADA,HAL , non of them agree for further delays

Adding Ballast is a very usual process in aviation and it is done for maintaining CG and enhancing the flight performance. It is very similar to adding weight clips on wheel while doing wheel alignment of a car or other vehicle. It was not a part of design but later added during correction whenever required. More experience in jet designing will reduce the amount of Ballast weight.

Anyways, you may feel odd, but NLCA has the lightest Ballast weight.

Due to extra precautions, ADA made the airframe slightly heavier than the required as per design which will be reduced in further production airframes. And it will be between 300-400kgs. And it will be get balanced by reducing or shifting the Ballast.

As far as NLCA is concerned, it has extremely heavier gears than AF LCA because carrier landings are officially known as simulated crash landings with wire assisted breaking. Hence all carriers borne (not VTOL) jets have strengthened landing gears either it is F/A-18 or Rafale-M or any other jet.

=======

Mod edited.

 

[Sancho]

These weight optimization is going to happen in mk1A is HAL's claim. That's why HAL says that IAF mk1A itself will cater to IAF needs , however we will hv to wait for clarity to emerge on mk1A final spec

To know how much weight reductions are gonna happen in mk1A.

If I may jump in here, we already have some infos on that:

HAL Chairman and Managing Director (CMD) T Suvarna Raju

HAL developing LCA-1P with AESA Radar
May 2015

...The new LCA-MkI-P variant with the EW Package will also add some 50 kilos of more weight, but then, Mr Raju explained, the capability of the aircraft increases significantly, offsetting the disadvantage of a smaller engine.

The current LCA-MkI version uses 210 kilos with ballast in the nose to stabilize the aircraft. This will be removed, and the AESA and EW suite weighing about 250 kilos will be added. The net weight gain will be of about 50 kilos...

http://www.indiastrategic.in/topstories3767_HAL_developing_LCA-1P_with_AESA_Radar.htm

But you are right, without having a proper MK1A airframe, the new AESA radar and EW selected and integrated, not even HAL will be sure about the specs.