ADA Tejas (LCA) News and Discussions

[p2prada]

Anyways does anyone know how time delay induced beam steering in planar array radars differs from time delay induced beam steering in ESA radar? @Twinblade

You mean a slotted planar array? Because planar arrangement can be used on both phased and slotted arrays.

This requires a bit of research.

To keep it simple, in a slotted array, the entire array needs to be moved to steer the beam.

In phased array, phase shifters are used. Changing the phase allows changing the direction of the beam, so each antenna can be individually steered.

So the entire principle is different.

 

[Defcon 1]

You mean a slotted planar array? Because planar arrangement can be used on both phased and slotted arrays.

This requires a bit of research.

To keep it simple, in a slotted array, the entire array needs to be moved to steer the beam.

In phased array, phase shifters are used. Changing the phase allows changing the direction of the beam, so each antenna can be individually steered.

So the entire principle is different.

I was talking about slotted arrays. I was reading Karlo Copp's article and and he has written that beam focusing is achieved by inducing time delays in slotted arrays, which in my opinion should make it similar to ESA radars where time/phase delays are used to steer the beam according to the principal of interference.

Specifically, my question is, if you are able to induce time delays in slotted arrays, what is the need to move them around like MSA radars?
@Apollyon Any idea EE?

 

[Twinblade]

Anyways does anyone know how time delay induced beam steering in planar array radars differs from time delay induced beam steering in ESA radar? @Twinblade

Planar arrays are ESA arrays. Phase shifting is used most widely for beam steering and time delay is very rarely used. In phase shifting, an array of phase shifters causes shift in phase angles of waveforms, thus the time at whic waves originating from different elements reach their crests and troughs at a gradually changes from one end of the array to another leading to an angled wavefront off boresight.

In time shift, beams are physically delayed by time shift devices, resulting in angled wavefront.

 

[Defcon 1]

Planar arrays are ESA arrays. Phase shifting is used most widely for beam steering and time delay is very rarely used. In phase shifting, an array of phase shifters causes shift in phase angles of waveforms, thus the time at whic waves originating from different elements reach their crests and troughs at a gradually changes from one end of the array to another leading to an angled wavefront off boresight.

In time shift, beams are physically delayed by time shift devices, resulting in angled wavefront.

No, there is a category of planar array radars which are not ESA. They are called slotted arrays. They are also moved mechanically. Nevermind, I got my answer from wiki. The slotted arrays use physical slots to induce time delays to focus the beam which can then be moved around like an MSA. Thanks anyways

 

[p2prada]

Planar arrays are ESA arrays.

Planar array is just an arrangement for the emitters. Whether it is ES or MS, it doesn't matter.

Phase shifting is used most widely for beam steering and time delay is very rarely used.

Phase shift is a common word. You can shift the phase of the wave using both frequency and time or both.

 

[Defcon 1]

Planar array is just an arrangement for the emitters. Whether it is ES or MS, it doesn't matter.



Phase shift is a common word. You can shift the phase of the wave using both frequency and time or both.

Using frequency?? Care to explain that part, how will you achieve perfect interference with waveforms of differing frequencies?

 

[p2prada]

Specifically, my question is, if you are able to induce time delays in slotted arrays, what is the need to move them around like MSA radars?

Slotted array and MS are the same.

This is a slotted array, what we call Mechanical Scan because we need to physically move the antenna on a gimbal.

Slotted means a waveguide, which is just a hollow cuboid, has cuts/slots in them.
Like this,

They generally have planar arrangement.

A slotted array uses only one main lobe while an AESA can generate multiple main lobes and that's where the difference lies. And yes, even this array uses a phase shifter, but only in the time domain. A time delay can be introduced, but the functional capabilities of the radar is very, very limited. Like it can just track a few targets compared to the hundreds on ESA.

This is what you get from an AESA.

Whereas, with MS or slotted arrays you get this.

Bringing in a time delay helps you steer the beam around, but you can see why the AESA is more important in this case.

Even if we can steer the main lobe by introducing time delays, the reason why the array needs to be moved around using a gimbal is to correct positioning errors, so this way you can get much better angular accuracy. Naturally, the radar is also able to cover a greater area.

 

[Defcon 1]

Slotted array and MS are the same.

This is a slotted array, what we call Mechanical Scan because we need to physically move the antenna on a gimbal.

Slotted means a waveguide, which is just a hollow cuboid, has cuts/slots in them.
Like this,

They generally have planar arrangement.

A slotted array uses only one main lobe while an AESA can generate multiple main lobes and that's where the difference lies. And yes, even this array uses a phase shifter, but only in the time domain. A time delay can be introduced, but the functional capabilities of the radar is very, very limited. Like it can just track a few targets compared to the hundreds on ESA.

This is what you get from an AESA.

Whereas, with MS or slotted arrays you get this.

Bringing in a time delay helps you steer the beam around, but you can see why the AESA is more important in this case.

Even if we can steer the main lobe by introducing time delays, the reason why the array needs to be moved around using a gimbal is to correct positioning errors, so this way you can get much better angular accuracy. Naturally, the radar is also able to cover a greater area.

No, no. Actually what happens here is that time delays are only used to focus the beam at a single point. Note that these time delays are created by using physical slots, so they can't be used to steer the beam, since the slots can't change their physical position.

One that focus has been achieved, you can simply move it around like normal parabolic MSA. The major advantage of planar MSA over parabolic MSA is that the beam quality is better due to better focus achieved through interference rather than reflection. Thats why modern ESA radars are based on interference. The beam quality in ESA radars is even better.

Actually when I wrote MSA radars in the previous post, I was talking about parabolic MSAs.

 

[p2prada]

Using frequency?? Care to explain that part, how will you achieve perfect interference with waveforms of differing frequencies?

Huh? Actually that is wrong. I don't know why I put frequency there. Phase has nothing to do with it.

 

[p2prada]

No, no. Actually what happens here is that time delays are only used to focus the beam at a single point. Note that these time delays are created by using physical slots, so they can't be used to steer the beam, since the slots can't change their physical position.

One that focus has been achieved, you can simply move it around like normal parabolic MSA. The major advantage of planar MSA over parabolic MSA is that the beam quality is better due to better focus achieved through interference rather than reflection. Thats why modern ESA radars are based on interference. The beam quality in ESA radars is even better.

Actually when I wrote MSA radars in the previous post, I was talking about parabolic MSAs.

Yeah, there is no beam steering in MS.

 

[Twinblade]

So HAL-ADA lied about the deadlines for the thousandth time again. Either that or the incompetence runs so deep that the higher ups have no idea about the situation on ground. SP-1 was supposed to begin ground runs in June and fly in August, which was earlier supposed to be rolled out by 31st March 2014 which was August 2012 before. So many slippages at the last stage of the program when the last design and technology challenges were wound up half a decade back is shameful to put it mildly.





2623th flight on 28 June
TD1 : 233, PV1: 242, PV3: 382, LSP1: 74, LSP3: 202, LSP5: 270, TD2 : 305, PV2: 222, PV5: 49, LSP2: 294, LSP4: 125, LSP7: 112, NP1: 25, LSP8 : 88


2627th flight on 02 July
TD1 : 233, PV1: 242, PV3: 382, LSP1: 74, LSP3: 205, LSP5: 270, TD2 : 305, PV2: 222, PV5: 49, LSP2: 294, LSP4: 126, LSP7: 112, NP1: 25, LSP8 : 88

2660th flight on 30 July
TD1 : 233, PV1: 242, PV3: 384, LSP1: 74, LSP3: 215, LSP5: 277, TD2 : 305, PV2: 222, PV5: 51, LSP2: 294, LSP4: 128, LSP7: 115, NP1: 25, LSP8 : 95

2668th flight on 06 Aug
TD1 : 233, PV1: 242, PV3: 385, LSP1: 74, LSP3: 217, LSP5: 278, TD2 : 305, PV2: 222, PV5: 52, LSP2: 294, LSP4: 128, LSP7: 115, NP1: 25, LSP8 : 98

Also, Tejas is ulikely to attain FOC till July 2015.

Also,
[tweet]498396452012302337[/tweet]

 

[ersakthivel]

So HAL-ADA lied about the deadlines for the thousandth time again. Either that or the incompetence runs so deep that the higher ups have no idea about the situation on ground. SP-1 was supposed to begin ground runs in June and fly in August, which was earlier supposed to be rolled out by 31st March 2014 which was August 2012 before. So many slippages at the last stage of the program when the last design and technology challenges were wound up half a decade back is shameful to put it mildly

If all the tech challenges were wound up half a decade back they would have declared FOC by then itself.Please enlighten us all about how all the challenges were wound up half a decade back?

It is common knowledge that the prime reason for this delay is the inability of HAL to quickly upgrade all the LSPs to IOC-2 standard , which is tough challenge as each of these fighter was built in stages with different design changes getting incorporated on the go due to the flight test program updates.

2660th flight on 30 July
TD1 : 233, PV1: 242, PV3: 384, LSP1: 74, LSP3: 215, LSP5: 277, TD2 : 305, PV2: 222, PV5: 51, LSP2: 294, LSP4: 128, LSP7: 115, NP1: 25, LSP8 : 95

2668th flight on 06 Aug
TD1 : 233, PV1: 242, PV3: 385, LSP1: 74, LSP3: 217, LSP5: 278, TD2 : 305, PV2: 222, PV5: 52, LSP2: 294, LSP4: 128, LSP7: 115, NP1: 25, LSP8 : 98

Also, Tejas is ulikely to attain FOC till July 2015.

Also,The cost of a Tejas MK-1 as of today is around Rs 200 crores plus.

— Saurav Jha (@SJha1618) August 10, 2014
[tweet]498396452012302337[/tweet]

Does Saurav Jha know that the first 500 test flights carried out by the first few prototypes which took five years from 2001 to 2005, form a critical database that will be the back bone of control laws for any future Relaxed Static Stability fighter with digital fly by wire delta airframe that ADA is going to develop in the future?.

In fact these are invaluable IP resources on which no amount of monetary value can be put, because no one is ready to part with this data even if you are ready to pay the entire project cost of tejas in one go.

Also the composite tech developed for tejas is present on Su-30 MKi,

the retractable probe developed for tejas mk2 will be common for AMCA as well,

the avionic expertise developed for tejas mk1 formed the back bone of SU-30 MKI avionics, Even russians were impressed with that to the extent of ordering 64 sets of avionics along with Mission computer with weapon release software for their Su-30 SM (the same MKI version).

All the techs developed for mk1 using the mk1 project money is going to be used for tejas mk2,

So if we delete the monetary value of above contributions from tejas mk1 developmental effort, the cost will be far lesser than any value put out by Shaurav Jha or HAl.

And delays in FOC is not going to affect production time table. SO a six month or even an year's delay is not going to affect the induction timeframe,

The mirage-2000 spent 5 years in IAF with nothing but a gun,

The 40 SU-30s spent a dcade in IAF with far less capacity than the prescribed SU-30 MKI specs, and exchanged for 40 new SU-30 MKis after a decade of service in IAF fleet.

contrary to that if a kargil like war erupts in near future every single non FOC fighter would be good enough to precision bomb the baddies in the Himalayas with Mig-29s as escort just as Mirage-2000 did a decade ago in kargil with flying colors((In fact this role of mirage-2000 impressed IAF so much that they wanted to buy 126 Mirage-2000 fighters which has morphed into MMRCA tender.)

Because tejas mk1 even now has lower wing loading and higher thrust to weight ratio than Mirage-2000. And already finished all weather, wake penetration tests and cold weather trials in Leh.

Tejas is good enough to replace even mirage-2000 in IOC config, just gun firings and BVR trials , which have no relation to the basic airframe and control laws of fly by wire tech.AOA increase will go on beyond FOC as stated by SUneeth Krishna in IOC-2.

It has lower wing loading, higher TWR and lesser RCS than even the upgraded Mirage-2000.


Are more expensive weapons automatically more capable � Defense Issues

If we consider the slippage of six months as so big, then consider the ten year timeframe needed for IAF-MOD combo to complete the fatally flawed MMRCA tender, things will make sense then.

Also the whole MMRCA tender is simply flawed.

they did not define the tech they wanted on the MMRCA like,
1. lower clean config RCS,
2. Higher thrust to weight ratio and lowewr wing loading combo,
3. Relaxed static stability fly by wire platform,
5. Certain range or weapon load,
6. Product at the begining of the cycle development guaranteed of future upgrade,
7. A plane which is produced and servivng in a number higher than 100 in their home airforce with the engine present on the demo plane(to avoid the T-90 like no support for AC fiasco).

in place of the above tech wish list they simply put the below 30 ton weight category as prime criteria to shoo off the russian Su-35


If the above 7 conditions were made as their primary requirement for MMRCA RFP,
then we would have only typhoon and rafale to choose between.
And we could have chosen one before 2009 easily, well before the financial bids getting lapsed.

And we could have procured the fighter for MMRCA at a much lower cost in dollar(and rupee as well as rupee was trading at 50 a dollar then).

but it was a political circus with planes nearing their end of upgrades like F-16 and F-18 competeing with plane that has just one developmental prototype with not even an IOC like gripen E.

IAF evaluated all these 6 fighters to their heart's content well after the financial bid has lapsed and landed the country in a mess.

And when a capable tejas mk1 and mk2 getting near the induction line(tejas not ready and Mirage-2000 were needed after their good performance in kargil was the defining need for the original tender of 126 mirage-2000 which grew into this MMRCA circus.) IAf is simply hell bent on killing local industry once again by channeling a huge 20 billion dollars spread over the next few decades into rafale , whose all jobs can be done by Tejas mk2 and Su-30 MKi combo at a much lower cost.

Considering the monumental csts to the nation from this aspect the six month time delay is nothing to whine for thousand times,

Thats why the deal is attracting such severe criticism from all quarters.

Every body knows that this rafale deal will dump the same fate on tejas mk2, which was dumped on Arjun with t-90 procurement, simply there will be no money for us to induct much more costlier FGFA immediatley after rafale and still have meaningful tejas numbers.

SO this six month slippage is nothing compared to IAF's letting financial bids expire and buying the same fighter at a substantially high cost with more than five years of time delay .

 

[cobra commando]

HAL and Business Partners to increase Indigenization in Tejas to 80%

Bangalore: Hindustan Aeronautics Ltd (HAL) and its business partners that are associated with India's prestigious Light Combat Aircraft – the lightweight multirole fighter jet – have resolved to ensure the indigenous content of components used in the aircraft touches 80 percent in next three years at the indigenous strategic partners' meet of LCA organized by HAL here yesterday. As per to SA to RM, Mr. Avinash Chander, it is possible to achieve such a goal since 165 out of 344 Line Replacement Units (LRUs) are already made in India. In his address to the vendors, representing around 50 companies, he pointed out that LCA dream has been achieved in- spite of denial of technology. "It is clear that we have capability and the government will do everything possible to strengthen the knowledge base. Even funding can be provided and national facilities (such as testing) may be shared with private players to bring down costs to create a vibrant aerospace eco-system", he added. Dr. R.K. Tyagi, Chairman HAL said the production of LCA is on track with the creation of dedicated production division at HAL Bangalore. "We are aiming to roll- out 16 LCAs every year from the initial target of eight per year. Having specific business partners on such an important project has been of great help", he added. Dr. K. Tamilmani, Director General (Aeronautical Systems) and Mr. P.S. Subramanyam, Director, Aeronautical Development Agency (ADA) also spoke on the occasion. Mr. T. Suvarna Raju, Director (Design and Development, HAL) in his address said coming together of stakeholders is necessary to understand and share the knowledge since India is poised to have its own fighter aircraft comparable to the best in the world.
HAL and Business Partners meet to increase Indigenization in LCA Tejas to 80% | Frontier India

 

[Jagdish58]

Tejas Mk2 team targets 2017 for first flight | idrw.org

With Separate Project team from ADA and HAL already in place for Tejas MK-2 , MK-2 Team are targeting to carry out first flight in early 2017 as per sources close to idrw.org . under MK-2 Project HAL will roll out two Prototypes by 2016 which will be be powered by the more powerful GE-F414-INS6 engines .
In 2013 Initial contract for 8 GE-F414-INS6 engines was awarded to Ge and GE will start delivering engines by end of 2015 and will also help in Integration of the engines with the MK-2 airframe in India for which a dedicated team will arrive from US , Currently GE team in US has carried out design reviews for integration of the engines in the MK-2 .

MK-2 Project team also been tasked to make it more Maintenance friendly and increase operational availability of the aircrafts once it enters service with IAF. MK-2 not only will get new engines but also will get Active Electronically Scanned Array (AESA) radar , onboard oxygen-generating system; an advanced Electronic Warfare (EW) suite,Pilot friendlier cockpit display, retractable mid-air refuelling system . older PV-1 aircraft currently has been used has a Test Bed for Electronic Warfare system.

MK-2 Project team learning from the past mistakes , will source all required systems and components to be integrated in MK-2 before actual work on first Prototypes begins so that delays can be avoided for want of one particular part from one lab. Team plans to field both test aircrafts around same time so that certification of various components are not delayed due to lack of aircrafts and also enter Production once they are certified .

Clearly it will be a uphill task for ADA and HAL team to put together an aircraft which Internally will require lot of changes and upgradation to its current systems, but also need to certify and enter production in shortest period of time to keep the technology developed for the aircraft relevant in 2025 when IAF will induct MK-2 in large numbers .

 

[Jagdish58]

Re: HAL and Business Partners to increase Indigenization in Tejas to

Business partners decide to increase indigenisation to 80 % in LCA Tejas | idrw.org

The business partners working on India's prestigious Light Combat Aircraft – a lightweight multirole fighter jet – have decided to ensure the indigenous content of components used in the aircraft touches 80 per cent in the next three years.

At the indigenous strategic partners' meet of LCA organised by Hindustan Aeronautics Limited here, Scientific Adviser to Defence Minister, Avinash Chander said it is possible to achieve such a goal since 165 out of 344 Line Replacement Units (LRUs) are already made in India.
In his address to the vendors yesterday, representing around 50 companies, he pointed out that LCA dream had been achieved in-spite of denial of technology, according to an HAL release.

"It is clear that we have capability and the government will do everything possible to strengthen the knowledge base. Even funding can be provided and national facilities (such as testing) may be shared with private players to bring down costs to create a vibrant aerospace eco-system", he added.

HAL Chairman R K Tyagi said the production of LCA is on track with the creation of dedicated production division at HAL Bangalore.

"We are aiming to roll-out 16 LCAs every year from the initial target of eight per year. Having specific business partners on such an important project has been of great help", he added.

T Suvarna Raju, Director (Design and Development, HAL) in his address said coming together of stakeholders is necessary to understand and share the knowledge since India is poised to have its own fighter aircraft comparable to the best in the world.

 

[Pulkit]

Re: HAL and Business Partners to increase Indigenization in Tejas to

Business partners decide to increase indigenisation to 80 % in LCA Tejas | idrw.org

The business partners working on India's prestigious Light Combat Aircraft – a lightweight multirole fighter jet – have decided to ensure the indigenous content of components used in the aircraft touches 80 per cent in the next three years.

At the indigenous strategic partners' meet of LCA organised by Hindustan Aeronautics Limited here, Scientific Adviser to Defence Minister, Avinash Chander said it is possible to achieve such a goal since 165 out of 344 Line Replacement Units (LRUs) are already made in India.
In his address to the vendors yesterday, representing around 50 companies, he pointed out that LCA dream had been achieved in-spite of denial of technology, according to an HAL release.

"It is clear that we have capability and the government will do everything possible to strengthen the knowledge base. Even funding can be provided and national facilities (such as testing) may be shared with private players to bring down costs to create a vibrant aerospace eco-system", he added.

HAL Chairman R K Tyagi said the production of LCA is on track with the creation of dedicated production division at HAL Bangalore.

"We are aiming to roll-out 16 LCAs every year from the initial target of eight per year. Having specific business partners on such an important project has been of great help", he added.

T Suvarna Raju, Director (Design and Development, HAL) in his address said coming together of stakeholders is necessary to understand and share the knowledge since India is poised to have its own fighter aircraft comparable to the best in the world.

80% is very difficult till the time we don't have our own engine...
R K Tyagi says LCA production is on time but we are yet to see 1st aircraft out of few the promised will be delivered in 2014.... but still 4 months are there ....
I hope they have got a magic wand..... They are facing delays are every end.... and thats not unusual for HAL.....

 

[Jagdish58]

Re: HAL and Business Partners to increase Indigenization in Tejas to

80% is very difficult till the time we don't have our own engine...
R K Tyagi says LCA production is on time but we are yet to see 1st aircraft out of few the promised will be delivered in 2014.... but still 4 months are there ....
I hope they have got a magic wand..... They are facing delays are every end.... and thats not unusual for HAL.....

Yup you are right , but we don't have any other alternative other than HAL that is main issue . Fighter aircraft has evolved for 5th genration soon will be superseded to 6th generation now we are talking abour privatisation FDI 49% etc

HAL being a Monopoly Aircraft industry a public entity can play games not much can be done

 

[Pulkit]

Re: HAL and Business Partners to increase Indigenization in Tejas to

That trend is changing as you know a private venture has been initiated for IAF from which HAL is kept out...
So monopoly of HAL will be long gone before the 6th Generation Aircrafts actually Starts to appear on paper...

Only Russians have claimed to have started working on it No other nation...

As of now 5th Generation is our priority and that will lead way for 6th gen in the next 2 decades....

Regarding 49% its sufficient we have not matured enuf to give the control to a foreign vender.... And on the contrary we just need experience rest all resources are available within our country.....

Yup you are right , but we don't have any other alternative other than HAL that is main issue . Fighter aircraft has evolved for 5th genration soon will be superseded to 6th generation now we are talking abour privatisation FDI 49% etc

HAL being a Monopoly Aircraft industry a public entity can play games not much can be done

 

[Twinblade]

2668th flight on 06 Aug
TD1 : 233, PV1: 242, PV3: 385, LSP1: 74, LSP3: 217, LSP5: 278, TD2 : 305, PV2: 222, PV5: 52, LSP2: 294, LSP4: 128, LSP7: 115, NP1: 25, LSP8 : 98

2675th flight on 11 Aug
TD1 : 233, PV1: 242, PV3: 386, LSP1: 74, LSP3: 219, LSP5: 278, TD2 : 305, PV2: 222, PV5: 54, LSP2: 294, LSP4: 128, LSP7: 115, NP1: 25, LSP8 : 100

 

[proud_indian]