India Jet Engines and Gas Turbines

[Raptor]

https://twitter.com/i/web/status/1357177174264934400

https://twitter.com/i/web/status/1357177743301959680

Indigenous kaveri derivative for Ghatak UCAV!

 

[Nilgiri]

https://twitter.com/i/web/status/1381564385915674624

 

[Philip the Arab]

https://twitter.com/i/web/status/1381564385915674624

Can turbojets be converted to turboshafts? How does this work in this case?

 

[Nilgiri]

Can turbojets be converted to turboshafts? How does this work in this case?

Yes they certainly can be, if the turbojet (i.e effectively the gas turbine "core") is axial compressor type.

Turbojet/core seeks to output its power fully in the form of jet exhaust.

Essentially all of the variants....be it turbofan, turboprop or turboshaft look to "gear" what this core does....by say converting the jet exhaust into rotary action by addition of one extra turbine at the end (or the equivalent of this with an existing turbine stage).

It is that turbine modification choice that powers a fan, prop or shaft essentially to "gear" air to flow at larger volume but lower speed (compared to what a turbojet does).

Turboprops and turboshafts are especially intimately connected/related to each other...essentially you just design a "free" power turbine to sit on its own spool at the end and that powers either the prop or shaft (which leads to the rotor).

There are generally practical constraints to how far this can be done at small size turbojets/cores (or if they use centrifugal compression)...but if you set up the core correctly with further variants in mind...it should not be too difficult.

Of course this is from new production side (for variants), you can't simply retrofit an existing turbojet to be something else generally.

 

[Nilgiri]

https://twitter.com/i/web/status/1386712949134299137

https://twitter.com/i/web/status/1386633037371281411

 

[Raptor]

https://twitter.com/i/web/status/1386712949134299137

https://twitter.com/i/web/status/1386633037371281411

Damn single crystal blades
I think now we're close in developing our engine but this needs redesigning of kaveri engine
@Cabatli_53 @adenl @anmdt @Test7 @Zapper @Combat-Master @FalconSlayersDFI

 

[Nilgiri]

Damn single crystal blades
I think now we're close in developing our engine but this needs redesigning of kaveri engine
@Cabatli_53 @adenl @anmdt @Test7 @Zapper @Combat-Master @FalconSlayersDFI

Not a total redesign, but there will likely be specific cooperation with Safran (ex-Snecma) most likely on the lagging areas in hot section. Especially crucial to bring the engine up to snuff for later AMCA.

Safran is also heavily involved (quite a long time) in the helicopter engine program for India through turbomeca-HAL Shakti.

So we seeing acceleration in Indian capacity naturally (single crystal is just one) as the program grows and service branches demand grows for next set of engines.

It makes sense to partner up with Safran more broadly (with economy of scale in mind) for Indian military and civil engine ecosystem in gas turbine area....and special strategic relationship being cultivated with France a long time now.

CFM LEAP is example of civil supply chain setting up in India (posts 25 + 26):

India - France Relations

Exercise picture @Vergennes Credit: IAF

defencehub.live

@Vergennes

 

[Combat-Master]

Damn single crystal blades
I think now we're close in developing our engine but this needs redesigning of kaveri engine
@Cabatli_53 @adenl @anmdt @Test7 @Zapper @Combat-Master @FalconSlayersDFI

Thought India had already developed this capability with kaveri engine. They could get slot more power out of kaveri engine with single crystal blades and ceramic coatings

 

[Nilgiri]

Thought India had already developed this capability with kaveri engine. They could get slot more power out of kaveri engine with single crystal blades and ceramic coatings

Kaveri engine (developed so far) was stuck to directional solidified, which is tier just below SCB....but significant tier difference in the end.

DRDO/GTRE local efforts were aided somewhat by using some level of ToT given by Russians on SCB for MKI engine (koraput production+MRO facility has this machinery and process control I believe)....but maturing the RnD for new effort based only on that was cumbersome in the end ithas turned out....and you are stuck with Russian final level in end too anyway (which is inferior in raw MRO-hours/thrust terms especially compared to western i.e you have not mastered the best option you now have available).

With Indian RnD funding more established in area, SAFRAN/SNECMA now more involved with Indian aviation sector, and from sounds of things (in last couple years) specific consultancy for Gas Turbine Ecosystem going forward at the scale involved, things should bear more fruit this decade given India long term objectives and growing needs in this sector, in both civil and military domain.

There will be a few more core competencies needed to be realised to make jump within SCB though..... from the heli shakti class of turboshaft HPT to the (far more serious) turb-inlet+exit conditions found in HPT and LPT of much larger turbofan....specifically the internal geometries involved for cooling and their process and quality control.

i.e it is a series of steps in SCB field too rather than everything unlocked 1:1 by one initial sub-area.

 

[Raptor]

DRDO develops Critical Near Isothermal Forging Technology for aeroengines​

Posted On: 28 MAY 2021 1:58PM by PIB Delhi

Defence Research and Development Organisation (DRDO) has established the near isothermal forging technology to produce all the five stages of high-pressure compressors (HPC) discs out of difficult-to-deform titanium alloy using its unique 2000 MT isothermal forge press. The technology has been developed by Defence Metallurgical Research Laboratory (DMRL), a premier metallurgical laboratory of DRDO at Hyderabad. This is a crucial technology for establishing self-reliance in aeroengine technology. With this development, India has joined the league of limited global engine developers to have the manufacturing capabilities of such critical aero engine components.

To meet the bulk production requirements, DMRL technology was transferred to M/s MIDHANI through a licensing agreement for technology transfer (LAToT). Using the isothermal forge press facility available at DMRL, Hyderabad, bulk quantity (200 numbers) of HPC disc forgings pertaining to various compressor stages have been jointly (DMRL & MIDHANI) produced and successfully supplied to HAL (E), Bengaluru for fitment in to Adour Engine that powers the Jaguar/Hawk Aircrafts.

In India, the Adour engine is overhauled by HAL (E), Bengaluru under a licensed manufacturing agreement with OEM. Like in any aeroengine, the HPC Drum assembly has to be replaced after a specified number of operations or in case of damage. The annual requirements of these high value HPC discs are quite large, warranting indigenisation. HPC drum is a highly stressed sub-assembly and is also subjected to low cycle fatigue and creep at elevated temperature. The raw materials and forgings for HPC drum are required to be of the highest quality which can meet the specified combination of static and dynamic mechanical properties.

DMRL developed this forging technology by integrating various science and knowledge-based tools. The methodology adopted by DMRL is generic in nature and can be tuned to develop other similar aeroengine components. The compressor discs produced using this methodology met all the requirements stipulated by the airworthiness agencies for the desired application. Accordingly, the technology was type certified and letter of technical approval (LoTA) was accorded. Based on the exhaustive component level and performance evaluation test results, HAL (E) and Indian Air Force cleared the components for engine fitment. Apart from DMRL and HAL (E), various agencies such as MIDHANI, CEMILAC and DGAQA worked in unison to establish this crucial technology.

Raksha Mantri Shri Rajnath Singh has congratulated the scientists of DRDO, Industry and all other agencies involved in the development of this critical Aero Engine related technology.

Secretary Department of Defence R&D and Chairman DRDO Dr G Satheesh Reddy expressed his satisfaction on achieving this crucial milestone and congratulated the teams involved.

ABB/Nampi/DK/Savvy/ADA

DRDO develops Critical Near Isothermal Forging Technology for aeroengines

Defence Research and Development Organisation (DRDO) has established the near isothermal forging tec

pib.gov.in

 

[Nilgiri]

Something odd, how can PTAE-7 power the CATS Warrior if it is made for a single use target drone? Does the upgraded compressor allow this?

AFAIK, lakshya is designed to be reusable (including the engine)....it has a parachute recovery system in it. Unsure about engine (PTAE-7) MTBO and lifetime in this role though.

After it is launched (rocket boost--->rocket jettison---->turbojet switches on) and achieves the relevant altitude, two actual targets (one under each wing) are unlocked and essentially towed behind the main PTA at some distance...and I think can be jettisoned too depending on target profile need.

These two are what are fired at in most training missions involving the Lakshya, though I suppose the main PTA can also be targeted if needed (at cost to system).

Generally the main PTA needs to survive + be recovered (via parachute system) since it carries a lot of the useful telemetry data regarding the effectiveness of the weapon w.r.t towed targets/decoys.

So PTAE-7 is reusable, it was developed (in its smaller scale) from the know-how and understanding India initially got from the orpheus 703 many examples of which were retired early with the HF-24 Marut

These examples were thus studied/tested extensively in the 80s. Though they were a generation older even at that time they provided some of the basis to take forward....like was done in Kaveri and HTFE-25 (at the mid-larger scales).

Orpheus engines that had lot of lifetime left on them were derated and used on Kiran II trainer too.

Anyway, the (two) towed targets of the lakshya formed the basis of the related Abhyas system which is expendable one-use (very much like a cruise missile) and I suppose uses a one-time-use cheaper gas turbine than lakshya. But that is not a PTAE-7 (maybe a cheaper + smaller version of it, I forgot what its thrust/sizing is).

In any case PTAE-7 will be improved material and tolerance wise for use in CATS.

I would assume it (first variant of it) hits somewhere in the 4 kN thrust range so x2 = 8kN for about ~2 tonne mass of CATS. P/W is thus in region of high subsonic a/c...which is its planned max speed (since no afterburner).

Lot of this is off top of my head,, so I might have gotten some details wrong.

And another question, are turbojets engines scalable below a certain size? Could you in theory scale up a 1kn engine to a 3kn engine?

You can scale an engine to some degree (though not perfectly 3D isotropically most people think when "scaling")...i.e apply the same set of technologies and overall layout to a larger size (with maybe more compressor/turbine stages and modifying requisite hand-off zones like guide vanes.... and other things which do not scale in same linear way).

But there is diminishing returns (in utility of doing this approach compared to starting from relative scratch) past a point (as engine gets larger and larger) especially as the Turbine Inlet Temperature (among other things, but long subject) starts to really increase which needs far more deep design changes in the intrinsic turbine capability to cool itself and have higher resilience to such operating conditions.

It is actually this Turb inlet temp (relative to materials research + frontier fabrication processes we have at hand) that pretty much sets the overall bounds for the current maximum size (or max thrust or converted power for given size) jet engines reach today.

 

[Nilgiri]

https://twitter.com/i/web/status/1411352322542751744

 

[Nilgiri]

Aeroengine technology, genuinely not an ‘elephant in the room’ for India - Indian Aerospace and Defence Bulletin - News for aerospace and defence in India

by Gp. Capt. Anupam Banerjee (r.) Ensuing, the recently held Virtual Summit between the Prime Ministers of India and UK, a very significant statement was issued by British High Commission in India. The high commission stated “In addition to commitments on the Indo-Pacific, the two countries...

www.iadb.in

Aeroengine technology, genuinely not an ‘elephant in the room’ for India​

June 6, 2021

by Gp. Capt. Anupam Banerjee (r.)

Ensuing, the recently held Virtual Summit between the Prime Ministers of India and UK, a very significant statement was issued by British High Commission in India.

The high commission stated “In addition to commitments on the Indo-Pacific, the two countries agreed to build on existing government-to-government collaboration on India’s future combat air engine requirements. As part of a ‘2030 Roadmap’, they agreed to work closely together in support of India’s indigenous development of the Light Combat Aircraft Mark 2” (https://www.gov.uk/government/news/...nisters-announce-enhanced-defence-cooperation).

As far as history recalls, aero engine technology has proved to be the Achilles heel of India’s quest for self-reliance in combat aircraft manufacturing. The first indigenous fighter aircraft Marut that was developed by HAL was plagued by aero engine issues.

Few decades later the ‘Kaveri’ engine story followed a similar tale of failure to harness this difficult yet critical technology. Kaveri failed its high-altitude trials in Russia in the year 2004, leaving no choice for LCA designers to look for a viable alternative. The US manufactured General Electric GE-F404IN engine was finally selected as the replacement and is currently in use with the Tejas fighter that entered service for the IAF in 2016.

The reasons that delayed the development of Kaveri engine can be broadly categorized as technological complexity of design and development, lack of critical equipment and materials, engine technology denial by countries having the technology, inadequate domestic testing facilities, and non-availability of specialized manpower.

Though Kaveri project is no longer linked with LCA, the under development Ghatak UCAV (Unmanned Combat Aerial Vehicles) is going to be powered by a derivative of Kaveri engine and will be a 46-kilonewton dry variant of the Kaveri aero engine, thus ensuring some utilization of significant amount of money and effort that has so far been spent on the said project.

Big Question ?

So, what does the future of India’s quest for aero engines look like – the issue is very complex and may not fetch a straight answer for it. Suffice to say no effort can be termed as a complete waste of effort. Critical knowledge that was gained in the development process can be leveraged in future Joint Ventures (JV) for aero engines. It is in this context that the statement of the UK High Commission assumes greater significance. So far Rolls Royce and Safran have shown interest to partner with India to fulfill such requirements.

At Aero India 2021, HAL and Rolls Royce agreed to expand their existing partnership. In fact, more than 750 Rolls-Royce engines of 10 engine types are being used by the Indian Armed Forces already. The significant ones being the Adour Mk811 powering Jaguar, Adour Mk871 of Hawk AJT, AE2100 engine of strategic airlift aircraft C-130J Hercules and AE3007 engine for VIP and Surveillance aircraft Embraer ERJ145. Any company with this kind of footprint in a country will in normal course be interested to increase such engagements.

On the other hand, Safran Aircraft Engines at the aero show also signed a MoU with HAL. A statement issued by them mentioned that under the terms of the MoU, HAL and Safran intend to explore opportunities to assemble the Safran M88 engine and manufacture components for the engine with HAL for the Rafale fighter aircraft fleet of India.

The MoU contemplates transfer of a significant amount of technology in the assembling or manufacturing programs. The MoU also envisages significant collaboration between HAL and Safran for indigenization programs relating to design and development of high thrust engines of 110 kN power and above with transfer of key technology in the framework of this development.

These are significant developments and in conjunction with knowledge gained by GTRE during Kaveri R&D can lead to breakthroughs, provided, it is pursued in a coordinated manner where the key stakeholders will exchange knowledge and will be steered by the clarion call of “Atmanirbharta”.

Optimum utilization of existing milestones

In addition to GTRE under DRDO, HAL also has an Aero Engines Research and Design Centre (AERDC) established in 1960 that carries out design and development of Gas Turbine Engines. The Centre designed and developed small aero engines which are in successful operation with our Indian armed forces.

At present AERDC is tasked to develop two engines namely, Hindustan Turbo Fan engine (HTFE-25) of 25 kN thrust which can power trainer aircraft, UAV’s, Twin engine small fighter aircraft and Hindustan Turbo Shaft engine (HTSE-1200) of shaft power rating which can power Light & Medium weight helicopters (3.5 to 6.5 tonnes in single/ twin engine configuration). As of now both these projects have carried out successful trial runs of 25 kN core engine and 1200 kW Jet mode version engine up to 100% RPM. HAL also has engine overhauling facilities for its licence production aircraft.

Despite developing such good facilities over the last few decades, the gestation period for development of aero engines in India is sluggish and disappointing. That being said, it is imperative to mention that designing of aero engines for a modern-day fighter aircraft is an extremely complicated process with amalgamation of various technologies, as far as that includes subject domain like metallurgy, as well.

Interestingly, with our present knowhow of metallurgy, India has been able to successfully make engines for spacecraft, though the breakthrough for fighter jet engines remains elusive.

The reason for this being design complexity of fighter engines that should be able to perform across the range of aircraft maneuvering envelope. Also, this being a strategic capability it is highly unlikely for other nations to share the technology with us in totality.

Closer home, China has had its issues with development of WS-10B Taihang turbofan engines for its J-10 fighter aircraft. China has been testing these engines for almost a decade now while using Russian AL-31 engines as an interim measure. It is only recently that news of its success has surfaced. It is because of the level of technological challenges only a handful of nations so far have been able to master this technology.

Over the next two decades India is going to purchase or replace close to 2000 aircraft from its inventory including fighters, transport, and helicopters (both military and civil) and UAVs. Most of these aircraft will be multiengine. In an aircraft lifecycle the engines are replaced on an average of three to four times.

Thus, we can look at many engine production/overhaul costs amounting a significant sum of money. If we as a nation quickly do not master this capability most of this business will be outsourced overseas.

Also, once we develop this capability, we are looking into a large potential export market in parallel. Thus, though it might appear to be a huge investment of money and effort to get this capability, once successful, the potential returns can be phenomenal for a longer period.

Moral of the story

All said and done, bottom-line is India needs to make indigenous aero engines for its future aircraft projects. Rather than looking at the whole process of engine manufacturing as a problem statement, or challenge, if it is broken down into smaller sub-parts of various problem-solving statements which can be derived at by identifying the critical technology challenges that we have encountered in our years of service put into this field, it may be easier to find a path of solutions.

The need of the hour is to have a consortium approach with all key stakeholders of Indian Defence manufacturing ecosystem getting involved in this process. As it involves a lot of capital, talent, and infusion of multiple technologies. DRDO and HAL should consider involving our fast-emerging private defence industry partners as well, while taking help of foreign OEMs specifically for critical areas.

Opening of existing facilities to Private industry partners can be a starting step forward. The Govt on its part has made its intent very clear by giving the engine manufacturing special status. In the recently published Defence Acquisition Procedure (DAP) 2020 where para 29 (g) of Chapter 1 states that Aero engines manufacture need to be taken up as projects of National importance. It also states that Aero engines in India will mandatorily be procured for applicable defence equipment as Buyer’s Nominated Equipment (BNE)/ sub-assemblies and clarifies that these procurements will not be considered as Single Vendor Cases (SVC).

India’s defence manufacturing landscape is different today from what it was earlier. Proactive approach of MoD in the last few years along with various policy reforms have ensured an upbeat mood in the ecosystem, thus repeating the old approach of problem solving may result in similar failures of the past.

Difficult problems need different solutions and leadership approaches. India might soon be able to make an important breakthrough in this critical sector by thinking ‘out of the box’. So, to ensure happy landings and efficiency !

About the author: Group Captain Anupam Banerjee (r.), is a senior advisor- Society of Indian Defence Manufacturers and former spokesperson of Indian Air Force.

 

[Nilgiri]

https://twitter.com/i/web/status/1412407172277968911

 

[Nilgiri]

https://twitter.com/i/web/status/1453264865234145294

 

[Nilgiri]

https://twitter.com/i/web/status/1457388035268497409

 

[SavageKing456]

kaveri program issues have been resolved
@Gautam's Post from another forum brings you the details

(Post edited by mod)

Credit to @Gautam and all original references/sources:


The major problems of the current Kaveri engine were the creep, screech & combustion instability. The last 2 problems were being caused by the afterburner. The dry Kaveri doesn't have the AB section so those problems don't exist on that variant. The creep related problems were sorted out sometime back. So the dry Kaveri was ready for flight tests then, the wet version is ready now. GTRE needs to get on with flight testing quickly.

After flight testing you van certify them to be ready. But what do you deploy these engines on ? There is no current user for the Kaveri with the AB. The Tejas could be a user but the engine doesn't produce enough power & the engines of the Tejas are still very new. Each fighter needs 2 sets of engines. So maybe when the Tejas needs new engines the Kaveri with AB could be used. That's at least a decade away, GTRE has enough time to improve on the engine's AB.

The engine dry thrust is good enough. Further increase in dry thrust will come from the new fan & the high pressure compressor. The fan is already here, the HP compressor is still being worked on. The wet thrust needs to at least match the current 84-85 kN of the GE 404. The Kaveri could get to 81-82 kN with the AB but couldn't sustain that level of thrust due to screeching & combusting instability. Without those problems & with the new compressor we should be able to get to 85 kN. The next set of challenges would be making alloys that can help us get to a higher TET & sustain it for long periods of time.

In the mean time the dry version is going to be operationalized with the Ghatak. With that LSP of the engine will start. Serial production will bring its own challenges. When the production line is established the Kaveri with AB can also be produced there. Thing are looking up for the Kaveri, for the 1st time in many many years.

==============

Thanks for the pdf.

Here is Dr. K. Ramachandra's biodata. He was the director of the GTRE sometime back & was actively involved with both the Kaveri, KMGT & the Manik engine development work. Here is how he describes his work in the past few years:

Dr. K. Ramachandra is still involved with the GTRE & is working on the following projects :

A lot of the projects shown above are targeting operationalization of the K9 standard engine for example the FOD monitor, damping engine components etc. Other projects are mostly meant for the K10 engine like the boltless disks, vaneless turbines, BILSK, anti-icing, thrust vectoring nozzle etc.

We have seen some of the prototypes already. Here is the 100% 3D printed anti-icing nose cap for the K10 engine :

HAL is going for 3D printed blades, disks, HP & LP turbines, HP & LP compressor of the HTFE-25. GTRE has followed suit by 3D printing many components of the Manik engine. It is likely that GTRE would 3D print the HO compressor of the K10 engine.

DMRL with the help of HAL has re-designed their single crystal blades with intricate cooling channels. Previous generations of DMRL's single crystal blades often could not be used for improper design of cooling channels. The K10 is likely to see the use of single crystal blades made out of DMRL's DMS4 nickel based superalloy. Single crystal blades & vanes made from the DMS4 alloy have been tested on the Su-30MKI's AL-31FP engines:

DMRL has recently put out a tender to start manufacturing the blades, the blade design is given below. Notice the many holes for passing the coolant:

The K9 engine uses the Yttria Stabilized cubic Zirconia (YSZ) based Thermal Barrier Coating (TBC). The theoretical maximum temperature at which YSZ based TBC can survive against a CMAS attack is 1450 deg C. The TET of the K9 is ~1430 deg C. This is the best we can do YSZ. Our coating, nano-material synthesis methods for YSZ are on par if not better than the global standard. Many of the private companies that supply equipment & materials for coating YSZ to GTRE also supply to many global engine OEMs & recently to NASA:

Thermal Spray Coatings From India Of Interest To NASA | A&A Thermal Spray Coatings

Every material has a limit to its performance & we have reached the limit of YSZ with the K9 engine. Thus the need for a better TBC came to be. DMRL in the past few years have started working on a bi-layer TBC. Basically they will apply a coat of Lanthanum Zirconate (LZ) over the presently used YSZ. Both the layers together is called the bi-layer TBC.

DMRL has used the AL-31FP engine to test the endurance of the new bi-layer TBC. The results were promising. The AL-31FP has become the test bed for all new jet engine technology.

In the recent years research publications on YSZ & LZ TBC is booming. Some examples:

ShieldSquare Captcha

(PDF) Effectiveness of lanthanum zirconate and Yttria stabilised zirconia freestanding APS thermal barrier coatings against natural CMAS attack at high temperatures

(PDF) Study on thermal, mechanical, microstructural properties and failure analyses of lanthanum zirconate based thermal barrier coatings: A review

https://www.researchgate.net/profil...-THz-TDS-measurements-A-comparative-study.pdf

https://www.researchgate.net/profil...-natural-CMAS-attack-at-high-temperatures.pdf

Additive laser deposition of YSZ on Ni base superalloy for thermal barrier application

Collating what we know of the K10 engine so far the specs they are targeting for are as follows:

Dimensions: L=3.49m, D=0.9m (same as K9)
Dry weight: 1100 kg (down from 1235 kg)
LP compressor pressure ratio: 4:1 (up from 3.4:1)
HP compressor pressure ratio: 6.75:1 (up from 6.4:1)
Overall pressure ratio: 27:1 (up from 21.76:1)
Maximum Thrust: Dry= 57-58 kN, Wet= 88-90 kN [my guess]
Thrust to Weight ratio: Dry= 5.38:1 (up from 4.29:1) Wet= 8.29:1 (up from 7.8:1) [my calculation based on the guess]
Turbine Entry Temperature: 1550-1580 deg C (up from 1430 deg C)
Mass flow: 78 kg/s (same as K9)
Bypass ratio: 0.16:1 (same as K9)

A thrust of weigh ratio of 8.29 is pretty good, 8.5 is the benchmark for great engines. GTRE must continue improving the engine as they prepare to make the dry K9 variants for the Ghatak program.

The K8 was 1430 kg, K9 was 1235 kg & the K10 is projected to be 1100 kg. The 11th prototype, K11, would need to drop the engine's weight to less than a ton to be in the "great" category. The K11 has to integrate BLISK, increase the use of 3D printing & develop newer lighter alloys.

It makes sense to go from the K10 to the DRDO-Rolls Royce joint venture for the 110+ kN engine. Going from the 80 kN class K9 engine to a 110+ kN engine would be quite the jump.

Here you have a photo from early 2020 of the DRDO chief showcasing a model of the K10 engine to PM Modi:

Really hope he is keeping track of this project. The Kaveri engine project should be of the stature of the IGMDP. A lot of the facilities & testing infrastructure needed cannot happen without political will.

Ashwin said:
Ghatak is suppose to be 8-10 all up weight.

Are you sure of that ? Last I heard the Ghatak was supposed to have a MTOW of "less than 15 tons". A high ranking DRDO official said that a few years back. "Less than 15 tons" is not very specific but at that time it seemed like the MTOW of the Ghatak would be greater than that of the Tejas.

I don't know if that is still the case. There were some recent reports of derating the dry Kaveri from 52 kN to 46 kN for the Ghatak UCAV. The derating was supposed to bring better fuel efficiency & more range for the Ghatak. Apparently 52 kN wasn't needed for the UCAV. So either the "less than 15 ton" MTOW figure is wrong or the UCAV max speed will be in high subsonic range.

@Nilgiri @Zapper @Cabatli_53 @Test7 @Nein2.0(Nomad) @MisterLike @Lonewolf @Indos @T-123456

 

[Lonewolf]

A

kaveri program issues have been resolved
@Gautam's Post from another forum brings you the details
Post in thread 'GTRE Kaveri Engine' http://www.strategicfront.org/forums/threads/gtre-kaveri-engine.93/post-188401



Post in thread 'GTRE Kaveri Engine' http://www.strategicfront.org/forums/threads/gtre-kaveri-engine.93/post-188500

Creep issues along with combustion instability and screetch issue has been resolved



@Nilgiri @Zapper @Cabatli_53 @Test7 @Nein2.0(Nomad) @MisterLike @Lonewolf @Indos @T-123456

Afterburner issue remaining

 

[SavageKing456]

A

Afterburner issue remaining

You mean not sufficient thrust right?
They're redesigning it completely to get more thrust

 

[Lonewolf]

You mean not sufficient thrust right?
They're redesigning it completely to get more thrust

Ya ,but I meant weight issues too ,hope they don't make it too heavy , if weight is controlled we might see it going into Ghatak ,and some tejas