Kaveri & Aero-Engine: News & Discussion

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hanumadu
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Re: Kaveri & aero-engine discussion

Post by hanumadu »

India's largest CNC company has high speed 5 axes machines
http://www.jyoti.co.in/

Jyoti has a french subsidiary Huron
http://www.huron.fr/index.aspx

So atleast machining technology does not seem to be an issue here. Only material technology.
Prem Kumar
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Re: Kaveri & aero-engine discussion

Post by Prem Kumar »

Its not just materials. The fundamental design was inefficient because of a low bypass ratio. That was N^3's point, as Maitya also states above. This needs to be reworked first. Lots of experiments, trial & error, CFD etc. Good, old fashioned engineering. With a better design, we can get more thrust even with the existing materials
ramana
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Re: Kaveri & aero-engine discussion

Post by ramana »

DRDO on Gas Turbine research

useful for measuring progress
SaiK
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Re: Kaveri & aero-engine discussion

Post by SaiK »

Prem Kumar wrote:Its not just materials. The fundamental design was inefficient because of a low bypass ratio. That was N^3's point, as Maitya also states above. This needs to be reworked first. Lots of experiments, trial & error, CFD etc. Good, old fashioned engineering. With a better design, we can get more thrust even with the existing materials
en.wikipedia.org/wiki/Bypass_ratio Low bypass ratios tend to be favored for military combat aircraft as a compromise between improved fuel economy and the requirements of combat, which values higher power-to-weight ratios, supersonic performance, and the ability to use afterburners which are more compatible with low bypass engines
nachiket
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Re: Kaveri & aero-engine discussion

Post by nachiket »

SaiK wrote: en.wikipedia.org/wiki/Bypass_ratio Low bypass ratios tend to be favored for military combat aircraft as a compromise between improved fuel economy and the requirements of combat, which values higher power-to-weight ratios, supersonic performance, and the ability to use afterburners which are more compatible with low bypass engines
The bypass ratio of fighter engines is lower than those of the very high bypass ratio engines used in commercial aircraft. But the Kaveri's bypass ratio is so low that the design is more of a leaky turbojet than a true turbofan engine.
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Re: Kaveri & aero-engine discussion

Post by SaiK »

but then going by:
..which values higher power-to-weight ratios, supersonic performance, and the ability to use afterburners which are more compatible with low bypass engines.
then it should actually increase wet thrust ? any gyan?

--
added later:

http://books.google.com/books?id=uCI5Kh ... et&f=false

check page 205

http://books.google.com/books?id=8UoR7o ... et&f=false

page 157

on leaky turbojet. more gyan needed.
shiv
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Re: Kaveri & aero-engine discussion

Post by shiv »

Will wrote:

Just goes to show why PSU's wont attract top brains on a regular basis. If the govt allows in private players and nutures them to an extent of even 25% of what they do with the PSU blackholes, one will see wonders in a decades time, where the Indian defence industry is concerned. Only private players have the leeway to attract the best brains from around the globe and retain them with salaries and perks and a competative work culture.
If not we will be stuck with DRDO and HAL sticking labels like they did on the Identification Friend or Foe system that was developed by Cassidian and calling it their own development. At least Cassidian has setup a local unit and hopefully used a lot of Indian brains in that development. That is the way to build up local expertise. Give them a challenging environment with good pay packets. PSU's cant match that with a 9 to 5 culture.
Fmr CNS Arun Prakash has an interesting take in the latest Issue of Vayu. He says that th armed forces can induct engineers and scientists on a short service commission with a career path in DRDO after they finish from the armed forces. This seems attractive because a short service commission itself is an attractive carer path for many and combines the excitement of being in the armed forces, a good salary and not a permanent commitment and the possibility of a reasonable bank balance at the end of the commission. Modern day engineering graduates who get insane salaries may think this sounds stupid - but for medical graduates who earn paltry salaries this is a great option as it might be for science graduates who do not get to earn high salaries from day 1.
Nick_S
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Re: Kaveri & aero-engine discussion

Post by Nick_S »

indranilroy wrote:I can't imagine my reaction if one day I see a N^3 or Arun_S post. I will really do a Ganguly-style t-shirt twirl.
I think Arun_S posts on a different forum.

He really used to make awesome posts back when he was here. I dont know why he left BR.

----

If i am not mistaken, this is the same Arun_S here -
http://www.india-forum.com/forums/index ... iscussion/
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Re: Kaveri & aero-engine discussion

Post by SaiK »

There are threads you guys can discuss and actually find out reasons etc.. why this thread?
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Re: Kaveri & aero-engine discussion

Post by merlin »

nachiket wrote:
SaiK wrote: en.wikipedia.org/wiki/Bypass_ratio Low bypass ratios tend to be favored for military combat aircraft as a compromise between improved fuel economy and the requirements of combat, which values higher power-to-weight ratios, supersonic performance, and the ability to use afterburners which are more compatible with low bypass engines
The bypass ratio of fighter engines is lower than those of the very high bypass ratio engines used in commercial aircraft. But the Kaveri's bypass ratio is so low that the design is more of a leaky turbojet than a true turbofan engine.
So the question is why have the low bypass ratio in the first place? Its not as if GTRE would be unaware of the pros and cons of various bypass ratios.
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Re: Kaveri & aero-engine discussion

Post by shiv »

merlin wrote: So the question is why have the low bypass ratio in the first place? Its not as if GTRE would be unaware of the pros and cons of various bypass ratios.
As you know well I am nowhere near being an expert on this issue. But I suspect that there is a tricky balance between thrust that is planned, the bypass ratio and the temperatures and pressures needed in the core. And I am guessing that a working model that achieves a good balance of these parameters requires the creation of three or four model engines -each with a variable proportion of bypass, airflow mass, temperature, pressure etc. I suspect that once parameters are frozen they cannot be changed later - so I think experience in designing 3 or 4 failed designs would be better than trying one frozen design.

We will never know what the chief designers at GTRE did. Knowing the way Indian education works I think it is likely that GTRE's early work on design may have been based on paper/math calculations as to what may work rather than a slew of 3-4 experimental designs actualy constructed and tested. The former would have been cheaper and also would have given control to a nerdy guy who was good in college studies rather than a hands on type guy.

I think the first engines were designed by trial and error and observing what failed rather than by hi-funda calculus, thermodynamics and fluid mechanics or whatever
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Re: Kaveri & aero-engine discussion

Post by Singha »

could the whole "flat rated for Leh ops" fetish have something to do with it? all engines lose perf at high alt but this "flat rating" fetish was supposed to resolve this dharmic question.
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Re: Kaveri & aero-engine discussion

Post by shiv »

Even today I suspect that if you take 100 fresh Indian mechanical or aero engineering graduates and ask them design a model jet engine for a model aircraft/UAV and promise to pay them, 90% will submit a paper design and only a handful will try to build one.

That is the way our engineering education has worked from the time of my father's generation (1940s engg college). Brainy guys good at solving paper problems but zeros in hands on work. I bet Kaveri is the result of lots of calculations and very few bruised and cut hands in the early years.
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Re: Kaveri & aero-engine discussion

Post by NRao »

A redesigned, bigger, Kaveri should suffice.

The dry numbers are close. It is the wet one that is the problem (as far as we know). To increase that number the engine has to either a) increase the amount being pushed out or b) push out what it is pushing out faster. This assumes that the current Kaveri has absorbed all the latest techs (give and take some).

?????
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Re: Kaveri & aero-engine discussion

Post by shiv »

NRao wrote:A redesigned, bigger, Kaveri should suffice.

The dry numbers are close. It is the wet one that is the problem (as far as we know). To increase that number the engine has to either a) increase the amount being pushed out or b) push out what it is pushing out faster. This assumes that the current Kaveri has absorbed all the latest techs (give and take some).

?????
I thought vina or someone pointed out that by increasing the low pressure bypass part more air goes to the musharraf where it can be phyrred by an afterburner. I know it is easier to say than do, but we do have a working core and an engine that flies.
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Re: Kaveri & aero-engine discussion

Post by SaiK »

wouldn't that mean that the major thrust for afterburners comes from the combustion (musharraf thrust) rather the compression chambers (fan thrust) in the case of high bypass?

Image
panka thrust [hi bp]

vs.

Image
musharraf thrust [lo bp]

the bottom: the low bypass should have helped in high power to weight. so, the problem might be just the blades onleee.
Last edited by SaiK on 16 Feb 2013 09:49, edited 1 time in total.
Singha
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Re: Kaveri & aero-engine discussion

Post by Singha »

How does a jet engine start...how does the fan get spun initially to force air inside for combustion to start ?
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Re: Kaveri & aero-engine discussion

Post by SaiK »

perhaps they need :

Image
full core musharraf zero bypass.

--

Kaveri has JFS (jet fuel starter).. gas generator. / air start system tested working in leh and will start upto 6km alt.

GTSU-110
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Re: Kaveri & aero-engine discussion

Post by geeth »

So the question is why have the low bypass ratio in the first place? Its not as if GTRE would be unaware of the pros and cons of various bypass ratios.
Reasons are:

1. In high bypass ratio, major part of the air is pushed through the annular space between the core and outer casing - this air have large mass and lower velocity.Being of lower velocity, contributes less towards overall thrust. Advantage are:

(a)The noise of the engine is much less, a must for commercial engines.
(b) Mass of air available is much more for burning more fuel in the afterburner (no after burner for commercial engines though)
(c) better specific fuel consumption figures

Disadvantages:

(a) will have a larger cross sectional area hence not suitable where space is less.
(b) Generally, will have higher TET, since lesser mass flow of air through the core. But here again, it is a compromise depending on available material.

2. In low by pass engines, more air passes through the core and hence more fuel is burnt. Lesser by-pass air passes through the annular space.

Advantages :

(a) Cross sectional area is less, since you don't need large fan blades.
(b) Lower TET, since the combustion gas is cooled by higher mass flow through core

Disadvantages

(a) More noise
(b) Higher SFC
(c) Can pump lesser fuel only for After burning


I feel Kaveri thrust problem is basically due to less efficient compressor blade design. They may not be the most advanced. In a GT, most of the energy consumed is to rotate the compressor - the more efficient the compressor, more energy is available in the jet exhaust in other words, higher pressure gas will exit through the tailpipe). Come to think of it, axial flow compressor is nothing but qa series of propeller blades arranged one behind the other to compress the air.
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Re: Kaveri & aero-engine discussion

Post by maitya »

merlin wrote:
nachiket wrote: The bypass ratio of fighter engines is lower than those of the very high bypass ratio engines used in commercial aircraft. But the Kaveri's bypass ratio is so low that the design is more of a leaky turbojet than a true turbofan engine.
...
SaiK wrote: en.wikipedia.org/wiki/Bypass_ratio Low bypass ratios tend to be favored for military combat aircraft as a compromise between improved fuel economy and the requirements of combat, which values higher power-to-weight ratios, supersonic performance, and the ability to use afterburners which are more compatible with low bypass engines
So the question is why have the low bypass ratio in the first place? Its not as if GTRE would be unaware of the pros and cons of various bypass ratios.
Merlinji, a million dollar question - and frankly, nobody outside the GTRE core-design team would know the exact reason. However, here's an attempt of moi to try and explain this design choice.

All this wailing about low-bypass ratio etc have started 25yrs down the line after a design decision were made but the product has failed to meet the other primary design goals (e.g. Wet Thrust).
As they say hindsight is always 20/20 - what really needs to be understood what was the prevailing contemporary (not only indigenous but also international) technological-maturity level in the context of which these types of decisions (by the GTRE folks) were taken.

Contemporary Gas Turbine Material Technology - Back in late 1980s and early-1990s, the most widely held viewpoint was,
1) SCB Gen 2 and Gen 3 are firmly in laboratories unheard of outside a very few select labs/orgs
2) Gen 1 SC technology is well-known - but didn't offer any fundamental advantage over last-gen DS in terms of thermal stress and creep-resistance - not that commonly applied yet
3) last-gen of DS, is a decade old concept, most commonly used in military turbofans

The following schematic illustrates this further:
Image

And moreover in the SDRE indigenous jet-engine design and development realm, by the late 80s, GTRE had allready got the experience of upgrading one of their turbojets (GTX37-14U) to an experimental turbofan (GTX37-14UB).

Resulting Design Choice: So IMVVHO, and given the general backwardness of indigenous manufacturing engineering base back then (and in fact even now), GTRE folks took a conservative approach of upgrading a turbojet (GTX-35) to a turbofan design GTX-35VS (which later got called as Kaveri - and the core as Kabini).
They simply took a well thought-out risk mitigated approach of delivering a working turbofan (keeping in mind the dimensions of LCA) by migrating the only available turbojet (with similar thrust levels) which they understood inside-out (aka they themselves have designed and manufactured it).

And may I also add that any sensible design team, in an extreme naval-gazing and if-its-indigenous-it-must-be-worthless national culture of ours, would have done so.
So, most of the high-level design goals (BPR, OPR, TeT, SFC, Thrust-levels etc) are all enhancements/improvements of a turbojet and not that of a plain-sheet turbofan design. The low BPR design goal needs to be understood from that context.

Furthermore, in order to understand in detail the migration approach taken then, pls refer to one of my earlier posts (in response to a ramanaji's post then) in the LCAthread - here:

Reposting in full
maitya wrote:
ramana wrote: maitya, To add to your post if the choice was to be RD-33, thenit should have been the GTRE own turbojet which alteast they had full design control of. It was the requirement for the turbofan which was bleeding edge technology at that time that led the Kaveri down the river!

The plan all along was to prove the plane with a proven engine and later ingetrate the engine.

The SLCA should be named after Sleek Smitha
Absolutely - basically, trying to graduate from a 64kN class turbojet (GTX37-14U) to a 80 kN turbofan, and that too while being intrinsically linked to almost an ab-intio aircraft development program in the background of our very very poor industrial base, we aimed too high. Plus given our Orephus experience about an decade or so less back then, it certainly looks almost an unobtanium to aim for.

But that's all with the luxury of a hindsight of course.

As the contrasting theory can be, if GTRE had aimed for say a 10% dry and wet thrust creep (so 45kN to 49kN dry and 64kN to 70kN wet) in a 3 stage LP, 7 stage HP setup of the same turbojet, and be successful in say 2001/3 timeframe, GTRE would may well have been blamed for creating a "bulky, very underpowered and 2 gen less useless" engine.
People would have bayed for their blood for being too SDRE and navel-gazing in their outlook/planning.
(shiv, can always back this above claim of mine up by his piskological analysis of a desi mindset).

So IMHO, GTRE didn't frankly have any option but to aim for the Kaveri specs back then.
And they did try to de-risk it as much as possible by building,

1. first a turbofan version (GTX37-14UB) around very similar core-layout (3 LPC, 7 HPC, 1 HPT and 1 LPT) and achieving the baseline wet thrust level (IIRC 88kN was achieved, need to check though) by increasing the frontal area and with a modest BPR of 0.215. This ofcourse required playing around with the core airflow vol, essentially compensating for the inherent drop in airflow vol/mass due to the introduction of by-pass of trying to go from a turbojet to a turbofan.

2. then in GTX-35, going back to enhance/improve the baseline turbojet by trying to reduce the weight of the core by eliminating the 2 HPC stages (so 5 from 7), and trying to compensate with the inevitable drop in core airflow by increasing the Turbine Inlet Temperature and, to a some extent, by improving the combustor efficiency.
Of course, like any other turbojet, this even though may have given very close thrust parameters, wouldn't have been acceptable as is, on the dry and wet SFC counts.

So, when they decided to aim for GTX-35VS (which later got called as Kaveri - and the core as Kabini), they were basically trying to emulate the GTX37-14U to GTX37-14UB migration on GTX-35 (plus ofcourse other modern add-ons like FADEC, Flat rating etc).

GTRE most probably thought, they will be able to manage the drop in core-inflow vol/mass (from trying to introduce BPR to a turbojet design) by increasing the HPC stage number (from 5 to 6) - which IMVHO, was not a various ambitious thing to plan for, given their earlier history/experience of migrations.
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Re: Kaveri & aero-engine discussion

Post by vic »

Does the new tender specifications mean that GTRE has launched a enhanced Kaveri with same Kabini core but "New LP" for higher bypass and more thrust 75kn/110kn. Though this engine would be bigger in dia(??). I think that would be good idea. If we are getting adequate dry thrust on Kaveri then it means fundamentals are in place and we need to tweak the LP for a more powerful engine. This was also what Secma was offering. They wanted to use M88 core with a new LP but all the work was to be done in France.
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Re: Kaveri & aero-engine discussion

Post by SaiK »

per the tender, the dia specified appears to be for the inner core., and assuming if they have maintained the outer dia the same, then you can expect the an increase of lower bypass to slightly higher as said by many. but, we have no exact specs of the gaps - ie, actual volume in flow.
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Re: Kaveri & aero-engine discussion

Post by nachiket »

merlin and maitya, I have heard another reason for the low bypass ratio. To have a high bypass ratio without increasing the cross sectional area of the engine, the core needs to be smaller in diameter. GTRE did not have the technological expertise to design a core which would produce sufficient thrust and yet be smaller than the current one. A large core diameter meant that they could not increase the bypass ratio without increasing the engine cross-sectional area, which meant that the engine would not fit inside the LCA. Their inability to reduce the size of the core (without reducing thrust) is ultimately connected to inferior materials which necessitated lower maximum temperatures and pressure inside the core, and inexperience in design.

As an example just compare it to the F404. The Kaveri is actually wider in diameter than the F404 (910mm vs 889mm), yet the F404 has a bypass ratio of 0.34:1 compared to the Kaveri's 0.16:1. Just points to the huge technological gap that GTRE has to somehow overcome. I don't fault them for searching for foreign partners.
Last edited by nachiket on 16 Feb 2013 12:46, edited 1 time in total.
Pratyush
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Re: Kaveri & aero-engine discussion

Post by Pratyush »

After reading the last few pages of this thread, one simple question for all the gurus.

Is the Kavari ready to be flown as a regular engine for a regular jet fighter?
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Re: Kaveri & aero-engine discussion

Post by Yagnasri »

I guess considaring, but not fully understadning, the probelms reported here it may take some more time.
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Re: Kaveri & aero-engine discussion

Post by vina »

Shiv wrote:We will never know what the chief designers at GTRE did. Knowing the way Indian education works I think it is likely that GTRE's early work on design may have been based on paper/math calculations as to what may work rather than a slew of 3-4 experimental designs actualy constructed and tested. The former would have been cheaper and also would have given control to a nerdy guy who was good in college studies rather than a hands on type guy.
Well, it seems that Kaveri as is current is descended from some experimental projects back in the 70s which served as a test bed for some Kaveri concepts (Maitya seems to know more about it). The design choices were made keeping our limitations in mind back then. The state of art just move on since then and we are having to catch up.
I think the first engines were designed by trial and error and observing what failed rather than by hi-funda calculus, thermodynamics and fluid mechanics or whatever
Trouble is, it is 2013, and you cant design today's engines by trial and error alone ,without any of the calculus, thermodynamics and fluid mechanics. If linear approximations could suffice for the theory until the 70s, the jump in computing power and the field called computational fluid dynamics and modelling of everything means that you cannot do anything contemporary today without deep investments in those areas, which of course is really cutting edge. It takes time, but we are nearly there. Need to keep at it and since we seem to be over the hump, follow the route downhill to the solution.
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Re: Kaveri & aero-engine discussion

Post by shiv »

Pratyush wrote:After reading the last few pages of this thread, one simple question for all the gurus.

Is the Kavari ready to be flown as a regular engine for a regular jet fighter?
Anyone who goes by post count alone on this thread will think I am a guru which I am not. As far as my information goes, no serious problem cropped up in the flight trials so if we were in the 1960s I guess that someone might have been bold enough to put it on a fighter and give it a try.

I get the sense that it is almost there but there is currently no aircraft in our inventory that can use it and perform like a modern day fighter. We may have just re discovered what was known all along. You have to design a fighter for a known, proven engine. Or else you take a proven fighter which already has an engine and then design a new engine for it. India has twice attempted to design fighter and engine simultaneously. We failed both times and this is a lesson we cannot forget,

We will simply have to design a fighter (or UCAV) for the Kaveri. Kaveri needs to be refined using foreign help and finally tried out on the LCA, underpowered or not.
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Re: Kaveri & aero-engine discussion

Post by prashanth »

This article by a materials scientist at Rolls Royce describes the latest developments in gas turbine tech. It explains the process of manufacturing fan blades in some detail. Apparently, the turbine entry temperature they have achieved is about 1550C.
Got this link from wiki.

Pdf -5.2 mb
http://users.encs.concordia.ca/~kadem/Rolls%20Royce.pdf
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Re: Kaveri & aero-engine discussion

Post by Singha »

End 2013 the kaveri will be fitted one a tejas td . The two td engine bays were sized for kaveri and adapted to 404 later, while lsp and pv were not sized for kaveri. Ada has confirmed to media they will make the plane available.
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Re: Kaveri & aero-engine discussion

Post by NRao »

Singha wrote:End 2013 the kaveri will be fitted one a tejas td . The two td engine bays were sized for kaveri and adapted to 404 later, while lsp and pv were not sized for kaveri. Ada has confirmed to media they will make the plane available.
True. But the "Kaveri" in this case will be the one we have right now - as is - and proposed for some UAV.

Not to be confused with a potential Kaveri for the the LCA.
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Re: Kaveri & aero-engine discussion

Post by suryag »

PV1 is very similar to TD dimensions, because when they got money to build two TDs they were able to build one extra which became PV1. So i assume PV1 will have the same dimensions as TDs
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Re: Kaveri & aero-engine discussion

Post by pentaiah »

The predecessor of Kaveri was HJE2500 of the 1970s



HJE-2500 ETBRDC, HAL, INDIA:

HJE-2500 was the first turbojet engine designed and developed in India. The engine of 2500 lb (11.1 kN) thrust, developed by “Engine Design Bureau- EDB” of Hindustan Aeronautics Limited, was one of the most prestigious, indigenous engine development activities undertaken in India in the mid 1960s. HJE-2500 was developed for basic jet trainer aircraft, HJT-16 MK 2.

Engine Design Bureau- EDB subsequently renamed as Engine and Test Bed Research and Design Center (ETBRDC), started functioning in the year 1960. Mr. T.V. Vareed, recruited from Rolls Royce, England was instrumental in starting the engine design bureau in HAL. Initially, the task of the division was to design engines and engine accessories for the indigenous aircraft designed by the Aircraft Design Bureau (ADB), HAL.

Mr. Vareed, as chief designer, launched India’s first indigenous turbojet engine design project, the Hindustan Jet Engine (HJE-2500), along with other talented designers, Mr. R. Ramakrishnan, Mr. V. Govindan, Mr. N.H. Balakrishna, Mr. Gururaja Rao, Mr. Rama Reddy, Mr. Srinivasan, in the year 1960.

A prototype development of the engine was taken up by the team and the first run of the engine was successfully achieved in April 1965 at the Casuarina test bed, on a modified Pegasus piston engine test rig, near the present day BEML complex.

HJE-2500 Specifications
Year 1965 Mass Flow 45.2 lb (20.5 kg)/sec at 12,500 RPM
Type Turbojet SFC 1.11 kg/kg thrust/hr
Compressor Seven stage axial (Pressure ratio 4.2:1) Diameter 660 mm
Combustor Can-annular combustor with seven flame tubes Length 2160 mm
Turbine Single stage turbine Frontal Area 0.3 square meter
Takeoff thrust 2500 lb (11.1 kN) at 12,500 RPM Weight 585 lb (265 kg)

http://admirableindia.com/karnataka/hal ... jet-engine
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Re: Kaveri & aero-engine discussion

Post by SaiK »

I think we should focus on the capabilities and improving capabilities and walk towards maturity path, rather keep harping on we lacked this and that. How long our kids and future gen will accept that notion? GTRE needs pull up their sleeves and start asking these questions. For this the right men should head the state of affairs.
NRao
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Re: Kaveri & aero-engine discussion

Post by NRao »

pentaiah wrote:The predecessor of Kaveri was HJE2500 of the 1970s
I do not think it had any thing to do with the Kaveri effort. IIRC it was Bengali gentleman that they plucked from France (Snecma?) (if memory serves me right) (at around the same time they plucked a few from the US/Europe for the LCA effort). That gentleman was unceremoniously dumped - after which began the down fall of the Kaveri. It could have been a diff engine and not named the Kaveri itself. Will have to check a source and get back. Whatever, that effort was a fresh effort for sure.
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Re: Kaveri & aero-engine discussion

Post by Singha »

Some say sticking with the hal engine design bureau would have been a better outcome but due to some politics, it was entirely shut down and instead gtre came up.
SaiK
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Re: Kaveri & aero-engine discussion

Post by SaiK »

I would say no body is late in gas turbine business. GA and make our days while sunshine. prove it on smaller scale like home grown SCB/blisk and superior FADEC performance engine of 414/EJ tech nature, perhaps for the various jet trainers and a/cs.
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Re: Kaveri & aero-engine discussion

Post by chetak »

Del.

Duplicate post
Last edited by chetak on 17 Feb 2013 12:19, edited 1 time in total.
chetak
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Re: Kaveri & aero-engine discussion

Post by chetak »

chetak wrote:
Singha wrote:How does a jet engine start...how does the fan get spun initially to force air inside for combustion to start ?
Electrical start....usually a combination starter generator, mounted on the engine, turns the compressor, starts off as a starter motor fed by the aircraft battery or external power from (battery cart or a diesel powered generator called the Ground power unit)

Air start .......
Older military engines like the Rolls Royce Nene used a cartridge starter where an explosive cartridge was used to generate the burst of air to initially turn the compressor. This system is not so popular these days.
chetak
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Re: Kaveri & aero-engine discussion

Post by chetak »

Singha wrote:Some say sticking with the hal engine design bureau would have been a better outcome but due to some politics, it was entirely shut down and instead gtre came up.
Such was the power of DRDO but not any more :)
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Re: Kaveri & aero-engine discussion

Post by anishns »

^^^
Flight of the phoenix :-) had one of those engines
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