IAF Rafale News and Discussions - 26 May 2015

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shiv
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Re: IAF Rafale News and Discussions - 26 May 2015

Postby shiv » 23 May 2016 18:18

From what I hear from multiple sources there is no alternative to experience and hands on in engine building. I am no expert but what little general knowledge I have tells me that:

The math (physics) part dominates the design - the size of the engine face dictates the volume of air. The number of "stages" and diameter of the compressor dictate the amount the gas gets compressed; the fuel combustion and the compression dictates the temperature and pressure - and that pressure dictates the power of the engine and the speed at which the turbine turns - and the faster it turns, the faster the vanes at the front of the engine turn, pushing in more gas for compression and the engine RPM is in high thousands or tens of thousands of RPM.

Each row of turbine blades has dozens of blades. Each of those blades must be exactly the same size and shape or else the engine will soon vibrate and break apart at those high rotation speeds. And those blades - spinning so fast are subject to intense centrifugal forces as well has high temperatures and oxygen - a formula for corrosion - the average metal of a car body will corrode in minutes under such conditions.

So the machining and finish of each blade has to be perfect apart from each blade being made of a single crystal that is grown. And because there are so many parts - things going wrong with even one blade is fatal. Some hot parts of the engine may have blisks where a solid cylinder of metal has been cut into shape to have blades sticking out of a central hub. Again, material and machining must be perfect. And after all this if your original math/physics calculations about mass of air that needs to go through and temperatures is wrong (as happened for the Kaveri IIRC) the engine will not perform as expected.

Shaping and machining those blades and giving the final touches is skilled work by workers who need the skill to do it right. "transfer of technology" would also mean making workmen sit with older experienced workers watching how they do the final machining under the supervision of a boss who knows what works.

And after putting all this together the engine has to be tested to produce power under different conditions of temperature and airflow and should be able to run for hours on end. No "transfer of tech" will give anyone all this. This is hands on experience and experiencing failure - seeing what fails and what works and what needs to be done. For too long we on BRF have imagined that there is some magical tech transfer that is possible for engines. There isn't. Hands on and acceptance of failures and is the only way forward. This is cutting edge stuff. If it was easy everyone would be doing it.

Typically as Indians we have no clue about how complex a jet engine is. We think someone will give tech transfer and some will give us everything - but still things can go wrong and we will curse our own people as being bums and compare with GE/Snecma/RR . "Give it to Infosys. Give it to ISRO" etc. Sorry to rant - but I simply love this statistic: Nearly 100% of Indians in the US are graduates and I think 60% are postgraduates. In India we have only 4% postgraduates. that is a reflection of "general thick-thackness" in our society when it comes to technology. Like Congress party, surgery is what we need.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby ldev » 23 May 2016 18:23

Jewel in the crown: Rolls-Royce’s single-crystal turbine blade casting foundry

Great article. Read it in full as it details the hellishly complicated process of casting those single crystal blades used in the Rolls Royce Trent turbofans. Nobody is going to give India this level of technology. This has to be learnt by trial and error preferably with somebody who is experienced standing by you, but somebody who is part of "your team" and not a technology transfer counterparty!!

By Stuart Nathan 8th June 2015 8:30 am
An ancient form of metalworking is being used to create turbine blades for jet engines.

Casting is one of the oldest and most basic methods of metalworking. If you can make a fire hot enough to melt a metal, and manufacture a crucible to melt it in and a mould that can withstand the heat, you can cast complex metal forms; and we’ve been doing it for millennia. The oldest-known casting is a copper frog made 6,000 years ago in Mesopotamia. Many of the gleaming marble sculptures of Ancient Greece are in fact more recent Roman copies of originals that had been cast in bronze: the few surviving originals, such as the Riace Bronzes of Greek warriors found in the sea off Sicily, show the incredible sophistication and level of detail achieved by these long-dead masters of metals.

Yet this most ancient of skills is still in use today, and indeed is still being developed. Its most recent incarnation is arguably the most advanced procedure that has ever been undertaken in metals, and is vital for one of the emblematic activities of the modern world: routine air travel. It is to be found in the UK’s historic centre of metalworking, Sheffield, at Rolls-Royce’s Advanced Blade Casting Facility (ABCF), a facility purpose built near Sheffield University’s Advanced Manufacturing Research Centre in Rotherham.

The components the ABCF is producing are not ones that most people ever see: they are the turbine blades that are hidden away in the hottest part of jet engines. For from the decorative brilliance of Greek bronzes, they combine a utilitarian appearance with complexity of form and function and a jewel-like internal perfection: weighing only about 300g and small enough to fit in the palm of a hand, they are in fact perfect single crystals of a metal alloy whose composition has been fine-tuned over many years to operate in the hellish conditions of the fastest-moving part of a jet engine.

“Back at the birth of the jet engine, Sir Frank Whittle’s prototypes were made entirely of steel,” said Rolls-Royce chief of materials Neil Glover. “Steel is great for strength and surface hardness, but if you need high-temperature performance it isn’t actually very good; 450–500°C is about its limit.”

Its unsuitability led to a search for a more temperature-resistant material, and jet makers turned to nickel alloys. Relatively abundant, with large deposits in Australia, and low in price, nickel melts at 1,728K (1,455°C) and is resistant to corrosion – both valuable properties for components that function inside a jet engine. Even more important is its ability to form alloys, and the particular property of one of those alloys, a compound known as gamma-prime in which nickel combines with aluminium, to retain its strength at high temperatures. “In steel or even titanium, the strength rapidly drops off as you reach 40–50 per cent of the melting point,” Glover said. “Nickel alloys retain their strength up to 85 per cent of the melting point.

And engine manufacturers make full use of this property. Jet engines work by positioning turbine blades, which spin in the current of hot gases expanding out of the combustion chamber, on the same shaft as the compressor blades that force air into the engine at high pressure. So at the back of the engine, the low-pressure turbine blades, which operate in a gas stream that has cooled down somewhat, are on the same shaft as the large fan blades at the front of the engine, which accelerate air to generate the engine’s thrust. This shaft runs through the middle of the shorter, wider intermediate pressure (IP) shaft, which again has turbine blades at the back and compressor blades at the front. Outside this is the high-pressure shaft, which runs the compressor that forces air into the combustion chamber itself. The combustion chamber is annular, with an exit ring at the back controlling the flow of exhaust gases, and it’s here where the single-crystal blades are found. The gases, fresh from combustion, are at around 1,700°C; and the shaft spins at speeds in excess of 12,000rpm.

This means the blades operate in an environment several hundreds of degrees hotter than the melting point of the nickel alloy. To stop them melting, the metal must be cooled. This is done via two mechanisms: the blades are coated with a low-conductivity ceramic; and they are riddled with a complex, branching structure of internal channels. “Air is drawn from the HP compressor, routed through the core of the engine and into the root of the blades,” explained Glover.

“It passes through the cooling channels and exits through a myriad of holes in the surface of the blade, to create an envelope of cool air around the blade. So the metal is never above its melting point, even though the environment is. The cooling air isn’t actually that cool; it’s at about 600–650°C, but we have to take it from the hot core of the engine so it has enough pressure to get through the channels and out of the holes. It’s still enough to keep the blade temperature down to about 1,150°C.”

Heat is vital to jets; the hotter they can operate, the more energy they can extract from their fuel. This is the major point of competition between engine makers, so over the six decades jets have been in operation, forcing the temperature higher, and developing turbine blades that can withstand the heat, has been one of the most important technology races in the sector. It’s been a gradual process, Glover said, culminating in the development of single-crystal blades in the late 1980s.


The single-crystal structure isn’t intended to cope with temperature, however; it’s to make the blades resistant to the huge mechanical loads that result from their rotational speed. “Every single blade extracts power from the gas stream equivalent to a Formula One car engine,” Glover said. “And the centrifugal force on them is equivalent to the weight of a double-decker bus.

Normally, metals are composed of many crystals – ordered structures of atoms arranged in a regular lattice, which form naturally as the metal cools from a molten state. These crystals are typically of the order of tens of microns in size, positioned in many orientations. At high temperatures and under strain, the crystals can slide against each other, and impurities can diffuse along the boundaries between the grains. This is known as creep, and it badly affected early turbine blades, which were forged from steel and later nickel bars.

The first stage in development was to get rid of any grain boundaries at right angles to the centrifugal loading, which led to the development of blades that were cast so the metal crystals all ran from top to bottom. Later, this was optimised further by casting single crystals, with no grain boundaries at all. It’s a highly complex process: not only must the blades be cast with the internal cooling channels already in place, but the crystals are not homogeneous. Rather, zones of different composition and crystallographic structure exist within the blade.

“You can think of nickel superalloys like these as being like composites,” said Rolls-Royce’s aerofoil turbine materials technologist Neil D’Souza. “It’s a mixture of two phases, one of which – gamma-prime – gives rise to the sustained increase in strength at high temperature.”

When it crystallises, nickel forms a structure known as face-centred cubic (fcc); each cube has a face with five atoms, one at each corner and one in the middle. When alloys are made, generally the atoms just swap in and out of the fcc lattice. But under the right conditions, aluminium and nickel combine in such a way that nickel goes to the centre of the faces and aluminium to the corners. This is known as a precipitate; it forms islands of greater order within the bulk of the alloy, about half a micron in dimension, packed closely together in a rectilinear formation. Because the size of the lattices of the precipitate and the less ordered bulk alloy are almost identical, they are all part of the same crystal.

“You could imagine building a ball and stick lattice model,” said Glover. “In the bulk alloy, you’d place the balls representing the components of the alloy, about 10 different elements including nickel, aluminium, chromium, tantalum and titanium, pretty randomly, and when you got to the gamma-prime precipitate you’d put in this ordered arrangement of aluminium at the corners and nickel in the middle. It’s all on the same regular lattice, oriented the same way, so it’s all the same crystal, but you have these much stronger regions where there’s the array of gamma-prime precipitate.”

But this doesn’t just happen naturally. To make the blades, the first stage is a ceramic ‘core’, of the form of the tortuous internal cooling channels. Wax is injected around this to form the shape of the aerodynamic blade, plus several other features that assist in the casting process. Platinum pins are inserted to support the core inside the wax; then the form is ‘shelled’ by coating it in an slurry of alumina-silicate material to form a ceramic coat. Several more coats of different compositions are applied and then the wax is melted out to leave a void in the shape of the blade. This is investment or ‘lost-wax’ casting, the same technique those Ancient Greek sculptors used to make the Riace Bronzes.

Molten metal is then poured into the mould, which is placed inside a furnace to keep the metal molten. At the base of the mould is one of the additional casting features: a helical structure about the same shape as three turns of a standard corkscrew. Known as the pigtail, this is attached to a plate that is cooled by water. Once filled, the mould is slowly withdrawn from the furnace into a cooler chamber. The metal starts to solidify at the chilled plate, and crystals begin to grow into the pigtail. The crystals grow in a straight line in the direction that the mould is being withdrawn, but because of the pigtail’s twisted shape, all but the fastest-growing crystals are eliminated. Only a crystal with the correct orientation emerges into the blade mould proper, and the gradual withdrawal of the mould ensures the crystal continues growing through the melt into the rest of the space.

The formation of the vital precipitates results from careful control of the external temperature and from the design of the mould; those multiple layers of ceramic determine how fast the heat from the molten metal can dissipate, and this provides the extra finesse to achieve the required internal structure. The platinum pins holding the core in place diffuse into the alloy without affecting its properties.

Once solidified, the casting is removed from the mould and the first of some 20 processes begins to prepare it for assembly into an engine. First, the ceramic cores are dissolved away with caustic alkalis. Then the extra features for casting are machined away. The holes for the cooling air to escape are drilled using electrical discharge machining, which forms the required hole geometry to direct the air to the points where it is needed. Finally, the blade receives its insulating ceramic coating by electron-beam plasma deposition.


The ABCF in Rotherham concentrates on components for large civil airliner engines because, with the advent of aircraft such as the Airbus A350 XWB, for which Rolls-Royce has developed the Trent XWB engine, this is where the company sees its main growth coming from.

Costing some £110m, the ABCF was built to automate as much of the production process as possible. “Single-crystal casting is expensive, and many parts of the process have traditionally been very hands-on,” said ABCF manufacturing manager Steve Pykett. “Our people are fantastically skilled, but they’re human, and no human is going to produce the same quality of work at the end of a shift as they do at the beginning.”

The production of the wax assembly is a good example of this philosophy. “You’ll always find a wax room at an investment casting foundry,” Pykett said. “It requires hand-eye co-ordination and dexterity to make the wax form, but that doesn’t deliver consistency.”

Working with the Manufacturing Technology Centre near Coventry, Rolls-Royce developed an automated system to hold the ceramic core, inject wax, pin the core in place and conduct the assembly process. “It used to take a whole shift to make an assembly; now it takes an hour,” Pykett said. “But time was not the main driver here. We now know that we have consistent product coming out of the wax process, whatever the time of day, and that gives us a solid platform from which we can reduce cost.”

Some other processes have also been automated, including the dressing operation to remove the sacrificial features of the casting. The blades then go into inspection, where Rolls-Royce has replaced five processes with two. The castings are then shipped to another plant at Crosspointe, Virginia, for further machining of the features that will allow them to be attached to their discs in the engine, and for drilling of the cooling holes; they come back to a plant in Annesley, Nottinghamshire, for coating.

“This process is so complex, with precise control of temperatures and materials handling to manage, virtually atom by atom, how the blades are formed,” said casting manufacturing executive Mark Hulands. “What we’ve done is to transfer some of the skills in making these components from the manufacturing engineers on the line to the process developers,” Hulands said. “And that doesn’t mean we’ve de-skilled. Our engineers still need to be highly skilled to keep the processes running smoothly, but they’re different skills and we’ve improved the consistency so we can drive costs down.”

shiv
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Re: IAF Rafale News and Discussions - 26 May 2015

Postby shiv » 23 May 2016 18:35

^^thanks ldev. That article is a keeper because it is written for the lay person with some basic school level science awareness

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby ldev » 23 May 2016 18:45

^^
Shiv, it's all about material science, composition and design. I've no idea where/who in India has the greatest domain experience in material sciences, but they are the guys who should be working on this at least initially.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby ldev » 23 May 2016 19:02

To give an idea of the small size of the single crystal blades described in the article posted by me above, here is an image. That small blade extracts as much power from the exhaust stream of a jet engine core as a Formula 1 car produces, about 1200 hp. And it is capable of withstanding a centrifugal force equal to the weight of a double decker bus i.e. about 12 tons.

Image

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Gagan » 23 May 2016 19:23

And they have pores and circulating channels to keep the blade itself cool enough! Talk about micro engineering!

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby member_20292 » 23 May 2016 23:12

We have some of the best material scientists in the world, in India. However, a lot of them have taken to doing other , more worthy things, like figuring out how to make more people click on ads on cellphones

Out of a batch of 40 of the people from my II Chai . Four of us went for PhDs in good universities in the Etat Unis. Three of us finished and are working in Mat Sci. The rest all went to making people click on ads on cellphones!

So - we dont have good aero engines because we dont have a good program. The Kaveri is a good program, if DRDO wants to give it to someone with deep pockets, like Tata, they should. Its a slow burn process. ROI is unclear on the investment. Much easier to make people click on ads on cellphones :)

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Y. Kanan » 24 May 2016 08:27

shiv wrote:From what I hear from multiple sources there is no alternative to experience and hands on in engine building. I am no expert but what little general knowledge I have tells me that:

The math (physics) part dominates the design - the size of the engine face dictates the volume of air. The number of "stages" and diameter of the compressor dictate the amount the gas gets compressed; the fuel combustion and the compression dictates the temperature and pressure - and that pressure dictates the power of the engine and the speed at which the turbine turns - and the faster it turns, the faster the vanes at the front of the engine turn, pushing in more gas for compression and the engine RPM is in high thousands or tens of thousands of RPM.

Each row of turbine blades has dozens of blades. Each of those blades must be exactly the same size and shape or else the engine will soon vibrate and break apart at those high rotation speeds. And those blades - spinning so fast are subject to intense centrifugal forces as well has high temperatures and oxygen - a formula for corrosion - the average metal of a car body will corrode in minutes under such conditions.

So the machining and finish of each blade has to be perfect apart from each blade being made of a single crystal that is grown. And because there are so many parts - things going wrong with even one blade is fatal. Some hot parts of the engine may have blisks where a solid cylinder of metal has been cut into shape to have blades sticking out of a central hub. Again, material and machining must be perfect. And after all this if your original math/physics calculations about mass of air that needs to go through and temperatures is wrong (as happened for the Kaveri IIRC) the engine will not perform as expected.

Shaping and machining those blades and giving the final touches is skilled work by workers who need the skill to do it right. "transfer of technology" would also mean making workmen sit with older experienced workers watching how they do the final machining under the supervision of a boss who knows what works.

And after putting all this together the engine has to be tested to produce power under different conditions of temperature and airflow and should be able to run for hours on end. No "transfer of tech" will give anyone all this. This is hands on experience and experiencing failure - seeing what fails and what works and what needs to be done. For too long we on BRF have imagined that there is some magical tech transfer that is possible for engines. There isn't. Hands on and acceptance of failures and is the only way forward. This is cutting edge stuff. If it was easy everyone would be doing it.

Typically as Indians we have no clue about how complex a jet engine is. We think someone will give tech transfer and some will give us everything - but still things can go wrong and we will curse our own people as being bums and compare with GE/Snecma/RR . "Give it to Infosys. Give it to ISRO" etc. Sorry to rant - but I simply love this statistic: Nearly 100% of Indians in the US are graduates and I think 60% are postgraduates. In India we have only 4% postgraduates. that is a reflection of "general thick-thackness" in our society when it comes to technology. Like Congress party, surgery is what we need.


Slightly off topic but advances in 3D metal printing (such as laser sintering) may prove to be something of a great equalizer, allowing nations that traditionally suck at metallurgy to finally produce reliable advanced jet engines of their own. This could end up being our saving grace.

3D metal printing isn't a panacea but could allow India to produce many of the finely machined components of a modern jet engine that we currently find very hard or impossible to produce consistently.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Kersi D » 24 May 2016 09:16

shiv wrote:From what I hear from multiple sources there is no alternative to experience and hands on in engine building. I am no expert but what little general knowledge I have tells me that:

The math (physics) part dominates the design - the size of the engine face dictates the volume of air. The number of "stages" and diameter of the compressor dictate the amount the gas gets compressed; the fuel combustion and the compression dictates the temperature and pressure - and that pressure dictates the power of the engine and the speed at which the turbine turns - and the faster it turns, the faster the vanes at the front of the engine turn, pushing in more gas for compression and the engine RPM is in high thousands or tens of thousands of RPM.

Each row of turbine blades has dozens of blades. Each of those blades must be exactly the same size and shape or else the engine will soon vibrate and break apart at those high rotation speeds. And those blades - spinning so fast are subject to intense centrifugal forces as well has high temperatures and oxygen - a formula for corrosion - the average metal of a car body will corrode in minutes under such conditions.

So the machining and finish of each blade has to be perfect apart from each blade being made of a single crystal that is grown. And because there are so many parts - things going wrong with even one blade is fatal. Some hot parts of the engine may have blisks where a solid cylinder of metal has been cut into shape to have blades sticking out of a central hub. Again, material and machining must be perfect. And after all this if your original math/physics calculations about mass of air that needs to go through and temperatures is wrong (as happened for the Kaveri IIRC) the engine will not perform as expected.

Shaping and machining those blades and giving the final touches is skilled work by workers who need the skill to do it right. "transfer of technology" would also mean making workmen sit with older experienced workers watching how they do the final machining under the supervision of a boss who knows what works.

And after putting all this together the engine has to be tested to produce power under different conditions of temperature and airflow and should be able to run for hours on end. No "transfer of tech" will give anyone all this. This is hands on experience and experiencing failure - seeing what fails and what works and what needs to be done. For too long we on BRF have imagined that there is some magical tech transfer that is possible for engines. There isn't. Hands on and acceptance of failures and is the only way forward. This is cutting edge stuff. If it was easy everyone would be doing it.

Typically as Indians we have no clue about how complex a jet engine is. We think someone will give tech transfer and some will give us everything - but still things can go wrong and we will curse our own people as being bums and compare with GE/Snecma/RR . "Give it to Infosys. Give it to ISRO" etc. Sorry to rant - but I simply love this statistic: Nearly 100% of Indians in the US are graduates and I think 60% are postgraduates. In India we have only 4% postgraduates. that is a reflection of "general thick-thackness" in our society when it comes to technology. Like Congress party, surgery is what we need.


JET ENGINE

I may have written about this incident before but I am tempted to put it down again. Many years ago I visited the stall of EUROJET during one of the DEF EXPO. As usual I just trolled and listened to all the talk. Then I started my questions.

I asked the gentleman at the stall "If EUROJET were to develop any entirely new jet engine from the scratch, without considering any previous "cores" what would it cost and how much time would to take to develop it" Sounds familiar eh.......

The gentleman laughed. He said "it is so expensive and time consuming to develop a new engine that no one would ever do it. (except some SDRE !!!)

Then he said that if EUROJET (or any major jet engine manufacturer like GE / Pratt & Whitney / Rolls Royce / Snecma ) were to develop a entirely new jet it would cost at least Euro 5 billion and take at least 5 years. By developing they would be making a few prototypes and testing them all over. No production related costs at all.

At today's rate say Euro 1 = Rs 75, the development costs would be Rs 37,500 crores !!!!!!!!!!!!!!!

And how much have we spent on Kaveri program ? Rs 3,750 crores ????

A major jet engine manufacturer would take about 5 years to develop a new jet engine. These manufactures have millions of man hours of experience in terms of physics, maths, material science, combustion, fluid mechanics, CFD modelling, structrural design, FEM design and what-not.


Shiv. How many jet combat aircraft, right from 1940s - 1980s, had a premature retirement because they were under-powered and a suitable engine was not ready / available ? Quite a few !!! Most British jets fighters were under-powered except English Electric Lightening, but again the after burning RR Avon was a fuel guzzler and Lightening had very short legs. The hawker Hunter and definitely Gloster Javelin could have been more effective with a better engine.

Let us accept the inevitable
Jet engine is a state-of-art technology.
We cannot buy it.
Nobody will "give" it to us.
Nobody will sell it to us.

WE HAVE TO GO THROUGH THE LEARNING PANGS. THERE ARE NO SHORT-CUTS.

We go through this cycle or we keep buying for ever.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby svinayak » 24 May 2016 10:26

Kersi D wrote:
A major jet engine manufacturer would take about 5 years to develop a new jet engine. These manufactures have millions of man hours of experience in terms of physics, maths, material science, combustion, fluid mechanics, CFD modelling, structrural design, FEM design and what-not.



WE HAVE TO GO THROUGH THE LEARNING PANGS. THERE ARE NO SHORT-CUTS.

We go through this cycle or we keep buying for ever.

India has to spend $5B and there is no short cuts.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby brar_w » 24 May 2016 14:01

I think the Eurojet person was a bit optimistic on the timeframe. Developing a new, clean sheet engine for military application is a decade + affair. In fact form taking something that is a concept, to fielding it as a reliable, fully developed and tested product can take up to 15 years. Over the years, as combat aircraft designers have matured and as designers have learnt form the previous generations, the greatest level of system risk is attributed to propulsion...more than anything else.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Austin » 24 May 2016 14:20

ldev wrote:Great article. Read it in full as it details the hellishly complicated process of casting those single crystal blades used in the Rolls Royce Trent turbofans. Nobody is going to give India this level of technology. This has to be learnt by trial and error preferably with somebody who is experienced standing by you, but somebody who is part of "your team" and not a technology transfer counterparty!!


HAL Chairman mentioned they already have SCB technology via AL-31FP program

http://www.thehindubusinessline.com/bli ... 460500.htm
"As HAL will do 80 per cent of the manufacturing, it will acquire new technologies like the directionally solidified blades, which will give us the technology for the future engines. Similarly, from the Sukhoi (Su-30 fighter deal) we acquired the single crystal blade technology, which will be the basis for all future turbine blades. This way, we get to master these technologies and meet our own requirements and exports, which is the thrust at HAL," Mr Mohanty said.

"The aircraft engine has single crystal blades which are capable of withstanding very high temperatures. Considering that the aircraft is huge and has to operate in hot conditions, and its twin engines have the 11,500kg thrust each, the single crystal blades ensure that the thrust remains optimum. The Russians have given this technology to us for the first time."

http://forum.keypublishing.com/showthre ... ost1471619

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby DexterM » 24 May 2016 14:32

Austin, I may be wrong but imvho directionally solidified is not the same as the latest generation single crystal blade technology that even Midhani has.
Our basic problem is not with acquiring the tech (that is already lab proven), but in mass scale manufacture at the consistent quality specified.
PS: You have linked to a 2003 article - which has been followed by many others that said the Russians did not come good on the early promises, but it didn't matter eventually.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Austin » 24 May 2016 14:42

DexterM wrote:Austin, I may be wrong but imvho directionally solidified is not the same as the latest generation single crystal blade technology that even Midhani has.
Our basic problem is not with acquiring the tech (that is already lab proven), but in mass scale manufacture at the consistent quality specified.
PS: You have linked to a 2003 article - which has been followed by many others that said the Russians did not come good on the early promises, but it didn't matter eventually.


The Directionally Solidified Blade is for HJT engine and HAL does makes SCB and Directionally Solidified blade

From Offical HAL Press 2014

http://hal-india.com/Air%20Chief%20Calls/ND__85

The Division presently has state of the art facilities for manufacturing 4th generation aero engines, which include, Robotized TIG Welding (Manned Chamber Welding), Electron Beam Welding, Detonation Coating, Hot Isostatic Pressing (HIP), Isothermal Forming, Cold Rolling of Blades, Ion Nitriding, Alphatization and a battery of CNC machining centers. The Division has also mastered critical technologies for manufacturing Single Crystal Blades and Directionally Solidified Blade casting

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby ldev » 24 May 2016 15:56

^^
All that having the scb "technology" for the AL-31 engines and the "directionally solidified technology" for the Hawk engines means IMO is that HAL can produce "those specific engines". Again, what is being produced from metal and what components are still imported is opaque.

Truly absorbing that technology means the ability to learn from that technology "given" to HAL, and having the ability to design a clean sheet engine. That translates into a group of engineers in HAL/GTRE having true domain experience and had this truly been the case with the technology that Russia supposedly provided way back in 2003 and the technology made available with the Hawk production line, then the Kaveri program would not have been wound up 10+ years later.

It always comes back to "TOT" in the Indian context being defined as the "ability to assemble that specific product" and go in for a higher level of TOT when the West/East/Russia go on to the next level of technology. That can at best be described as manufacturing expertise for a specific product and cannot be described as technology IMO.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby JayS » 24 May 2016 17:24

brar_w wrote:I think the Eurojet person was a bit optimistic on the timeframe. Developing a new, clean sheet engine for military application is a decade + affair. In fact form taking something that is a concept, to fielding it as a reliable, fully developed and tested product can take up to 15 years. Over the years, as combat aircraft designers have matured and as designers have learnt form the previous generations, the greatest level of system risk is attributed to propulsion...more than anything else.


I also thought $5B/5yr was on lower side for clean sheet design even for the 'Big Three'. Min 2 yrs needed just for testing and Certification, using about 20-30 engines. A long lead time of over 2 year for a lot of components mean, that if you find an issue it takes min 2 years to get rectified in many instances. So iterations take quite a while. Even the seasoned manufacturers take time to stabilise production of components. A variation of existing engine can be done in 5yrs perhaps, but clean sheet design definitely would take more time.

And when we say "by OEMs like EuroJet, RR, GE, PW" we are implying that they will be using their already well established design processes and manufacturing processes, leveraging decades of testing data and all that. A newbie has to first create all these supporting structure from ground up. This itself takes more than a decade to come up in proper shape. Its said that you are always faster when you do it for second time. Because by then you have the ground work laid up and you can do things much faster. I hugely respect what GTRE has achieved in whatever meagre funding, lack of motivation, thankless job, rubbish politics and lot of freeloaders piggybacking the hardworking guys and so on. But as a country, India still lacks in the most crucial part of the whole story and that's the Manufacturing. I would say designing an engine is far more easier than making one, and making one which flies reliably over decades. We need to start making Kaveri ASAP. There will be many more issues coming up during manufacturing that the designers didn't even consider in their wildest dreams. And another thing we need to learn about it MRO. A lot of new things are coming up in this field. I was amazed to see a simple idea of keeping track of how many hours the jet engine has flown and under precisely which operating conditions can help increase its operational life significantly. Its a kind of solution we can easily implement given our ITvity prowess. But we need Kaveri up and running for that first. In nutshell we have taken fair strides in designing a jet engine, but we still lack by miles in making one and operating it reliably.

Y. Kanan wrote: Slightly off topic but advances in 3D metal printing (such as laser sintering) may prove to be something of a great equalizer, allowing nations that traditionally suck at metallurgy to finally produce reliable advanced jet engines of their own. This could end up being our saving grace.

3D metal printing isn't a panacea but could allow India to produce many of the finely machined components of a modern jet engine that we currently find very hard or impossible to produce consistently.

I agree its a great equaliser for a country like India, if we can sink in some good mullah on this NOW!!
One crucial problem design engineers face wrt 3D printed parts is they don't know how to analyse them with the confidence they can today analyse normal metal components. Reliable material data and engineering analysis methodology is yet to catch up. This is one aspect which is holding back proliferation of 3D printed parts apart from the manufacturing technology itself.

Austin wrote:
The Directionally Solidified Blade is for HJT engine and HAL does makes SCB and Directionally Solidified blade
.

I highly doubt HAL can make SCB for any engine other than AL-31FP. (would love to be proved wrong on this one) And DMRL SCB tech need some more time to industrialize. I am not sure how much efforts are being put into it. I guess HAL does have a lot of knowledge of manufacturing SCB, DMRL should have good understanding of the know-why. Both the parties should be working together to industrialize SCB for Kaveri.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Austin » 24 May 2016 21:35

I think SCB technology that HAL mastered is specific to AL-31 , scb for Kaveri when they develop can't be used on Al-31 or M88 or vice verse these materials composition process and manuf are engine specific and can't be cross polinated , hal is owner of these tech and not gtre

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby JayS » 24 May 2016 22:29

^^ What engine specific things are there in SCB tech anyway which take significant efforts to surmount?? My thinking is: Its basically a casting process. If you know how to do it properly, you should be able to make blades for any engine, with little efforts. AL-31FP already has fairly advanced SCB, which should be good enough for Kaveri.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Karan M » 24 May 2016 22:55

Austin wrote:I think SCB technology that HAL mastered is specific to AL-31 , scb for Kaveri when they develop can't be used on Al-31 or M88 or vice verse these materials composition process and manuf are engine specific and can't be cross polinated , hal is owner of these tech and not gtre


Right
HAL got DS for Adours and SCB for AL-31FP, neither of which can be applied to Indian blades & hence we have to do everything inhouse.
DMRL cracked DS sometime back & then SCB for protos. Series production is another issue altogether.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Prem » 25 May 2016 09:03

Rafale deal: France rejects bank guarantee, awaits India’s reply

http://indianexpress.com/article/india/ ... MTYbg.dpuf

[quote]The initial French offer for the 36 fighters made by Dassault Aviation was for around Euro 10.5 billion, following which the Indian side asked for a 30 per cent cut. The latest offer, made in the French minister’s letter, is of around Euro 7.8 billion, said sources.Days before the letter was sent, the French side had rejected an Indian request for a sovereign guarantee or a bank guarantee for the deal, and instead offered to provide a “comfort letter” from their prime minister.As reported by The Indian Express on March 14, the law ministry had raised objections over France’s refusal to provide any bank guarantees. Asked about Le Drian’s letter, the defence ministry said it does not comment on ongoing negotiations between two governments.Sources said there was “a significant difference” between the two offers. The original offer included a ten-year product support period, which has been brought down to five years, they said. The latest figure also does not include the cost of setting up infrastructure at two airbases for two Rafale squadrons, said sources/quote]

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Philip » 25 May 2016 09:57

So what's the big difference? 5 years less support guarantee and who knows what costs for setting up the infrastructure at bases with OEM eqpt. which will also cost an arm and a leg. When one examines the MKI situ in comparison,there will be no such extra costs at all. Time to pack the Rafale into its hangar at dassault.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Lalmohan » 25 May 2016 13:06

french are in a relatively strong position, defence order books are full and there is a production backlog
they can take their time
we cannot...

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby DexterM » 25 May 2016 14:35

nileshjr wrote:^^ What engine specific things are there in SCB tech anyway which take significant efforts to surmount?? My thinking is: Its basically a casting process. If you know how to do it properly, you should be able to make blades for any engine, with little efforts. AL-31FP already has fairly advanced SCB, which should be good enough for Kaveri.

I think it is the alloy that folks are talking of. Casting process is difficult but we've already lab proven it.
Again, might be wrong.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Arunkumar » 25 May 2016 15:02

With All defence deals signed in 10 year UPA rule under scanner, especially the europeon ones things dont look bright for Rafale. With DM parikkar stated confidence to substitute WASS blackshark torpedo with hitherto unnamed one, I have a feeling something similar might be in store for this one.
The recent joy ride by ACM in Tejas was kind of mahua moitra type signal sent to french.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby kit » 25 May 2016 15:09

Wonder how much the Rafale would be able to successfully operate in an airspace protected by the S400 Triumph

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Aditya_V » 25 May 2016 15:09

So HAL has started SCB for SU-30 only in 2014, so they probably have a handle on the Tech only now, so GTRE probably have access only recently and it will take a few years to develop the engine if we have have the necessary wind tunnels and Test bed flying aircraft in India. I don't think we will ever develop and engine if testing team has to go to Russia every-time.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby nits » 25 May 2016 16:24

Jhujar wrote:Rafale deal: France rejects bank guarantee, awaits India’s reply

http://indianexpress.com/article/india/ ... MTYbg.dpuf

The initial French offer for the 36 fighters made by Dassault Aviation was for around Euro 10.5 billion, following which the Indian side asked for a 30 per cent cut. The latest offer, made in the French minister’s letter, is of around Euro 7.8 billion, said sources.Days before the letter was sent, the French side had rejected an Indian request for a sovereign guarantee or a bank guarantee for the deal, and instead offered to provide a “comfort letter” from their prime minister.As reported by The Indian Express on March 14, the law ministry had raised objections over France’s refusal to provide any bank guarantees. Asked about Le Drian’s letter, the defence ministry said it does not comment on ongoing negotiations between two governments.Sources said there was “a significant difference” between the two offers. The original offer included a ten-year product support period, which has been brought down to five years, they said. The latest figure also does not include the cost of setting up infrastructure at two airbases for two Rafale squadrons, said sources/quote]


And what does Comfort Letter mean... what is its validity in eyes of Law. i think comfort is only for French to milk some good money from this deal :cry:

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Gagan » 25 May 2016 17:01

I guess the french are afraid GoI will encash the bank guarantee if a corruption scandal comes to fore.

They are behaving like my neighbourhood sabzi-wala. He will keep one hand on his sabzi, until he has verified that the note given to him is genuine in the sunlight... Just being insecure and petty.

The french will most likely lose the Rafale contract. All these things are building up towards a US airplane assembly line being set up in India.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Philip » 25 May 2016 17:19

We will most probably see more MKIs acquired and :LCA production ramped up,plus a new fighter,a fight between the new Gripen and the F-18. Here,costs again will be vital.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby kit » 25 May 2016 17:22

don't think any sane business man would sink billions on a deal of this magnitude without any guarantee !! ..it would probably come back to bite

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Lalmohan » 25 May 2016 19:45

typhoon camp has been a bit quiet of late...

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Karan M » 25 May 2016 23:49

kit wrote:Wonder how much the Rafale would be able to successfully operate in an airspace protected by the S400 Triumph


Tactics, tactics, tactics.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Karan M » 25 May 2016 23:50

Lalmohan wrote:typhoon camp has been a bit quiet of late...


If we can't afford the Rafale, how can we afford the EF... :oops:

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Lalmohan » 26 May 2016 01:33

depends on the deal, and who is hungrier to sell

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby RoyG » 26 May 2016 01:50

They are playing hardball too. I think we'll win out tho.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby srai » 26 May 2016 03:56

None of the MMRCA contenders will be chosen at the end. This process will drag on for few more years. Anyone thinks they can get in a new line would need to wake up ;) Just think about how long it will take to negotiate ToT, 50% Offsets, license assembly, infrastructure setup and lifecycle support costs along with weapons and customizations. Does anyone think that it will happen in a year or two???

By then, LCA Mk.1/A production would be in full force along with additional orders for Su-30MKI. In the near future FGFA, if differences can be worked out, will also be joining the fleet. LCA Mk.2 will also be joining around that time. IMO, the urgency for "medium" category buy at-any-cost is an artificially created one. (Note: it was a real one back in 2000.) But 16-years later, there are other more sensible options available immediately and in the near future. It may not be "ideal" but it will be a more realistic one that fits in with budget and priorities.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby kit » 26 May 2016 10:13

I think the very fact that the French are not providing bank guarentees mean that they are not playing this deal straight
If it was a straightforward one no one would have had any issues

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Philip » 26 May 2016 10:33

Advice from a top journo on the Raffy issue.
We should stick to the Russians. The performance of their aircraft in Syria has left Americans and others gaping, as has the operations of their forces on the ground. Putin has put everything behind the regeneration of the Russian armed forces, and the results are showing.

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby member_29341 » 26 May 2016 12:50

I think the way this works is that the Frogs will have to pay for Bank guarantees, even if the risk is low. This is the cost they may want to factor into the overall deal cost

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Re: IAF Rafale News and Discussions - 26 May 2015

Postby Kersi D » 26 May 2016 13:14

Philip wrote:Advice from a top journo on the Raffy issue.
We should stick to the Russians. The performance of their aircraft in Syria has left Americans and others gaping, as has the operations of their forces on the ground. Putin has put everything behind the regeneration of the Russian armed forces, and the results are showing.


Natasha at worrk !!!!


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