Kaveri & Aero-Engine: News & Discussion

JayS · Post by **JayS** » 15 Dec 2017 10:36

Rakesh wrote:We in India, don't care. We are happy with F404 tech Good enough is good.

srai & ArjunPandit: Just a FYI....the M88 and the EJ200 are both state-of-the-art and modern engines. The fact that the M88 and EJ200 are F404 era tech is just another unbstantiated claim that has no merit. Otherwise provide the evidence that they are. As you are well aware, both engines power the Rafale and Eurofighter Typhoon. Both aircraft that passed the technical evaluations in the original MMRCA contest. And you are aware, that the F-16 and F-18 both did not make the cut.

At the end of the day, India will have to invest in her own R&D in engine tech. But partnering with Snecma and Rolls Royce is a very good start. License producing the F414 in India is a very good move as well. Ignore the naysayers. They are there at every turn in life.

Arguably, EJ200 is ahead of M88 and F404 from pure technology perspective. The proposed (around 1999 IIRC for Rafale) M88 upgrade version that never happened would have rivalled EJ200 and F414.

Cybaru · Post by **Cybaru** » 16 Dec 2017 07:40

The EJ200 has a thrust vectoring working set as well. Plus the stage 2 enhancements put the EJ2XX close to 78KN dry and 120KN reheated. If they are pushing for these specs, nothing like it. It can replace many a engine in IAF inventory.. There are exciting possibilities to this one (LCA, AMCA, maybe even the MKI)

Rakesh · Post by **Rakesh** » 18 Dec 2017 21:06

Post by BRF Member csaurabh. Originally posted by him in the Single Engine thread. But I moved it here.

----------------------------------------------------------------------------

Posting a reply from a Chinese person on quora. They seem to really get it.

I see our Indian friends often underestimate how much it takes to make an engine. We Chinese are often laughed at. Let’s put it this way, how much did the F-35 costs to make? Around $600 billion dollars, maybe a trillion dollars. A Chinese J-20 costs around the same at more than $110 million each. When we see India asks for technology transfer from other countries, we scratch our heads. When India’s military budget is $50 billion, you can’t be offering nearly what it costs. There is a reason why only wealthy countries are able to make jet engines. For China, it took us 50 years at least. We started accumulating knowledge before we can even test or make it. Rocket engines last only a few minutes, they are not turbo fan engines. They have to last thousands of hours. The US has a century of experience. When building an engine, the hard part is…you are not just building an engine…you are trying to build one of the best engines the world has ever known, for it to qualify to be on a 5th gen jet. A single part like the turbo fan takes a whole ecosystem of matured industry. A fighter jet is the combined science and industry of an entire country. An engine, takes at least 10 years to test, even if you are Rolls Royce or General electric.

It is also an art form. Think of a Ferrari, is a Ferrari just technology? Indian politicians often want to take credit for an achievement. India, I am sorry to say, have made great mistakes in strategy. Most Indians do not know that your politicians lie to you. You didn’t make the engines on the Brahmos, nor do you have the technology for rockets, nor the Mars orbiters, nor did you absorb tech from making the Sukhoi. They are all foreign owned, assembled in India. A country fully supported by the US, Israel, could not make engines for a big drone. India’s method wasted valuable time and you pretty much have to start from zero. Think of it, how could you have built all that when you have no infrastructure to support it? Nor a testing facility? Nor funding for such mammoth R&D? This is difficult to accept, I know. But you have to have infrastructure first. The Tejas took 40 years because the testing facility is in Europe. Most of the kit parts are made outside India. You have to developer your economy first. Even an advanced economy like Japan has no such capability since they are forbidden to do such research after WW2. Which brings me to another point. The most important one. The west are very sensitive on this type of research. They actively go around the world stopping countries from doing this type of research. They would come and pretend they are helping, but in reality sabatoging your project, or making you produce much weaker engines. If they see you are about to succeed, they will offer to sell you theirs, further delaying your project and robbing you at the same time. The west work together on this. Only when you stand up to them like China or Russia, Iran, north Korea ,could you ever begin your research. It comes with heavy price. Countries who they can’t stop receives sanctions like China, Russia, Iran, North Korea. They are well known to murder your scientists. So, making any high tech in the world means you have to stand up to the west. There is no going half way. Either you are with them, or against them. They have no problem messing with your economy to get you to behave. Stop dreaming about , if we provoke China for them, they will then give us technology and expertise. The west isn’t like that. Wake up. Everywhere you look, those who use their tech have no independent foreign policy, enslaved forever. with watered down equipment. They will demonize you, call you Hitler like they do Putin, if they have the chance sodomized you like Qaddaffi.

Yes, an engine relates to this much stuff.

Varoon Shekhar · Post by **Varoon Shekhar** » 18 Dec 2017 21:34

^

Some valid observations, but just a tad over-the-top on the only assembled in India idea. Can't believe someone could be so brazenly arrogant, or stupid, about India's achievements in 2017. Even a non-technical layman can spot the audacious arrogance and/or ignorance.

Rakesh · Post by **Rakesh** » 18 Dec 2017 21:41

^^^ It is a bit of everything - cajoling, whining, mocking, pleading and laughter. Classic example of Chinese psy ops.

ArjunPandit · Post by **ArjunPandit** » 18 Dec 2017 22:00

SS's post in Neutering Chinese thread, explains their behaviour

chola · Post by **chola** » 18 Dec 2017 23:01

Rakesh wrote:^^^ It is a bit of everything - cajoling, whining, mocking, pleading and laughter. Classic example of Chinese psy ops.

Psyops are completely worthless if no one listens.

Intelligence on what your rival is doing is important IMHO.

So at the risk of being called a chicommie sympathizer . . .

As I have posted earlier in thread, the PRC have a full range of pistons, turboprops and turbojets which allowed them to pitch and sell endless varieties of UAVs, light utility aircraft and jet trainers. We have to import piston and turboprop for our Rustom I/II drone programs. We have no production turbojet.

For the glamorous turbofan space we have the medium class Kaveri and the light HTFE-25.

For Cheen, they run mutiple backup options in parallel for all of their major aircraft programs:

J-20: flying on Russian AL-31; parallel heavy turbofan programs — WS-10X and WS-15

J-31: flying on Russian RD-93; parallel medium turbofan programs — WS-13 and WS-19

Y-20: flying on Russian D30KP; parallel high by-pass turbofan programs — WS-18 and WS-20

C919: flying on French Leap XC; parallel civilian turbofan programs — SF-A and CJ-1000A

Even if just one of the eight major turbofan programs listed above is successful, it would be a massive win. But the betting line has to be four since the WS-10X, WS-13, WS-18 and SF-A are designed as low hanging fruits to backup the more ambitious WS-15, WS-19, WS-20 and CJ-1000A.

Maybe all of this is a product of money but the chinis plan far better for the future than anything we’ve done. We could have developed the GTX35 core of the Kaveri as a turbojet backup but we never did. They have backup plans for everything and we’ll see how well they’ll do in the coming years.

Rakesh · Post by **Rakesh** » 18 Dec 2017 23:16

chola, you are correct on the Chinese programs. I could not disagree. But China is getting takleef because now Snecma and RR have two separate programs running in India - one for Kaveri revival (by Snecma) and the other for AMCA (by RR). Not to mention license production (onlee screwdrivergiri) of the GE F414 engine in India.

In India, it is a lack of vision and no desire to be top dog. China has plenty of both and as you have so clearly illustrated, they have the programs to prove it. And although China is definitely leaps and bounds ahead of India in this regard, the situation is similar for China when compared to Snecma and RR. They are pissed off that India has partnered with France and the UK on turbofans, even though the IP of hot engine tech will firmly remain in Snecma and RR's hands. What has taken them decades to master and in some respects still to master, India has now taken a short cut. They do not enjoy that luxury.

Take a look at the HAL Shakti turboshaft, which is a Turbomeca turboshaft in all respects. Can India build a Shakti-type turboshaft from scratch? I don't believe it can. But has that stopped HAL for doing screwdrivergiri on that engine for the Dhruv helo? Nope. A similar model will likely be adopted for the Kaveri88 and Kaveri200.

The key thing to note is that whether the RR and Snecma programs will eventually come to fruition. From a technical standpoint, I believe it will. I see no evidence otherwise. Also successful completion of both programs, will create a path for future partnerships as well.

ramana · Post by **ramana** » 18 Dec 2017 23:47

Rakesh, We have to see if these fructify. its all khyali pullao till then.

Our scientists' hint at paper programs and we are supposed to swoon over them.
And all this despite pathetic track record of GTRE.
And HAL has not one piston engine program even though they have been making Lycoming Continental engines since eons.

For example the Snecma were consultants to Kaveri since donkeys years.

And RR will never part with even obsolete technology to India. It never has in the past.

Bot firms are leading us on a garden path and have the Indian aircraft bull by the nose ring.

If you recall the Kaveri M88 is supposed to fly by 2019 airshow. Contract was signed in 2017. Not even a hint of any progress. Or hopeful statements from either HAL or DRDO.
No statements on screech suppression etc.

ramana · Post by **ramana** » 18 Dec 2017 23:50

So chola is right.

Engines are Achilles heel of Indian aircraft industry.

Rakesh · Post by **Rakesh** » 19 Dec 2017 00:13

Ramana-ji, absolutely it is khyali pullao. But right now - in the absence of any other viable option - this is the only hope, apart from the license production of GE F414 engine. And if turns out to empty promises and tall claims, we will be at square one onlee.

ramana · Post by **ramana** » 19 Dec 2017 00:21

Yiddish saying from New York: "Overfeed on hope, you die of starvation!'

Some one person should be in charge of the engine program and not this divided responsibility to incompetents.

chola · Post by **chola** » 19 Dec 2017 00:59

First of all, the fact that we got a turbofan like the Kaveri to the testing stage is a massive achievement previously restricted to only Amreeka, Roos, the Euros and Japan.

But what bothers me to no end is the lack of a base behind that achievement.

Take any of the other countries that tested a turbofan and you see that there is an industrial eco-system creating pistons, turboprops and turbojets as well as the pinnacle turbofans.

We do not. So even though we have a Kaveri whose technical level puts us in the elite we do NOT have ANY engine lower on the technical totem pole that we can use for ANYTHING. As I said before, at the very least an aviation industry the size of ours should have a piston for our drone programs.

I hope with all my heart that the SNECMA succeeds (the RR eggs are too far into the future to start counting chickens.)

But I would be just as happy if we can develop a small turboprop for drones. Otherwise, even a successful M88 Kaveri will feel like a single isolated golden apple without a tree behind it. A tree formed by an eco-system that would allow us to grow more and different fruits all the way up the spectrum from humble pistons to supercruising turbofans.

ramana · Post by **ramana** » 19 Dec 2017 02:51

I have a question on the comparison of the RR Adour and Honeywell F-125 for the Jaguar.

If you look at the basic specs the Honeywell Engine is better in thrust, sfc and weight than the Adour.

However how will it fit in the engine well of the Jaguar?

Is the Jaguar Engine well large enough to fit two 36" diameter engines?

Something is not right.

F-125 is larger in dia (36") and shorter in length(102")

https://en.wikipedia.org/wiki/Rolls-Roy ... meca_Adour

General characteristics
Type: Turbofan
Length: 114 inches (2.90 m)
Diameter: 22.3 inches (0.57 m)
Dry weight: 1,784 lb (809 kg)

Components
Compressor: 2-stage LP, 5-stage HP
Turbine: 1-stage LP, 1-stage HP

Performance
Maximum thrust: 6,000 lb (27.0 KN) dry / 8,430 lb (37.5 KN) with reheat
Overall pressure ratio: 10.4
Bypass ratio: 0.75-0.8
Fuel consumption: dry 0.81 lb/(lbf⋅h) (23 g/(kN⋅s))
Thrust-to-weight ratio: 4.725:1

Honeywell F-124...

https://en.wikipedia.org/wiki/Honeywell/ITEC_F124

General characteristics
Type: Turbofan
Length: 102.1 in (259 cm)
Diameter: 36 in (91.4 cm)
Dry weight: 1050 lb (521.6 kg)

Components
Compressor: 3 axial fan (low pressure compressor) stages, 4 axial high pressure compressor stages, 1 centrifugal high pressure compressor stage
Turbine: 1 stage high pressure turbine, 1 stage low pressure turbine

Performance
Maximum thrust: 6280 lbf (28 kN)
Overall pressure ratio: 19.4:1
Bypass ratio: 0.49:1
Specific fuel consumption: 0.78 lb/lbf-hr (82.6 kg/kN-hr)
Thrust-to-weight ratio: 5.3:1

ramana · Post by **ramana** » 19 Dec 2017 03:03

OK, The engine is F-125IN and not the generic F-125. Let me dig into this more.

ramana · Post by **ramana** » 19 Dec 2017 03:08

Indranil Would this F-125IN fit in the HAl Hawk if needed?

ramana · Post by **ramana** » 19 Dec 2017 04:44

Indranil wrote:LCA allows much more flexibility than the Jags. Jags were not designed for multi-role swing-role capabilities of LCA. It was designed for one role and one role only. And it can do that satisfactorily. But in 2020s, it is in desperate need of more power.

That F125IN upgrade is a no brainer. I have no idea why something so low lying and performance enhancing is not prioritized instead of motley of projects that we are undertaking.

From reading the multiple stories on the F-125IN upgrade, the contract is for 270 to 280 engines for the 120 Jaguars. They seem to be in no rush. The plan is to have Honeywell make the engine in India either in a JV or with HAL. Set up a depot etc.
Its hung up on offset clause. Honeywell wants to mfg 25% parts and assy and integration of the engine. That's where its stuck.

Meantime 60 of the old DARIN I Jaguars are being upgraded to the DARIN III standard. The rest have DARIN II. All will have the engine once the wrinkles are ironed out. Meanwhile due to delay price goes up and MoD is whiling the time away so they can get the offset clause implemented.

F-125IN is a version for the Jaguar upgrade. Wonder if it can go on some of the Hawks. The RR offered the Hawk engine as an alternative.

Vivek K · Post by **Vivek K** » 19 Dec 2017 13:02

And due to the delay the aircraft get older.

Neela · Post by **Neela** » 27 Dec 2017 14:52

Rakesh wrote: Take a look at the HAL Shakti turboshaft, which is a Turbomeca turboshaft in all respects. Can India build a Shakti-type turboshaft from scratch? I don't believe it can. But has that stopped HAL for doing screwdrivergiri on that engine for the Dhruv helo? Nope. A similar model will likely be adopted for the Kaveri88 and Kaveri200.

.

I have seen the tenders for the hot section blades for HAL HTSE in the HAL website. Saurav adds this:

Saurav Jha on twitter
It seems that HAL has also made progress on the HTSE-1200 turboshaft engine that it is developing for helicopter use. In-house component fabrication as well as sourcing is presently underway.

prasannasimha · Post by **prasannasimha** » 28 Dec 2017 11:08

Chaiaala tells paanwaal that the river in South India is flowing better

ramana · Post by **ramana** » 28 Dec 2017 11:52

Good
And quiet flows the River.
Ponin selvan

dinesh_kimar · Post by **dinesh_kimar** » 28 Dec 2017 12:27

^ what this means in layman terms pls?

deejay · Post by **deejay** » 28 Dec 2017 12:41

dinesh_kimar wrote:^ what this means in layman terms pls?

You mean Ponin Selvan or Ponniyin Selvan. Ponniyin Slevan

for a lay man as explained by wikipedia https://en.wikipedia.org/wiki/Ponniyin_Selvan

"Ask no questions and you will hear no lies" phamous chaiwala saying

chola · Post by **chola** » 28 Dec 2017 13:08

Nice.

@Dinesh, Kaveri is the mother river of the Cholas. Ponni is another name for Kaveri.

The River in the South Flows Again.

Meaning our Kaveri is up and running once more.

Like the Rebirth of the Cholas under Ponniyin Selvan or Arulmozhivarman.

chetak · Post by **chetak** » 28 Dec 2017 20:41

shiv wrote:We do know for example that gunfiring has caused some aircraft engines to seize up because of smoke ingestion.

The engine surges/stalls/sometimes flames out due to disturbances in the airflow at the air intake caused by the firing gun(s).

Engines are designed to operate reliably in heavy rain. Some smoke is not going to affect them.

JayS · Post by **JayS** » 28 Dec 2017 21:13

chetak wrote:
shiv wrote:We do know for example that gunfiring has caused some aircraft engines to seize up because of smoke ingestion.
The engine surges/stalls/sometimes flames out due to disturbances in the airflow at the air intake caused by the firing gun(s).

Engines are designed to operate reliably in heavy rain. Some smoke is not going to affect them.

It could. Gun firing and missile fire testing do evaluate gas ingestion and its impact on engine. You could argue though that modern engines mostly don't have to bother about it now a days. But AFAIK still need to be tested to prove no significant impact.

shiv · Post by **shiv** » 28 Dec 2017 21:21

chetak wrote:
Engines are designed to operate reliably in heavy rain. Some smoke is not going to affect them.

Not true.

Flt Lt Nachiketa's engine flameout was said to be gun gas ingestion
http://www.rediff.com/news/2008/jul/14kargil.htm

Despite initial difficulties, the Vayu Sena Medal awardee identified the target and fired 40 rockets in one salvo and attacked again, this time with 30 mm guns.

"I then eased out of the dive, but felt a backward jerk due to sudden deceleration. The speed dropped to 500 kmph and realised the engine had flamed out. I immediately jettisoned the rocket pods and attempted a relight. Informing my leader Sqn Ldr Mandhokot, I further lowered the altitude to maintain the speed which had fallen to 450 kmph," he said.

With hills surrounding the area and no sign of the engine restarting, Nachiketa realised that eviction was inevitable and pulled the ejection handle.

chetak · Post by **chetak** » 28 Dec 2017 22:21

JayS wrote:
chetak wrote:
The engine surges/stalls/sometimes flames out due to disturbances in the airflow at the air intake caused by the firing gun(s).

Engines are designed to operate reliably in heavy rain. Some smoke is not going to affect them.
It could. Gun firing and missile fire testing do evaluate gas ingestion and its impact on engine. You could argue though that modern engines mostly don't have to bother about it now a days. But AFAIK still need to be tested to prove no significant impact.

every single aero engine is going to be fully tested, no matter what.

and it's nobody's argument that modern engines don't bother about this, that or the other. Mil engines are extensively tested because of reliability/battle damage issues and commercial engines are also extensively tested because of commercial as well as liability issues.

rain will turn to steam ( not much different from smoke) quite early in the compressor stages itself.

aircraft firing guns mounted in the front and near the intakes will cause turbulence problems along with some gas ingestion issues. The turbulence is caused by the high velocity exit of the bullet from the barrel(s) and guns these days have cyclic rates of 2-4000 rounds with gatling types easily exceeding those numbers.

Likewise, simultaneous firing of many missiles will also cause disruption and turbulence in the airflow. The missile exhaust is highly turbulent anyway. Just like the gasses that are produced during the firing of the gun.

Is it anybody's argument that the missile exhaust/gunfire gasses are not highly turbulent and if ingested by the engine, it is this turbulent and highly disturbed airflow that is going to affect the engine much more than the content of the missile exhaust smoke/gunfire gas per se??

Its like the wake turbulence of a heavy aircraft that can persist in that locality for a long enough time to catch another unsuspecting aircraft and the results of entry into such turbulent airspace is sometimes fatal. That's why the distance/time separation of a following aircraft is determined by the weight category of the aircraft that has just passed through a specific airspace. That may be the reason why heavy aircraft type pilots always preface their call signs with the word "Heavy"

Whatever happens, the effect on the engine is either a surge/stall sometimes resulting in a flame out or in some cases even a wrecked engine that may have shed a blade or two or three.

In a surge/stall situation, it has to be understood that individual blades can surge/stall as opposed to the entire engine surging/stalling. Sometimes the stresses exceed limits and the blades detach.

shiv · Post by **shiv** » 28 Dec 2017 22:42

http://www.aircraftinformation.info/art_gnat.htm

Primary armament on the Gnat consisted of two 30-mm Aden Mk 4 revolver-type cannon mounted in the outer portions of the air intakes with 115 rounds per gun. On most other aircraft this would have caused the engines to flameout from gas ingestion, but this never happened to the Gnat as the muzzles were carefully designed to deflect gases out to the sides of the intakes. A row of four circular holes on the outside of each barrel and triangular extensions of the intake in front of each muzzle kept gas from being sucked into the engine.

shiv · Post by **shiv** » 28 Dec 2017 22:51

Smoke and rainwater are completely different issues wrt jet engines. Gun gases in particular are not just "smoke" but particulate matter that is at a high temperature and uncombusted propellant - like squirting explosive into the intake.

Plain smoke can be bad enough - all aircraft must avoid volcanic plumes that can be cool but 30000 feet high. Rain cloud is safe. Chalk and cheese

chetak · Post by **chetak** » 28 Dec 2017 22:57

shiv wrote:http://www.aircraftinformation.info/art_gnat.htm
Primary armament on the Gnat consisted of two 30-mm Aden Mk 4 revolver-type cannon mounted in the outer portions of the air intakes with 115 rounds per gun. On most other aircraft this would have caused the engines to flameout from gas ingestion, but this never happened to the Gnat as the muzzles were carefully designed to deflect gases out to the sides of the intakes. A row of four circular holes on the outside of each barrel and triangular extensions of the intake in front of each muzzle kept gas from being sucked into the engine.

it simply means that the designers had found a clever way to keep the turbulent and disturbed airflow away from the engine intakes.

Such a simple and perhaps elegant solution is rarely possible these days.

It also means that the right and left guns were perhaps not interchangeable.

shiv · Post by **shiv** » 28 Dec 2017 22:59

chetak wrote:Is it anybody's argument that the missile exhaust/gunfire gasses are not highly turbulent and if ingested by the engine, it is this turbulent and highly disturbed airflow that is going to affect the engine much more than the content of the missile exhaust smoke/gunfire gas per se??
.

Don't know if there is any argument but every single reference to flame out after missile firing that I have seen speaks of plume ingestion and not turbulence or "ingestion" of turbulence. Will try and locate MiG 21 history in this regard. Not tonight though.

shiv · Post by **shiv** » 28 Dec 2017 23:00

chetak wrote:
it simply means that the designers had found a clever way to keep the turbulent and disturbed airflow away from the engine intakes.

Such a simple and perhaps elegant solution is rarely possible these days.

It also means that the right and left guns were perhaps not interchangeable.

Would prefer to see a reference other than your post

JayS · Post by **JayS** » 28 Dec 2017 23:29

chetak wrote:
JayS wrote:
rain will turn to steam ( not much different from smoke) quite early in the compressor stages itself.

Hmm. Food for thought. Ever wondered why Mil thrust of Mil engine is called dry thrust and AB thrust, wet thrust..?

No more on this from me in this thread. May be engine thread.

chetak · Post by **chetak** » 28 Dec 2017 23:33

shiv wrote:Smoke and rainwater are completely different issues wrt jet engines. Gun gases in particular are not just "smoke" but particulate matter that is at a high temperature and uncombusted propellant - like squirting explosive into the intake.

Plain smoke can be bad enough - all aircraft must avoid volcanic plumes that can be cool but 30000 feet high. Rain cloud is safe. Chalk and cheese

volcanic plume is not just smoke. It has a very very high particulate matter content. Google for a british airways(?) flight in which all four engines shut down in flight with the crew completely clueless and also unaware that they had flown through a volcanic eruption zone at night.

All frantic attempts to relight had failed and they here losing height. Stiff brit upper lips were not all that stiff on the flight deck that night. As they nosed down lower into much clearer air, they managed to relight their engines one by one until all four came back on line.

Heavy particulate matter content will do that to you.

Jet engines have a very high aspiration rate. The ratio of the mass flow through the engine as compared to the amount of gun gas injection they may have aspirated momentarily is small to negligible. Uncombusted propellant particles in the engine will just burn and not explode.

A sivakasi deepavalli cracker explodes because of the way it is tightly packaged. If you deconstruct it, empty out the "masala" and pile it up on the floor and set it alight, it just burns, it will no more explode.

You can set C4 on fire because it also just burns. A detonator is needed to make it show it's true colors and explosive capabilities.

Aircraft guns are fired for a few seconds and the gun gasses will start to disperse immediately thereafter because of the airflow so not all of it is aspirated into the engine intakes. What is problematic however is the disruption in the airflow. GTs are usually rugged beasts and don't mind a bit of rain or smoke but what they don't tolerate well is turbulent air hitting their compressor faces. Air Intake design is critical to ensure that the airflow to the compressor is as smooth as they can make it.

chetak · Post by **chetak** » 28 Dec 2017 23:36

JayS wrote:
chetak wrote:
Hmm. Food for thought. Ever wondered why Mil thrust of Mil engine is called dry thrust and AB thrust, wet thrust..?

No more on this from me in this thread. May be engine thread.

Have you heard of water injection during take off?? There is actually lots to wonder about.

chetak · Post by **chetak** » 29 Dec 2017 00:28

shiv wrote:
chetak wrote:Is it anybody's argument that the missile exhaust/gunfire gasses are not highly turbulent and if ingested by the engine, it is this turbulent and highly disturbed airflow that is going to affect the engine much more than the content of the missile exhaust smoke/gunfire gas per se??
.
Don't know if there is any argument but every single reference to flame out after missile firing that I have seen speaks of plume ingestion and not turbulence or "ingestion" of turbulence. Will try and locate MiG 21 history in this regard. Not tonight though.

What's the difference between plume ingestion and "ingestion" of turbulence??

It is the plume that is causing the turbulence and it causes more turbulence as it blooms or grows bigger. Missiles often drop away before they ignite, no??

The plume exits the gun barrel at speeds comparable to the bullet. More often than not, the bullet is supersonic with all the attendant effects of shock waves et al. This causes the local turbulence or disruption of airflow in the region around the intake.

If the plume is ingested, it is the attendant turbulence that is also automatically and inescapably ingested.

Plume and turbulence are inseparable in your example.

Rishi_Tri · Post by **Rishi_Tri** » 29 Dec 2017 07:12

Is the river flowing on its own? Where can it be heard flowing?

Rakesh · Post by **Rakesh** » 29 Dec 2017 07:21

FANTASTIC!!!!!

prasannasimha-ji, would you happen to know if this is the Snecma-GTRE venture? Can you provide any more info other for us jingos? I am waiting on the Rolls Royce-GTRE venture as well.

Kaveri is our LAST hurdle. We master this (even if RR and Snecma still have the golden key i.e. hot section) and India will have arrived. The Jet Engine Technology Joint Working Group (JETJWG) with the US will become an afterthought. Sad, but what to do.

On the bright side, *certified* Kaveri88 (via Snecma) and *certified* Kaveri200 (via Rolls Royce) will pave way for Tejas Mk1A and Tejas Mk2 without a doubt. AMCA will follow suit.

Fly Baby, Just PLEASE FLY!!!! And Touch the Sky with Glory! The prayers & best wishes of every Indian is with you. Jai Hind!!!

तस्मादज्ञानसम्भूतं हृत्स्थं ज्ञानासिनात्मन: |
छित्त्वैनं संशयं योगमातिष्ठोत्तिष्ठ भारत

asmād ajñāna-sambhūtaṁ hṛit-sthaṁ jñānāsinātmanaḥ
chhittvainaṁ sanśhayaṁ yogam ātiṣhṭhottiṣhṭha bhārata

Therefore, with the sword of knowledge, cut asunder the doubts
that have arisen in your heart. O scion of Bharat, establish yourself
in karm yog. Arise, stand up, and take action!

shiv · Post by **shiv** » 29 Dec 2017 10:24

chetak wrote: Plume and turbulence are inseparable in your example.

Particulate matter sir, exists in smoke and missile plumes which can cause enough damage to prevent relighting
http://aviationweek.com/awin/compressor ... elicopters