Search found 204 matches

by agupta
11 Sep 2019 19:57
Forum: Military Issues & History Forum
Topic: Indian Military Aviation - 06 March 2019
Replies: 182
Views: 33424

Re: Indian Military Aviation - 06 March 2019

It seems like HAL Aircraft will go to ANY lengths to prevent the emergence of ANY alternate systems/aircraft integrator in India... probably to hide its own dismal efficiency and yield issues that drive up cost of "indigenized" systems.
by agupta
07 Sep 2019 08:59
Forum: Military Issues & History Forum
Topic: Indian Missiles News & Discussions - 17 Dec 2018
Replies: 1629
Views: 418307

Re: Indian Missiles News & Discussions - 17 Dec 2018

^^^ Agree. 50 —> so called “production” setup 100 —> labeled as “initial” order ??? —> ??? Even though in the article it states: The extensive and rigorous trials have successfully validated the Astra missile’s warhead capability, its maximum launch ranges against both head-on and manoeuvring targe...
by agupta
07 Sep 2019 08:45
Forum: Military Issues & History Forum
Topic: Indian Missiles News & Discussions - 17 Dec 2018
Replies: 1629
Views: 418307

Re: Indian Missiles News & Discussions - 17 Dec 2018

why the order for indigenous system is always so less...are they proofing the manufacturing process - The missile was anyway tested and passed. Will the 100 go another round of testing before bulk order is given or there is no plan B and 100 is the bulk order? Same reason why no bulk orders are giv...
by agupta
29 Aug 2019 07:26
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 4864
Views: 913249

Re: Kaveri & Aero-Engine: News & Discussion

Please tell me, is following situation possible..? 1. There is enough dampening built in the jet pipe and the A/B is well design, enough not to produce strong acoustic waves of high frequency, and whatever is produced is well attenuated by the screech liner. But we still have screech in the superso...
by agupta
29 Aug 2019 07:20
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 4864
Views: 913249

Re: Kaveri & Aero-Engine: News & Discussion

I think you are talking about the final effect and I am talking about the origin of the acoustic waves. I have not denied that A/B generated acoustic waves would not result in jet screech, I just said I am not sure, they will always be able to produce strong enough instabilities. What I have been t...
by agupta
28 Aug 2019 02:04
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 4864
Views: 913249

Re: Kaveri & Aero-Engine: News & Discussion

Overview of Gas Turbine Augmentor Design, operation And Combustion Oscillation https://engineering.purdue.edu/AAECourses/aae537/2009/Afterburner%20Review The phenomenon referred to as “screech” (see Section 6.2) is a type of combustion instability characterized by high frequency, high amplitude pre...
by agupta
27 Aug 2019 19:27
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 4864
Views: 913249

Re: Kaveri & Aero-Engine: News & Discussion

These screech waves produced by A/B may or may not induce Jet screech, depending on whether they can induce flow instabilities in the flow at the throat of the nozzle strong enough that would travel thru the diffuser and then in the outside jet shock structure. I am not too sure about this part whe...
by agupta
27 Aug 2019 18:42
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 4864
Views: 913249

Re: Kaveri & Aero-Engine: News & Discussion

Guys, I have some queries regarding screech issue with Kaveri. I ask as I have no clue what so ever regarding a jet engine. 1) If it is related to after burner then non after burning application should still have a flyable engine? Correct? 2) the screech, is it is physical issue that will adversely...
by agupta
27 Aug 2019 10:04
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 4864
Views: 913249

Re: Kaveri & Aero-Engine: News & Discussion

Do you mean to say, screech cannot be generated by the instabilities in the jet itself..? Anyway this is off topic for Kaveri. No that's not what I meant. Just saying screech is defined as a sub-set of (and happens only in) supersonic jet phenomena. Some instability (wether driven by a sharp lip or...
by agupta
26 Aug 2019 09:53
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 4864
Views: 913249

Re: Kaveri & Aero-Engine: News & Discussion

Err...not quite, JayS. Yes - Absolutely correct its in the afterburner fuel injectors - and the region where the combustion instability sets up ("the driver") may be subsonic, but does not change the fact that "screech" is associated with supersonic jet flows. Remember usually t...
by agupta
23 Aug 2019 21:39
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 4864
Views: 913249

Re: Kaveri & Aero-Engine: News & Discussion

agutpa, I have seen those characteristic shock vortices/Mach waves in rocket exhaust also. Thanks for the paper. The sound intensity as a function of Mach Number aka eighth power law is first formulated by Dr. Lighthill. You might be surprised but IIT Madras had quite a few books in the library on ...
by agupta
23 Aug 2019 21:32
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 4864
Views: 913249

Re: Kaveri & Aero-Engine: News & Discussion

Just one point, the screech in context of Kaveri is related to the combustion instability in the Afterburner (where flow is actually low subsonic, so no shocks involved). Screech is due to the acoustic waves generated by the thermo-fluidic instabilities which results in lower than expected thrust. ...
by agupta
22 Aug 2019 08:51
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 4864
Views: 913249

Re: Kaveri & Aero-Engine: News & Discussion

Ok so the phenomena is the well known acoustic noise due to organ pipe effect. So how would a modified core change the screech effect? It won't, Ramanaji. A clean explanation that you might enjoy @ http://daniel.edgington-mitchell.com/research/silencing-the-screech-tone-noise-suppression-in-superso...
by agupta
16 Jul 2019 20:38
Forum: Military Issues & History Forum
Topic: Chandrayan-2 Mission
Replies: 1937
Views: 207293

Re: Chandrayan-2 Mission

It's the ISRO culture. No fawning, sucking up... just factual, tenacious work until you succeed. THIS is worth celebrating...the modern version of Karma Yoga; especially in comparison to other central agencies. One old timer put it strictly down to not having HQ in N. Delhi and avoiding "pollut...
by agupta
21 Jun 2019 08:11
Forum: Military Issues & History Forum
Topic: Indian Navy News & Discussion - 03 July 2018
Replies: 1921
Views: 422945

Re: Indian Navy News & Discussion - 03 July 2018

Chaiwala inputs from a recent N Delhi trip is that the PSU lobbies have been moving heaven and earth to kill off ANY private sector "intrusion" into naval projects... various yards which used to vie with each other are collaborating to keep L&T etc. out; lots of "burnt hair" ...
by agupta
11 Jun 2019 21:02
Forum: Military Issues & History Forum
Topic: Transport Aircraft for IAF
Replies: 3744
Views: 328168

Re: Transport Aircraft for IAF

Interesting discussion re An70. I think we're missing a few key facts: * There is NO evidence that the Ukes are willing to do ANYTHING more than a JV. For all their desperation... it may be even possible there is nothing left to sell except documents. This was a program from the 80s and 90s and 20 y...
by agupta
31 Jul 2017 07:46
Forum: Trash Can Archive
Topic: LCA: News & Discussions - October 2016
Replies: 4125
Views: 755531

Re: LCA: News & Discussions - October 2016

UlanBatori wrote:Wow! Thanks for the pic, Gagan. Why the elaborate nacelle I wonder.


Instrumentation. Its a test-bed after all. Accounts for a significant cost and complexity barrier - and also an experience barrier.
by agupta
28 Feb 2017 23:44
Forum: Military Issues & History Forum
Topic: India's R&D in Defence DRDO, PSUs and Private Sector
Replies: 3756
Views: 500628

Re: India's R&D in Defence DRDO, PSUs and Private Sector

Apologies if posted before Interview | Dr S. Christopher The Indian Army is likely to accept 68-ton Arjun Mark II tank for two more regiments. Of Arjun Mark I, 91 out of 124 tanks are in operational condition. We have resolved all the maintenance issues. Ammunition was an issue, and we resolved tha...
by agupta
29 Nov 2016 22:45
Forum: Trash Can Archive
Topic: Indian Military Aviation - 21 Sept 2015
Replies: 4458
Views: 513337

Re: Indian Military Aviation - 21 Sept 2015

yeah but its a tendency of goras to put down everything to caste system. its plain bigotry pure and simple. they come to india, take a look around and then fit everything to their own decided notions. the real answer is in india there is an excess of (un) skilled labor and hence its cheaper to have...
by agupta
31 Oct 2016 17:31
Forum: Military Issues & History Forum
Topic: India's R&D in Defence DRDO, PSUs and Private Sector
Replies: 3756
Views: 500628

Re: India's R&D in Defence DRDO, PSUs and Private Sector

Thanks Vaibhav ji Those with connections with DRDO/DPSUs will wince and recognize the " tests/trials were successful or X, Y, Z were successfully evaluated" language. As in " I successfully tried to be an astronaut", or I "successfully wrote the JEE exam "... What it me...
by agupta
07 Oct 2016 22:26
Forum: Military Issues & History Forum
Topic: Military Acquisitions, Partnerships & Developments
Replies: 2812
Views: 446009

Re: Military Acquisitions, Partnerships & Developments

Aah..that makes sense now. Thanks.

Is the near-LOC area colored in camouflage colors or in conventional black and white on your board, sir ? :rotfl:
by agupta
07 Sep 2016 01:14
Forum: Trash Can Archive
Topic: LCA Tejas: News and Discussions
Replies: 4036
Views: 295906

Re: LCA Tejas: News and Discussions

Would you like to discuss it here. There are a few things: 1. That vortex (direction) at the LE of the LEVCON is very interesting. 2. No Slats either. This looks like close to 15 degree AoA. The vortex burst must have crept very close to the TE, if not already over it. I am not sure if they are usi...
by agupta
07 Apr 2016 02:17
Forum: Trash Can Archive
Topic: IAF Rafale News and Discussions - 26 May 2015
Replies: 3973
Views: 237488

Re: IAF Rafale News and Discussions - 26 May 2015

+1 Viv S I think we underestimate the sophistication of the FUD-machinery that's aligned against a truely effective and efficient defence acquisition set up in N. Delhi... lots of people make too much money, and unlike BRF-group-think, its equally corrupt when the gutter pipes are filled with Rupees...
by agupta
15 Mar 2016 07:50
Forum: Military Issues & History Forum
Topic: US military, technology, arms, tactics
Replies: 1414
Views: 195502

Re: US military, technology, arms, tactics

^^^ Not just about aero / supermaneuverability vs other aspects. More focus on energy mgt., power (not just for flight) and the whole software and sensors enabled systems Brarji can do a lot more justice, but Shiv is essentially right... the Billions of $$ are going into this v. consciously, whereas...
by agupta
14 Mar 2016 21:29
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 4320
Views: 703112

Re: Indian Military Helicopters

^^^
All the much better to absorb enemy bullets and drive them into bankruptcy...

higher form and skin friction drag, so lower speed capability can make for a better platform for tourists...
by agupta
14 Mar 2016 17:03
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 4864
Views: 913249

Re: Kaveri & aero-engine discussion

So, GTRE is also using 3D printing. Hopefully some prototype test results will be known soon. Tullji - It depends on what you mean Lest the uber-brochure-technologists on BRF get carried away, this is NOT using 3D printing on a working engine. And you can already see the ambiguous use of the word &...
by agupta
11 Mar 2016 20:32
Forum: Trash Can Archive
Topic: Indian Missiles and Munitions Discussion - June'14
Replies: 4681
Views: 740126

Re: Indian Missiles and Munitions Discussion - June'14

unknown sources also a perfect way to create a vitiated atmosphere ahead of time - for projects not meeting their targets, or designed with the wrong targets, or pet initiatives, or... Basically anything to talk about other than: "what is the right thing to do?" "are we doing it well ...
by agupta
11 Mar 2016 09:41
Forum: Trash Can Archive
Topic: Indian Missiles and Munitions Discussion - June'14
Replies: 4681
Views: 740126

Re: Indian Missiles and Munitions Discussion - June'14

Ever occur to the worthies here that these news articles are equally probably "false flag" pre-emptive pay - and info- ops ? Strange its always the nameless IAF officials , and the even more nameless "sources" who claim to either be or are supposed to be quoting nameless IAF offi...
by agupta
22 Feb 2016 07:13
Forum: Trash Can Archive
Topic: Indian Navy News & Discussion - 22 April 2015
Replies: 4211
Views: 331953

Re: Indian Naval News & Discussion - 22 April 2015

Maz - that one post alone makes it worthwhile wading through 10 pages of flotsam ... many thanks
by agupta
22 Feb 2016 07:10
Forum: Trash Can Archive
Topic: Indian Military Aviation - 21 Sept 2015
Replies: 4458
Views: 513337

Re: Indian Military Aviation - 21 Sept 2015

On a different note, I see why HAL/BAE want to produce the combat hawk. But I don't understand what is the use of a combat hawk in IAF. I see a use for combat HTT-40. It provides different capabilities than a jet. Hawk can only provide a cost advantage, but how much? There isn't. IAF is being smart...
by agupta
20 Jan 2016 09:06
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 4320
Views: 703112

Re: Indian Military Helicopters

Folks - where is all the CT about Kamv playin anyone coming from No-one forced HAL to bid for the Ka JV job; it was purely HALs choice to throw their hat in the ring perhap even surprising the private players. I hope this does not turn out to be LCA-IJT-HTT40 redux. It can be argued MoD should've pu...
by agupta
05 May 2015 02:19
Forum: Trash Can Archive
Topic: Rafale & MMRCA News and Discussions-9 August, 2014
Replies: 3963
Views: 151306

Re: Rafale & MMRCA News and Discussions-9 August, 2014

Offsets can be VERY creative. And such creativity is found even in countries with very "equal" relationships e.g., NATO allies. One example I know of is a collaboration/tech transfer between an Aerospace major and an Energy equipment maker in Scandinavia; you normally wouldn't put the 2 co...
by agupta
31 Mar 2015 09:26
Forum: Trash Can Archive
Topic: LCA Tejas: News and Discussions
Replies: 3980
Views: 157187

Re: LCA Tejas: News and Discussions

^^

Simply plan what was promised in the contract for a known number. N_aircraft by 2XXX (so assumed yield, EMD execution) - that is supposed to be the advantage for a vertically integrated player.
by agupta
17 Feb 2015 01:23
Forum: Trash Can Archive
Topic: Indian Missiles and Munitions Discussion - June'14
Replies: 3963
Views: 168525

Re: Indian Missiles and Munitions Discussion - June'14

^^ C-C is Carbon Carbon composites (So both fiber and matrix are carbon/graphite). Karan-M: THx for bringing those slides back up. If/when we get the SLBM's mature - its a great first effort mixing some mature and interesting variations; Aerospike's ala Trident and the extendable nozzles for max eff...
by agupta
09 Nov 2014 04:19
Forum: Trash Can Archive
Topic: LCA News and Discussions, 22-Oct-2013
Replies: 3964
Views: 148745

Re: LCA News and Discussions, 22-Oct-2013

[ What is the downside if the MoD/IAF were to order 80 Mk1s and ask the production rate to be pushed up past 20/yr? Worst case scenario, HAL is only able to achieve a rate of 15-16 units per year. So be it. Viv - I'd like to understand in what personal/government spending that kind of thinking make...
by agupta
09 Nov 2014 04:06
Forum: Trash Can Archive
Topic: LCA News and Discussions, 22-Oct-2013
Replies: 3964
Views: 148745

Re: LCA News and Discussions, 22-Oct-2013

Agupta sahab, I don't think you appreciate what ADA/HAL has to do to create those assembly lines. They have to give a shoutout. Is there anybody out there who can make this hardware? In the western world, where there are lots of established players who cater to various high precision manufacturing ...
by agupta
09 Nov 2014 03:58
Forum: Trash Can Archive
Topic: LCA News and Discussions, 22-Oct-2013
Replies: 3964
Views: 148745

Re: LCA News and Discussions, 22-Oct-2013

Because the IAF does not realize what it takes to develop , ab initio, such things. They do not have the engineering and scientific talent at the highest, decision making levels - its all the fly boys doing everything. Its jocks vs. geeks all over again. When the geeks are gora, then one is able to...
by agupta
09 Nov 2014 03:57
Forum: Trash Can Archive
Topic: LCA News and Discussions, 22-Oct-2013
Replies: 3964
Views: 148745

Re: LCA News and Discussions, 22-Oct-2013

Same way ADA does not get an order to build 24 prototypes of Tech Demos, a smaller number is sufficient for HAL to develop/demonstrate its PRODUCTION capabilities and ability to SUSTAIN the rest of the value chain (incl. delivering production variants of the Trainers as well) while the last changes...
by agupta
09 Nov 2014 03:32
Forum: Trash Can Archive
Topic: LCA News and Discussions, 22-Oct-2013
Replies: 3964
Views: 148745

Re: LCA News and Discussions, 22-Oct-2013

CM sahab, Wrong analogies and counter points aside, just answer this question. What is so wrong with the Mk1 that we can't have 4 squadrons of Mk1? Basically, I have the wherewithal to build 16 mk1 in the next 2 years and 16 more annually from then on. Why shouldn't I use this capability till Mk2s ...
by agupta
04 Nov 2014 08:52
Forum: Trash Can Archive
Topic: Rafale & MMRCA News and Discussions-9 August, 2014
Replies: 3963
Views: 151306

Re: Rafale & MMRCA News and Discussions-9 August, 2014

How is it that MKI production is around16/yr and Tejas so small despite being a desi bird with no hand-holding? You are talking about production rate of MKI which has been running for more than 10 years now. What was the production rate of the MKI back in 2002/3/4/5/6? Rai-ji - may I enquire if you...

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