Search found 222 matches

by agupta
13 Nov 2019 02:44
Forum: Military Issues & History Forum
Topic: India's R&D in Defence DRDO, PSUs and Private Sector
Replies: 3860
Views: 538756

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

^^ Really nice article about Midhani's achievements. I would not have guessed 500 distinct alloys produced by them! ( maybe 20-30 if i were asked :oops: ) Interestingly, they are downplaying or not even mentioning maraging steel. It was a major breakthrough when it was announced in the late 80s/ear...
by agupta
11 Nov 2019 08:18
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 5009
Views: 965944

Re: Kaveri & Aero-Engine: News & Discussion

does the word 60% yield here means that out of 100 blades made, 60 passed QA? Quiet so... Fanne ji. Production yield is a manufacturing technology CTQ. It means that the rest of 40% is "wasted" - and even if raw material is recycled, all the time/effort/cost unto that point is lost and th...
by agupta
11 Nov 2019 08:07
Forum: Military Issues & History Forum
Topic: India's R&D in Defence DRDO, PSUs and Private Sector
Replies: 3860
Views: 538756

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

+1 And MIDHANI doing HDPE ??? Or did they just loan someone a heat treatment cell ? I call DDM... hopefully something genuine IS happening No DDM here. It's a fairly straightforward report. Five minutes on any search engine Original: http://ajaishukla.blogspot.com/2019/07/barcs-bhabha-kavach-to-pro...
by agupta
10 Nov 2019 08:51
Forum: Military Issues & History Forum
Topic: India's R&D in Defence DRDO, PSUs and Private Sector
Replies: 3860
Views: 538756

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

srai wrote:^^^
Any specific reason BARC doing R&D for BPJ? Bit odd.


+1

And MIDHANI doing HDPE ??? Or did they just loan someone a heat treatment cell ?

I call DDM... hopefully something genuine IS happening
by agupta
29 Oct 2019 17:11
Forum: Military Issues & History Forum
Topic: Advanced Medium Combat Aircraft: News & Discussion - 30 August 2019
Replies: 306
Views: 51988

Re: Advanced Medium Combat Aircraft: News & Discussion - 30 August 2019

fanne wrote:For a AMCA to super cruise it needs 120 kn engine, not the f414. No one is making one yet,....



Err...https://en.wikipedia.org/wiki/Pratt_%26_Whitney_F135 says otherwise ???

Wether/when that's made available for foreign sales is a different question
by agupta
28 Oct 2019 07:43
Forum: Strategic Issues & International Relations Forum
Topic: J&K Union Territory-2019
Replies: 3064
Views: 421884

Re: J&K Union Territory-2019

If I may wander into a rotten-tomato-throwing contest... I don't think postor aguptaji meant to diss postor CRamSji. He merely pointed out that refusing overflight permission to the Indian PM was a "victory for the small-minded". I am pretty sure he meant the Pakis and I think anyone with...
by agupta
27 Oct 2019 22:48
Forum: Strategic Issues & International Relations Forum
Topic: J&K Union Territory-2019
Replies: 3064
Views: 421884

Re: J&K Union Territory-2019

Guys, explain this to me. What I ModiJi trying to achieve or demonstrate by repeatedly begging TSP for flying over their air space. Those ass holes refuse with contempt and India expresses 'regret'. Whats going on? https://www.indiatoday.in/world/story/pakistan-denies-use-of-its-airspace-to-pm-modi...
by agupta
26 Oct 2019 01:28
Forum: Military Issues & History Forum
Topic: Tejas Mk.1 & Mk.1A: News & Discussions: 23 February 2019
Replies: 1463
Views: 419225

Re: Tejas Mk.1 & Mk.1A: News & Discussions: 23 February 2019

This may not be an appropriate equivalence... will be true only when HAL is held accountable to its promised deliverables with the level of open-ness that the US OEMs are. Is the only evidence here, Shukla's Blog and the HAL chief's one-sided public complaining ? Any commentary on what the rational...
by agupta
25 Oct 2019 19:23
Forum: Military Issues & History Forum
Topic: Tejas Mk.1 & Mk.1A: News & Discussions: 23 February 2019
Replies: 1463
Views: 419225

Re: Tejas Mk.1 & Mk.1A: News & Discussions: 23 February 2019

^^^ Will a private company do the same? They will go bankrupt if they have to keep paying salaries and purchases, but their clients hold up payments. Boeing, LockMartin, Raytheon and the rest are all private companies. The US government pays them on time and at a premium to keep a vital industry al...
by agupta
24 Oct 2019 22:32
Forum: Military Issues & History Forum
Topic: Military Flight Safety
Replies: 2586
Views: 330187

Re: Military Flight Safety

^ +1

Its criminal - and inexplicable... the delays in the wire cutter assembly being integrated; hard to rationalize it with the otherwise very proactive Helicopter div. You indicated some time ago, IIRC, that you knew what was happening... is now an OK time to share?
by agupta
24 Oct 2019 02:13
Forum: Military Issues & History Forum
Topic: Tejas Mk.1 & Mk.1A: News & Discussions: 23 February 2019
Replies: 1463
Views: 419225

Re: Tejas Mk.1 & Mk.1A: News & Discussions: 23 February 2019

^^^ The funds are supposed to come from the budget allocated to the IAF. Who “releases” them seems to be a complicated question. Is it the IAF, or, MoD, or MoF, or ....? How many approval signatures are required :(( Have seen such comments before on BRF and am curious if anyone (Sraiji included) ca...
by agupta
12 Oct 2019 17:53
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 5009
Views: 965944

Re: Kaveri & Aero-Engine: News & Discussion

I wish people like Maitya ji, JayS, Agupta ji wrote an article about the development of aero engines in India. Compared the same with successful projects abroad and bring out how a ToT is can at best be termed as a penny wise, pound foolish idea. I think Maitya has done a good job so far in corrall...
by agupta
12 Oct 2019 17:36
Forum: Military Issues & History Forum
Topic: VayuSena Rafale: News and Discussions - 17 Oct 2016
Replies: 2810
Views: 463487

Re: VayuSena Rafale: News and Discussions - 17 Oct 2016

What will happen if we export AMCA or Tejas MK2 -- how will we guarantee that our secrets our always protected ? Export versions are typically “downgraded” in one form or the other. I assume the relevance to the OP is that you're saying export Tejas's will have a different "hi-observable"...
by agupta
12 Oct 2019 17:32
Forum: Military Issues & History Forum
Topic: VayuSena Rafale: News and Discussions - 17 Oct 2016
Replies: 2810
Views: 463487

Re: VayuSena Rafale: News and Discussions - 17 Oct 2016

Could you please elaborate on how ? It seems to me your hypothesis is that every OEM will handout the anechoic chamber radar sig profile, emissions spectrum characterization at a fidelity and completeness necessary to devise countermeasures to Pak/China within 18-24 months. Is that what you are tru...
by agupta
12 Oct 2019 17:15
Forum: Military Issues & History Forum
Topic: Kaveri & Aero-Engine: News & Discussion
Replies: 5009
Views: 965944

Re: Kaveri & Aero-Engine: News & Discussion

Nam-ji: I think you guys believe that there is a curve that goes like "$$ invested vs. Thrust". It's not so simple, will be my humble submission. If we extrapolate from that 1 SAFRAN slide (a very dangerous exercise in guesswork), then one would say the Kaveri's real problem is aerothermal...
by agupta
12 Oct 2019 16:54
Forum: Military Issues & History Forum
Topic: Transport Aircraft for IAF
Replies: 3764
Views: 342423

Re: Transport Aircraft for IAF

[quote="chola"]Larger transports like A-400 can be bought off the shelf for now. But we need to MII a mid-sized platform. The C-295 will likely be screwdriver giri since it is unlikely we'll get controllable tech from Airbus. And is there anyway to start a homegrown project like the MTA bu...
by agupta
12 Oct 2019 07:56
Forum: Military Issues & History Forum
Topic: Tejas Mk.1 & Mk.1A: News & Discussions: 23 February 2019
Replies: 1463
Views: 419225

Re: Tejas Mk.1 & Mk.1A: News & Discussions: 23 February 2019

Admiralji mentioned Safran engine development. Safran is in partnership with GE. More than likely If Safran is in financial trouble or GE spins off its engine division, then one of the two will become the managing company, however it’s partnership will only strengthen. The Safran partnership for In...
by agupta
11 Oct 2019 21:29
Forum: Military Issues & History Forum
Topic: VayuSena Rafale: News and Discussions - 17 Oct 2016
Replies: 2810
Views: 463487

Re: VayuSena Rafale: News and Discussions - 17 Oct 2016

I can assure you within 18-24 months the PAF will have a complete Rafale radar signature profile from an anechoic chamber that will be very precise. On top of that, they’ll have the Raafale’s radar emission spectrum and will get countermeasure data too. The Chinese will assist them on it. The only ...
by agupta
11 Sep 2019 19:57
Forum: Military Issues & History Forum
Topic: Indian Military Aviation - 06 March 2019
Replies: 187
Views: 36560

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: 1924
Views: 508249

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: 1924
Views: 508249

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: 5009
Views: 965944

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: 5009
Views: 965944

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: 5009
Views: 965944

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: 5009
Views: 965944

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: 5009
Views: 965944

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: 5009
Views: 965944

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: 5009
Views: 965944

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: 5009
Views: 965944

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: 5009
Views: 965944

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: 5009
Views: 965944

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: 2186
Views: 259158

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: 2111
Views: 473309

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: 3764
Views: 342423

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: 771116

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: 3860
Views: 538756

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: 531707

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: 3860
Views: 538756

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: 2822
Views: 457430

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: 309417

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...

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