Bharat Rakshak

maitya

I tweeted following stuff few days back. Tender from HAL for outsourcing of Single Crystal Blade castings for HPT and LPT. Interesting. My best guess is this is for Adour 871 engines which power IAF's Hawk AJT fleet. <snip> Even more interestingly, GTRE is looking for 3D printed HPT Nozzle Guide Va...

maitya

^^ Betw from the same TF 2011 doc ... The process is currently being used for making silica cores for Kaveri aerofoil castings that include HPT turbine blades and vanes and LPT blades. It is being adapted for making alumina cores that are required for producing single crystal aerofoil casting Produc...

maitya

Is Hal trying to upgrade the Jag engine in-house? That would be something... Adour engine project has been ongoing for a while now. compressor side appears to be done and turbine side is being done now. Blades were machined by a private company in bangalore earlier. Not sure if they're being done n...

maitya

DMS4 is a marginally better material than CMSX-10 according to DMRL. GE -414 uses FSX 414. And they built their sc blades at koraput iirc. So it wouldn't be far fetched to assume HAL make the htse scb blades themselves. Yep if one goes by raw temp handling capability alone ... quote from my previou...

maitya

I just noticed that there was a tender floated by GTRE in Jan Feb 2019 period for Machining, Brazing and TBC for SCB . Most likely for Kaveri. Given the inflow of a number of tenders in last frlew months on various modules, its safe to conclude they are building new prototypes. Are they intending t...

maitya

4) When DMS4 based SC blade tech was already available in house, why didn't HAL engine division use it for the HPT stages for HTFE-25? Why did they constraint themselves to 1200deg K TeT levels via equiaxed casted ones ? HTFE-25 have In718 3D printed cooled blades. rotor blades as well as HPT NGV. ...

maitya

SC blades are made in the country. We have infra to investment cast of SC blades. We have been doing it for last one and half decade. In early days rejection rates were high. That has been under control. However we never used the infra for our own design till now. Obviously we also produce DS blade...

maitya

Penny wise pound foolish. The Americans, Soviets, and the French did not spend hundreds of millions to develop their engine technology. They spent billions of dollars in their R&D to develop basic versions of fighter jet engines and more billions to refine those engines into the engines we know...

maitya

[Part 3] A word about 8YSZ and LZ TBCs - note, Wiki has good level of general details wrt the TBC concept : 1) The "traditional" 8YSZ TBC (that has been ther for 4 decades now) allows for maximum surface temperature capability of about 1200 °C - beyond that degradation of the coating (in ...

maitya

[Part 2] Thus one assertion can be - that higher TeT is desired of, DS to SC graduation is inevitable in any modern turbofan development program. But that is not because of incremental metal temperature capability addition etc (at best 20-60 deg C advantage). The actual advantage of moving from DS ...

maitya

copying on ramana's request from BRF twitter dhaaga: --- <snip> No Jay, I meant the SCBs were almost ready from our labs and it was only a question of jigs. I don't recollect any news after that we made to make the prototype (k9?). The failure was with the existing blade.. and we were working on th...

maitya

even within the EU biraderi, for the typhoon eurojet engine, RR does not really share the hot section tech with MTU who makes the cold section. hot section fluid dynamics, physics, material science is one of the highest crown jewels of IP. @ world class level only saturn, GE, P&W, snecma and RR...

maitya

This very old (circa 2014) post of mine should have been "preserved" in this sticky thread ... but for some reason I didn't - so doing now: A long article: An 'engine' for India's growth ... ... Given the specifications of the AMCA a much higher thrust engine than the designed output of th...

maitya

<snip> Earlier, they had got to within 1 m/sec of the desired sink rate with the fixed Levcon position. This last detachment, the Levcon was controlled by the pilots. They reached over half the sink rate desired. Every thing went really well. Now they are back in Bangalore to tweak the computer and...

maitya

Interesting, really really interesting ... HTFE TET: 1450 deg C but using equiaxed HPT blades (Wow!! in fact double Wow!!). Also OPR of 20 is respectable (but 27 would have been the WoW factor). HTSE: Uses SCB (but doesn't say the TET achieved there) - assuming the TET is 1550deg C (one can have li...

maitya

^^ Neelaji, is the HTFE weight of 450kg correct (even JayS mentions it) ... asking as I have seen a weight of 350Kg mentioned at quite a few places. Another point is, the bulleted-points that I mentioned in my previous post, all would help reducing the weight (and few other things as well), quite a ...

maitya

Also any data on the HTFE-25 engine for that will be used to power this plane. https://twitter.com/nileshjrane/status/1099755134601576448 Interesting, really really interesting ... HTFE TET: 1450 deg C but using equiaxed HPT blades (Wow!! in fact double Wow!!). Also OPR of 20 is respectable (but 27...

maitya

<snip> A guy who has popular tea stall was overheard saying that Kaveri hot parts are going to become composite for weight and performance advantage. ( not HP turbine though). <snip> I think he's alluding to Titanium Aluminide (TiAl) for the HPC stages (currently they are all "traditional"...

maitya

^^^Again, it seems these queries wrt delta-wing being more-draggy-less-draggy etc tend to keep coming up from time to time - so thought of reproducing one of my very old posts from Jan 2015 , which may help people (since it was made as much as possible in lay-man terms) get a perspective of lift-vs-...

maitya

Indranil wrote:Certainly, it is for new Kaveri.

Sorry I may have missed recent news items etc, but what is this new kaveri?

maitya

^^the double delta should generate more drag could that be the reason? Ummm, would you really need Thrust and only Thrust to negate drag is it? How about lift? And how about vortex-induced lift and more so about flow-attachment aspects of LCAs double-delta config etc. Some references are here and h...

maitya

Ok, so here it is ... a simplistic (yes, I must admit almost embarrassingly simplistic) side-by-side comparison of this so-called Kaver-with-M88-core, original Kaveri and “paper-injin” called “Improved Kaveri”. (and no I can’t use Ganga, as it is copyrighted by Vinaji). https://imgur.com/xe3xRgJ.pn...

maitya

Ok, so here it is ... a simplistic (yes, I must admit almost embarrassingly simplistic) side-by-side comparison of this so-called Kaver-with-M88-core, original Kaveri and “paper-injin” called “Improved Kaveri”. (and no I can’t use Ganga, as it is copyrighted by Vinaji). https://imgur.com/xe3xRgJ.png...

maitya

<snip> I will tell you my gut feeling: GTRE had a turbojet engine that works in prototype. So they wrapped a small fan around it and claimed its a turbofan. A BPR of 0.16:1 is almost like nothing. Its practically a turbojet. Might as well put a Rallis fan (my old hostel fan) in front of the turboje...

maitya

Maitya, Maybe I should have addressed you? IR if you know any Kaveri design guy ask him how a M88 core(designed for BPR 0.3) will work in a Kaveri (Designed for BPR 0.16) shroud? I don't think it will unless its de-rated. And they say its dia is smaller than the Kaveri shroud. Ramanaji, apologies, ...

maitya

<snip> What Maitya sir, JayS, UB, Haridas ji can teach us is what would be the BPR of a Kaveri fan with a M88 core. These numbers can be easily calculated from numbers present online. Maitya sir had a good excel sheet going. <snip> Hello Indranil, I think you are talking about this excel: http://i....

maitya

<snip> one day i read that kaveri met all the specifications...immediately after few days another report will be published that kaveri is not meeting specs and can be useful only for fitment on locomotives and war ships? You have stated that GTRE doesn't have engine testbeds? Hope you know that AL-...

maitya

Kaveri has not reached a stage where it can be tested on a Mig-29 replacing say one of the RD-33 with Kaveri .....even one has to reach that stage ........All this talk about meeting dry thrust and not meeting wet thrust is juggling with words from Certification POV you need to meet the requirement...

maitya

Gaganullah, no canards. They have not found any distinctive advantage with the canards with LCA config. LCA navy MK1 will soon have active LEVCONs to increase control at lower landing speeds. Whether they port it to the the AF version needs to be seen. It might help with CnBeta and marginally bette...

maitya

Simply increasing the mass-flow will give higher thrust ratings but at the cost of propulsive efficiency (2nd and 3rd last rows) etc - which would mean poor SFS etc (but that's price to pay for "leaky-turbofan" type design, a la F404, presumably for achieving flat-rating requirement etc)....

maitya

Report is now available on Blog http://ajaishukla.blogspot.in/2017/08/tejas-fighter-finally-achieves.html ... HAL has created five “Tier-1” suppliers that each build a part of the Tejas. The front fuselage is supplied by Dynamatic Technologies Ltd, Bengaluru; the centre fuselage by VEM Technologies...

maitya

I think Austin saar is right That we manufacture 60% Kaveri and assemble 40% m88 core in numbers maybe 300 + engines. Second option is that: 2. We keep working on Kabini core for another decade and keep assembling 100% GE 404 / 414 engines. Option 1 is better this way we will learn the production i...

maitya

<snip> Betw Vinaji, not sure how and where to host an image and link it's URL from here ... (like I earlier used to do, before that site went kaput). Your above thesis was backed by my back-of-envelope-simulator which showed Thrust growth options and corresponding impacts to TeT and OPR and Thermal...

maitya

Yes the M88 core was offered in the past too but not taken as GTRE did not think they need it. They focused on the LP/AB thinking they need to get more out of them. If you note DRDO chief's statement 60% of new Kaveri will be GTRE. So the LP/AB were not the problem. there is the ~ 60%. If I had the...

maitya

<snip> They didn't go for co-cured structure because that technology was simply not there for the use on LCA. Its a recent development in NAL and is still not so mature that they can use it on an operational fighter . Not even MK2 will have co bonded co-cured wing. Only AMCA will have it. Even toda...

maitya

Ideally, a stealthy Mk3 which is spiral development of Mk2. Basically what the Chinese are doing with their J-10s. In this, respect if LM accepts to codevelop what they fielded for the South Korean program with us; or if SAAB agrees to merge their 5th gen program program with our Mk-3 version, we s...

maitya

One thing that i have contemplated is why not ADA hand over MK1A and Mk2 development to HAL and get on full fledged development of AMCA . It will be good as all turf wars can be avoided and MK1A lessons will easily flow into Mk2. But, I think there is too much pride at stake here. I don't know if s...

maitya

This is a good enough confirmation that the test was a success Prime Minister Narendra Modi congratulates DRDO for successful Agni-V missile launch . Buried within the report are congratulations from the President as well. Now off to User Trials ... betw with the success of Agni-V, why do we really ...

maitya

What happened to the much displayed desi AESA radar at the last Aero-India? Another great 'technology demonstrator" what? If this is not trolling of worst kind (combined with naked flame-baiting), I don't know what trolling is!! Response will be there, but after allowing the admins to express ...

maitya

<snip> In the hind sight it would be easy to criticise but it would have been good if they went with two engine program one by GTRE and other by HAL to develop an engine for Tejas. The GTRE team simply lead every one on a rosy path that told us Kaveri would be ready , Now if they did not anticipate...

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