Bharat Rakshak

maitya

My Understanding of LCA To follow up to my earlier discussions on LCA, I did lot of reading and also tried to understand the posts and articles of Indranil ( courtesy lockdown ). I had always been perplexed with (aerodynamic) design choices of LCA and had no satisfactory answer. Though I hasten to ...

maitya

The USAF is moving to MRAAM's that are going to be required to exceed the "CCM" performance capability of its current CCM (AIM-9X-II+), while also bettering the end game performance of the AIM-120. So both short range performance and end game agility will be top priority. They've spent mo...

maitya

BTW, what happened to DARE's High Band Jammer pod? It was supposed to replicate the functionality of the SAP-518 and not have the drawback of interference with the indigenous RWR..could it be the DARE HBJ in the picture with the IAF Su-30MKI and not the SAP-518? The item should be in development/te...

maitya

Prasad wrote:We have GaN xband trmms. That's confirmed.

Oh, at what Gain, max O/P Power and PAe figures?
Being GaN Power density would be very good anyway, so not asking.

maitya

Manufacture of GaN-based (gallium) chips for AESA. 2052 is GaAs based TRM. We don't GaN from Israel, as we already have them. There is a nice little TRM from BEL, with GaN transmitter & GaAs receiver. a way to reduce cost. Regarding the ToT, i really don't know what HAL is "producing"...

maitya

V_Raman wrote:I dont fully understand why Kaveri as it exists cannot be mated to a LCA and ~~at least ground tested~~flown in regular squadrons as squadron reserve platforms.

There, corrected it for you ...

maitya

Boost for 'Make in India': HAL's 25 kN aero engine completes inaugural run; can be used for trainer aircraft https://img.etimg.com/thumb/msid-50173781,width-300,imgsize-241461,resizemode-4/boost-for-make-in-india-hals-25-kn-aero-engine-completes-inaugural-run-can-be-used-for-trainer-aircraft.jpg <s...

maitya

<snip> The truth about Kaveri is somewhere in between the uninformed bashing that it receives and the adulation in this forum. The truth is that Kaveri non-afterburning engine is entering production. EOI is out for a potential 80 engine production run. It cannot be without a modicum of success. <sn...

maitya

Agupta sahab, I don't understand your arguments on the lack of an FTB is not a serious impediment. <snip> <snip> This is why I found Maitya's post about other metrics being met so interesting. For DRDO to admit defeat directly, lots of other stuff would have gone wrong than just LCF on the FTB or A...

maitya

Maitya, How much do you think the current Kabini core cost out of the total Kaveri program? to me looks like the turbo fan, casing the after burner are per requirement. So what will it take to come up with a new engine that will poser the MWF and the Naval Tejas Mk2. Nice if it can power AMCA but n...

maitya

Source for your claim that HAL made such claims? I have not yet seen a single authoritative article that claims such weight reductions. Here is link from same thread from 2016. The proposed 800 Kg weight reduction is being discussed. This was in the original HAL proposal, when they pitched the MK1A...

maitya

Cybaruji, I never said that we should do this alone - certifications etc aside, I'm saying yes, by all means, we should go ahead and ask for the hand-me-down cores from GE/Snecma/whosoever. If we are desperate to reimburse R&D budgets of these orgs, so be it ... but we should atleast maximise th...

maitya

We continue to re-hash the same old points that has got discussed umpteen number of times in the past - so maybe, one more time wouldn't hurt: 1) Developing a Turbofan for 110/xx/yy/zz KN with an imported core - this is like asking to develop LCA with an imported FCS. Might as well go for lic-mfg of...

maitya

the LCA was designed for the Kaveri. And the Kaveri has dimensions which made it comparable to the RD-33. The dimensions are fine. It is similar to F404, but not the weight. Extra weight means redesign of LCA . <snip> That's not correct ... accommodating some 100 odd Kg extra weight is easily withi...

maitya

Yes sir. Specifically these blades have the ysz tbc-coating by ebpvd done at arci with cooling holes. Actually I's hoping (against hope and almost a wet dream) that GTRE would take the easy way out and go for a LZ-YSZ bilayer TBC tech for both HPT and LPT blades and vanes, without delving too much ...

maitya

Prasadji, have highlighted the operative word of the below quote: ... Presently, efforts to make use of single-crystal turbine blades developed by Defence Metallurgical Research Laboratory (DMRL) ... As we all know we have had lab-production-level DMS4 based (4th Gen) SC blades from atleast 2015 onw...

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...

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