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Search found 2801 matches

by JayS
20 Jan 2018 02:06
Forum: Military Issues & History Forum
Topic: LCA: News & Discussions: 15 August 2017
Replies: 3225
Views: 401974

Re: LCA: News & Discussions: 15 August 2017

The flying daggers are an awesome squadron. They are married to the aircraft. They sense that what they are doing is very rare in the history of IAF and the country. You have heard how pilots have said that they stayed up all night with the technicians trying to fix something. What a feeling it mus...
by JayS
19 Jan 2018 20:05
Forum: Military Issues & History Forum
Topic: LCA: News & Discussions: 15 August 2017
Replies: 3225
Views: 401974

Re: LCA: News & Discussions: 15 August 2017

SP5 has turned out to be the trouble-child of first-time parents. In the latest HSTT, some oil leaks were reported. The aircraft has now been re-assigned to Line 1 for rectification. Line 1 is now delivering an aircraft in less than 2 months. The last one was delivered in middle of Dec. So middle o...
by JayS
19 Jan 2018 13:26
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Zynda keep it here for focus and continuity. A few questions to you: - 2024 is weldable? What is its fracture toughness strength? Looks like 1/2 of good steel like 4340 (24 vs 50). Yes 2024 is welable. Al 6013 is more suitable, is welable and in addition stronger than 2024 & corrosion resistant...
by JayS
18 Jan 2018 23:02
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

^^I meant weld line already provides one load path...why have another fastener load path. Hi Loks are used instead of rivets rather than bolts because hi loks are permanent fasteners. Usually hi-loks are for high strength applications and they provide better fatigue resistance than normal rivets. A...
by JayS
18 Jan 2018 22:25
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

I wonder what is the purpose of the hi-lok fasteners & attachment to a composite component. I think it may be to serve as an alternate load path to provide multiple load path capability. Only single load path is there. Hi-lok are preferred for tight spaces due to installation ease. As such hi-l...
by JayS
18 Jan 2018 21:59
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Akshay Kapoor wrote:Sorry just to be clear avg wt of soldier is 70 KG


Saar, I would use 95 percentile weight not the average. With that and max possible combat load ever, and some margin, 300kg looks OK for 2 Soldiers.
by JayS
18 Jan 2018 21:52
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

JayS, I dunno how expensive a casting manf process would be...as Ramana pointed out, the inner surface is primed with chromate conversion coating to give a degree of protection from corrosion. Would be easy to apply on the inner wall surface of the tube if it was a separate component. I am sure it ...
by JayS
18 Jan 2018 20:36
Forum: Military Issues & History Forum
Topic: LCA: News & Discussions: 15 August 2017
Replies: 3225
Views: 401974

Re: LCA: News & Discussions: 15 August 2017

We have had discussions on this very many times. Like IN, IAF and IA needs to develop its own technical/engineering cadre as well as highly specialized acquisition and program management cadre. A lot of admin power needs to be shifted to the Forces from MoD babus. Ideally the system should have wor...
by JayS
18 Jan 2018 18:37
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

I would want to point out that the following "analysis" is based on a lot of assumptions which will render it highly approximate. IMO, the boom is fabricated using Aluminum 2024-T3 Extrusion and not cast. Just curious. How would a the component be extruded..? The flanged component which f...
by JayS
18 Jan 2018 12:02
Forum: Military Issues & History Forum
Topic: LCA: News & Discussions: 15 August 2017
Replies: 3225
Views: 401974

Re: LCA: News & Discussions: 15 August 2017

We have had discussions on this very many times. Like IN, IAF and IA needs to develop its own technical/engineering cadre as well as highly specialized acquisition and program management cadre. A lot of admin power needs to be shifted to the Forces from MoD babus. Ideally the system should have work...
by JayS
18 Jan 2018 11:57
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Like many here, I 'think' the failure is fatigue related. Somehow, the 2-man restriction was not followed religiously. The heli itself seems to be very stable under the 3-man-on-the-rope load which may have provided a false sense of security. The boom got over-stressed again and again, finally lead...
by JayS
18 Jan 2018 11:45
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Even if it’s 300 kg it should have some margin built in. A soldier with rifle and packs would not be more than 100 kg som3 soldiers at 300 kg should not create this stress. There is one issue and I am not an engineer to speak with authority. There are two types of loads - static load and dynamic lo...
by JayS
18 Jan 2018 01:38
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Even if it’s 300 kg it should have some margin built in. A soldier with rifle and packs would not be more than 100 kg som3 soldiers at 300 kg should not create this stress. For all we know, there is enough margin. Until the root cause analysis points out to design deficiency, we cannot say there wa...
by JayS
18 Jan 2018 01:25
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Like many here, I 'think' the failure is fatigue related. Somehow, the 2-man restriction was not followed religiously. The heli itself seems to be very stable under the 3-man-on-the-rope load which may have provided a false sense of security. The boom got over-stressed again and again, finally lead...
by JayS
17 Jan 2018 20:05
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Just to confirm Indranil's chaiwalla account - 2 pers at a time, 300kg, indeed the limit for ALH. Army knows what went wrong from their side (might not have stopped failure of that component IMO but definitely would have stopped the fall of Soldiers). I expect hole would be plugged soon enough from ...
by JayS
17 Jan 2018 10:57
Forum: Technology & Economic Forum
Topic: Aerospace Engineering - Aerodynamics, Structures, Avionics, Flight Dynamics - Technical Discussions
Replies: 63
Views: 5754

Re: Aerospace Engineering - Aerodynamics, Structures, Avionics, Flight Dynamics - Technical Discussions

Interesting stats from a recent news: 2017 is termed as the Safest year ever for Aviation Travel. Not a single jet accident or not a single live lost. Though some serious accidents happened e.g. Fan module loss from French A380. But overall pretty impressive feat. As of today the chances of a Jet in...
by JayS
17 Jan 2018 10:55
Forum: Technology & Economic Forum
Topic: Civil Aviation Development & Discussion
Replies: 4244
Views: 264658

Re: Civil Aviation Development & Discussion

2017 is termed as the Safest year ever for Aviation Travel. Not a single jet accident or not a single live lost. Though some serious accidents happened e.g. Fan module loss from French A380. But overall pretty impressive feat. As of today the chances of a Jet involving in an accident is 1 is 16 Mill...
by JayS
16 Jan 2018 21:41
Forum: Military Issues & History Forum
Topic: LCA: News & Discussions: 15 August 2017
Replies: 3225
Views: 401974

Re: LCA: News & Discussions: 15 August 2017

You can do geodesic and nongeodesic winding for pressure vessels and various other things like T bars etc. Other method is to layer sheets or tapes depending on the need. Tejas uses multiple layers of carbon fibre sheets. Everything I have read points to tapes being used in LCA, not fabric/sheets. ...
by JayS
16 Jan 2018 19:53
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Karan, I am questioning the wisdom in designing and qualifying the rope system for only two persons at a time (which is what Indranil is pointing to) precisely considering the real life limitations on maintaining such SOP in strictest sense, especially in the actual war scenarios. There are multipl...
by JayS
16 Jan 2018 14:44
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Just doing some googling. I find something which I didn't see before. May be it answers my question to some extent. But can't say for sure. Rope insertion System for Bell helicopters. It allows 4 persons at a time on each side. https://www.aero-access.com/products/bell-205-212-412-uh-1h-fast-rope-ki...
by JayS
16 Jan 2018 14:15
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Also ALH is being given pride of place, by IA IMHO to correctly demonstrate to the powers that be, how many important acquisitions are from domestic sources. By undertaking this op the very next day, when IA could have justifiably pulled out the ALH, is a big boost for both ALH and HAL. I hope HAL ...
by JayS
16 Jan 2018 14:12
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

It looks like Dhruv is hovering a bit lower than the accident video. Also, it looks like they are doing one man at a time. YESExgrTNzM In the accident video, there were somethings which looked at a little different to my untrained eye than other demos. I don't know if they contributed to anything, ...
by JayS
16 Jan 2018 12:56
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Jay, I don’t see your point. How do you know that the 2-man decision was unilateral? At the very least, the armed forces accepted the boom with the restriction. How difficult would it be to specify 2 is not enough, we need 3. And how difficult would it be for HAL to redesign the boom for 3? We don’...
by JayS
16 Jan 2018 12:42
Forum: Military Issues & History Forum
Topic: LCA: News & Discussions: 15 August 2017
Replies: 3225
Views: 401974

Re: LCA: News & Discussions: 15 August 2017

prasannasimha wrote:They use sheets of carbon fibers. It is not wire wound like ISRO's geodesic wound tanks.


Wire wound..? Can you direct me to some source where I can see what is this process exactly..?
by JayS
16 Jan 2018 12:41
Forum: Military Issues & History Forum
Topic: LCA: News & Discussions: 15 August 2017
Replies: 3225
Views: 401974

Re: LCA: News & Discussions: 15 August 2017

He said the IAF would induct Mark 2 fighters with higher thrust engines and new weapons by 2027. This is a realistic and doable timeline if money flows as and when required. They should also be able to obtain the Enhanced F414s allowing some margin on weight and performance for the late 2020s if th...
by JayS
15 Jan 2018 18:55
Forum: Military Issues & History Forum
Topic: LCA: News & Discussions: 15 August 2017
Replies: 3225
Views: 401974

Re: LCA: News & Discussions: 15 August 2017

Not when you lay with hands. I have never came across a single aplication where unidirectional tape is hand lay-up-ed.
by JayS
15 Jan 2018 18:15
Forum: Military Issues & History Forum
Topic: LCA: News & Discussions: 15 August 2017
Replies: 3225
Views: 401974

Re: LCA: News & Discussions: 15 August 2017

Which part of LCA is manufactured using tape..?? I have never seen or heard. Why would anyone choose tape layup if its to be done with hand rather than going for normal weaved cloth..? Is this a case of DDM reporting..?
by JayS
15 Jan 2018 13:00
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

JayS, what you are supposing is that only this demo saw three people on the boom. What if this has happened repeatedly because therebwas sone sort of miscommunication that >2 people could be on the boom. And if this occurred repeatedly wouldn't the metal age/ fatigue faster? Could that be a reason,...
by JayS
14 Jan 2018 19:19
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

No Jay, US special forces have a strict restriction of no more than three guys on the rope at any given time up to a maximum of 600 lbs. Even for heavy helis like the CH-53. Weight saving on the boom is not an issue here. Indranil, do you think that restriction is in anyway because of limitation of...
by JayS
14 Jan 2018 14:45
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Paanwalla, chai walla, cigarette walla everybody telling me that the boom is qualified for two persons at a time. Those of you who can access the manual can check for yourself. Meanwhile Army and HAL maintaining dignified silence as is desirable now. I deliberated a lot before sharing this. But I a...
by JayS
14 Jan 2018 14:19
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

JayS, Chopped fiber also won't see the fiber. We need a good picture. I would expect fibres on the failed section whether its chopped or weaved. Generally glass fibres are chopped to like a inch or two length. (Using a finely chopped fibres would be basically defeating the whole purpose of using co...
by JayS
14 Jan 2018 13:46
Forum: Military Issues & History Forum
Topic: Indian Military Aviation - 21 Sept 2015
Replies: 3556
Views: 242581

Re: Indian Military Aviation - 21 Sept 2015

Mod Note: I have moved all recent Saras and Civian aviation releted posts to Civian aviation thread. Let's keep Saras in Civilian domain unless we are discussing IAF version specific things.
by JayS
14 Jan 2018 12:57
Forum: Military Issues & History Forum
Topic: Indian Military Aviation - 21 Sept 2015
Replies: 3556
Views: 242581

Re: Indian Military Aviation - 21 Sept 2015

Rakesh Sharma left in 1998, before LCA's first flight. So he never flew LCA. But I suppose he did indeed test flew LCA's FCS on the F16 emulator in US.
by JayS
12 Jan 2018 20:15
Forum: Military Issues & History Forum
Topic: Su-30: News and Discussion - August 9, 2014
Replies: 2326
Views: 184566

Re: Su-30: News and Discussion - August 9, 2014

John wrote:
ramana wrote:X-Post:

IMO while ability to carry is what is promoted as reason for structural change it will also allow it to carry few other type of missiles.

Such as..?
by JayS
12 Jan 2018 20:15
Forum: Military Issues & History Forum
Topic: Su-30: News and Discussion - August 9, 2014
Replies: 2326
Views: 184566

Re: Su-30: News and Discussion - August 9, 2014

raj-senthil wrote:Image


That's an impressive portfolio. I really have high hopes from companies like Dynamitic, VEM, Alpha Tech to be the key pillars of Indian MIC.
by JayS
12 Jan 2018 20:10
Forum: Military Issues & History Forum
Topic: 'Make in India' Single engined fighter
Replies: 5153
Views: 454450

Re: 'Make in India' Single engined fighter

A prudent way could be to engage the import lobby in the great Indian Bureaucratic process while keep working on LCA MK2 with full pace. :mrgreen:
by JayS
12 Jan 2018 11:56
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Exactly. Chopped fiberglass and not Metal Then failure can be explained. It's difficult to control it's properties. So it's a CFRP load transition block to which composite boom is attached with those pins and collars. That explains the pin and collar which are common for composites. OK, some misund...
by JayS
12 Jan 2018 09:43
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

From the pics, not just the none-metallic outer pylon, even the inner metallic one also seemed to have snapped off at the bolt holes. Its actually the inner one which failed. The outer part would have had a clean separation if not for the two intact bolts at bottom. Note that this part is upside do...
by JayS
11 Jan 2018 23:28
Forum: Military Issues & History Forum
Topic: Indian Military Helicopters
Replies: 3133
Views: 317003

Re: Indian Military Helicopters

Zynda, look carefully. Its easy to figure out top side and bottom. Load pulling down on cantilever. Top side in tention. See top side in picture. Torn off. All bolts missing. Bottom side in compression. So two bolts still there. Lower part didnt fail. A part of boom remained attached. The boom obvio...

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