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#380
by
edkyle99
on 15 Dec, 2014 14:48
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There's one thing that leaves me curious: how are the boosters attached to the core stage? How is the load path?
The way this thing looks on the launch pad it looks like the main load is transferred through the forward attachment, much like Shuttle SRBs. But that forward attachment point connects to the interstate and this would mean that the whole structure has to be designed to pull the completely fueled first stage. But designing the whole thing including the interstate to cope with these tensile loads has to add a lot of weight, doesn't it? OTOH they don't have to design a load path that carries both the first and second stage weight through the bottom of the second stage during maximum acceleration by the boosters and the core stage probably pulls fewer g's when it's still fully loaded so this might offset it a bit.
But still... How did this work out for the ET for Shuttle, it must have pulled the LH2 tank section, too, plus the orbiter, although with at least some compensating thrust by the SMEs.
To my eyes it looks like the load path is through the upper solid rocket motor connection, which is near the top of the interstage. Yes, the interstage structure has to be strong enough to handle the tensile loads produced by the hanging core stage, but the design also relieves the core stage and interstage from having to be designed to handle the likely greater loads produced by the solids. (Also, wouldn't the interstage have to be able to handle compression loads of the same magnitude regardless?) Shuttle used a similar setup, though loads were transferred via. a beam rather than by trunnions (or whatever the connections are called on GSLV Mk 3). On Titan III/IV, which in my mind are similar to GSLV Mk 3, the solids, interestingly enough, pushed from the base of the core stage.
- Ed Kyle
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#381
by
pippin
on 15 Dec, 2014 15:28
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Well, push and pull loads are still a pretty different story. For push loads you can pretty much just stack aligned tubes while for pull loads you need to design your interconnects to carry the load.
Plus, I disagree that the design relieves the interstage and the first stage because they now have to carry both push and pull loads.
I think it was the same for shuttle but that's why I was wondering whether there were estimates about how much of a weight penalty it meant.
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#382
by
antriksh
on 15 Dec, 2014 15:38
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Thrusters in action (after 9:18).
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#383
by
AJA
on 15 Dec, 2014 19:06
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Well, push and pull loads are still a pretty different story.
...
Plus, I disagree that the design relieves the interstage and the first stage because they now have to carry both push and pull loads.
Huh? I get that materials may have different tensile and compressive strengths.... but let me illustrate my doubts with an example.
Isn't a beam that's being loaded with 20 N of compressive force, equivalent (structural dynamics wise) to an I-beam that's being loaded with 80 N of compressive force, and 60 N of tensile force... ON THE SAME BEAM?
Or is this something to do with how the force will remain 20 N compression even in the case of some small strain in the first beam, but might reach 75 N compression, with 60 N tension in the second case - given the same strain? Leading to a net effect of 15 N compression... which then leads to more (possibly) divergent behaviour between the behaviour of the beams.
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#384
by
pippin
on 15 Dec, 2014 19:12
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Huh? I get that materials may have different tensile and compressive strengths.... but let me illustrate my doubts with an example.
Isn't a beam that's being loaded with 20 N of compressive force, equivalent (structural dynamics wise) to an I-beam that's being loaded with 80 N of compressive force, and 60 N of tensile force... ON THE SAME BEAM?
Or is this something to do with how the force will remain 20 N compression even in the case of some small strain in the first beam, but might reach 75 N compression, with 60 N tension in the second case - given the same strain? Leading to a net effect of 15 N compression... which then leads to more (possibly) divergent behaviour between the behaviour of the beams.
The question is a different one: you can have completely different profiles you apply force to.
Extreme example:
1. Take a glass.
2. Put a plate on top of it (just lay it down)
3. Lift the glass. You can lift the plate along with the glass (compressive force)
4. Lift the plate. The glass will stay where it is (no tensile force transferred).
In this case you will have attachment points between the stages and even the pressure vessels and outer skirts within a stage and all of this will have to take very different load distributions whether you push or pull. Now the first stage will have to _both_ push and pull so you will probably have a rigid structure that can take pull and push loads equally well and the separation plane to the 3rd stage is still above the booster attachment points so it may be possible to design the whole thing to take both forces equally well, I just wonder (and I don't know the answer) whether there still will be a cost in terms of structural weight.
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#385
by
abhishek
on 16 Dec, 2014 02:11
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A0920/14 - IN VIEW OF DNG ZONE DECLARED BY INDIAN AUTHORITIES DUE TO LAUNCH OF FLIGHT VEHICLE MARK III (REF A2212/14 VOMMYNYX) FLW AREA WI COLOMBO FIR DECLARED AS DNG ZONE. 0615N 09055E 0624N 09101E 0600N 09200E 0532N 09200E THE LAUNCH WILL BE ON ANY ONE OF THE DAY DURING THE PERIOD. ACTUAL DATE OF LAUNCH WILL BE INTIMATED 24HRS IN ADVANCE THROUGH A SEPARATE NOTAM WHEN DECLARED BY INDIA. MSL - UNL, DLY BTN 0330-0730, 18 DEC 03:30 2014 UNTIL 31 DEC 07:30 2014. CREATED: 05 DEC 09:32 2014
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#386
by
vyoma
on 16 Dec, 2014 13:13
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No brochures yet?
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#387
by
antriksh
on 16 Dec, 2014 13:43
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No brochures yet?
yeah
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#388
by
vyoma
on 16 Dec, 2014 15:32
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- Mission Readiness Review (MRR) and Launch Authorisation Board (LAB) met on Dec 16, 2014 to review progress of prelaunch activities and cleared launch for Dec 18, 2014 at 09:30 hrs (IST)
- 24 and a half hour countdown for the mission will commence at 09:00 hrs (IST) on Dec 17, 2014
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#389
by
pargoo
on 16 Dec, 2014 21:06
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What are the chances of any hi-res's of this new vehicle. I find it impossible to pay attention to a program that only releases tiny postage-stamp images. Like going to see the Mona Lisa and looking at it through a pair of back-to-front binoculars from the other side of the room
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#390
by
atnanda
on 17 Dec, 2014 01:45
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Is there a broadcast link for this launch ? I do not see it on ISRO's website
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#391
by
abhishek
on 17 Dec, 2014 02:33
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24 and a half hour countdown for the launch begins
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#392
by
abhishek
on 17 Dec, 2014 02:36
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Is there a broadcast link for this launch ? I do not see it on ISRO's website
Yes!
You can watch it live on DD's Youtube channel or else in ISRO's website directly tomorrow.
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#393
by
abhishek
on 17 Dec, 2014 02:45
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#394
by
Steven Pietrobon
on 17 Dec, 2014 03:41
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You can watch it live on DD's Youtube channel or else in ISRO's website directly tomorrow.
Could you give a link for DD's Youtube Channel? I don't know what DD stands for and couldn't find it in a Google search.
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#395
by
seshagirib
on 17 Dec, 2014 03:49
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You can watch it live on DD's Youtube channel or else in ISRO's website directly tomorrow.
Could you give a link for DD's Youtube Channel? I don't know what DD stands for and couldn't find it in a Google search.
https://www.youtube.com/user/DoordarshanNationalDD stands for Doordarshan
Door (Hindi) = far, distant
Darshan (Hindi) = see, view
edit: fixed the hyperlink.
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#396
by
Kryten
on 17 Dec, 2014 03:52
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Could you give a link for DD's Youtube Channel? I don't know what DD stands for and couldn't find it in a Google search.
"https://www.youtube.com/user/DoordarshanNational"
DD stands for Doordarshan
Door (Hindi) = far, distant
Darshan (Hindi) = see, view
Given that link doesn't seem to lead anywhere,
here's a working one.
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#397
by
pargoo
on 17 Dec, 2014 05:06
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Here's a quick airbrush of one of them, minus the idiotic text.
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#398
by
Kryten
on 17 Dec, 2014 05:23
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Does anyone have a good image of CARE before encapsulation? The only ones currently in this thread are one with a clearly erroneous aspect ratio and one with a logo crudely photoshopped onto it.
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#399
by
hpras
on 17 Dec, 2014 05:42
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That rocket does look the business.
Here's a quick airbrush of one of them, minus the idiotic text.
