Our proud stealth frigates fleet now fully operational
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how to reduce RCS!!
This is the right spirit--
I find many modern navay ships(names of countries omitted)
just dunt follow these simple rules!!
quote
Total stealth design - no stone is left unturned
In order to achieve optimum stealth properties virtually every part of the vessel is examined, evaluated and adapted to minimise the signature.As an example, the work done to achieve an extremely favourable radar cross-section has included the following:
- Shaping, i.e. flat hull sides inclined outwards and flat superstructure and mast surfaces, arranged into truncated pyramids.
- Structure of sandwich-construction carbon fibre reinforced plastic (CFRP) for good conductivity and the necessary flatness, i.e. without the “starved horse pattern” commonly associated with steel and aluminium plating on a supporting framework.
- Concealed installation of weapons, sensors, sonars, cranes, boats etc.
- All external doors and hatches of “smart” design, with conductive coaming.
- Stealth adaptation and platform integration of all above-deck equipment.
- Use of flush-mounted, cavity-backed, miniature and retractable antennas.
- Use of frequency selective surfaces (FSS) for covering some antennas.
- Limited use of radar absorbent material (RAM)
- Special attention is given to the design of external details, e.g. air intakes/outlets, windows etc.
- RCS analysis using advanced prediction tools.EOQ
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http://www.kockums.se/aboutkockums/navalstealthmain.html
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Yes, I'm aware that turning the FCR on a Helo will announce to the whole world one's presence. But if I have something to shoot him with, and I think he's gonna shoot me with something, I better shoot him FIRST.
Besides, when I was talking about detecting the helo, I really meant the eyes in the sky doing the job. AWACs has to keep track of all these.
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few photo here
http://www.sgforums.com/forums/1164/topics/326579?page=5
I think the design follow the letters and spirit of this--
http://www.kockums.se/surfacevessels/visby.html
http://www.kockums.se/aboutkockums/navalstealthmain.html
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gOOGLE SEARCH BY ''F21+heavy+guided+torpedo''
Search Radar
Thales Herakles Multi-function Radar (MFR)
Navigation Radar
Terma Electronic Navigation Radar
Surface Missile
Harpoon Surface Missile System
Anti-Missile Missile
MDBA Aster Anti-Missile Missile System
Naval Gun
OTO Melara 76mm Gun
Sonar
EDO ALOFTS Active-Passive Sonar
Torpedo
Whitehead A244S System
Communications
ST (Elect) CET Integrated Communications System
Gun Fire Control System
EADS Gunfire Control System
Command and Control
DSTA in-house developed Combat Management System (CMS)
Standard Operating Common Consoles
ST (Elect) SES
http://www.mindef.gov.sg/weapons/frigate/combatsystems.asp
KKK
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u can read ythe book here
The Naval Guide of Combat Fleets of the world
by ERIC WERTHEIM
http://books.google.com.sg/books?id=5iDJCTRvNjEC&pg=PA198&lpg=PA198&dq=%27F21+heavy+guided+torpedo%27&source=bl&ots=8jQ-o7fHEc&sig=2IJTwid98aLih3B0Z-79kQGfhR4&hl=zh-CN&sa=X&oi=book_result&resnum=6&ct=result#PPA700,M1
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WHy the hell is Lionnoisy glorifying some cheap unexceptional frigate that is merely bang for buck for the current size? You do realise that for all that stealth, when the ship is rocking away in uneven waters, or when water is splashing about, the RCS goes up a few orders of magnitude?
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and for that matter, in the formidable class frigate, we cut back on the stealth design by featuring a all steel ship.
even the taiwanese and UAE la fayette variants have some form of composite components to help reduce weight and RCS.
and the joke of it is, DCNS built the formidables, why is he quoting kockums ? so a few nicely illustrated pictures can show stealthly/ vs not stealthy ? so if i show a picture of a flying pig, conclusively
1) all pigs can fly
2) flying is for pigssimply dosent do credit to the complexity of the issue.
atypical lionnoisy. noise, crap and in desperate need of a lobotomy.
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Originally posted by sgstars:
and for that matter, in the formidable class frigate, we cut back on the stealth design by featuring a all steel ship.
even the taiwanese and UAE la fayette variants have some form of composite components to help reduce weight and RCS.
and the joke of it is, DCNS built the formidables, why is he quoting kockums ? so a few nicely illustrated pictures can show stealthly/ vs not stealthy ? so if i show a picture of a flying pig, conclusively
1) all pigs can fly
2) flying is for pigssimply dosent do credit to the complexity of the issue.
atypical lionnoisy. noise, crap and in desperate need of a lobotomy.
Actually composites for a ship is a very very bad idea. There was a Norweigian mine hunter that was an all composite ship and the end result after a fire was the ship literally burnt itself out into ashes very very fast. That's why the Swedish put in a lot of effort to make sure the Visby has a lot of fire retardation, but odds are, when it gets hit by a anti-ship missile, all that rocket fuel with oxidizers is simply going to burn the ship up.
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Originally posted by Fingolfin_Noldor:
Actually composites for a ship is a very very bad idea. There was a Norweigian mine hunter that was an all composite ship and the end result after a fire was the ship literally burnt itself out into ashes very very fast. That's why the Swedish put in a lot of effort to make sure the Visby has a lot of fire retardation, but odds are, when it gets hit by a anti-ship missile, all that rocket fuel with oxidizers is simply going to burn the ship up.
hmm, wow i didnt know that. an all composite ship must be pretty expensive isnt it ? but it offers other stuff like increased payload (same displacement, lighter weight) and increased acceleration (less energy needed to move the ship as hull weight is lighter)
but i was thinking of a composite-steel mix. steel gives the frigate a much larger RCS dosent it ? if we had some portions which were made out of composites, could have had more room for other weapons systems and potentially lower RCS.
anecdotal evidence with rust stains visible on the hull and area just below the bridge on formidable frigates out on exercises may hint that the low RCS steel is possibly maintainence intensive.
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Originally posted by sgstars:
hmm, wow i didnt know that. an all composite ship must be pretty expensive isnt it ? but it offers other stuff like increased payload (same displacement, lighter weight) and increased acceleration (less energy needed to move the ship as hull weight is lighter)
but i was thinking of a composite-steel mix. steel gives the frigate a much larger RCS dosent it ? if we had some portions which were made out of composites, could have had more room for other weapons systems and potentially lower RCS.
anecdotal evidence with rust stains visible on the hull and area just below the bridge on formidable frigates out on exercises may hint that the low RCS steel is possibly maintainence intensive.
Yeah, pretty. The ship in question was the Okla. She sank because of an engine fire that went out of control. Take a look at this article:
http://www.ericgreeneassociates.com/images/Fire_Protection_for_Marine_Composite_Construction.pdf
Notice one of the first few lines on the article: Composites are combustible.
Composite-steel mix might be viable if the composites are kept away from most of the important spaces. Use them in the superstructure and you run into potential problems.
The only serious way to reduce RCS for a ship is shaping. But don't shape too much. The DDG-1000 has some very serious issues that might render them useless because of overzealous shaping and issues with system integration and radar layout. This is why electrical engineers are not supposed to design ships.
Sure hope that none of the airliners with composites out there run into fire troubles...
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Originally posted by Fingolfin_Noldor:
WHy the hell is Lionnoisy glorifying some cheap unexceptional frigate that is merely bang for buck for the current size? You do realise that for all that stealth, when the ship is rocking away in uneven waters, or when water is splashing about, the RCS goes up a few orders of magnitude?
i hope you are not referring to our frigate as CHEAP and UNEXCEPTIONAL... you better dont pray pray with the effort of our navy and all the people working in DSO, DSTA and MINDEF.
and for you info, eversince the victory MCV top heavy issue, our navy have learn to deal with the "rocking" issue during the design phase of our frigate.
and if you think high waves is bad for ships RCS... think again..in fact high waves helps conceal a ships RCS as water hides a submerged submarine.
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So....who has taken a ride on one of our "cheap and unexceptional" frigates here?
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not for the unappreciated...
wanna ride? grab two coconut and jump into the water... very cheap and very unexceptional.
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So how he came to the conclusion that it "rocks"?
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you on the sea... you will rock, holding onto two coconut or sqauttng inside an aircraft carrier dont make much difference.
but there are systems available that can help to mitigate the level of "rock"... our MCV haves it... so does our frigate... though different systems were used.
our formidables were designed for rough seas... not that it wont rock... but the rock would be mitigated.
the only way you can dont "rock" in the navy is to join the submarines..
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Originally posted by tripwire:
i hope you are not referring to our frigate as CHEAP and UNEXCEPTIONAL... you better dont pray pray with the effort of our navy and all the people working in DSO, DSTA and MINDEF.
and for you info, eversince the victory MCV top heavy issue, our navy have learn to deal with the "rocking" issue during the design phase of our frigate.
and if you think high waves is bad for ships RCS... think again..in fact high waves helps conceal a ships RCS as water hides a submerged submarine.
I will not hold back any words for fools who think the ship doesn't need any close in weapons system like RAM. So yes, tehy are cheap and unexceptional. Nothing to them. They are merely good for what they do vis a' vis our neighbours. I will be more impressed if we bought the Aegis system, and not something fostered upon us by the French.
And no, high waves have always been bad for ship RCS because radio waves reflect off water. -
Hang on... last I checked, tall waves and rough seas give more clutter problems.
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hang on number 2... i have never said our ships doesnt need any CIWS like RAM ok...
in fact... i was disappointed our frigates didnt come with more substantial CIWS systems.
but if the navy feels that the CIWS as well as new AShM will be a later addition to the frigate... i can only pray its sooner and better then i wish or dare to dream.
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Originally posted by Shotgun:
Hang on... last I checked, tall waves and rough seas give more clutter problems.
If you consider normal sea conditions and a ship that sends water flying up as it steams at high speed? On radar, it's going to start to show the "stealth" ship.In any case, most ships don't. But ships the size of corvettes or gunboats would.
In fact, for the DDG-1000, this might be a serious problem because the hull form is meant to pierce the waves and send waves flying and streaming over the hull... and possibly open up all the PVLS tubes.
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Originally posted by tripwire:
hang on number 2... i have never said our ships doesnt need any CIWS like RAM ok...
in fact... i was disappointed our frigates didnt come with more substantial CIWS systems.
but if the navy feels that the CIWS as well as new AShM will be a later addition to the frigate... i can only pray its sooner and better then i wish or dare to dream.
Vis a' vis our neighbours, the navy probably thought it isn't a problem. None of the regional navies have pretty developed naval patrol and sea attack doctrines.
The Chinese up north however, is a totally different matter.
With regard to the "fools" part, it was more towards the DSTA people and the MINDEF ppeople who approved the design. God knows what was going in their heads, or did the French roughshod them?
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Originally posted by Fingolfin_Noldor:
If you consider normal sea conditions and a ship that sends water flying up as it steams at high speed? On radar, it's going to start to show the "stealth" ship.In any case, most ships don't. But ships the size of corvettes or gunboats would.
In fact, for the DDG-1000, this might be a serious problem because the hull form is meant to pierce the waves and send waves flying and streaming over the hull... and possibly open up all the PVLS tubes.
Just checking, have you seen what radar returns look like at high sea-states?
Sporadic high-SNR returns all over the place, often require most operators to adjust their gain just to filter those out. Generally, the gain is adjusted to a level where the noise from the sea is significantly contrasting from actual returns. Theoretically, a stealthy vessel that scatters the radar waves off its hull, should actually be less detectable in rough seas. Unless you are postulating that it scatters of radar waves in such a coherent manner that it sticks out above noise-levels caused by rough seas...?
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There's different modes in the radar that uses different wavelengths.
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Originally posted by 16/f/lonely:
There's different modes in the radar that uses different wavelengths.
I'm not sure about what modes you're talking about. I've messed around with civilian surf search radar only.
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Originally posted by Fingolfin_Noldor:
Actually composites for a ship is a very very bad idea. There was a Norweigian mine hunter that was an all composite ship and the end result after a fire was the ship literally burnt itself out into ashes very very fast. That's why the Swedish put in a lot of effort to make sure the Visby has a lot of fire retardation, but odds are, when it gets hit by a anti-ship missile, all that rocket fuel with oxidizers is simply going to burn the ship up.
Wow F_N! Very authoritative statements couched in very strong terms ... except that you seem to be indulging in sensationalistic rhetoric rather than realistic analysis ...
"There was a Norwegian mine hunter that was an all composite ship and the end result after a fire was the ship literally burnt itself out to ashes very very fast"
Gee, "burnt itself out to ashes" indeed ... let's look at a picture of the salvaged wreck of the HNoMS Orkla ...
Hardly burnt to an ash is it?
The accident report on the fire on the Orkla attributed the fire and resultant sinking to ...- Poor understanding of Composite ship building requirements and technology by the Norwegian shipbuilding industry. The Atla Class was the first ever composite ship constructed by Norwegian shipyards. The fast buildtime between vessels of class meant that no error feedback was obtained to rectify the intrinsic errors in the design that led the fire and sinking.
- Poor maintenance and design in the Lift Fan Room led to the cause of the fire.
- Unprotected flammable soundproofing materials were installed in the LFR, which was classed as a non-fire hazard area. This provided fuel for the fire to set.
- Failure in the Hydraulics system further flash fed the fire, providing even more fuel for the fire to set.
- Failure to classify the LFR as a fire hazard area also meant that the composite material there was not treated with a flame retardant/protectant.
- Failure of the shipboard fire fighting pumps led to a period of loss of water pressure for ~10mins when the fire fighting was critical.
- Flaw in design of superstructure (lack of reinforcements) contributed to failure of vessel and ultimate sinking.
Quite unlike the simplistic picture painted where if you build a GFRP vessel, heavens help you if it burns. FYI, almost all MCMVs are pretty much built of GFRP or composites. Our guys in the Bedok class must be crapping their pants now. Or are they? After all, according to the report you so kindly posted, a british minesweeper suffered and engine room fire that blazed for a few hours but didn't sink? Instead of headlining and sensationalising "Composites are combustible", why didn't you tell us of the incident, just a few pages further?
To quote your report ... "Because composites are such good insulators, fires often don’t spread to adjacent compartments. When a British minehunter suffered an engine room fire that lasted several hours, fuel that was in a composite day tank failed to ignite."
In reality, composites can be made safer by a variety of treatment and construction methods. While they may not as good as Steel with regards to Ship Board Fire and Damage Control, the risk may be outweighed by considerable benefits to vessels such as MCMVs and other small, stealth focused vessels. Besides, there are already plenty of fire & smoke hazards on a ship ... wire cladding materials, POLs, paints, furniture padding, crew personal effects, etc to be just focusing on composites as the root of all evils.
On an aside, I think it may be worth considering that the RSN/Mindef/DSTA may have weighed the cost/benefits and decided that ... the better SBF&DC benefits of steel outweigh the stealth benefits of a composite structure. Rather than that composites are fire hazards and to be avoided at all cost ... after all we do operate 4 Landsort/Bedok MCMVs.
Another bone to pick with you on sensationalising issues.
"You do realise that for all that stealth, when the ship is rocking away in uneven waters, or when water is splashing about, the RCS goes up by a few orders of magnitude."
You do realise what is an order of magnitude right? A mutiple of x10. A Formidable giving a radar return of a fishing boat ... that's about an order of magnitude.
A Formidable going up 1 magnitude, looks like a non-stealthed Formidable.
A Formidable going up 2 magnitudes, looks like an aircraft carrier.
A Formidable going up 3 magnitudes, looks like the world's largest Super-Tanker.
Since you said "a few" OoM, I'd assume you meant 3 or more OoM. Really now?
I know this is sgforums where a lot of crap gets thrown around. But really, if you want to sound authoritative, don't sling so much BS lah.
Care to tell us what you realy understand about Radar Signals, RCS, RCS-SM issues in high Sea States and how a ships radar return actually gets amplified by a few order of magnitudes in high sea states? Quite a few people, including myself, are quite interested to know.