By: ls1 miata
- 26th May 2010 at 00:59Permalink- Edited 1st January 1970 at 01:00
2 stealthy tails - 1 bigger, 1 smaller. The smaller will have less reflection. (Please save me your Americans tails > Russian tails BS)
Not necessarily.
He [Kelly Johnson] told me later that he was surprised to learn that with flat surfaces the amount of radar energy returning to the sender is independent of the target's size. A small airplane, a bomber, an aircraft carrier, all with the same shape, will have identical radar cross sections. "By God, I never would have believed that," he confessed.
By: ls1 miata
- 26th May 2010 at 01:39Permalink- Edited 1st January 1970 at 01:00
How can you shape a bomber and aircraft carrier the same LOL?
Seems like you are trying to twist some LM story into some sort of scientific fact.
If you have 2 tails, OF THE SAME SHAPE, the smaller SHOULD have less reflection, no?
So, given good levels of engineering, on 2 separate aircraft, the smaller tails would most likely reflect less back.
If you have objects of the same shape, lets say an object in the shape of an F-117. One of these objects is the size of a car. The other is the size of an aircraft carrier. Both of these objects will have a similar (not exactly the same, but similar) RCS. If you don't believe it, don't worry. Kelly Johnson had a hard time believing it, and he was one of the greatest aerospace engineers of the 20th century. So you're in good company.
Wrightwing is, well...right. RCS is independent of size.
By: Erkokite
- 26th May 2010 at 01:51Permalink- Edited 1st January 1970 at 01:00
If you have objects of the same shape, lets say an object in the shape of an F-117. One of these objects is the size of a car. The other is the size of an aircraft carrier. Both of these objects will have a similar (not exactly the same, but similar) RCS. If you don't believe it, don't worry. Kelly Johnson had a hard time believing it, and he was one of the greatest aerospace engineers of the 20th century. So you're in good company.
Wrightwing is, well...right. RCS is independent of size.
For some objects yes. Other objects, no. Conductive flat plates, spheres, cylinders, there most certainly is a size dependency. However, for an object like the F-117, things are probably far more dependent upon shape.
By: dionis
- 26th May 2010 at 01:52Permalink- Edited 1st January 1970 at 01:00
If you have objects of the same shape, lets say an object in the shape of an F-117. One of these objects is the size of a car. The other is the size of an aircraft carrier. Both of these objects will have a similar (not exactly the same, but similar) RCS. If you don't believe it, don't worry. Kelly Johnson had a hard time believing it, and he was one of the greatest aerospace engineers of the 20th century. So you're in good company.
Wrightwing is, well...right. RCS is independent of size.
By: ls1 miata
- 26th May 2010 at 01:52Permalink- Edited 1st January 1970 at 01:00
For some objects yes. Other objects, no. Conductive flat plates, spheres, cylinders, there most certainly is a size dependency. However, for an object like the F-117, things are probably far more dependent upon shape.
Yes, for some objects. Mainly flat objects (as described in my quote), like tail planes.
Where did I say, "not entirely"? I did say "not exactly", but the differences will be so small that there wouldn't be an advantage to the smaller object.
As for your wiki link, it's in the context of a non-stealth object. My source from Ben Rich's (probably another one of the best aerospace engineers of the 20th century) book is speaking in the context of flat surfaces, like tail planes (or an aircraft with all flat surfaces like an F-117).
By: Cola1973
- 26th May 2010 at 02:31Permalink- Edited 1st January 1970 at 01:00
So a B-2 should have a much larger RCS than a Cessna right?
Larger surfaces reflect better than small ones. That's out of the question and size iz directly related to RCS, so your assertion is wrong.
Where did you get the idea that an ordinary F22 and F22 that is 5 times bigger, but otherwise identical in shape, will have the same RCS from the same angle, against same wavelength?
Yes, B2's RCS is much larger than Cessna's but differently distributed, so it only appears to be smaller.
New
By: Anonymous
- 26th May 2010 at 03:00Permalink- Edited 22nd October 2019 at 22:31
You'll note(well now you will anyhow) that I said IF they achieved that, THEN there were more than "minor" changes made.
As I said – when you look at the graph of Flanker’s RCS (which shows RCS values that are averaged over the range of angles ± 30 °), you’ll see that frontal sector RCS (+/- 30 from the nose) is closer to 18-20m2. I don’t know where did you get that 15 m2 from underside claim. I think it’s just your wishful thinking. And BTW: looking directly at the nose RCS peaks around 30 m2.
The huge parabolic/Cassegrain antenna of the original N001 radar probably contributes a lot of the difference between the Su-27 and the Eagle with its flat plate antenna. Other than that, I don't see how there would be a lot in it between the two in terms of RCS - certainly not a 300% factor. So simply by giving the more recent Flankers a different radar a handsome reduction has probably come about. Add RAM (features on most recent production variants), a coated canopy (apparently at least being tested on Su-30MK #02) as well as possibly a FSS radome (no information on whether Russia has developed this though) and you could likely slash signature quite a bit. All without altering the actual airframe in any significant way, effectively just by replacing the materials in selected areas. Define "minor".
Like the ones that previous Russian Air Force fighters have continuously received?:rolleyes:
Yes, exactly like those. Su-27SM, Su-25SM, Su-24M2, MiG-29SMT, MiG-31BM - there are upgrades available for every tactical aircraft in the Russian inventory, their pace and scope has just been hampered in the past by crippling economic problems. Prior to that, the Soviet Union did not believe in the upgrade idea at all, preferring to use hardware until it was obsolete and then replace it with up-to-date newbuilds - that era is not really a relevant example.
By: wrightwing
- 26th May 2010 at 11:46Permalink- Edited 1st January 1970 at 01:00
The huge parabolic/Cassegrain antenna of the original N001 radar probably contributes a lot of the difference between the Su-27 and the Eagle with its flat plate antenna. Other than that, I don't see how there would be a lot in it between the two in terms of RCS - certainly not a 300% factor. So simply by giving the more recent Flankers a different radar a handsome reduction has probably come about. Add RAM (features on most recent production variants), a coated canopy (apparently at least being tested on Su-30MK #02) as well as possibly a FSS radome (no information on whether Russia has developed this though) and you could likely slash signature quite a bit. All without altering the actual airframe in any significant way, effectively just by replacing the materials in selected areas. Define "minor".
I understand all of these things can certainly contribute to reductions, but take the Super Hornet vs. Legacy Hornets- there was a lot of actual physical redesign involved, as well as additional RAM treatment, radar blockers, change of radar array type, etc.. The Flanker's shape hasn't changed much, was what I was concerned about. We'll have to wait and see about the canopy and radome mods. I'm just skeptical about slapping RAM on a bad shape to get large improvements, without the other things I've discussed.
Yes, exactly like those. Su-27SM, Su-25SM, Su-24M2, MiG-29SMT, MiG-31BM - there are upgrades available for every tactical aircraft in the Russian inventory, their pace and scope has just been hampered in the past by crippling economic problems. Prior to that, the Soviet Union did not believe in the upgrade idea at all, preferring to use hardware until it was obsolete and then replace it with up-to-date newbuilds - that era is not really a relevant example.
My point wasn't that updates were available. It was how many have been updated(i.e. how many Flankers in the RuAF are comparable to an MKI variant, if any, etc.....). The fact of the matter is that the vast majority of the RuAF has been updated very little.
By: Cola1973
- 26th May 2010 at 11:50Permalink- Edited 1st January 1970 at 01:00
So for practical matters(i.e. what the search radar sees), the B-2 appears much smaller, which supports my point. Shape is more important than size.
It doesn't matter if it's for practical, or other matters.
You make false claims.
B2 only appears smaller than Cessna but really isn't, which is precisely the place where will the anti-stealth combat begin and it already did with widespread of networked combat systems.
By: wrightwing
- 26th May 2010 at 12:13Permalink- Edited 1st January 1970 at 01:00
Okay so you don't believe what you've heard about RCS - alright then...
Are the Su-35 prototypes in fully production representative(i.e. radar blockers, modified radome and treated canopy, etc...)? If not, what method was used to verify the claimed improvements?(computer sims, anechoic chamber, etc...) I have no doubts that improvements have been made, but haven't heard the methodologies used to back up some of the claims.
I don't believe what I've heard either... journals, colleagues, etc - where are they pulling these numbers, other than their posterior? They certainly don't have a testing lab with T-50 scaled models do they?
Perhaps not, but having worked with similar projects, they can look at something and have a pretty good idea if a design feature will be contrary to the goal of achieving a low RCS.
Yeah, the T-50 was vapor-material on Jan 1, 2010. Look what we have now?
Using that measure, the F-35 should in theory be ready for mass production.
Ah man, that good old argument. Certainly you must have some excellent data on those T/R modules to back up that baloney right?
I suppose you have some data showing how Russian engineers have been able to skip steps in terms of design and materials, to reach parity on their first attempt, with their unlimited budgets. Even Carlo Kopp would agree that this isn't the case.
Yeah, since the budget permit it since about 2004, there have been swatches of new upgrades coming in for everything from MiG-29s and -31s, to Su-24/25/27 aircraft.
How many airframes have received significant upgrades(i.e. glass cockpits, modern ECM, comms, etc...)?
Larger RCS of what? Jammers?!?
The platform.
No one knows what angle they tracked them from, how many were trying to track, etc.
If you have done any reading on the matter, they've tried coming at all altitudes high and low, co-altitude, high speed, low speed, purpendicular, etc.
each time with the same result. The F-22s have also had significant testing on calibrated radar ranges, radar test stands, anechoic chambers, etc..
When you combine this with the fact that the F-22's systems know what its RCS is from different aspects, and fuses that info with any emissions from search radars, to let the pilot know how far away the plane needs to stay, to minimize the chance of detection. It mitigates concerns over inadvertantly being detected in the manner you suggested.
By: wrightwing
- 26th May 2010 at 12:15Permalink- Edited 1st January 1970 at 01:00
It doesn't matter if it's for practical, or other matters.
You make false claims.
B2 only appears smaller than Cessna but really isn't, which is precisely the place where will the anti-stealth combat begin and it already did with widespread of networked combat systems.
What matters is how far/near you can detect an incoming platform. Whether the B-2 only appears smaller to the radars that are looking for it, is kind of an important detail.
By: Cola1973
- 26th May 2010 at 12:25Permalink- Edited 1st January 1970 at 01:00
What matters is how far/near you can detect an incoming platform.
What's your point?
During WW2, detection was performed by eyes and by the end of the war by radar.
This was technically and conceptually much larger leap than today's switch from mono-static to networked warfare (multi-static/multi-sensor), which enables tracking (for detecting itself, a monostatic LF system is enough) and engaging of such targets.
Whether the B-2 only appears smaller to the radars that are looking for it, is kind of an important detail.
Posts: 220
By: ls1 miata - 26th May 2010 at 00:59 Permalink - Edited 1st January 1970 at 01:00
Not necessarily.
"Skunk Works", page 33, Ben R. Rich
Posts: 1,856
By: dionis - 26th May 2010 at 01:29 Permalink - Edited 1st January 1970 at 01:00
How can you shape a bomber and aircraft carrier the same LOL?
Seems like you are trying to twist some LM story into some sort of scientific fact.
If you have 2 tails, OF THE SAME SHAPE, the smaller SHOULD have less reflection, no?
So, given good levels of engineering, on 2 separate aircraft, the smaller tails would most likely reflect less back.
Posts: 220
By: ls1 miata - 26th May 2010 at 01:39 Permalink - Edited 1st January 1970 at 01:00
If you have objects of the same shape, lets say an object in the shape of an F-117. One of these objects is the size of a car. The other is the size of an aircraft carrier. Both of these objects will have a similar (not exactly the same, but similar) RCS. If you don't believe it, don't worry. Kelly Johnson had a hard time believing it, and he was one of the greatest aerospace engineers of the 20th century. So you're in good company.
Wrightwing is, well...right. RCS is independent of size.
Posts: 567
By: Erkokite - 26th May 2010 at 01:51 Permalink - Edited 1st January 1970 at 01:00
For some objects yes. Other objects, no. Conductive flat plates, spheres, cylinders, there most certainly is a size dependency. However, for an object like the F-117, things are probably far more dependent upon shape.
Posts: 1,856
By: dionis - 26th May 2010 at 01:52 Permalink - Edited 1st January 1970 at 01:00
Well, as you've admit, not entirely :)
http://en.wikipedia.org/wiki/Radar_cross-section
What do you make of this?
Posts: 220
By: ls1 miata - 26th May 2010 at 01:52 Permalink - Edited 1st January 1970 at 01:00
Yes, for some objects. Mainly flat objects (as described in my quote), like tail planes.
Posts: 220
By: ls1 miata - 26th May 2010 at 02:00 Permalink - Edited 1st January 1970 at 01:00
Where did I say, "not entirely"? I did say "not exactly", but the differences will be so small that there wouldn't be an advantage to the smaller object.
As for your wiki link, it's in the context of a non-stealth object. My source from Ben Rich's (probably another one of the best aerospace engineers of the 20th century) book is speaking in the context of flat surfaces, like tail planes (or an aircraft with all flat surfaces like an F-117).
Posts: 1,206
By: Cola1973 - 26th May 2010 at 02:31 Permalink - Edited 1st January 1970 at 01:00
Larger surfaces reflect better than small ones. That's out of the question and size iz directly related to RCS, so your assertion is wrong.
Where did you get the idea that an ordinary F22 and F22 that is 5 times bigger, but otherwise identical in shape, will have the same RCS from the same angle, against same wavelength?
Yes, B2's RCS is much larger than Cessna's but differently distributed, so it only appears to be smaller.
By: Anonymous - 26th May 2010 at 03:00 Permalink - Edited 22nd October 2019 at 22:31
The huge parabolic/Cassegrain antenna of the original N001 radar probably contributes a lot of the difference between the Su-27 and the Eagle with its flat plate antenna. Other than that, I don't see how there would be a lot in it between the two in terms of RCS - certainly not a 300% factor. So simply by giving the more recent Flankers a different radar a handsome reduction has probably come about. Add RAM (features on most recent production variants), a coated canopy (apparently at least being tested on Su-30MK #02) as well as possibly a FSS radome (no information on whether Russia has developed this though) and you could likely slash signature quite a bit. All without altering the actual airframe in any significant way, effectively just by replacing the materials in selected areas. Define "minor".
Yes, exactly like those. Su-27SM, Su-25SM, Su-24M2, MiG-29SMT, MiG-31BM - there are upgrades available for every tactical aircraft in the Russian inventory, their pace and scope has just been hampered in the past by crippling economic problems. Prior to that, the Soviet Union did not believe in the upgrade idea at all, preferring to use hardware until it was obsolete and then replace it with up-to-date newbuilds - that era is not really a relevant example.
Posts: 4,042
By: wrightwing - 26th May 2010 at 11:18 Permalink - Edited 1st January 1970 at 01:00
So for practical matters(i.e. what the search radar sees), the B-2 appears much smaller, which supports my point. Shape is more important than size.
Posts: 4,042
By: wrightwing - 26th May 2010 at 11:46 Permalink - Edited 1st January 1970 at 01:00
I understand all of these things can certainly contribute to reductions, but take the Super Hornet vs. Legacy Hornets- there was a lot of actual physical redesign involved, as well as additional RAM treatment, radar blockers, change of radar array type, etc.. The Flanker's shape hasn't changed much, was what I was concerned about. We'll have to wait and see about the canopy and radome mods. I'm just skeptical about slapping RAM on a bad shape to get large improvements, without the other things I've discussed.
My point wasn't that updates were available. It was how many have been updated(i.e. how many Flankers in the RuAF are comparable to an MKI variant, if any, etc.....). The fact of the matter is that the vast majority of the RuAF has been updated very little.
Posts: 1,206
By: Cola1973 - 26th May 2010 at 11:50 Permalink - Edited 1st January 1970 at 01:00
It doesn't matter if it's for practical, or other matters.
You make false claims.
B2 only appears smaller than Cessna but really isn't, which is precisely the place where will the anti-stealth combat begin and it already did with widespread of networked combat systems.
Posts: 4,042
By: wrightwing - 26th May 2010 at 12:13 Permalink - Edited 1st January 1970 at 01:00
Are the Su-35 prototypes in fully production representative(i.e. radar blockers, modified radome and treated canopy, etc...)? If not, what method was used to verify the claimed improvements?(computer sims, anechoic chamber, etc...) I have no doubts that improvements have been made, but haven't heard the methodologies used to back up some of the claims.
Perhaps not, but having worked with similar projects, they can look at something and have a pretty good idea if a design feature will be contrary to the goal of achieving a low RCS.
Using that measure, the F-35 should in theory be ready for mass production.
I suppose you have some data showing how Russian engineers have been able to skip steps in terms of design and materials, to reach parity on their first attempt, with their unlimited budgets. Even Carlo Kopp would agree that this isn't the case.
How many airframes have received significant upgrades(i.e. glass cockpits, modern ECM, comms, etc...)?
The platform.
If you have done any reading on the matter, they've tried coming at all altitudes high and low, co-altitude, high speed, low speed, purpendicular, etc.
each time with the same result. The F-22s have also had significant testing on calibrated radar ranges, radar test stands, anechoic chambers, etc..
When you combine this with the fact that the F-22's systems know what its RCS is from different aspects, and fuses that info with any emissions from search radars, to let the pilot know how far away the plane needs to stay, to minimize the chance of detection. It mitigates concerns over inadvertantly being detected in the manner you suggested.
Posts: 4,042
By: wrightwing - 26th May 2010 at 12:15 Permalink - Edited 1st January 1970 at 01:00
What matters is how far/near you can detect an incoming platform. Whether the B-2 only appears smaller to the radars that are looking for it, is kind of an important detail.
Posts: 1,206
By: Cola1973 - 26th May 2010 at 12:25 Permalink - Edited 1st January 1970 at 01:00
What's your point?
During WW2, detection was performed by eyes and by the end of the war by radar.
This was technically and conceptually much larger leap than today's switch from mono-static to networked warfare (multi-static/multi-sensor), which enables tracking (for detecting itself, a monostatic LF system is enough) and engaging of such targets.
What?
Posts: 13,432
By: swerve - 26th May 2010 at 12:56 Permalink - Edited 1st January 1970 at 01:00
Right throughout the war by radar, in the UK. Germany also had operational radars at the start of the war.
Posts: 1,206
By: Cola1973 - 26th May 2010 at 13:12 Permalink - Edited 1st January 1970 at 01:00
Yes, but I was referring to aircraft installations and it was not until the end of the war that interceptors could operate during night.
Posts: 13,432
By: swerve - 26th May 2010 at 14:03 Permalink - Edited 1st January 1970 at 01:00
RAF night fighters with radar were operating in late 1939, & Luftwaffe in 1942. The RN was using airborne radars for sub-hunting in 1940.
By the end of the war, both sides were using an impressive array of airborne radars, counter-measures, counter-counter measures, etc.
Posts: 1,206
By: Cola1973 - 26th May 2010 at 14:13 Permalink - Edited 1st January 1970 at 01:00
Really?
How many Luftwaffe's bombers they shot down during August/September of 1940?
Posts: 248
By: jdsgn - 26th May 2010 at 14:24 Permalink - Edited 1st January 1970 at 01:00
Isn't that kinda the important point here?