What is considered an authoritative source?

[Dfox071]

Thanks Mike!

I found another interesting article on stealth/RCS. This one from computational modelers. Though it doesn't have numbers for the SR-71, it does list a number of other aircraft. I'm sure it would be useful to compare this analysis vs other sources.

The document is at scienpress, Vol 204_1_9

[Dfox071]

I just ran across another source. This is from an additional interview. Please check the video. Once again, this is from an SR-71 pilot. Again, the video and interview discuss the purposeful stealthing of the craft, and like the original video, the pilot specifies a 1 Sq. meter RCS. I'm not sure as to exactly how this translates into a dB measurement, although this 1 Sq. m seems to be around what an F-18 or Rafale would have, and seems considerably better than what's currently in the DB for the SR-71.

Here's the video link if I can post it this time:

https://www.youtube.com/watch?v=U6ABvIHohG0&t=1222s

[CV60]

I'm not vouching for the article below. However, it gives the RCS for a variety of aircraft. The SR-71 is given as 0.01m2
http://mil-embedded.com/guest-blogs/rad ... f-stealth/

However, other sources have given an RCS as high as 10m2, sourcing a book for this number (https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird)

With that said, possibly the best source I have come across is a declassified study on using the SR-71 as an interceptor. The study has been posted here: https://www.secretprojects.co.uk/thread ... ects.3780/

Of interest to the RCS question are two slides (1-29 and 1-30) which indicate the SR-71I had a RCS of 2M2:




The SR-71 had many low observable features, so it makes sense that it had a lower RCS. Give that this is a formerly classified study, it is probably as good as you will find on the SR-71

[c3k]

The SR-71 incorporated many advanced stealth features. Shapes, coatings, and internal structures were all part of it. Disappointing if CMANO does not have this accounted for.

[CV60]

RE: What is considered an authoritative source? - 8/16/2019 1:20:00 AM   

The SR-71 incorporated many advanced stealth features. Shapes, coatings, and internal structures were all part of it. Disappointing if CMANO does not have this accounted for.

I wouldn't say disappointing. The CMANO database is very extensive, but is required to use unclassified data. There is a wide range of data concerning the RCS of aircraft, and much of it is contradictory, as it depends on a wide variety of factors: Radar, target angle and materials among them. Much of this is or was classified, and even if declassified it is not easy to find. The 10m2 figure for the SR-71 is one such figure. I have seen it several places, but I think it derives from books written in the mid-1990s. A lot has been declassified since then. The CMNAO database used the unclassified figures that are available. As more information becomes available, we refine the database. Possibly the now-debatable 2 square meter RCS for the SR-71 is one such update. That is why we have the database update thread: https://www.matrixgames.com/forums/tm.a ... ey=�

[Filitch]

https://www.secretprojects.co.uk/thread ... ects.3780/

According calculations above - AWACS Tu-126 with radar modification of P-30 (http://www.radartutorial.eu/19.kartei/1 ... 61.en.html) can detect SR-71 at 150 nm and ground-based radars at 200 nm.

[RoryAndersonCDT]

I think the structural difference between F-117 and SR-71 shows that fundamentally SR-71 isn't stealthy.

Radar doesn't care if the chassis of the aircract is painted black, or what pilots are told, radar cares about what soviet scientist Pyotr Ufimtsev wrote about.

Just looking at a crosssection of the SR-71 engine intake should provide enough information to think that the SR-71 isn't 'stealth' as we think of it today.

(This is just my opinion, I don't edit the DB at all)

[CV60]

I think the structural difference between F-117 and SR-71 shows that fundamentally SR-71 isn't stealthy.

Radar doesn't care if the chassis of the aircract is painted black, or what pilots are told, radar cares about what soviet scientist Pyotr Ufimtsev wrote about.

Just looking at a crosssection of the SR-71 engine intake should provide enough information to think that the SR-71 isn't 'stealth' as we think of it today.

(This is just my opinion, I don't edit the DB at all)

One of the sources I looked at classified the SR-71 as a "Low Observable" vice Stealth. Part of the distinction (according to the site) was that while the SR-71 design deliberately tried to reduce it's RCS as one of its goals, the primary design goal of the aircraft was speed, which it did not compromise for a lower RCS. I'm not knowledgeable enough to comment on this distinction, but it sounds like a reasonable distinction to me. If the SR-71's RCS is 2m2, than it clearly had a smaller RCS than most other aircraft of the era. See https://ntrs.nasa.gov/archive/nasa/casi ... 007797.pdf for a NASA paper that addresses the design's secondary goal of reducing the RCS. While the attached paper doesn't give an actual RCS for the SR-71, it clearly claims that that was one of the goals of the project.

[PN79]

Some declasified data from CIA:
https://www.cia.gov/library/readingroom ... 471734.pdf

Also A-12 was damaged by SA-2 over Vietnam in 1967 (btw. by 11D missile):
https://www.cia.gov/library/readingroom ... 471735.pdf

SR-71 and A-12 were never an issue for eastern radars. They were visible very early. The issue was speed and height.

[SeaQueen]

It probably depends a lot on the target aspect. I suspect from the front, the SR-71 had a pretty low RCS, just from looking at it. From the top/bottom, though, it was probably huge. RCS data is notoriously difficult to get one's hands on. It's also highly frequency dependent. Without a lot of qualifications, any RCS data you see in in open source is probably not to be taken too seriously.

[ARCNA442]

ORIGINAL: RoryAndersonWS

I think the structural difference between F-117 and SR-71 shows that fundamentally SR-71 isn't stealthy.

If your only idea of stealth is what the F-117 looks like and you saw an F-22 or F-35 for the first time without being told anything about them, would you think that they are stealthy?

Honestly, the nose chines, canted tail fins, smooth blended body, and wing geometry of the SR-71 are all quite reminiscent of modern stealth aircraft.

ORIGINAL: PN79

SR-71 and A-12 were never an issue for eastern radars. They were visible very early. The issue was speed and height.

That is far from the impression I got from the documents you linked.

"The radar cross section of the two aircraft in a clean configuration is relative low for both the SR-71 and the A-12"

"North Vietnamese Air Defense Radar networks have tracked the aircraft and have steadily improved their tracking capability"

"the Controller congratulated the Battalion on their being the 'first unit to be able to pick it up and launch"

If detecting an SR-71 was "never an issue" then why did both US and Vietnamese think it worth commenting on?

[CV60]

The declassified source that I provided (https://www.secretprojects.co.uk/thread ... ects.3780/ ) indicates that the SR-71 could be tracked by the USSR. The issue is not so much whether it could be detected and/or tracked, but rather whether it could be detected with sufficient time to be tactically useful to the defender. Usually, the SR-71's combination of speed and smaller RCS made it impossible or almost impossible to intercept.

[PN79]

There is a difference between tracking the aircraft as air controller and as a SAM operator. Contrary to that F-117 was special in that way that Iraqi and Yugoslav air controllers were not able to track them reliably (if at all). But SR-71 and A-12 were never an issue in detection and observation of their flight path. To "lock" them and engage them with SA-2 was however something completely different as SA-2 has minimal window of opportunity to engage them.

For example Czechoslovak air controllers were easily observing SR-71 flying along West German/East German and West German/Czechoslovak border but MiG-23 trying to intercept it head on was unable to "lock" it.

EDIT: I will add that I don't know what should be ideal RCS in CMANO. I just want to point that actual stealth aircrafts (F-117 and later) are something completely different regarding their abilities.

[Dfox071]

ORIGINAL: PN79

There is a difference between tracking the aircraft as air controller and as a SAM operator. Contrary to that F-117 was special in that way that Iraqi and Yugoslav air controllers were not able to track them reliably (if at all). But SR-71 and A-12 were never an issue in detection and observation of their flight path. To "lock" them and engage them with SA-2 was however something completely different as SA-2 has minimal window of opportunity to engage them.

For example Czechoslovak air controllers were easily observing SR-71 flying along West German/East German and West German/Czechoslovak border but MiG-23 trying to intercept it head on was unable to "lock" it.

EDIT: I will add that I don't know what should be ideal RCS in CMANO. I just want to point that actual stealth aircrafts (F-117 and later) are something completely different regarding their abilities.

They are completely different in as much as the F-117 takes some of what was done on the SR-71, refines it, and adds the discoveries made regarding radar reflection from Petr Ufimtsev. I don't think anyone has suggested that the SR-71 should have a cross section (or more accurately the dB rating) similar to that of the F-117 (approx 0.003 sq.m according to global security). Making such a comparison, respectfully, seems like a straw man.

What has been suggested, and what I advocate for, is that the current level of "low observability" is likely substantially off, and too easily detected, for the SR-71 in reality. Obviously this is difficult to pinpoint for a myriad of reasons, but several have claimed here that the SR-71 is not a stealth aircraft, but this is demonstrably wrong given that the source material, and anecdotes from the era, clearly indicate that low observability was a design goal, and in use the SR-71 was considered something unusual, and difficult to track given it's size.

So, no, no one here is thinking 0.003 Sq.m. On the other hand, the current value of RCS (derived from dB) of 11.5 Sq.m seems unjustifiably large, even for a 100 ft aircraft due to the construction of the SR-71 itself having a substantial focus on low observability. Also, multiple sources indicate the RCS of something around 1 to 2 square meters, and some much lower than that, and none over 10 Sq.m.

Several sources, some first hand from the manufacturer, and some previously classified list the RCS of about 1 Sq.m or about the same as "a man". I, personally, believe these sources to be the most trustworthy.

So, having said that, as I asked way back when, if we are going by the available information, why is the RCS of the SR-71 around 11.5 when no source suggests it's that high, and multiple, reputable sources suggest it is more likely around 1 to 2 Sq. m? What justifies the 11.5 number other than a very basic "look how big it is" argument. Such an argument is not backed by any source whatsoever, right?

[Gunner98]

I'm just thinking that this is one aircraft type - 3 DB entries, it flies at 80-90,000 feet @ Mach 3 out of reach of the vast majority of potential threats - and is rarely used in scenarios.

Is it a big issue?

[ARCNA442]

ORIGINAL: Gunner98

I'm just thinking that this is one aircraft type - 3 DB entries, it flies at 80-90,000 feet @ Mach 3 out of reach of the vast majority of potential threats - and is rarely used in scenarios.

Is it a big issue?

I have to agree that there are much larger problems with much more commonly used DB entries (ie the Nimitz-class armor scheme) and if the OP had posted in the DB3000 thread his information would probably have gone without comment.

However, I don't think that is really the purpose of this thread (just look at the title) - it is more about what information should be considered for the DB. While I side with the OP on the question of the SR-71 RCS, I think this thread is amply demonstrating why the CMANO team tends only edit stuff if they have a black and white number from a published source - doing anything else opens them up to endless debate.

[SeaQueen]

1 sq. m rcs = 0 dbsm.

'm not sure as to exactly how this translates into a dB measurement, although this 1 Sq. m seems to be around what an F-18 or Rafale would have, and seems considerably better than what's currently in the DB for the SR-71.