Two vertical stabilizers on the F-22 Raptor angled

[RandomGuy88]

two "vertical" stabilizers on the F-22 Raptor angled

Why are the two "vertical" stabilizers on the F-22 Raptor angled sort of like a V-Tail as opposed to being completely vertical?

 

[FredGarvin]

To my understanding it is a stealth issue. Right angles are a no-no. I would imagine there are also benefits from getting some more horizontal effect instead of pure yaw control as well.

 

[RandomGuy88]

Thanks! Using it as an elevator was the only thing I could think of as well. Why are right angles a no-no when it comes to stealth?

 

[mgb_phys]

If you imagine a right angle corner.
Whatever angle an incoming radar beams hits one surface at it will bounce of that then the other and return along the same direction - directly back to the radar set.
With an obtuse angle it will be reflected away in another direction.

It's the same principle as a corner cube - where you want the light to go back the same way.

 

[RandomGuy88]

Cool. That makes sense, thanks!

 

[Cyrus]

I do not buy this "stealth" argument. Many aircraft, F-18, etc use angled twin tails and is not for stealth. It probably has more to do with stability. Note: these aircraft were designed well before stealth design methodlogies were discovered.

 

[turbo]

Perhaps not fully a stealth issue, but you've got to admit that replacing those two splayed control surfaces with one bigger one mounted vertically, would result in a larger radar signature.

 

[RandomGuy88]

How would it improve stability?

 

[Cyrus]

How would it improve stability?

I emailed a good friend who is head of our wind tunnel. I will quote his response in our email:

There are 2 considerations that have a strong influence on the vertical tail arrangements. Both come into play for rather high angles of attack and occur because of strong vortices which originate near the wing root-fuselage intersection or at a wing leading edge sweep change for some designs. These vortices cause high amplitude buffeting if the tails are too close to them at the most critical angles of attack. The F-14 and F-15 aircraft were strongly affected and had a lot of extra maintenance because of this. The other factor is for certain angles of attack and sideslip one of these vortices impinging on a vertical tail can lead to forces which are in the wrong direction so there needs to be one which is on the upwind side and is completely clear of such wake interactions to guarantee the needed control authority over all angles of attack and sideslip.

So, it's pretty much not for stealth. Note: the F-14, F-15 have straight tails. This was a good observation and interesting question RandomGuy88!

 

[RandomGuy88]

Very cool, thanks for the response.

 

[FredGarvin]

Note: these aircraft were designed well before stealth design methodlogies were discovered.

I don't doubt your source for a second (because it is repeated in the link below). However the stealth issue is part of the equation. The SR-71 had them loooooooong time ago and Hav Blue was in the mid 70's and Lockheed was working on it prior to that. So stealth has been around as long as say the F-14, just not in the open.

http://www.aerospaceweb.org/question/planes/q0157.shtml

http://books.google.com/books?id=fVQRmQo-bfUC&pg=PA17&lpg=PA17&dq=kelly+johnson,+canted+vertical+tails&source=bl&ots=eUPlC_78Qq&sig=WOYbMSciQuyGYzaqH686TVnHObU&hl=en&ei=5C4gS4qtO5XSMo78ucUC&sa=X&oi=book_result&ct=result&resnum=3&ved=0CAsQ6AEwAg#v=onepage&q=kelly%20johnson%2C%20canted%20vertical%20tails&f=false

Note page 8 here:
http://www.scribd.com/doc/18029452/NASA-SR71-Blackbird-Challenges-and-Lessons-Learned-2009

 

[DaveC426913]

The Raptor's vertical surfaces are significantly more oblique than other craft. Yes, this is to reduce radar signature. The fact that more conventional craft have moderately oblique tails does not change that.


http://www.globalsecurity.org/military/systems/aircraft/f-22-stealth.htm

"A quick look at the F-22 reveals an adherence to fundamental shaping principles of a stealthy design. The leading and trailing edges of the wing and tail have identical sweep angles (a design technique called planform alignment). The fuselage and canopy have sloping sides. The canopy seam, bay doors, and other surface interfaces are sawtoothed. The vertical tails are canted. The engine face is deeply hidden by a serpentine inlet duct and weapons are carried internally. "

 

[Andre]

I do not buy this "stealth" argument. Many aircraft, F-18, etc use angled twin tails and is not for stealth. It probably has more to do with stability. Note: these aircraft were designed well before stealth design methodlogies were discovered.

No Cyrus, it's not stealth only as in F-117 etc, the reduction of the radar cross section has been a worry for decades. The principle of the radar reflector was well known ages ago and and so was the notion that rectangles were the most effect radar reflectors.

So, experimenting with design versus radar cross section was done in the early days already. Also, for instance, if you see a bit of a golden hue on a canopy, it's because of generating radar reflection, so that all the rectangles in the cockpit don't act as a radar reflector. But it is still awkward that the F-15 has retangular fins, which are of course easier for structural integrity.

 

[Cyrus]

No Cyrus, it's not stealth only as in F-117 etc, the reduction of the radar cross section has been a worry for decades. The principle of the radar reflector was well known ages ago and and so was the notion that rectangles were the most effect radar reflectors.

The ability to defeat (thats a loose term) radar was not developted until the early 80s with the F-117. I do not consider this 'ages ago', as this knowledge came much after the existence of many twin tailed fighter jets.

So, experimenting with design versus radar cross section was done in the early days already.

True, but they were all uncessful up until the 80s. The U-2 was thought to be stealthy, until they flew it and discovered the Russians were tracking it the moment it left the ground.

Also, for instance, if you see a bit of a golden hue on a canopy, it's because of generating radar reflection, so that all the rectangles in the cockpit don't act as a radar reflector. But it is still awkward that the F-15 has retangular fins, which are of course easier for structural integrity.

Interesting, do you know when (timeline) this golden hue was added?

 

[FredGarvin]

The ability to defeat (thats a loose term) radar was not developted until the early 80s with the F-117. I do not consider this 'ages ago', as this knowledge came much after the existence of many twin tailed fighter jets.

Nope. The SR-71 used it and that was the late 50's and 60's with the YF-12. I would call that one pretty successful.

 

[Cyrus]

Nope. The SR-71 used it and that was the late 50's and 60's with the YF-12. I would call that one pretty successful.

The SR-71 was by no means stealthy to Radar. Read the book "Skunk Works" which disproves your claim. While its certainly true that they tried to incorporate some early methods, they were not sucessful as per the theory that lead to the design of the F-117or F-22.

 

[FredGarvin]

The link above that I gave directly states that they were canted in for reduction in RCS. Whether the aircraft was stealthy or not is a moot point (which I disagree with). They were canted because they were thinking about making the aircraft smaller on radar.

http://books.google.com/books?id=fVQRmQo-bfUC&pg=PA17&lpg=PA17&dq=kelly+johnson,+canted+vertical+tails&source=bl&ots=eUPlC_78Qq&sig=WOYbMSciQuyGYzaqH686TVnHObU&hl=en&ei=5C4gS4qtO5XSMo78ucUC&sa=X&oi=book_result&ct=result&resnum=3&ved=0CAsQ6AEwAg#v=onepage&q=kelly%20johnson%2C%20canted%20vertical%20tails&f=false

 

[mgb_phys]

The SR-71 was by no means stealthy to Radar.

It's not bad for an airframe that size. IIRC the major issue in practice was that the jet exhaust gave such a huge signature in the cold empty sky at those altitudes.
Stealth doesn't make the plane invisible (the loss of B2s in serbia proved that) it just gives you an edge. Like any other camouflage it just shifts that few % where they can just see you into the few % where they just can't.
The dihedral stabilizers are a combination of aerodynamics and radar return. The reflection from a corner cube was very well known before stealth. The same flat angled shape effect can be seen on low visibility ships.

Read the book "Skunk Works" which disproves your claim.

I went to a lecture by the British radar expert lockheed brought into perform the tests described in skunk works (don't have my copy here - can't remember his name).

They found a number of planes that were surprisingly stealthy, The Avro Vulcan was among the best - despite having a delta wing about the size of Iowa it has lots of non-constant radius curves which scatter the radar return, very deep oval engine inlets and a defrosting heating coating which turned out to be just the correct wavelength to absorb radar of the time.

 

[tyroman]

There was a program at AFMDC (Holloman AFB) in the late 50's and early 60's called RAT SCAT (classified at the time) which is now unclassified.

Google "rat scat" and then (after enjoying all the ads for rodent exterminators), search within results for "radar".

http://www.stormingmedia.us/57/5744/0574474.html

Yes, aircraft (and missile) radar cross sections have been an important military concern for a long time.

 

[turbo]

From Lockheed Martin's Code One, explaining why their F-22 design beat out General Dynamic's design with a single vertical tail and Boeing's similar configuration:
http://www.codeonemagazine.com/archives/1998/articles/apr_98/apra_98.html

The wing planform and airfoil design were chosen to minimize weight while providing the maximum turn capability and supersonic cruise. The single vertical tail, however, presented problems in achieving a totally stealthy design. General Dynamics ran many wind tunnel tests to find a location and shape for twin canted vertical tails on the T configuration. The vortex flow off the forebody and delta wing produced unstable pitching moments when it interacted with twin tails. Without horizontal tails, the aircraft did not have enough pitch authority to counteract these moments. A single vertical tail and no horizontal tails was finally identified as the best overall approach to the design despite the degradation of radar cross section in the side sector. The proposal configuration was designated T-330.

A few months before the proposals for the dem/val phase of the program were to be submitted, the Air Force amended its proposal request. The change significantly increased the importance of stealth in the design. Lockheed, with a stealthy configuration derived from the F-117, made no modifications to its design as a result of the new requirements. Boeing made some slight modifications to the design of their inlet to address the increased stealth requirements.The company was, however, satisfied that its twin-tail design would meet the stealth requirements.

The upgraded requirements forced engineers at General Dynamics to again reconsider twin tails in a variety of locations, including out on pods on the wing. The trailing edge of the wing and the control surfaces were cut into chevrons aligned with the leading edge, giving the wing a bat-like look. In the end, no acceptable location for the twin tails was found, and the design was submitted with a single centerline tail and a serrated trailing edge. The new final configuration was labeled T-333.

Note the animation here, demonstrating how the leading and trailing edges of wings and elevators are kept at the same angles to reduce radar signature AND the angles of the engine inlets and the splayed tails are lined up, as well.
http://www.f-22raptor.com/st_fa22tricks.php#stealthfeatures
http://www.f-22raptor.com/st_fa22tricks.php#stealthfeatures

 

[Cyrus]

The link above that I gave directly states that they were canted in for reduction in RCS. Whether the aircraft was stealthy or not is a moot point (which I disagree with). They were canted because they were thinking about making the aircraft smaller on radar.

http://books.google.com/books?id=fVQRmQo-bfUC&pg=PA17&lpg=PA17&dq=kelly+johnson,+canted+vertical+tails&source=bl&ots=eUPlC_78Qq&sig=WOYbMSciQuyGYzaqH686TVnHObU&hl=en&ei=5C4gS4qtO5XSMo78ucUC&sa=X&oi=book_result&ct=result&resnum=3&ved=0CAsQ6AEwAg#v=onepage&q=kelly%20johnson%2C%20canted%20vertical%20tails&f=false

Neat book, I may have to go out and buy this and read it!

 

[russ_watters]

The SR-71 was by no means stealthy to Radar. Read the book "Skunk Works" which disproves your claim.

One of my favorites. You may want to whip out your copy and flip to page 23:

...the low observable results we achieved in the 1960s building the Blackbird, which was actually the world's first operational stealth aircraft.

 

[Cyrus]

One of my favorites. You may want to whip out your copy and flip to page 23:

I stand corrected (It's been a while since I read it). This airplane is extremely interesting, and always has an ace up its sleeve.

 

[minger]

Speaking of which, did anyone see the program on History Channel (IIRC) that was about Hitler's secret wooden stealth bomber?

Northrop got like 15 minutes to study the aircraft and take notes. They then went back and tried to replicate and test it. Here's an interesting page with some neat pics.
http://www.dailymail.co.uk/news/wor...tlers-stealth-bomber-turned-tide-Britain.html

p.s. Not to completely hijack the thread...

 

[FredGarvin]

A tail-less wing in 1944. I would have doubted they would have gotten it to fly. Cool picture though.

 

[Cyrus]

Speaking of which, did anyone see the program on History Channel (IIRC) that was about Hitler's secret wooden stealth bomber?

Northrop got like 15 minutes to study the aircraft and take notes. They then went back and tried to replicate and test it. Here's an interesting page with some neat pics.
http://www.dailymail.co.uk/news/wor...tlers-stealth-bomber-turned-tide-Britain.html

p.s. Not to completely hijack the thread...

Interesting link!

 

[xxChrisxx]

Well I never knew that, it just goes to show that stuff you think of as a fairly new or a novel idea (B2) has already been done in some form somewhere before.

 

[FredGarvin]

Jack Northrop had a flying wing back in the late '50s and '60s in both prop and jet driven forms. All done prior to fly by wire. It was his pet project. Amazing. It was a bit of a death trap which is why it was shelved. I saw a show where the showed pictures of him before he died, getting to see a B2. Talk about coming full circle.

 

[turbo]

Well I never knew that, it just goes to show that stuff you think of as a fairly new or a novel idea (B2) has already been done in some form somewhere before.

Continuous curvature is a pretty well-established principle in stealth, since it softens the radar signature. The father of a good friend of mine was involved in the design and development of the Blackbird, and the chines and constantly-changing curvature of the fuselage were designed to help reduce the radar signature. Any assertion that the Blackbird was not designed with radar stealth in mind should be taken with a grain of salt. Its impressive speed could help get it out of some trouble, but without stealth, its penetration into target areas before detection would have been restricted, reducing its effectiveness.

 

[xxChrisxx]

Continuous curvature is a pretty well-established principle in stealth, since it softens the radar signature. The father of a good friend of mine was involved in the design and development of the Blackbird, and the chines and constantly-changing curvature of the fuselage were designed to help reduce the radar signature. Any assertion that the Blackbird was not designed with radar stealth in mind should be taken with a grain of salt. Its impressive speed could help get it out of some trouble, but without stealth, its penetration into target areas before detection would have been restricted, reducing its effectiveness.

I didn't mean the stealth aspect, more the 'flying wing' design in relation to that german thing and the B2.

I also never realized the Sr-71 was quite so old (I knew it must be as its been decommissioned) but my god Mach-3 in a plane that came to be in the 60's is impressive.

As you can probably tell I'm not really knowledgeable on planes, but I do find then interesting.

 

[Cyrus]

I didn't mean the stealth aspect, more the 'flying wing' design in relation to that german thing and the B2.

I also never realized the Sr-71 was quite so old (I knew it must be as its been decommissioned) but my god Mach-3 in a plane that came to be in the 60's is impressive.

As you can probably tell I'm not really knowledgeable on planes, but I do find then interesting.

If you read the history about only one airplane, read about the blackbird. It's an amazing machine.

 

[Brian_C]

I read somewhere that the SR-71 used some "stealthy" design features, but nevertheless had a massive radar signature.

 

[mgb_phys]

I read somewhere that the SR-71 used some "stealthy" design features, but nevertheless had a massive radar signature.

The chines (the flattened sides to the fuselage) and the canted tails were to reduce radar signature, there was also a special fuel that reduced the reflectivity of the exhaust plume - but its still a very large aircraft and in an empty high altitude sky it's easy to pick out.

 

[FredGarvin]

...there was also a special fuel that reduced the reflectivity of the exhaust plume

I can say that I have never heard the exhaust plume aspect of using JP-7. The main reason for the fuel had nothing to do with that. It was processed to have a very low vapor pressure because of the high altitudes the aircraft was operating at plus it had a slightly lower freezing point, higher net heat of combustion (because of its very low aromatics content) and was a bit more thermally stable. Where did you hear/see this factoid about the plumes? I am very curious.

 

[Mech_Engineer]

I was under the impression that the SR-71 ended up having a huge radar signature due to its exhaust plume.

The SR-71 was one of the first aircraft to be shaped to reduce radar signature. However, the aircraft was not stealthy and still had a fairly large radar cross-signature, and was visible on ATC radar for hundreds of miles, even when not using its transponder.[1] This fact is further corroborated by the fact that missiles were fired at them quite often after they were detected on radar. The aircraft flew so fast and so high that if the pilot detected a surface-to-air missile launch, the standard evasive action was simply to accelerate.

...the radar signature aspects of the SR-71 design did not take into account the extremely hot engine exhaust, and it turns out that this exhaust can reflect radar. Ironically, the SR-71 was one of the largest targets on the FAA (Federal Aviation Administration) long range radars, which were able to track the plane at several hundred miles.

http://www.aircraftguru.com/aircraft/aircraft-information.php?craftid=80

Several webpages make reference to a mysterious "cesium-based compound A-50" that was used to help mask the exhaust, but I'm not sure that claim is made by reputable sources with references.

The fuel also contained fluorocarbons to increase its lubricity, an oxidizing agent to enable it to burn in the engines, and even a cesium compound, A-50, which disguised the exhaust's radar signature.

Even if there was a compound called A-50 used in the fuel to help mask the exhaust signature, it obviously didn't work very well.

 

[Cyrus]

I was under the impression that the SR-71 ended up having a huge radar signature due to its exhaust plume.

http://www.aircraftguru.com/aircraft/aircraft-information.php?craftid=80

Several webpages make reference to a mysterious "cesium-based compound A-50" that was used to help mask the exhaust, but I'm not sure that claim is made by reputable sources with references.

Even if there was a compound called A-50 used in the fuel to help mask the exhaust signature, it obviously didn't work very well.

I stand re-corrected (back to my original statement)!

Either way, this is a good discussion with interesting links!

My understanding from the book "Skunk Works" is that they tried to design ad-hoc stealth features into the airplane, but this was years before they had any methodology (mathematics they got from a Russian paper on radiowaves) in the early to mid 80s.

Sure, they tried to make the blackbird stealthy, but that does not mean it was. The book "Skunk Works" also glosses over the big problems they had with the Blackbird engines going through violent restarts.

BTW, those chins were in the way for a sensor that was being developed for the airplane, which is why one early variant had them missing near the nose. The lack of chins caused problem with the stability and so they had to add big fins at the bottom rear of the aircraft. They also developed and fired the pheonix missile specifically for the Blackbird.

but it was eventually used on the F-14 instead.

The book "Lockheed SR-71 Operations in the far East" has many good stories and pictures. There are pictures captured of rusisan missiles being fired at the SR-71 but not being able to reach its altitude. You can see the missile streaks in the picture, which is why I never bought the "SR-71 is stealth" argument put forth in this thread.

Interestingly enough, it was also used exensitvely in the middle east (over Iran).

 

[mgb_phys]

My understanding from the book "Skunk Works" is that they tried to design ad-hoc stealth features into the airplane, but this was years before they had any methodology (mathematics they got from a Russian paper on radiowaves) in the early to mid 80s.

Ufimtsev paper described the effects from the edges of flat surfaces, but IIRC one of the surprising results was that the return from a flat surface was independant of the size.
Other techniques like the non-constant radius curves and avoiding corner cubes (tails and engine inlets) were already obvious in WWII - they are basically optics.

 

[DaveC426913]

...and avoiding corner cubes ...

In exactly the way that boats don't.

http://store.crowleys.com/catalog/DI152.jpg

 

[FredGarvin]

Ufimtsev paper described the effects from the edges of flat surfaces, but IIRC one of the surprising results was that the return from a flat surface was independant of the size.
Other techniques like the non-constant radius curves and avoiding corner cubes (tails and engine inlets) were already obvious in WWII - they are basically optics.

They had the methodology but did not have the computing power to put it to real use at the time.

 

[Cyrus]

Continuous curvature is a pretty well-established principle in stealth, since it softens the radar signature. The father of a good friend of mine was involved in the design and development of the Blackbird, and the chines and constantly-changing curvature of the fuselage were designed to help reduce the radar signature. Any assertion that the Blackbird was not designed with radar stealth in mind should be taken with a grain of salt. Its impressive speed could help get it out of some trouble, but without stealth, its penetration into target areas before detection would have been restricted, reducing its effectiveness.

There was something that just didn't sit right with your post, and now I remember why. The fact that the blackbird was un-stealthly, along with its Ma 3+ speeds, was used to perform fake 'penetrations' into Russian airspace. The radar operators would see the blackbird coming in at high altitude and high speed and turn on all their radars to track it better. The blackbird had a sensor package that would then record the incoming radar signals so the engineers could evaluate what types of radar the Russians were using. Your last comment is inaccurate.

 

[shoehorn]

Stealth doesn't make the plane invisible (the loss of B2s in serbia proved that)

No B-2s were downed in Serbia, or indeed anywhere else. One of them crashed on takeoff in Guam a few years back, but none have ever been shot down.

I went to a lecture by the British radar expert lockheed brought into perform the tests described in skunk works (don't have my copy here - can't remember his name).

They found a number of planes that were surprisingly stealthy, The Avro Vulcan was among the best - despite having a delta wing about the size of Iowa it has lots of non-constant radius curves which scatter the radar return, very deep oval engine inlets and a defrosting heating coating which turned out to be just the correct wavelength to absorb radar of the time.

Heh. That the Vulcan was stealthy is one of those odd myths that have never gone away in spite of being contradicted by almost everyone who was ever involved with the aircraft. I was sitting in the control tower last September for an airshow to celebrate 100 years of Marshall's here in Cambridge. One of the highlights of the show was a refurbed Avro Vulcan that flew an air display. You wouldn't believe the radar returns from it: we compared signal intensity from a variety of aspects at 10, 20, and 50 miles and they were an order of magnitude larger than anything else that flew that day. Even in clean configuration with gear up the engine inlets and tail bounce a large amount of radar energy back to ground.

The Vulcan was a lot of things, but stealthy it ain't.

 

[shoehorn]

If you read the history about only one airplane, read about the blackbird. It's an amazing machine.

The U-2 is a far more interesting and impressive aircraft, imo, particularly in terms of its contribution to science over its lifespan. For instance, it's doubtful we'd have gone to the trouble of launching COBE and collecting such detailed data on the CMB were it not for the fact that NASA allowed Alvarez, Muller, and Smoot to put a differential radiometer on a U-2 all those years ago.

 

[turbo]

There was something that just didn't sit right with your post, and now I remember why. The fact that the blackbird was un-stealthly, along with its Ma 3+ speeds, was used to perform fake 'penetrations' into Russian airspace. The radar operators would see the blackbird coming in at high altitude and high speed and turn on all their radars to track it better. The blackbird had a sensor package that would then record the incoming radar signals so the engineers could evaluate what types of radar the Russians were using. Your last comment is inaccurate.

How many Blackbirds were shot down by the Russians? Give us a ball-park number.

At the same time, you might want to give us a ball-park number of how many Russian high-altitude aircraft invaded US air-space during the same period. An order of magnitude or two error is OK, if you can cite some reliable sources.

 

[Cyrus]

How many Blackbirds were shot down by the Russians? Give us a ball-park number.

Zero, but what does this have to do with what I said?

At the same time, you might want to give us a ball-park number of how many Russian high-altitude aircraft invaded US air-space during the same period. An order of magnitude or two error is OK, if you can cite some reliable sources.

Again, why is this relevant? The answer, is at least one. The Russian built a spy space station that flew over the US every time it orbited over and took photos using a high resolution camera. This was linked by (Ivan?) in the GD thread a while back to a PBS special (maybe it was BBC). It was really interesting, I wish I kept the link. If you search you'll find it. If you have any interesting links to contribute, please share!

 

[mgb_phys]

No B-2s were downed in Serbia, or indeed anywhere else. One of them crashed on takeoff in Guam a few years back, but none have ever been shot down.

Sorry, It was the other one (F117?), the stealth bomber we are calling a fighter cos bombers aren't as cool.

The Vulcan was a lot of things, but stealthy it ain't.

Great list of Vulcan stories here.
http://www.pprune.org/aviation-history-nostalgia/111797-did-you-fly-vulcan-merged.html

Including the optomistic plans to issue the crew with walking boots because after nuking Moscow they wouldn't have enough fuel to make it out of Russia and were supposed to crashland and hike to Turkey.

 

[Cyrus]

Sorry, It was the other one (F117?), the stealth bomber we are calling a fighter cos bombers aren't as cool.


Great list of Vulcan stories here.
http://www.pprune.org/aviation-history-nostalgia/111797-did-you-fly-vulcan-merged.html

Including the optomistic plans to issue the crew with walking boots because after nuking Moscow they wouldn't have enough fuel to make it out of Russia and were supposed to crashland and hike to Turkey.

You're right, I didn't realize one had been shot down before!

http://www.serbnews.com/f117/f117_2.jpg​

[/URL]

 

[russ_watters]

I read somewhere that the SR-71 used some "stealthy" design features, but nevertheless had a massive radar signature.

The plane itself did not: it had a rediculously small radar cross signature given its size. In Skunk Works, they said it looked like a Piper Cub on radar despite being as large as a WWII bomber.

I tend to consider the exhaust plume question a separate issue...

 

[FredGarvin]

I have read the stories of the SR simply out running SAM launches, but I have never read anything that said it had a "huge" RCS. I'm going to have to dig out some more books on this one.

I got to see the Vulcan fly about 15 years ago. What a cool airplane (if you weren't one of the crew). I can't imagine, with that HUGE vertical stabilizer, how it could be stealthy. I'd say someone looking at it from an ATC standpoint pretty much squashes that rumor.

 

[FredGarvin]

Including the optomistic plans to issue the crew with walking boots because after nuking Moscow they wouldn't have enough fuel to make it out of Russia and were supposed to crashland and hike to Turkey.

Wow. Jimmy Doolittle was alive and well in those planning meetings.

 

[FredGarvin]

Another hijacking of this thread:

NASA's Lessons Learned from the SR-71 program. This paper has TONS of really good information. It does have a blurb on page 36 about meeting the customer's requirements for RCS reduction, but it doesn't really go into detail.

http://www.scribd.com/doc/18029452/NASA-SR71-Blackbird-Challenges-and-Lessons-Learned-2009