Blackbird SR-71 Flight Manual (2010) | Hacker News Reader

Blackbird SR-71 Flight Manual (2010)

sr-71.org

385 pointshazzamanic149 comments

A comment[0] by ehnus[1] from last time this was submitted[2] said:

> My favorite section is emergency procedures which contains gems like this:

> "If both the A and B hydraulic systems fail as indicated by illumination of the A HYD and B HYD warning lights and confirmed by loss of A and B hydraulic pressure and deteriorating control effectiveness:

> 1. Eject"

========

[0] https://news.ycombinator.com/item?id=1338777

[1] https://news.ycombinator.com/user?id=ehnus

[2] https://news.ycombinator.com/item?id=1338504

If you enjoy such gems, check out the procedures for C130 transport aircraft. An old colleague used to be a load master on them (before going into tech), and said the action required for a situation where your load is jammed on exit and you can’t cut the chutes deployed to extract the load from the cargo hold is “prepare for crash landing”.

I do enjoy the bluntness of military checklists.

I just checked a modern copy I have lying around and couldn't find that particular phrasing. However there are lots of other gems such as "a malfunction of the extraction system that causes cargo to move can be extremely hazardous."

Oh really. You don't say.

Might have been a C17A/21/26 instead of a C130. I’ll dig tonight to find it.

the video of that crash is just hear breaking. you see how the pilots try to recover, did everything right, but it was an impossible task.

Here is a video of the crash from a dashcam. This is probably the most detailed view of the stages of a plane crash I've ever seen. https://www.youtube.com/watch?v=dLAvN4IUzoI

What's #2?

I believe you shout "Не стреляй, я сдаюсь." a bunch.

Google translate: "Don't shoot, I give up."

"... I surrender"

No idea, but #3 is probably "change underwear"

What other options would you have in such an extreme situation? It seems to make sense to me.

Right, you have no control over the lift surfaces in this scenario. This would be the equivalent of your steering wheel suddenly not turning the wheels.

Except, even if my steering does go out, I can typically hit the brakes and come to a stop. Airplanes do not have that as on option.

the SR-71 , at that point in failure, would still have the opportunity to 'hit the brakes' like you would in your car.

Both vehicles can still veer wildly out of control even under deceleration, sometimes being exaggerated by the event -- so the plane manual recommends ejection rather than other remediating maneuvers because it's understood that further maneuvers may put the plane into such an attitude that ejection is impossible or futile.

So, that said, the SR-71 can still hit the brakes at the point by which their primary control surfaces fail; it's probably just a mighty bad idea to try to do so. There's a few instances in a car that might be a bad idea, too.

Imagine the steering wheel falls off in heavy moderate speed traffic -- in many cases it'd be safer to let the car drift across the road crowning and slow itself on roadside barriers than it would be to slam the brakes and take the full force of the traffic behind you colliding with your vehicle.

Screw it. Where's my automotive ejection seat?

Yes, airplane check lists do tend to make sense.

Still, there is some humour in the laconic terseness and finality of that checklist, which is probably why it was brought up.

It's an emergency checklist - of course it's terse. I don't know what people expect.

It's funny. That's it. People just find it funny.

I guess I don't really get that then - it's funny that someone designed it sensibly? Not sure where the joke is.

Yes! The standard is so senseless that something sensible is hilarious.

In a mad world, a sane man is considered mad.

I originally downvoted both your comments, but after a few seconds of reflection realized that it's not deserved, and undowned both.

I think you _truly_ are missing the point of why it's funny, and that's fine. Humour is a pretty subjective thing in the end.

Laughter is provoked by a discontinuation of what your brain expects.

If you saw a dog walking a man on all fours, you would most likely laugh, because of the unexpectedness.

In this case, the unexpected terseness causes laughter. You don't expect what follows to just be "Eject". In a technical context like a manual, you expect what follows to be a detailed list of steps and instructions. When this expectation is shattered, you laugh.

Thanks for reading. Have a good day.

Speaking of humour, I can't tell what I find funnier: the fact that someone didn't see how these checklist items could possibly be construed as humorous, or your clinically precise explanation of the concept of humour itself, complete with a mechanistic explanation and example. Together, they're a beautiful example of the tone of HN.

Everyone says they're funny because they're unexpected, but simple direction and plain language is exactly what I'd expect from an aviation checklist, so I have no idea.

It's not just they're unexpected. They're both expected and unexpected. You also expect a manual to have details. It's the sudden ending that is both fitting and not fitting that creates the humour shock.

Thank you. This is my first time on HN actually, and I was captivated by the same tone you speak of. Are you interested in chess?

Don't worry, it's just humour being subjective.

I like to picture a little checkbox next to this, so that you can put a checkmark in that box as your hurtle through the air, then dig out the "parachute operating procedure" checklist and start it from the top.

If you're looking for that page, it's at https://www.sr-71.org/blackbird/manual/3/3-98.php.

In a similar vein, page 3-135[0] describes what to do when e.g. under missile fire ("the pilot is authorized to use the tactical limits listed...to exit the hostile area by the most expeditious means... Subsequent reentry into situations which rely on use of these limits is NOT authorized.") on the same page as the procedure for defogging the cockpit.

[0] https://www.sr-71.org/blackbird/manual/3/3-135.php

Nuclear propulsion manuals for the U.S. navy have similar wordings.

>By order of the commanding officer [actually a highranking person on carriers, compared to little ships where COs can be realtively junior and low ranking], this reactor limit may be ignored during tactical situations.

Legend has it that every CO (3, i think i heard) to invoke "when tactical" exceptions have been fired in the following review. The only thing worse than crashing a billion dollar boat is damaging the publics trust in naval nuclear power : )

I'm remembering back 40 years here. I worked in the engine room of a nuclear powered cruiser. We had a switch called something like "battle bypass" that would bypass all the auto scram functions. The military calls a shutdown scram while the commercial industry calls it trip. We had a captain rank captain and I believe all nuclear powered vessels had one.

I love the qualifying phrase "captain rank captain."

(And I understand why it's needed.)

“battle short”

When’s the last time a large US navy vessel was in a situation where exceeding limits was justifiable due to tactical needs? I’d probably wager that WW2 was the last time.

To be fair, on the same page also there is the “taxi slowly if broken tank” failure mode, because it “can be ingested by an inlet”.

For those who don’t have the picture in mind, the first DC-3’s fuel valve was next to the air inlet. One day the operator didn’t watch the refill (They didn’t have autostop valves at the time), the fuel overflowed into the inlet, which certainly mixed it studiously with the air and pulverized the whole into the cabin. Man, aviation was wild at its beginnings.

Must be nice to have that luxury. The same emergency in the AH-1Z basically says "good luck." Granted, a hydraulic failure of two redundant and independent systems is astronomically unlikely (and the outcome will almost certainly be fatal).

Well in that particular case it’s probably still a better option than ejecting.

Because it is a helicopter? Ejection seats have been done for those. Explosive bolts release the blades, and then everything proceeds as normal. Here is one such helicopter:

https://en.wikipedia.org/wiki/Kamov_Ka-50

I believe that was literally the first helicopter with working ejection and is newer than the grandparent’s example (Apache)

You can always go B-52 and eject downwards.

AH-1Z Viper, a successor to the SuperCobra, which succeeded the original Cobra from the late 60's.

Apache is very different machine.

That proves my point even more if the Cobra is even older. I imagine it would be extremely expensive to add an ejection system to a helicopter that wasn’t initially designed for it.

>Granted, a hydraulic failure of two redundant and independent systems is astronomically unlikely (and the outcome will almost certainly be fatal).

Triple system failure https://en.m.wikipedia.org/wiki/United_Airlines_Flight_232

“The crew contacted United maintenance personnel via radio, but were told that, as a total loss of hydraulics on the DC-10 was considered "virtually impossible", there were no established procedures for such an event.”

Fascinating/harrowing stuff: Despite these losses, the crew was able to attain and then maintain limited control by using the throttles to adjust thrust to the remaining wing-mounted engines. By using each engine independently, the crew made rough steering adjustments, and by using the engines together they were able to roughly adjust altitude.

With no control surfaces, and using the engine thrust they attempted a landing - of the 296 people on board, 111 died.

Cases like that one are the reason that passenger aircraft won't be fully automated any time soon. Autopilots are unable to cope with unexpected system failures.

I flew an L-39 with inoperative ejection rockets. The bailout procedure was:

1. Roll inverted.

2. Trim full nose down. (Down = skyward at this point.)

3. Blow canopy.

4. Fall out.

Every contingency planned for. Love it.

5. Swear or pray (or both!)

So... What do you suppose the chance is you would have hit the tail fin?

Imagine letting the nose fully roll over and having to time the ejection at max inertia... or you are doing a Dr. Strangeglove meets True Lies. So delightful.

Less than the chance of the original emergency killing you!

That’s what the full trim is for. It makes the aircraft pitch away once you let go of the stick.

What about seatbelts?

Crap, you're right. We'd better revise the manual.

Depends on whether your parachute is integral to the seat or you’re wearing a pack. If the chute is in the seat, I would highly recommend staying harnessed to it.

This is almost as good:

WARNING Do not pull the secondary ejection T-handle with the canopy still in place.

https://www.sr-71.org/blackbird/manual/1/1-199.php

>Foot Retention System

"Intentional spins are prohibited. The following technique is suggested if an inadvertent spin occurs; however, ejection may be the best course of action because spin recovery has not been demonstrated and is considered extremely unlikely."

Reminds me of my favorite line in the US Antarctic Program Field manual:

18.1i Crossing Crevasses ... If a snowmobile or sled starts to break through a snowbridge, experience and circumstances will dictate whether to brake and attempt to hold the fall, or continue driving forward in hopes of getting across before a catastrophic collapse of the snowbridge. In either case, a change of underwear is recommended.

No Blackbird post is complete without a link to the Speed Check story:

https://www.thesr71blackbird.com/Aircraft/Stories/speed-chec...

It all had lasted for just moments, but in that short, memorable sprint across the southwest, the Navy had been flamed, all mortal airplanes on freq were forced to bow before the King of Speed, and more importantly, Walter and I had crossed the threshold of being a crew.

Executive summary:

Cessna: How fast.

Tower: 6

Beechcraft: How fast

Tower: 8

Hornet: Yo how fast bro

Tower: Eh, 30

Sled: mfw

Sled: How fast sir

Tower: Like 9000

Sled: More like 9001 amirite.

Tower: ayyyyy

Sled: ayyyyy

Ayyyy.

Succinct summary of a timeless story.

Yes, but the telling is well worth listening to, as are his longer speeches. Including this gem: Navy pilots: "What did YOU do today?" Sled pilots: "Nebraska in 4.5 minutes, which is the best way to do Nebraska."

I've heard the ending

(lots of static, Russian accent) How is my velocity

Tower: about 27 Machs

I once got around two thirds through a certificate for flying ultralight planes. It sort of stopped making sense to me when we were practicing emergency landings over forest and I was told to aim for trees with thinner trunks.

This is sitting inside a cramped metal can with the engine in your lap and propeller in your face. There are so many ways to die in that situation that focusing on the diameter of tree trunks was just too much for me.

I would think you'd want a good clump of green tree canopy to hopefully take the impact "slowly" and stop the plane without the sudden smashing associated with crashing.

Such as:

http://www.fox5ny.com/news/plane-stuck-in-tree-idaho

Perhaps the smaller trees would be more likely to bend/snap, absorbing more energy

1. Scout out some good softwood.

That rescue is truly remarkable.

Not only did the plane remain stable in the tree, one of the volunteer first-responders had the appropriate tree climbing experience and equipment to reach the accident site.

That experience could have easily gone to waste - arborist climbing techniques and standards are very different from what is used for vertical rescue.

The fact that the rescuers made the pragmatic decision to go ahead with borrowed techniques is very unusual.

My favorite part is

>Officials are trying to determine how to remove the plane from its perch and warned people to stay away from it.

Landing on top of a dense forest is surprisingly survivable. It is actually more so than landing on top of suburbia

There is a testimony of a small girl who survived the entire dislocation of her plane while at 5000m over the amazon forest.

She had no bone hurt and a dozen people survived. Minus the injuries due to spending 10 days without disinfectant in the jungle.

I wonder if you mean Juliane Koepcke, but she was 17 at the time and the lone survivor.

https://en.wikipedia.org/wiki/Juliane_Koepcke

https://www.telegraph.co.uk/culture/books/authorinterviews/9...

https://en.m.wikipedia.org/wiki/Varig_Flight_254 is an interesting story.

The same is true for gliders and has saved lives (one i know).

I've landed in the top of a dense forest in a glider and survived just fine. (Of course, someone came to get me out of the tree with a kit, so I'm not sure how much that counts as "me surviving a tree crash".)

Better to think through these scenarios ahead of time so that you already have a plan if you find yourself in this situation, as others have. Tree landings can be survivable especially if you let the trees bend and absorb your energy.

Has the same kind of training. It is interesting to see the difference in culture between ultralight and general aviation flying.

In general aviation, the focus tends to be about doing things right: proper procedures, precise flying, etc... Ultralight tends to be more about getting prepared in case things go wrong. In fact, more than half of my training was about dealing with engine failures.

I think the difference in training comes from the fact that crashes are more frequent with ultralight aircraft but they are also more survivable. A big part of it is that ultralight aircraft are lighter (duh) and can fly slow, which mean mush less energy to dissipate, and it matters a lot if you are going to crash into a forest.

I used to fly gliders (sailplanes). There are many cases of pilots landing on trees with minimal damage, sometimes even to the glider. Of course the huge wing span helps.

Big aviation has no such procedures because crash landing a Boeing or a fighter jet is not an option. Even landing on water (perfectly doable in a glider, though all instruments will be kaput) is a huge achievement in an airliner.

Skunkworks [1] is a really great book by the designer of the propulsion system (and subsequently the first stealth airplane). I highly recommend it to anyone who wants to know how many drill bits you burn through trying to build a titanium airplane.

1- https://www.thriftbooks.com/w/skunk-works_ben-r-rich_leo-jan...

I‘d like to second that recommendation. The book certainly won‘t win any literature prizes, but it does tell a fascinating story and gives a glimpse into the „wild west“ engineering culture that created the Blackbird.

If it's the plane equivalent of "Blind Man's Bluff" then I'm in.

Skunkworks is a legend in aerospace, and rightly so. Shows what's possible if give brilliant people a common goal, some resources and leave them otherwise alone. The fact that the F-117 was developed in time and within budget says a lot. As usual nobody drew the right lessons from it.

I got my fingers on a report about the F-16 development from the eighties from the budget office. Funny to read it, especially the questioning of staggering spare part needs today when you know that Skunkworks "sourced" the F-117 material from the F-16 and F-15 programs.

The maintenance manual is a fun read too. A lot of the repair procedures end with PTF.

That means “Pound to Fit” (with a hammer or mallet). The panels flexed so much that they would come back a different shape than they were manufactured and had to be hammered into place.

Why were instruments (instruments? or panels?) so flexible? Was ut to sustain altitude, pressure, G and speed?

If I recall correctly the plane was built to stretch at high speeds, so the panels were designed to be loose, and the plane would leak a lot of fuel until it reached optimal speeds.

Q: How do you know there's fuel in the Blackbird?

A: It's leaking.

Same goes for oil in old Land Rovers!

> Was ut to sustain altitude, pressure, G and speed?

Heat expansion. That's also why it would leak fuel when on the ground (fuel lines would expand at speed so they needed expansion gaps when on the ground).

Outside emergency situation, the crew had to wait inside the plane after landing, waiting for the surfaces to cool down enough that they could safely get out without melting their gear.

There's a video walking you through the SR-71's cockpit which I found really interesting:

https://www.youtube.com/watch?v=tj9UwKQKE3A

13m04s: "Some guys were getting bank angles up around 60 degrees of bank at mach 3 and it just, uh, that's not good. Come very very close to losing the airplane." [He then proceeds to talk about a lamp.]

Thread needs a link to this great story about the sr71's slowest speed : https://foxtrotalpha.jalopnik.com/the-sr-71-blackbirds-most-...

For some not so heavy reading for SR-71 enthusiasts, I highly recommend Brian Shul's book "Sled Driver". They are out of print now I believe, and I've seen them on eBay for about $3000 at one stage, but I think they are more generally available at reasonable prices now second hand. I was lucky enough to be given a copy as a gift by a friend a couple of decades ago.

Beautiful book with amazing pictures and stories by a long time SR-71 pilot. A lot of the 'urban legend' stories going around about the Blackbird come from that book.

"Skunk Works", as mentioned by other posters here is also a good read.

Chart of speed vs altitude:

https://www.sr-71.org/blackbird/manual/5/5-9.php

That's the flight envelope chart, I went right to that page as well.

Does anyone know what the break in the Minimum Airspeed Restriction at Mach 1 is about?

Yes, Google for "Mcrit" or critical Mach number. It's the free stream airspeed at which any part of the airflow over the aircraft first becomes sonic. Usually the inner part of the wings near the root, the thickest section.

Airliners have the same but it happens below M1.0 because of the thicker wings. And it causes a much bigger change in drag and lift compared to an aircraft capable of super sonic flight, enough to make it impossible to take an airliner super sonic without losing longitudinal control and crashing.

I once took a filmmaking class from Robert Mehnert who directed a documentary about the SR-71 at a time when its production was at risk of being discontinued. At first only a few hundred people in Congress saw it, but based on the size of the order for new planes, he called the highest-grossing opening weekend of all time. (I haven't been able to find the film online anywhere.)

I tried too, but since the documentary is simply called "SR-71 Blackbird", it makes it hard. The subtitle "To keep the peace they fly alone... unarmed... into the unknown" ist cool but yields one result: an auction of the movie poster [0]

In turn, the movie poster however let me to a reverence to the movie in the book "SR-71 revealed the inside story" by Richard H. Graham, Col. USAF (Ret).

0: http://auctions.emovieposter.com/Bidding.taf?_function=detai...

I liked

"Maximum altitude is 85,000 feet. Do not fly over 85,000 feet unless you have prior authorization"

"No turns are allowed over 70,000 feet. Descend 2,000 feet prior to making any turns is recommended"

"The ANS is an inertial navigation system employing a star tracker to eliminate gyro drift and to limit position error."

Not your run-of-the-mill airplane, that's for sure...

Posting this here hoping that someone with more knowledge can enlighten me about this. After going down a bit of the rabbit hole, I see that the SR-71's first flight was in 1964. It has held the record for fastest air-breathing manned aircraft[0] since 1976. What is the reason that given all of the technological advances that record hasn't been broken?

[0] https://en.wikipedia.org/wiki/Flight_airspeed_record

I want to go out on a limb and say two things: (i) It probably is broken. (ii) That table doesn't show when the data was listed as public. The reference on the top speed is "Taylor 1988, p. [51]."

There are faster air-breathing aircraft (e.g. [0]), but none of them are manned because with modern technology there's no need to put a person in them, and the people funding these developments aren't interested in spending lots of money just to chase records.

There's also the outside possibility that faster manned aircraft exist, but remain classified [1].

[0] https://en.wikipedia.org/wiki/Boeing_X-51_Waverider [1] https://en.wikipedia.org/wiki/Aurora_(aircraft)

I just love how this super-hightech, experimental military aircraft has parts secured with duct tape in this Wikipedia photo: https://upload.wikimedia.org/wikipedia/commons/thumb/e/e5/X-...

-Wholly uneducated guess: many of the tasks handled by the SR-71 is adequately handled by satellites today.

Additionally, if someone had indeed broken the record in some black project or the other, chances are they would keep mum about it rather than calling Guinness Book of Records.

There's just never been a need. The SR-71 could already outfly missiles.

And in general, now that we have the technology, the SR-71's role is much better filled by unmanned craft like satellites anyway.

Stuffing a man inside one of these deathtraps and getting him home safely adds orders of magnitudes of difficulty. A better question might be, why would you want to send a person up in something like this, if you could possibly avoid it? It would most definitely be awesome, but it would come at the cost of billions of dollars and possibly human lives.

Also physics is a real bastard. Air resistance increases with the square of velocity. Even small gains over the SR-71's speed would come at a very, very high cost in terms of fuel burn rate, etc.

Basically, satellites took over They are cheaper to operate and less vulnerable to defensive countermeasures and other failure conditions. From a Los Angeles Times article from '89 [0]:

> "The Air Force decision to retire the Blackbirds in 1990 is based on several factors. In congressional testimony, Air Force Chief of Staff Gen. Larry D. Welch identified the increased survivability of reconnaissance satellites, SR-71 vulnerability to the Soviet SAM-5 surface-to-air missile and the cost of maintaining the SR-71 fleet."

[0] https://www.latimes.com/archives/la-xpm-1989-04-09-op-1582-s...

They took over, but there’s still an argument for spy planes; satellites arrive on their own schedule in predictable orbits. This makes it very hard to get timely photographs, and it makes them easier to defend against. A spy plane could get in and out of a trouble spot within an hour, all before the enemy can hide the nukes or whatever.

A modern spy plane however would have to be faster than the SR-71, which I don’t believe would be safe against modern SAMs.

The X-37B is likely a test platform for exactly that scenario (and more).

Based on the totally amateur knowledge level of someone that once spent a few hours researching stealth satellites (MISTY, etc), there's obviously a demand within the NRO for satellites that can be launched into a known orbit, with published two line elements, and then go stealthy and change their orbit into something which cannot be predicted by enemy nation-state ground forces.

I don't believe anything worthwhile about current capabilities has been declassified, it's all conjecture by people looking at the X-37 and similar systems.

There's no way to really "go stealthy" in space. If a satellite is operational then it has to emit enough heat to be clearly visible to IR sensors.

http://www.projectrho.com/public_html/rocket/spacewardetect....

No one has answered why; only answers have been "no marketable product".

There are several technical reasons why, none of which have been been subject to any technological advances in half a century.

1) There's a buffer factor where burning fuel adds a thousand degrees (or whatever) to temp of the air in the engine and steel / titanium / classified will melt several hundreds of degrees above that. Most all jet engines can only work with subsonic airflow. Supersonic aircraft use exotic inlet designs that are inefficient but can convert fast air into very hot compressed air. Somewhere around mach 2 to mach 4 the inlet air temp plus the heat of burning fuel will melt any metal turbine blade. You can pay a lot of money to get a couple mach numbers but fundamentally cheap steel gets you mach 2 and price is no object aerospace material tops out in the mid mach 3 range. True lab experimental materials might survive mach 4 temps, maybe. You just can't get a usable thrust to weight ratio inlet design that works above mach 4 or so.

2) Second aerodynamic problem is if you define "fly" as a lift to drag ratio better than a lawn dart, optimizing wing sweep etc for mach 3+ means its a truly awful performer below 5000 feet or so. Its hard to make an aircraft that actually "flies" above mach 4. Space shuttle L/D ratio was around or below 1:1. Essentially things flying thru the air above mach 4 don't fly in the sense of wings producing lift, they're ballistic trajectory like a missile or bullet, don't bother slapping wings on them.

None of the above can be solved with faster computer cycles. Titanium still melts at the same temp, etc.

There are relatively simple ramjets that fly at around Mach 4 speeds. They are unmanned and are accelerated to speed by solid rockets. Probably the ramjet can't even start below Mach 1 or so.

Designing an air breathing propulsion system for a wide speed range is difficult.

Rockets are much easier after a certain point. McDonnell Douglas and Paul Czysz had interesting projects. If you want manned reconnaissance, a Mach 6 air launched liquid rocket powered lifting body would probably be the next logical step from the Blackbird and would not even be super hard. With rockets you don't have the inlet problem at all and they have excellent thrust to weight ratio.

I remember being reported that SR-71 missile evasion procedure was simply to "accelerate and outpace". But I cannot find it in the manual :( !

I just finished "Skunk Works" by Ben Rich. I believe he said something similar in there, but I would have to find the exact quote.

I don't know if that would be in the flight manual. Presumably that's more a tactical/combat doctrine type thing.

Would totally depend on the missile and where it is coming from. Anything behind ... acceleration wouldn't matter as few missiles would have been fast enough to close the gap. Missiles to the side would be outrun. Missiles from the front are another story. A missile rising up from a point in front of the aircraft is a deadly threat. It doesn't even have to match velocity to make a kill. In short: acceleration for missiles below and to the sides. Stuff in front, time to turn. Stuff behind, forget about it.

This is what you are looking for: http://www.onceagreenberet.com/wp-content/uploads/2008/02/sr...

To think of it - I might have heard these two pass by. Not on that flight, but I lived with my parents in northern germany, not far from the danish border, and en route from the north to the baltic sea and on to russia. I often heard the badam, accompanied by a creak of the wooden roof.

This is a remarkably slow website for such a fast plane.

Appears to be crushed under the load of the flight enthusiasts found on HN.

It's probably being overloaded by HN readers right now. Try this: http://web.archive.org/web/20190509220204/https://www.sr-71....

Is content of this site a subject of ITAR restrictions?

No, everything about the aircraft is obsolete which is why no other country has attempted to develop anything similar. The J58's are really dated, though most of the thrust is generated by the inlets when supersonic.

That does not mean that this manual is not subject to ITAR restrictions.

> most of the thrust is generated by the inlets when supersonic

I've often heard this (also about the bypass in Concorde's engines), but I've never heard a clear explanation about how some element of an engine which doesn't involve burning fuel can generate thrust. Can anyone explain it?

If I remember correctly, in the book Skunkworks they explain that it would increase the air pressure. The analogy made was that it was similar to putting a finger on a garden hose to partially block it, thus increasing the water pressure.

Obviously there must be some complex physics going on but that was the gist of it.

Probably someone with more knowledge can confirm or correct me :)

Here's a great answer on avation.stackexchange.com that answers that exact question:

https://aviation.stackexchange.com/a/27024

Since the SR-71 is a perennial HN favorite:

https://news.ycombinator.com/item?id=13567554

I think the StackExchange answer linked below covers interesting aspects of supersonic inlet behavior, but doesn't do a great job answering your specific question.

I recently saw the one exhibited in the Smithsonian National Air and Space Museum, close to IAD airport: https://airandspace.si.edu/udvar-hazy-center

It got there from LA, and on it's way set 4 speed records: https://airandspace.si.edu/udvar-hazy-center

Just to throw my one cent in on these matters.

http://www.avialogs.com/index.php/en/aircraft/usa/northameri...

Is there a single page PDF?

I've created a pdf based on the available scans I could find on the site.

Added blank pages according to the a, b, and c pages. Added table of contents for the major sections. Also tried to do some ocr on it, it seems good enough for searching at least.

https://bayfiles.com/N9m6nbtfnc/SR-71_Blackbird_Flight_Manua...

I hate to sound like a choosy beggar, but any chance of putting it on a less-skeevy download site?

How about a Dropbox link?

Sure thing: https://www.dropbox.com/s/i5eucyo7gm67bv6/SR-71%20Blackbird%...

I don't really use dropbox any more so bayfiles was just the first thing that came to my mind, it's better than most free file hosting sites (no waiting and no excessive throttling)

Awesome, thanks! That worked.

In 1990/91 I was stationed at a base that once was a home for the SR-71. By the time I got there, though, they'd been retired.

Some of the spoken-word mythology that was shared with me by some of the AF elders:

* Each flight cost about $1M

* The SR-71 was so loud and created such massive sound waves, the crew chiefs had to be really far away from the ship when talking to the pilots inside so that their internal organs wouldn't be damaged...

* The engine cowling of the Blackbird would get so hot that the metal would be slightly transparent, where you could see moving parts _inside_ the engine.

* All of the pilots wore astronaut suits.

Worth noting all the above could be entirely false. But it made a big impression on me.

Point 3 goes against normal behavior of hot metals, which emit infrared or visible light as they get hotter. It's called black-body radiation, and it's why iron and steel glow in a blacksmith forge.

The "moving parts" may be due to heat waves moving through the air (see also: mirage at a distance)

>Point 3 goes against normal behavior of hot metals, which emit infrared or visible light as they get hotter.

You're right. People refer to it as 'transparent' because it begins to glow the same color as the jet plume under afterburner use.

https://gizmodo.com/this-is-an-image-of-the-very-last-test-o...

Differential heating could give the illusion of transparency; really it would just be the metal glowing brighter where something hotter is on the other side.

I wonder how the pilots managed to consult this manual while wearing big bulky astronaut gloves.

There's so much raw data in the manual, I can't imagine they were expected to memorise it all. Though I'm sure you need to have a very good memory to qualify as an SR-71 pilot.

It is safe to travel to Georgia after having read and downloaded this?

Site's crashed apparently, does anyone have a mirror or a PDF?

This is one of the reasons I love Hacker News

What's the procedure for runaway trim?

This thread is lacking the Blackbird ground speed check. https://oppositelock.kinja.com/favorite-sr-71-story-10791270....

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