SR-71 Blackbird Speed Check Story | Hacker News Reader

SR-71 Blackbird Speed Check Story

thesr71blackbird.com

229 pointswallflower179 comments

I never tire of that story.

Growing up in an aviation family, I have heard endless cool stories (but few so cool).

One of my favorites was when my grandfather was flying when the F15 was in early flight development. The skies were much less busy, and there was a bit less formality.

Ground knew who was where, so it asked my grandfather, “would you like to see something interesting?” GD agreed, and moments later an F15 pulled up alongside him, pointed at an upward angle and maintaining what was a slow flight speed for it. The two pilots were close enough to exchange waves, and moments later the F15 rocketed away.

Most likely that day, the F15 was the fastest thing in the air for several hundred miles.

The SR-71's actual top speed was classified, and the 'official' top speed was faster than anything else in production.

At several points growing up someone would come up with a new plane that encroached on the SR-71's speed record. Then a couple weeks later there would be an announcement about the SR-71 setting a new top speed.

I suspect someone in Intelligence had to decide that being officially the fastest was important, but exactly how fast being a secret made the plane and pilot a little bit safer. So they had to nudge the fiction a little bit closer to the truth any time there was a pretender. Or, manufacturing improvements nudged the maximum safe speed up over time, and they only bothered updating the public about this when a dick measuring contest was held in their honor. Or maybe both.

That said, we both know the shape of the SR-71, and the Compressor Inlet Temperature limit. The shape determines the smallest Mach angle that the entire plane fits inside, which gives a value for the maximum speed. The CIT limit gives a value for the maximum speed, which is roughly the same as the Mach angle value, at approximately Mach 3.3. To go faster, the plane would have to be skinnier, or the wing tips would poke beyond the Mach cone, and the entire tip would generate it's own set of shockwaves, which would most likely result in a sharp increase in temperature for the part outside the cone (which can be read as: the wing tips melt off).

It's just nuts to think about people on Concorde sipping champagne at Mach 2.04. I wonder if that's something which will be possible again in my lifetime.

It's likely there will be Starship-based passenger transport from point to point on Earth within 10-15 years.

The biggest hurdle will be getting countries to allow an ICBM filled with humans to approach their mainland.

Highly doubt. The Concorde's problem was economics not science and a rocket based solution is even less economical - even a reusable one.

For normal people sure, but for VIPs and especially military it will happen.

Imagine being able to drop Seal Team Six into Taipei, the Red Square, or literally any other piece of earth with a ~50ft clearing on ~30 minutes notice? That's a capability which is very hard to put a price on.

I'd like to not imagine a boots-on-the-ground shooting war, where you are launching a craft that is indistinguishable from an ICBM at a nuclear power's capital.

I'd like anyone at the DOD who is imagining it to either be fired or shot, before they drag the rest of us into their geno-suicidal fantasies.

Starship is worse than an ICBM. ICBM carries a handful of MIRV warheads. Starship potentially carries hundreds of warheads. It is a single rocket first strike. Nobody would put that many warheads on one rocket, but the target needs to act like it could.

In real life adetachment of a couple of hundred soldiers with very limited support dropped into the middle of enemy territory, with their destination known 30 minutes in advance to anyone with tracking satellites will be very quickly overrun. Said adversary will also be thankful for the gift of the vehicle delivered to them with now way to get it out.

You sir, have clearly never met us special forces. A “couple hundred” with combat load would be an absolute force to be reckoned with.

Is there any reason this would be more possible with a rocket than with, say, a plane? It has to land slow enough that the passengers survive, and during that process it can be spotted and shot down, or surrounded.

I mean I’m definitely in favor of getting some sci-fi style orbital drop troops, but I think it will require some development beyond the rockets; we’ll need to figure out how to get people who can survive a bunch of extra G’s.

A human being can withstand ~8g's for medium short duration with minimal accommodation, say tens of minutes - see fighter pilots. I would imagine that would be enough to get someone on the ground pretty quickly. 30 minutes door-to-door is also incredibly fast, how much of the world could be covered by AA or a fighter plane in time?

As a for instance, imagine if in the initial invasion of Ukraine Russia had the capability to drop a starship heavy's worth of men and supplies onto Antonov airport as soon as it was secure, instead of waiting for transport planes that didn't arrive in time.

You don't need the whole world to be covered. There is no point dropping special forces into the middle of nowhere. The air force can certainly respond within minutes to threats to major cities and strategic targets.

A starship wouldn't have made that much difference in the invasion of Ukraine. You're talking maybe two additional MBTs.

>There is no point dropping special forces into the middle of nowhere

Most of everywhere is the middle of nowhere and almost everything behind the lines is poorly guarded[0]. The vast vast majority of military strategy relies on two basic facts: things are far apart from each other[1] and one needs to move through another place to get to where one is going[2]. Ballistic transport gets around both of these limitations, which is why it is going to happen, costs be damned. Maybe it'll be drones getting dropped, or bombs, instead of people, but it'll be done nonetheless.

I don't know if you've ever played bughouse - but the timely application of even small amounts of resources can have a drastically outsized effect. A starship could have easily doubled the resources the Russians had to take that airport, a few more could have taken another while everyone was busy with the first.

[0]Because those resources are better spend on/near the line.

[1]Lines vs. back-lines vs. civilian areas, conventional logistics and its demands

[2]Walls, trenches, emplacements, AA defenses

If they have a predictable landing in a big clearing they are gonna be in a tough spot regardless of how capable they are.

Drop them with armored transport near a supply line and it could work if you have already done SEAD.

It's a preposterous scenario. China would blow the thing out of the sky long before it could land. And even if it did, they'd simply use armor and helicopters to decimate the forces.

Beijing is defended by two guards divisions. Who get woken up once it is determined that Beijing is the target and move into position.

Special forces are not very good against good regular troops. Special forces are really good light infantry. Regular troops have heavy weapons. Armored regiments have tanks. Mechanized infantry shows up with IFVs and troops.

The whole scenario would be like black hawk down ... but with less survivors.

Special Forces aren't great in head-to-head combat against well-equipped and well-supplied soldiers who know they're coming. They lose their advantage. Plus they would need a whole lot of resupply.

Starship is insanely vulnerable for landings. It starts fast but has to slow down for landing. Which means that is vulnerable to every SAM in Beijing region.

I guess it could be done as drop of pods or something. The problem is that target can’t know the pods are troops and has to assume that they are nukes and this is first strike. China has no choice but to launch ICBMs immediately.

Plus, this risks the Starship itself. It might be possible to drop pods, now space and recently capable, and change directions. But is more likely that get in range of anti-ballistic missile.

Concorde was profitable. Accidents + 9/11 pullback killed it. The major factor against supersonic is actually the fact that sonic booms are not allowed over the continental United states. Companies like Boom Supersonic are focussed on eliminating those.

https://simpleflying.com/did-british-airways-make-a-profit-f...

> If British Airways and Air France were looking for more profit, these issues would have to be addressed. And that was the plan. British and French aerospace divisions were looking to create a brand new supersonic aircraft before plans to take the Concorde out of service in 2000 were realized.

> Of course, that never happened. With a plethora of odds stacked against it, the 2000 crash in France, 9/11 affecting interest, and Airbus scrapping Concorde part replacements, the Concorde was shelved before its time.

The prohibition on sonic booms mysteriously appeared when it came out neither the Lockheed nor Boeing SST would ever become a reality, leading to the embarrassing situation of the only supersonic airliner being a British-French collaboration.

NASA's X-59 project is aiming for a very low sonic boom

> The major factor against supersonic is actually the fact that sonic booms are not allowed over the continental United states.

How do military pilots train then I wonder?

Only civil aviation above Mach 1 is prohibited by the FAA. Rulemaking to certify quieter supersonic planes is underway. [1]

1. https://www.faa.gov/newsroom/supersonic-flight

There are explicit supersonic-permitted areas used by military, but you can actually do supersonic flight as civilian too if you arrange their use (mainly a thing of scheduling so you don't collide with military/state aircraft).

The big rarity of that is that there are very low numbers of supersonic planes in civilian hands, and outside of Concorde and some Tu-144 models (not all of them), all are ridiculous fuel guzzlers in supersonic flight. I know there's one near Palo Alto, a civilian owned MiG-21.

Who the fuck owns a MiG-21?

Well, there's one guy in Palo Alto who had instructor permit on it even, and was looking for partner in its ownership (quite common solution for more expensive planes in civilian hands).

According to wikipedia: 44 people in the US and one big company that owns 30:

https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-21#Civili...

Numbers from 2012 tho... But probably won't be too different now.

More than 11.000 were made, wow.

Two quotes from the link you provided.

> In total, both the French and UK governments put in $1.44bn to get Concorde off the ground. $2.8bn went into realizing the world's first mass supersonic transport.

> At the end of it all, British Airways had gained £1.75bn in revenue with the Concorde against an operating cost of £1bn.

Making some money doesn't mean it was necessarily profitable enough to be worth flying. Typically you have a rate of return across the company that an investment needs to clear to be worthwhile. Especially when considering the aircraft almost certainly required specialized maintenance crews and parts, the bar was probably fairly high.

It was also limited in where it could operate out of. I'm guessing that landing Starship at SFO or JFK or Dulles is not going to happen, ever.

Ever is a long time! In 50 years when travel via rocket between cities on Earth is common, why wouldn't airports build rocket pads for it? When you can fly New York to Singapore in less than an hour, JFK isn't going to just give up that market, they're going to want to capture some of that money.

Probably because the blast radius during lift off is close to the entire JFK property size? Of course, let's not forget the blast radius of a Starship undergoing unscheduled rapid disassembly.

I mean, I like roller coasters, but I think the biggest challenge might be getting hundreds of humans on that ICBM with the current flight profiles.

That seems to be mostly scrapped, they sold off the offshore platforms they'd purchased. It also wouldn't be nearly as fast as the point to point numbers suggested because the trips out to the platforms would have been rather slow on either end.

Fifteen years is a long time in software but a blink of an eye in the world of infrastructure. A decade of Starship development has created a missile that blows up when launched. I'm sure they'll eventually get to orbit, but they're a loooooong way away from anything that the FAA will allow to operate for regular passenger flights near cities. And that's ignoring all the logistics involved in creating a profitable passenger service.

My aunt once rode the concord from Paris back home to NYC as an indulgence. She ended up sitting next to Jacque Cousteau of all people and had a fantastic time. It's one of her favorite stories.

I'd check into Reaction Engines, and the concept of precooled jet engines in general. The math says they should be capable of efficient cruising at speeds up to mach 5. The question is if anyone can make the engineering practical and affordable. But in terms of pure possibility, there's wide open possibilities.

Isn’t the temperature on the body surface the big factor here? The sr-71 would heat up tremendously and it barely had any air pressure to contend with.

It's difficult but not a show stopper. Materials have come a long way. Also, a pre-cooled engine will be using cryogenic fuels so active cooling is an option, even desirable (some of these engines harvest energy from the precooler using turbines on the hot side). SpaceX thinks they can handle the thermal loads of Starship re-entry with ceramic tiles and stainless steel.

Recently got inside the Concorde used for testing, now at Duxford. That plane is much cozier than I thought, even with no seats. And the number of fuses is slightly crazy.

The example at the Museum of Flight in Seattle (somewhat ironically resting at a Boeing factory...) still has original seating and the interior is open to the public - it's really cramped. What got me most though is the tiny portal of a window you got, due to the design constraints of supersonic flight etc. All that cost and prestige, but a cramped seat and no view.

Honestly, if I'm spending that much money for a ticket, I'd prefer luxury over speed. I don't know how many people would prefer a cramped supersonic aircraft over a trip that takes slightly longer and gives you a lay-down bed.

> I wonder if that's something which will be possible again in my lifetime.

Is there a historical situation where a form of travel was long forgotten only to be brought back decades or centuries later?

My thought goes to the Viking Colonies in Newfoundland.

Not really forgotten, but trams/streetcars definitely went out of fashion in many places and have been making a comeback in the form of modern LRT systems.

Many tram lines were built by developers at a time before cars were affordable. Otherwise there would have been no way for the homeowners to commute to work.

Yes, except I don't think developers have built tramlines anywhere but the US (and also the expansion to the suburbs didn't quite happen that way). I'm talking about the period of time that in Europe started in the 60s, and in the US earlier due to the earlier rise of the personal car, when many cities abolished their tram systems due to being "old-fashioned".

Region dependent on exact dates but common bicycle ownership predates common car ownership by 40 years or so.

So a lot of existing cities that are introducing dedicated bicycle infrastructure likely fit.

My toddler loves the movie Moana. Turns out part of the movie is based on a real historical time period where Polynesian people stopped sailing long distances to colonize new areas.

https://historydaily.org/disneys-moana-depicts-an-actual-eve...

I was sitting at JFK back in the day waiting for my flight back to London.

Over the speakers came an announcement: "if anyone is prepared to give up their seat on [my London flight] we'll fly them back tomorrow on Concorde and put them up in [a ritzy hotel] tonight".

I bolted for the service desk to take up the offer and got there in seconds but there were already several people ahead of me. Never got to fly Concorde.

I had a professor who said that in the early days of priceline he used to book fully refundable flights from London or Paris to NYC on the concorde then cancel them - just to pick them back up on priceline for a few hundred bucks at the last minute. Never knew if it was bullshit but certainly made a good story when I heard it in 2008. The context of the global financial crisis made the .com boom/bust look quaint.

That is (a reason) why airlines overbook

Blake Scholl and Boom Supersonic are trying to make that possible again.

https://boomsupersonic.com/

This might be a dumb question, but isn’t that the maximum sustained speed for the plane, and higher speeds would be possible for short bursts? (as in, before the wing tips get hot enough to melt off)

Yes, that is correct, though I guess an issue would be that the drag would increase sharply if parts of the plane is sticking out of the shockwave, necessating even more thrust.

My understanding of bomber height was 1) fighters and ground cannons cannot attack them directly, and 2) SAM missiles have to climb to meet them while matching velocity, and the bomber can shed altitude to increase ground velocity and outpace the missile long enough that it runs out of fuel.

That puts a big gap between top cruising speed and top speed.

> Compressor Inlet Temperature limit

How do we know this is also not part of an official/unofficial limit?

I guess the point is you can make an estimate of the CIT based on the geometry of the plane, and the speed and altitude it's traveling at. And similarly the CIT limit can be estimated from published data about the engine plus knowledge of the limits of the materials used when it was designed.

This is actually an engine limitation. It's to keep the turbine blades from melting. Unfortunately, you can't measure the turbine inlet temperature very well, because of the whole melting thing. So they determine what the limit should be, and then back calculate it to somewhere they actually can measure it (which is the front of the compressor). So, you could exceed the CIT limit, but you would run the chance of damaging the engines. The MiG-25 has famously destroyed it's engines by running to fast.

It’s like the lawyer attitude during a deposition: provide as little info as necessary. Classified by default.

A related quote from the same pilot on how fast the SR-71 could fly: “There really isn’t one number to give, as the jet would always give you a little more speed if you wanted it to.”

https://www.thesr71blackbird.com/Aircraft/Stories/sr-71-blac...

I’d recommend reading Skunk Works by Ben R. Rich for more on the engineering of the Blackbird and other special aviation projects.

I knew the Blackbird was fast, but didn’t quite realize how fast until reading this book. The SR-72 would cruise at Mach 3, or three times the speed of sound. It would do this at 80,000 feet, over twice the traditional cruising altitude of a 747. Even at this height, where the temperature is -60°F, friction would cause the fuselage to heat to 600°F. This would melt traditional aircraft, so the plane was built with titanium (ironically supplied by the Soviet Union). The Blackbird used to overfly North Korea five days a week in just ten minutes.

According to this [0] article it leaks fuel sitting on the runway because:

"The fuel system of the SR-71 could not be sealed permanently because there simply were no sealants that were flexible and durable enough to deal with those kind of temperatures and shrinking-expansion cycles."

I think that says enough about how bonkers fast that thing is.

[0] https://nodum.org/was-sr-71-blackbird-leaking-fuel/

Yeah, heat expansion made it airtight at Mach 3, but sitting on a runway with its parts contracted back to normal dimensions, it had leaks.

Not just on the runway. The hangers had big drains in them to catch the fuel and anyone unfortunate enough to have to work under the plane would get soaked. "Hey, I think the plane is leaking" -- me.

/second that book, one of the best on US aviation history and engineering.

Also iirc, ironically the technique for shaping the F-117 to reflect away radar came from a Soviet journal article on shaping nosecones to minimize their interference on radar emanating from them.

Another fun thing is that claims about no computers being used for A-12/SR-71 are mostly boasting possibly to avoid mentioning then black project details, like CIA buying a custom computer (PDP-2) to do calculations on A-12 shape.

What blows my mind is that this aircraft was originally shown, formally, in 1964.

1.9.6.4.

They had this level of engineering in 1964.

Just imagine what shit goes on behind closed doors today. It really does sort of stagger you.

Given how bloated and wasteful our government is today, and how much the dept of defense blew on the F-35, I would be staggered if anything useful happens behind closed doors, besides corruption.

I think we were able to accomplish a lot more in the past.

Powerpoint was created in 1987 and it was all downhill from there according to the military.

https://www.theatlantic.com/politics/archive/2010/04/why-the...

Thanks for the link, that's fascinating, and resonates so much. Do you know what they used instead?

Indeed https://m.youtube.com/watch?v=aZ-7U95LYTo

Not just for military:

https://mcdreeamiemusings.com/blog/2019/4/13/gsux1h6bnt8lqjd...

Turns out trying to contain a complex system within a simple system of abstractions is a trendline towards disaster for any enterprise.

>Given how bloated and wasteful our government is today, and how much the dept of defense blew on the F-35

You are listening to the fighter plane mafia too much. F-35 is a capable platform with a reasonable but large price tag for those capabilities. If you want to have a discussion of those capabilities, and whether those are needed, that's fine, but "big price tag == corruption" isn't a self supporting argument.

> "big price tag == corruption"

The DoD has failed 5 audits in a row. Take that however you want.

The DoD has had screwed up accounting systems for decades because Congress never appropriated funding to fix them. When the audits started a few years ago there was no expectation that they would pass. The goal is to identify the problems so that they can gradually be fixed without disrupting ongoing operations.

See: https://en.wikipedia.org/wiki/Iraq_for_Sale:_The_War_Profite...

Stop coping.

Is your argument that DoD fails audits because they don't have enough money?

The majority of the engineers where I live work for, or have worked for, defense contractors. I've shut down a defense contractor recruiter once a week or more for the last several months. It's insanity.

I've been a fly on the wall for so many conversations about the stuff they're accustomed to spending money on... Fighter plane mafia aside, I have no trouble believing that that money is going nowhere useful.

F-35 is an awful, awful, awful deal. It's an iteration on the F-22 that is expected to cost 1.7 trillion dollars in total. An absolutely unimaginable sum of money.

https://www.gao.gov/products/gao-22-105943

It's $1.7 trillion in 2023 dollars (I think) total costs across the entirety of the program until 2070 (not sure if the number is "starting today" or "from the start of the program in ~1993") for ~2000 planes for the US and ~1000 for allies (although I don't think the $1.7 trillion includes allies). But the question isn't "how much does the F-35 cost", it's "how much more/less does the F-35 cost compared to whatever else would fulfill its place". Would that be modernized F-15s and F-16s? Would those be able to fulfill the requirements set by the Air Force and indirectly by Congress? Or would there be another program instead that might cost even more than $1.7 trillion across ~50 years (or 80 if counting from the start of the program)?

Also, the F-35 isn't an iteration on the F-22. It's an entirely new airplane. It's a bit worse in aerodynamics but has far better sensors and electronics, reducing the importance of aerodynamics in the first place. In a dogfight the F-22 is better; in a realistic engagement involving multiple platforms and missions being performed at once with air, sea, and land targets and allies, the F-35 is better.

The F-35 program was absolutely mismanaged in its early years and it's a crime that nothing was done about that. There's parts of the program that are mismanaged today (see [0] for examples of what the Air Force is trying to do to avoid those problems with their next fighter). But the program now isn't substantially worse than what other fighters went through, and despite all the program's failings the product itself is fantastic

[0] https://www.thedrive.com/the-war-zone/avoiding-f-35-acquisit...

It's an iteration because it is basically just a more versatile F-22. But versatility isn't all that useful since we have bases all over the world*, and other similarly stealthy aircraft can perform surveillance and ground attacks. The F-22 is already fully capable of next-gen A2A combat.

The F-22 cost $138 million. F-35 is down to $70 million. The US only bought 200 F-22, they aren’t being made anymore, and they are needing replacement in decade. That doesn’t help with the thousands of other fighters that need replacement.

Name “other similarly stealthy” aircraft. All our allies are buying F-35 because it is the only affordable, good stealthy fighter available.

> F-35 is an awful, awful, awful deal. It's an iteration on the F-22

No, its not. While the program was initiated after the program that built the F-22 its a complement with a different set of niches, not an iteration on the -22. Loosely, the F-22 was the successor to the Air Force’s F-15s, and the F-35A, F-35B, and F-35C, was the successor to...every other contemporary fighter and fixed wing attack aircraft in the US Air Force, Navy, and Marine Corps inventory.

Apparently the Air Force is planning a new fighter program[1], which I guess is subsequent to the F-35 program.

I wonder where the money to pay for this program will come from. My understanding, which may be wrong, is that interest payments and social spending is going to significantly reduce what can be spent on defense. Corrections are welcome.

[1] https://www.defenseone.com/business/2023/05/usaf-opens-biddi...

Edit: Delete redundant phrase.

>>F-35 is a capable platform with a reasonable but large price tag for those capabilities.

We might have a different understanding of what reasonable actually means. I am curious if you are willing to share your understanding of how much has been spent to-date on the the F-35 program and your thoughts on how that price tag may be considered reasonable for what was delivered. I'm not being combative, I am genuinely curious.

They had Kelly Johnson in 1964. He is, quite literally, the godfather of high-speed aircraft including the U-2 and the A-12/SR-71. He was not only a highly skilled engineer, he was a manager of the first order. A former colleague of mine had the privilege of working for Johnson early in his career and said that he'd never worked for a better boss. I believe it.

I never understand this belief. The A-12 was only secret 20 months before the announcement so it wasn’t any mystery for long. The idea that there is some supermagic is weird. Materials science of titanium is known. It was new then. Turboramjet theory was novel then, but I read about the internals in the late 70’s in Airpower magazine.

Such a belief means there must be some unknown material or physics that has been embargoed, successfully, for decades.

There’s no there there to be staggered by. Look at a half century of fusion physics or billions on multiple failed hypersonic research. Shit is hard. There are no shortcuts.

I've got a lil titanium bowl for camping. Feels like alien material, it's so light and feels like you could snap it, but then it's incredibly strong. I used it in the oven last night to make TikTok feta pasta. No worries on being oven safe as its melting temp is 3,000°F.

Try working it with regular tools and you'll be even more amazed. It's incredible stuff.

I'm not sure how to take this comment. Is it unworkable or surprisingly workable?

It's quite well known for being difficult to machine generally.

Titanium is very hard to work with; for instance the carbide coatings on many drill-bits can cause it to degrade over time. Tooling for production of the blackbirds was a challenge in and of itself, as little was known about working with titanium at the time.

The more you cut titanium the harder it gets. It can eat even carbide drill / mill tools. Welding it is a nightmare.

Very much unworkable. I got a chunk of titanium tubing at some point of my more metal oriented years and tried to do something useful with it, it ate up my tools pretty quickly. Typical standing time for a regular HSS bit was < 1 hole. Carbide did a bit better, but still that too went much faster than usual.

Yeah I used to work in aerospace (defense) and was shown a large part, about 3 feet wide, with very complex geometry that was machined from a huge solid chunk of titanium. They said that one part was worth $1 million, on a vehicle that cost total $80m or so. I'm guessing a lot of it was due to difficulty in fabrication.

The early 80s Corvette used titanium for the air filter cover. There had to be all sorts of bulletins for mechanics. Even though the cover was held on by large plastic thumb screws (and thus needed no tools for removal) it was a very convenient flat spot in the center of the engine compartment for placing tools on. The cadmium coating on hand tools will cause titanium to corrode, so don't use ordinary hand tools.

That's super interesting, I did not realize that. Isn't Cadmium banned nowadays? It's a pretty bad compound to ingest, especially in dust form. Not quite Beryllium Oxide but not exactly flour either.

Our wedding rings are titanium. The engineering geek in me loves it for nerdy reasons, and the metal allergies in my wife love it for other reasons.

My materials science professor always used ring as an example in intro to matse classes of what not to do with titanium.

His point was that if you ever get into an accident and the first responders have to cut your ring for whatever reason (MRI machine, etc.), literally none of their tools would be able to do that on a titanium ring. None of the tools in hospital would work either. It may not always be feasible to pull it out the usual way.

Take it as you will.

Unfortunately, this is an urban legend. While titanium is amazing stuff a normal ring cutter can go through it.

If it's that dire then I'll just take losing the finger.

I got Tungsten Carbide rings for that reason (and they happen to also be extremely inexpensive). They’re very hard (scratch resistant) in everyday use, but also quite brittle and easy to shatter to remove if needed for a finger injury.

Titanium is more flexible and softer than steel. It also has a similar melting temperature.

I've heard it's just harder to machine because it's more flexible so it tends to bend away from the cutting tools, as far as I understand. Not because it's so strong. But I don't know much about machining so this is second-hand knowledge.

It's just a hell of a lot lighter than steel which is why it's so great for cutting-edge aviation stuff. It's much stronger than aluminium. It's the strength/weight combo that makes it special.

"His point was that if you ever get into an accident and the first responders have to cut your ring for whatever reason (MRI machine, etc.), literally none of their tools would be able to do that on a titanium ring"

As a somewhat-experienced jeweler, titanium is not terribly-difficult to work. It's a pain to solder and weld (I use it for wire-wrapping in various gauges,) but cutting it is relatively easy, a good pair of hardened-steel thick wire cutters will absolutely shear it.

> No worries on being oven safe as its melting temp is 3,000°F.

Two things:

- Your bowl is most likely not pure titanium and is probably made of an alloy.

- Over 1,200F titanium produces titanium dioxide and may give you titanium dioxide poisoning.

My oven only goes to 500F. Some go to 550F. Even Ooni's are 1000F at most.

What does yours do?

Well most oven won't burn any of your cookware no matter the material.

I just wanted to emphasize that there are danger below 3,000F.

>won't burn any of your cookware

Except PTFE coatings, which releases toxic gases above ~260°C/500°F

except this post was originally about titanium.

I'll bear that in mind the next time I decide to make lasagne in a crucible

It's grade 1 unalloyed titanium from Snow Peak: https://www.snowpeak.com/blogs/explore/ultralight-everything with the lowest oxygen content. Your hazard warnings are noted though, and I definitely will keep it at lower temps.

I've also got their titanium flask. I had it engraved from a random guy on youtube who had experience engraving on Ti, because everyone else I contacted (mostly jewelry shops) could only anodize it.

If there was a way to bend this particular exchange into the style of the article, I would. Its definitely in the same spirit.

This sounds like a job ChatGPT would excel at :) I will leave actually doing so as an exercise for the reader.

I'm pretty sure titanium dioxide is pretty inert. It's a primary ingredient in sunscreen and diaper cream.

Otherwise, I agree with your point.

Outside the body is one thing. The EU banned it as a food additive last year and some US states are considering it too. TiO2 has genotoxic traits, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8323234/

I always found it odd that my acrylic paint and my toothpaste share this ingredient.

Dihydrogen monoxide too!

Water isn't genotoxic. Titanium is. It's fair to be concerned about chemicals when the chemicals cause objective harm.

Correcting myself, I was thinking of Zinc Oxide. But it's still pretty inert. I wouldn't want a plate of it, but whatever level of toxicity it possesses, it is low enough that it requires careful study to detect.

Can also recommend this book. Good read.

Related. Others?

The Ground Speed Check – Tales from the Blackbird - https://news.ycombinator.com/item?id=36030304 - May 2023 (1 comment)

SR-71 Blackbird's ground speed check story - https://news.ycombinator.com/item?id=25733807 - Jan 2021 (12 comments)

SR-71 Blackbird 'Speed Check' - https://news.ycombinator.com/item?id=18101839 - Sept 2018 (1 comment)

SR-71 Blackbird Pilot Trolls Arrogant Fighter Pilot with Ground Speed Check - https://news.ycombinator.com/item?id=10902209 - Jan 2016 (3 comments)

Perhaps this is on occasion of https://news.ycombinator.com/item?id=36028041

Thanks! Macroexpanded:

SR-71 pilot, photographer and storyteller Brian Shul dies at 75 - https://news.ycombinator.com/item?id=36028041 - May 2023 (47 comments)

Have you thought of making an evergreen page for frequently reposted stories like this?

My favorite version of this story, from u/buryat:

SR-71 speed check

One time we were going fast

a small plane got on the radio and said "how fast am i going"

the tower said "you are going fast"

and then a bigger plane got on the radio and said "haha i think i am going faster how fast am i going"

and the tower said "you are going a little faster"

and then a jet fighter was going really fast and talked like a really cool guy and said "hey there, I sound like a cool guy, tell me how fast I'm going"

and the tower said "you are going very fast" but he sounded totally normal

And then I wanted to say something but that was against the rules, and then the other guy in my plane said "hey tower, are we going fast"

and the tower said "yes you are going like a million fast" and then the guy in my plane said "I think it's a million and one fast" and then the tower said "lol yeah ur plane is good"

and then I said "did we just become best friends"

and the other guy said "yes"

https://news.ycombinator.com/item?id=29373436

I love how it manages to dumb down and parody the original story while still retaining all the details, they really crossed every i and dotted every t.

To me the "slowest speed" story is better: https://www.thesr71blackbird.com/Aircraft/Stories/sr-71-blac...

I've read/seen both of these stories many times and everytime I come across them, I re-read them :-) Can't get enough of SR-71 stories.

And if you're in the UK, you can go and visit her at Duxford

https://www.iwm.org.uk/events/american-air-museum

My favorite SR-71 story. Must have been sight to behold down on the ground seeing the plane blast by at full afterburner.

Great story.

Brian Shul died just a few days ago. :( https://en.wikipedia.org/wiki/Brian_Shul

Oh man, this sucks. Learning about it from your comment. I always wanted to go see one of his speeches. I remember seeing them on YouTube and they were great. His story is truly inspirational. His books are incredible as well. I was gifted signed copies of Sled Driver and The Untouchables and I honestly treasure them. Guess I’ll just have to read them again today.

Two things:

1. The HN link should be to the actual video of the retired pilot telling the story firsthand. That's below

https://www.youtube.com/watch?v=8AyHH9G9et0

2. Most former SR-71 pilots consider the story not true, but it's a fun story to hear nonetheless.

https://www.reddit.com/r/aviation/comments/xis19w/reddits_be...

The story mentions:

"There he was, with no really good view of the incredible sights before us, tasked with monitoring four different radios. This was good practice for him for when we began flying real missions, when a priority transmission from headquarters could be vital."

Just because military aircraft don't use the same frequencies as commercial aircraft doesn't mean this SR-71 crew on a training mission wasn't listening in on commercial air traffic frequencies.

First the Flaming Hot Cheetos Inventor and now the SR-71 Speed Check?

What's next? Am I gonna find out that every TED talk is basically BS?

> Am I gonna find out that every TED talk is basically BS?

Uh, hi, I have bad news for you about the quality and consistency of TED talks...

That's kinda the joke

Yes I just chuckled so I played along. Now I'm meta-explaining, which is also a good joke.

Ted Talks peaked in 2013, with "2070 Paradigm Shift", one of the best speeches ever in the history of the planet earth.

https://www.youtube.com/watch?v=SmicRDpS5Gk

Imitated by many, never surpassed. Ted Talks were all downhill after this one.

That was fantastic.

In the same vein sorta, Reggie Watts: https://www.youtube.com/watch?v=BdHK_r9RXTc

Especially the first 2-3 minutes.

It's a great story that I loved reading, but I'm skeptical by nature:

Has there ever been any other recorded witness to this story? Obviously there was at least 3 other pilots and an air traffic controller, but I imagine there were more people on frequency at the time.

Additionally, can ATC equipment even depict that speed? For example, modern U.S. ATC equipment will not indicate the altitude of anything above FL600.

I remember there being a reddit comment that had quite a few upvotes debunking the story, but I can't remember what their reasons were.

I found this on Reddit which matches up. It's another SR-71 pilot that says the military aircraft wouldn't even be on the same radio frequency. But military does transit commercial space from time to time so you never know.

https://www.reddit.com/r/aviation/comments/xis19w/reddits_be...

But, then again, doing Mach 2.8 in Class A airspace is kind of unrealistic. And noisy.

I assume they were in Class E (TFA says "uncontrolled airspace" which E is technically not, but a reasonable assumption) above Class A.

> But, then again, doing Mach 2.8 in Class A airspace is kind of unrealistic.

My understanding is that the SR-71 flies so high (up to 90,000 feet) that they can go as fast as they like because there's nothing else up that high.

I wonder how loud a sonic boom from that high is at ground level.

https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-01... suggests that the SR-71 produces a relatively small sonic boom at high altitude.

I was visiting with a friend in the desert when Virgin Galactic made it's initial flight into space. I don't know how high they were when they passed overhead, but it certainly audible and rattled the garage door.

Edit: after a quick search, the VSS Unity is released from the carrier at 50k feet. But now I can't recall if the boom was on the ascent or on the way back.

What I very vaguely remember, from an airshow at Edwards AFB commeorating the 50th anniversary of Chuck Yeager's 1947 flight in the X-1, is that it is clearly audible, but not so window-shakingly loud as when an F-16 went supersonic below 10,000 feet (which they weren't supposed to) where I live. (The latter happened several years ago during Thunderbirds practice.)

I've heard a sonic boom out at Joshua Tree taking pictures at night. I thought a bomb went off until I saw the blur flying across the sky and figured out what it was.

https://theaviationgeekclub.com/did-you-know-the-sr-71-black...

Some of these incidents are probably false or exaggerated, but it does seem it produced enough of a boom to route away from cities.

Doesn't Brian Shul talk about the time Regan had them fly figure 8s over some foreign city during negotiations just to remind them with the sonic booms that we can touch them? https://youtu.be/3kIMTJRgyn0?t=1044

Yeah Nicaragua. They did it to Managua for years when they were also illegally arming the Contras.

There's a story of an SR-71 nosing around the Florida/Bahamas/Cuba area only to get a call from ATC asking them to divert due to traffic. At our altitude? So the pressure-suited pilots adjust course for a bunch of French tourists in their jackets and sundresses go past, because the one other plane that flew that high was Concorde.

Later in that thread someone mentions that the SR-71 has 4 radios (like the story mentioned) 2 UHF, 1 VHF, and 1 HF. So despite not being on the same frequency for most communications, they were definitely capable of monitoring and transmitting on civilian frequencies. A bored radio operator on yet another training flight could easily be listening into civilian radio traffic.

Not an SR-71, but a couple of weeks ago I was listening to a pilot/amateur radio operator making contacts on the 20m band while he flew from Texas to Nevada. I'm assuming their radios are a bit more flexible on what frequencies they can transmit on.

Edit -- Found him: https://www.qrz.com/db/K4RNN

Military aviation uses non-military frequencies to communicate with ATC, which they do except when operating in closed airspace. E.g. ATC is notified by the pilot of each aircraft entering the sidewinder low level training route in southern CA.

It was a different thread that I remember. Someone posted the story as a submission, and one of the top-level comments was debunking it. My Google-fu used to be extremely good, back when Google was a good search engine, otherwise I would have found it by now and posted the link.

I like the effect that the story has had, but I dislike the idea that it might have been an exaggeration.

The author of Sled Driver made a lot of appearances/talks, but I don't know how much he was paid for them.

The author states he doesn't normally monitor the frequencies as that was the other person's job, but the one time he does monitor, this happens?

Either things like this happen all of the time, in which case there would be plenty of people sharing their version of these kinds of stories, or the pilot got extremely lucky in his timing.

For me this is one of those things that's such a fun story, it hardly matter if it's actually true.

Oh, it does matter. I've made a living at times from non-fiction storytelling, and if you don't get in the habit of sticking to the facts, it's shamefully easy to slide ever closer to George Santos territory.

But there's a compromise that will keep us both happy. Nothing wrong with having this go into the "legends" category -- where it's harmless fun to keep them circulating. Just as long as we know that this isn't quite how everything works.

I always assume stories like these are "fish tales" - there's a nugget of truth in there somewhere, but with each retelling, the story gets more exaggerated.

As a US friend of mine puts it: "Never let the truth get in the way of a good story".

I've seen the video of Brian telling this story.

This is a master class in story-telling. It's the polar opposite of "keep it simple, get to the point, etc. etc."

He's got you in the palm of his hand, and he's going to keep you there as long as he wants to.

Farmer: "Slow?" ATC: "Yes"

Playboy: "Fast?" ATC: "No"

Stick Jockey: "Fast right?" ATC: "Not bad"

Sled Driver: "Oh hai" ATC: "Yup goes to 11"

they should just put this one on automatic rotation on the hacker news front page like the promoted ycombinator startup ads

I made a crude map of their sub-3 hour training route, it's mind boggling: https://i.imgur.com/ZwcgwsI.jpg

Ugh. Aviation before, say, 1990 was amazing. Still necessary to do things like ground speed checks, non-radar approaches, VOR to VOR, etc. Real pilot sh*t. And lots of the equipment going back decades was still flying. An amazing time to be a pilot. Now everything is so optimized and dumbed down. I was born too late.

Exactly, I love pre-glass instrumentation. I still fly DME arcs manually all the time... in flight simulator.

I have flown gliders though, which helps avoid excessive technology.

Ha. I did fly a real non-radar DME arc in a PC-12 using just the bearing pointer...once.

Fun fact https://theaviationgeekclub.com/sr-71-or-rs-71-how-the-legen...

Surprised no-one has posted this yet:

The Insane Engineering of the SR-71 Blackbird: https://www.youtube.com/watch?v=3hYSnyVLmGE

This is the last story I read to my dad that really made him smile, laugh and cry almost all at once... He had dementia and passed away a few months later after a life in civil aviation.

On a related note to the article, the book “Skunk Works” by Ben Rich and Leo Janos tells the story of the SR-71 and other secret aviation projects in a fascinating detail. Highly recommend.

I'm a simple man. I see the Blackbird speed check story, I click.

RIP sled driver.

RIP Brian Shul.

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