from the unless-someone-is-not-telling-us dept.
On 1 September 1974 two men made the fastest ever journey between New York and London. The astonishing trip – at three times the speed of sound – took less than two hours and set a record that still stands 50 years later.
Even the mighty Concorde, which set the record for the fastest commercial transatlantic flight in 1996, straggled in almost an hour behind.
The US air force Lockheed Blackbird SR-71 jet had a crew of two – pilot James Sullivan and reconnaissance systems operator Noel Widdifield – who completed the journey between the two cities in one hour, 54 minutes and 56 seconds before triumphantly landing to a fanfare welcome at the Farnborough air show in Hampshire.
[...] The aircraft had to take on fuel twice: when it took off, linking with a refuelling plane above California to fill it to capacity, and partway during the journey near to Greenland.
There was also an incident which would have looked terrifying from the outside but which the crew took in their stride. The Blackbird began to suddenly "yaw" – moving swiftly from side to side – after losing thrust.
The Blackbird took in air from the front to give thrust to the engines, and it was common for a device in the inlet to become displaced, causing one engine to lose much of its power momentarily.
All in a day's work... for some!
(Score: 1, Interesting) by Anonymous Coward on Wednesday September 04, @03:41AM (2 children)
I remember in the early 90s when they delivered a Blackbird to the Smithsonian, that it flew across country and crushed the speed record [theaviationist.com]
(Score: 0) by Anonymous Coward on Wednesday September 04, @04:56AM
Yeah, but how many bars/pascals of pressure at the tip of the plane during that run? (and how much was the plane engineered to withstand?)
(Score: 2) by OrugTor on Wednesday September 04, @04:32PM
I have to wonder, do the record-keepers maintain a speed record for every pair of locations in the US?
(Score: 4, Interesting) by PinkyGigglebrain on Wednesday September 04, @05:12AM (8 children)
The Blackbird could probably have gone even faster. The decision was to let that beautiful bird retire on a public high note, so the official record was set.
There has never been a publicly released statement from any official source stating that "The SR-71's maximum top speed at 100% throttle is XXXX".
All we know from this particular record is that the Blackbird's officially acknowledged top speed is at least Mach 3.3, not that that speed was at 100% throttle. There is an officially unconfirmed statement by a former Blackbird pilot that he took the plane to Mach 3.5 to evade a missile while over Libya in 1986. So was that at 100%? He didn't say.
The SR-71's also hold the record for highest sustained flight. Truly an incredible plan and a credit to everyone who brought it from concept to reality.
"Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."
(Score: 3, Interesting) by Rich on Wednesday September 04, @10:56AM
From what I've read, in my understanding, the top speed wasn't limited by the engine power, but by airframe temperature. E.g. they could go up to or even beyond 4000 kph (2500 mph) for a moment, but had to throttle back before the plane would melt.
"Sled Driver" is a fun story collection, although a little expensive for casual reading.
(Score: 4, Informative) by VLM on Wednesday September 04, @12:06PM (4 children)
The operations manual was declassified a long time ago and you can read all about it.
There are some simple physics limitations where the faster you want to go the more thrust you need (in level flight). A pitiful expression of
The EGT turbine temp limit is pretty well fixed and they give detailed helicopter-like limits (over X for Y seconds, over A for B seconds, over C for D seconds). Also running EGT too hot on that engine would cause occasional compressor stall which you can read about happening in cruise flight, so you can't run more thrust by "merely" running the EGT over 1000C.
The CIT turbine temp limit is also fixed around 427C (I have the manual open on another window) The faster you go, the hotter the inlet, the less thrust you can get for a given EGT by burning more fuel. There's no way to get colder air in the inlet because going higher means more compression means hotter, and going lower means more drag (fly slower). Notice in the graph of permitted CIT vs engine RPM the max RPM drops with inlet temp, so the hotter the input air the lower the redline for the engine. You can't increase thrust by running the turbine slower, all things being equal, and heat engines output power based on the difference between inlet and outlet temp.
Its kind of like an IC engine operating at a perfect ratio, going richer or leaner means less power. Likewise at optimum operating point, changing it means worse performance. Its a pretty well optimized airplane for something designed using 50s technology. In a way, performance of supersonic aircraft is controlled by inlet and outlet temps combined with some aerodynamic stuff
The wing aerodynamics are getting very sensitive, look at that chart of operational load limits, "low and slow" it won't stall or spin or otherwise go out of control -0.2g to 3.5g but when you get into that high speed corner they were cruising in the 2.6 to 3.2 mach band and the limits were only -0.1g to +1.5g so figure the supposed 3.3 max which is above published ranges must have been very unstable only for the smoothest air under the best conditions.
Could it touch mach 3.5 for a second in a descent under emergency conditions with a lot of luck? Yeah probably. Some crazy online claims about mach 4 or 5 are a non-starter with that airframe and engine.
Using more modern tech in the engine, maybe a faster SR71 could exist. An EGT limit around 850C should be possible to beat now a days. Then completely redesign the inlet so it maxes out performance at mach 4 instead of around 3.3.
Of course one problem is mach 3.2 was operationally effective for decades, despite claims that speed does not matter by people who are not in the know, so doubling opex by flying faster than necessary at mach 5 might be a huge waste so they never built one (never built a declassified one). If you already fly faster than your opponent's OODA loop, increasing speed doesn't gain much. Essentially the reason why we never had a declassified SR-72 that flies faster is the Russians never had better less dysfunctional communications and coordination. If they got their act together, which they never did, we'd probably have invested the cash into something even faster.
https://www.sr-71.org/blackbird/manual/ [sr-71.org]
Note that its easy to build something that flies at mach 6, the Russians built R-37s half a century ago that flew at mach 6 and those were pretty fast. The hard part is also being able to fly slow enough to land, and having a range longer than 100 KM or so, all three at the same time is a bit tricky.
(Score: 2) by VLM on Wednesday September 04, @12:18PM
I hate replying to myself but I just had a thought that reading the operations manual for the SR-71 and knowing what I do about turbojet engines from ground school and personal interest, the educated way to look at the performance limits of the SR-71 is the designers knew the psychology of military pilots and the overall system already runs past optimum performance or past redline, so a "damn the testosterone full speed ahead" attitude as portrayed in the Top Gun movies, etc, will result in a slower flight not a faster flight. It might be possible to break or crash the thing by pushing it, but it certainly won't fly faster, the engineers already hyperoptimized it to max out around 3.3 and doing seemingly anything other than straight and level will result in it flying slower.
You can't improve the T/D ratio or L/D ratio at max speed everything that would normally increase performance is either at or past the limit and already declining in performance.
The limit of speed of the plane has already been hot-rodded to the max such that its set by the shape of the aerodynamics in the inlets and exhaust, and the metallurgy of the engine. The pilot can't make it fly faster by merely stepping on the gas harder, its already been maxed out.
Like trying to make a dragster go faster by messing with the steering wheel... wiggling the steering wheel is not going to help the dragster if it's already optimized for straight line acceleration.
(Score: 2) by tangomargarine on Wednesday September 04, @03:27PM (1 child)
Plus the R-37 was a missile, so of course they didn't need it to land. Kind of disingenuous to compare missile design to aircraft design, unless you're specifically talking about the Me-163 or X-15.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 2) by VLM on Wednesday September 04, @04:07PM
It's a scalability thing. You can go really fast if you're not overly concerned about going very far. The most amazing thing about the SR-71 is not that it goes fast (plenty of things go really fast) but that it goes really far (admittedly with a lot of refueling, but still operationally useful distances)
Sidewinder missiles go "about" as fast as a SR-71 but only about 20 miles at best case.
(Score: 2) by Beryllium Sphere (r) on Friday September 06, @05:07AM
One of the people I met at an event was skeptical about ever developing anything faster if it had to keep a human alive inside. Of course a drone would be another story.
(Score: 2) by tangomargarine on Wednesday September 04, @03:24PM
True, although who knows if sustained flight at 100% was really safe. Apparently the X-15 had a problem where if they cranked it up to full throttle, it started shedding the leading edge of its wings due to air resistance and/or heat (?).
Wikipedia is rather disappointing on the technical details of the X-15, but if I'm remembering the Simon Whistler video [youtube.com] correctly, they wound up having to coat the plane with pink spray-on foam for heat resistance reasons. There were a lot of weird/funny details about it.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 2) by Beryllium Sphere (r) on Friday September 06, @05:01AM
I asked a mechanic at an event what he had heard from Lockheed. They didn't know. They gave a "never exceed" speed of 3.4, beyond which "too many unknowns". Even that would require colder than usual stratospheric conditions to meet engine limits.
(Score: 4, Informative) by Rosco P. Coltrane on Wednesday September 04, @05:39AM (2 children)
If you want to know all there is to know about the technical bits of the SR-71, watch this fabulous video [youtu.be] from Animagraffs. I guarantee you you'll be blown away, both by the engineering of the SR-71 and by the talent of Jake O'Neal with Blender.
(Score: 2) by Unixnut on Wednesday September 04, @10:21AM (1 child)
Thanks for sharing! Might as well make this the obligatory video thread :-)
Here are some links from my collection on the SR-71 and family:
https://www.youtube.com/watch?v=EVoWgsaiMVM [youtube.com]
https://www.youtube.com/watch?v=OBVmYi7mkZM [youtube.com]
https://www.youtube.com/watch?v=81ofbypM2aI [youtube.com]
https://www.youtube.com/watch?v=F3ao5SCedIk [youtube.com]
https://www.youtube.com/watch?v=S2xgI3wQbWQ [youtube.com]
Truly a beautiful plane, as well as an impressive feat of engineering. Shame nobody since has developed the concept further. To me it always seemed like a plausible base for a future single-stage-to-orbit vehicle.
(Score: 0) by Anonymous Coward on Thursday September 05, @11:03AM
It's a long way from Mach 3.2 to orbit. Orbit is at least Mach 25.
(Score: 1, Offtopic) by PiMuNu on Wednesday September 04, @10:04AM
Nowadays the Drop Pods being developed by SpaceX would probably win (if you don't mind that they probably technically go through "space" on the way)
https://duckduckgo.com/?q=drop+pod&t=lm&iar=images&iax=images&ia=images [duckduckgo.com]
https://spacenews.com/spacex-wins-102-million-air-force-contract-to-demonstrate-technologies-for-point-to-point-space-transportation/ [spacenews.com]
(Score: 2) by Snotnose on Wednesday September 04, @01:21PM (2 children)
I read the biography of the guy who ran Lockheed's Skunkworks at the time. The plane was called the RS-71 until Lyndon Johnson gave a speech calling it the SR-71. Lockheed went back and changed all their documents, blueprints, etc so they wouldn't have to tell the president he made a mistake.
That was a very interesting book, the same author wrote a biography of Chuck Yeager that was also really interesting. I'd get up and grab the book but I have a sleeping cat in my lap.
Bad decisions, great stories
(Score: 2) by tangomargarine on Wednesday September 04, @03:18PM (1 child)
according to Wikipedia
When I was at the USS Intrepid museum on the East Coast a few years back I saw an A-12 they had there. I still don't get why the heck they had to design two planes that were almost exactly the same, only one of them only had one pilot.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 3, Funny) by epitaxial on Wednesday September 04, @06:07PM
I was reading Annie Jacobson's book about the history of Area 51 and she explained that for the U-2 spy plane the CIA wanted their own planes separate from the military.
Good book until the end when it goes off on a tangent about Stalin having remote control hover technology and sending over surgically altered humans in a UFO.
(Score: 2) by gznork26 on Wednesday September 04, @03:21PM (1 child)
I was on a secret project at McDonnell-Douglass (St. Louis) in 1980, and was lucky enough to have to deliver software (an open reel data tape) to Strategic Air Command HQ in Omaha, Nebraska. They were having a war game while I was there, and our building got 'destroyed' on the day word went around that everyone should pile outside for a special treat. An SR-71 was being retired, and it was going to do a touch-and-go. We watched as it circled the airfield, then slowed as it descended to the tarmac. Once the wheels touched down, the pilot hit the afterburners, there was a sudden tail of flame, and the plane shot off into the sky.
That was the 2nd loudest thing I ever heard. the 1st was a Saturn V rocket from about 7 miles away.
Worth the trip.
Khipu were Turing complete.
(Score: 2) by VLM on Wednesday September 04, @04:15PM
Back in the 80s at one of the Oshkosh Fly ins, they had a SR-71 at least one year, and I can confirm it was deafening compared to literally everything else at the fly in, including F15s and stuff like that.
Even other ancient turbojets were quiet compared to the -71.
Honestly the entire field probably exceeded OSHA sound safety levels for that flyby.
Very impressed, though.
(Score: 2) by hendrikboom on Thursday September 05, @12:31AM (3 children)
Why would a flight from New York to London need to refuel in California?
(Score: 0) by Anonymous Coward on Thursday September 05, @02:25AM
> Why would a flight from New York to London need to refuel in California?
Don't know, but my guess is that CA was the home field for the plane. Without suitable landing facilities & support equipment near NY City there's not much point in landing there. From memory of reading a book about SR-71, it leaks/weeps fuel on the ground and the tanks seal up due to metal expansion, once it gets up to temperature in high speed flight. Another reason not to land at most airports--the home base includes big drip pans that are slid under the tank areas.
(Score: 2) by ncc74656 on Thursday September 05, @04:32AM (1 child)
If I'm not mistaken, they'd take off from Beale AFB (about 40 miles north of Sacramento) with only a partial load of fuel. This was a safety measure [thesr71blackbird.com], aimed at keeping the fumes in the tanks from igniting. Once it was in the air, it'd find the nearest KC-135 with a supply of JP-7 (vs. the JP-4 that pretty much everything else in the Air Force ran on), top off the fuel tanks, and get to work. As the fuel burned off, the empty space was filled with 100% nitrogen to prevent ignition.
(Score: 2) by hendrikboom on Thursday September 05, @05:21PM
So it was really a flight from California to London?
Maybe with only the New York airspace to London being at high speed?
(Score: 2) by Beryllium Sphere (r) on Friday September 06, @05:09AM
That magnificent, unparalleled machine was designed with slide rules.