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Insane that we can have places like the skunk works create the sr71 and operate on shoe string budgets but the largest passenger plane company in the world can’t accurately assess risk on planes far under the former planes Mach 3 record


Look up the hull loss numbers on the SR-71. More than a third of them were lost in incidents despite never making contact with the enemy.

It was also insanely expensive to operate: $300k/hour in 1990 dollars, and there aren’t reliable numbers on development costs with all of the black budgets.


33 percent attrition and could only fly once a week.

I know satellites and drones have replaced the sr71 but it would be cool if someone would build a plane as capable again.


It was replaced because the USSR managed to shoot one down.

Spy satellites are as of yet off limits.


Anti-satellite weapons have been demonstrated by the US, USSR, Russia, China, India, and if you stretch a bit Israel (they shot down a Houthi missile while it was above the Kármán line, the same system is probably capable of use as true anti-satellite weapon). Nobody has shot down anyone else's spy satellites, but it's not because it's impossible.


I think you might be misremembering the shoot-down of a U2 plane, which was also a U.S. spy plane operating around the same time.


> was

U2 is still in operation.


is there a reference for the USSR shooting an SR-71 down?


There is no reference for this, because it never happened.


the point I was trying to make is that the creation of the sr71 was a physics defying problem and something considered nigh impossible. A passenger plane has much less complex expectations. Now don't take this to meant none at all, of course they have to operate 24/ 7 and have high reliability and safety. However, in a world where we can build the SR71 I don't see what we can't build the latter. We can and should be building better planes. I think that's pretty evident with this issue and the infamous software issue of the other boeing planes.


The MD11 in question is a defunct design from 38 years ago. We are building better planes now.

UPS is as old as the plane in question and has only had three fatal accidents in that time with millions of flight hours, most of them on retired airliner frames.

Yes, Boeing had a monumental fuck up with the MAX redesign. However, their last blank page design was the 787 and is seen as completely revolutionary in terms of materials and efficiency. Let’s talk about that plane. It burns 20% less fuel than the planes it was designed to replace, and has a number of incredibly impressive engineering feats purely for passenger comfort- pressurization altitude and window size being the most impressive. It doesn’t sound impressive, but the design ask is: make a lighter plane, with bigger holes in the structure, that can withstand more pressure, and use a material and process that has never been used before. The only fatal incident on the 787 is still under investigation, but is almost certainly pilot error or suicide. Other plane and engine safety technology have allowed ETOPS making it possible to use efficient twin engine jets operate overwater flights that would have been unthinkable 40 years ago.

Jets today are quieter (by such a huge margin that it isn’t legal to operate the original 707 engines at most western airports), more efficient and safer than ever.

In the era that the SR-71 existed in, it was actually pretty common for planes to crash due to design defects (DC-10, Comet, 707, and more). The 737 MAX defect was so shocking because it has been 50+ years since that was common.

The SR71 is a simpler plane in many ways than a modern airliner. The composite technology to build a 787 didn't even exist at that time, and the engine alone on the 787 is far more impressive engineering and material science than the SR71. And there are two companies that figured out how to make them without a blank check from the CIA. The 787 produces more than double the thrust of the SR-71, and most passengers barely are aware of the miracle they are participating.

The SR-71 is an undeniably cool project. I have seen several up close, sat in the cockpit and they are literally awe inspiring. What we build today are airliners that are seemingly boring but built and designed with technology and materials that Skunkworks couldn’t have even attempted.

We aren’t building things like the SR-71 anymore because we are building things that are far better and more complex. We have Lockheed producing the F-22 and F-35, multiple companies reusing space launch rockets, etc. the real problem is that we have lost our sense of wonder at just how impressive modern aerospace engineering is.


I don't see that as a valid comparison. SR-71s could operate with a much higher level of risk than commercial passenger planes. IIRC, SR-71s leaked fuel on the ground, and their wings dragged on the ground without special attachments. Pilots needed special pressure suits, etc.

I also expect that they were much less complex than an aircraft that provides a comfortable, pressurized cabin; the high level of safety mentioned above; freight capacity; etc.

Also, despite Boeing's recent problems, I would guess that commerical passenger planes are far more safe than they were decades ago when the SR-71 was developed. Accidents were much more common despite many fewer flights, iirc.


12/32 SR71s were lost in the 33 years they were flying. 11/200 MD-11s have been hull-lost from 1988-2025. Not to mention that passenger/cargo planes will put on a lot more flight hours than the SR71s did in a given year.


the SR-71 leaking fuel on the ground was not a design flaw. it was designed to be operated at speed where things would expand to fill in. if they were filled in on the ground, they'd have no place to expand at speed/temps. the risk assessment was that it was better to leak fuel on the ground rather than blowing up at speed/temp


Right, it was risk management. I doubt that leaking fuel would be acceptable risk management for a commercial passenger plane at a public airport.

Obviously they could have designed something that could expand and contract if they thought it was worth it.


They designed special fuel that wouldn’t catch on fire under normal circumstances.

Also, this was done because airframe skin temps exceeded 400F during flight due to the high speeds.


The U-2 is the plane that drags the wings on dolly wheels.


Oops, thanks.


Much less complex? I'm not sure about that for a plane that's expected to travel so fast. In terms of features I'm sure modern passenger planes have quite a bit more. I'm sure planes are absolutely safer now, the point I'm trying to make is the SR71 was thought to be almost impossible to make yet they were able to do it with an impressively small team and (rumored) budget. Yet so many years later we struggle to make reliable workhorse planes that have no such expectations of going faster than anything before. I don't think it's a stretch to say that we could and should be making much better planes.


> have no such expectations of going faster than anything before

They have many other unprecedented expectations, such a fuel usage and safety.


The SR-71 is pressurized. Not to sea level pressure, obviously, but it wasn't exactly unpressurized either. The main reason the crew wore pressure suits is for heat retention and oxygen delivery.


Interesting; I wonder why the bothered to pressurize it. It would seem to add a more complexity to many things - every seal, seam, etc - plus the pressurization system. Maybe some equipment ran better with more pressure.

Even commercial passenger flights are not pressurized to sea level; I think it's something like 8,000 ft. IIRC, Boeing's 787 was designed to be pressurized a bit more which, from on-the-ground experience acclimatizing to altitude, I think could make a noticeable difference.


Running stuff in an unpressurized environment at that altitude brings another set of challenges.




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