3 ms·
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’
by vsgherzi 9mo ago
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
- mmooss 9mo agoI 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.
- imadethis 9mo ago12/32 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.
- dylan604 9mo agothe 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
- mmooss 9mo agoRight, 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.
- lazide 9mo agoThey 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.
- jacquesm 9mo agoThe 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.
- mmooss 9mo agoInteresting; 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.
- jacquesm 9mo agoRunning stuff in an unpressurized environment at that altitude brings another set of challenges.
- The_President 9mo agoThe U-2 is the plane that drags the wings on dolly wheels.
- mmooss 9mo agoOops, thanks.
- vsgherzi 9mo agoMuch 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.
- mmooss 9mo ago> have no such expectations of going faster than anything before They have many other unprecedented expectations, such a fuel usage and safety.
- dghlsakjg 9mo agoLook 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.
- tempest_ 9mo ago33 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.
- expedition32 9mo agoIt was replaced because the USSR managed to shoot one down. Spy satellites are as of yet off limits.
- SAI_Peregrinus 9mo agoAnti-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.
- jbn 9mo agois there a reference for the USSR shooting an SR-71 down?
- aggregator-ios 9mo agoThere is no reference for this, because it never happened.
- snowwrestler 9mo agoI 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.