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November 28, 2006 3:15 PM Subscribe
Doesn't highspeed crosswinds at high altitudes put tremendous stress on large airliners?
So, I'm flying Flight Sim X today (which is great, despite what some people have said), in a Project Opensky 767-400, when I notice I'm really dog tracking. I look at my wind indicator and it's 317 degrees at 104!
In real life, wouldn't a crosswind like that put *tremendous* strain on the airframe? Would a real airliner divert so that the crosswind wasn't so bad?
So, I'm flying Flight Sim X today (which is great, despite what some people have said), in a Project Opensky 767-400, when I notice I'm really dog tracking. I look at my wind indicator and it's 317 degrees at 104!
In real life, wouldn't a crosswind like that put *tremendous* strain on the airframe? Would a real airliner divert so that the crosswind wasn't so bad?
The plane is flying at 500 plus mph and you are worried about a 100 mph crosswind?
posted by caddis at 3:31 PM on November 28, 2006
posted by caddis at 3:31 PM on November 28, 2006
Best answer: 100 knot winds are pretty much par for the course at airliner altitudes.
Yes, you have a rather large force pushing the airplane sideways, but you also have a counter-force, that of drag. Assuming this wind comes out of nowhere (somehow you manage to fly from calm air directly into a 100kt crosswind), the plane would accelerate laterally until the drag force equaled the wind force. The two forces cancel and no longer matter.
The thing that really messes with airplanes is wind shear, or that sudden change in windspeed described above. Usually, though, the wind shear causes control loss rather than tearing the plane apart.
posted by backseatpilot at 3:46 PM on November 28, 2006 [1 favorite]
Yes, you have a rather large force pushing the airplane sideways, but you also have a counter-force, that of drag. Assuming this wind comes out of nowhere (somehow you manage to fly from calm air directly into a 100kt crosswind), the plane would accelerate laterally until the drag force equaled the wind force. The two forces cancel and no longer matter.
The thing that really messes with airplanes is wind shear, or that sudden change in windspeed described above. Usually, though, the wind shear causes control loss rather than tearing the plane apart.
posted by backseatpilot at 3:46 PM on November 28, 2006 [1 favorite]
For that matter, all of the air the plane is swimming in is already moving at around 1000mph eastward, depending on latitude. And the ground it's landing it is moving at around 67000mph!
posted by ROU_Xenophobe at 3:49 PM on November 28, 2006
posted by ROU_Xenophobe at 3:49 PM on November 28, 2006
It probably has something to do with the air pressure being so low at high altitudes (27% percent of sea level at 10000m). So wind at higher altitude will have less power then winds of the same speed at lower altitudes.
posted by robofunk at 4:06 PM on November 28, 2006
posted by robofunk at 4:06 PM on November 28, 2006
For that matter, all of the air the plane is swimming in is already moving at around 1000mph eastward, depending on latitude. And the ground it's landing it is moving at around 67000mph!
Huh?
posted by knave at 4:16 PM on November 28, 2006
Huh?
posted by knave at 4:16 PM on November 28, 2006
Huh?
Just remember that you're standing on a planet that's evolving
And revolving at 900 miles an hour,
That's orbiting at 19 miles a second, so it's reckoned,
A sun that is the source of all our power.
The sun and you and me and all the stars that we can see,
Are moving at a million miles a day
In an outer spiral arm, at 40,000 miles an hour,
Of the galaxy we call the Milky Way.
posted by meehawl at 4:30 PM on November 28, 2006
Just remember that you're standing on a planet that's evolving
And revolving at 900 miles an hour,
That's orbiting at 19 miles a second, so it's reckoned,
A sun that is the source of all our power.
The sun and you and me and all the stars that we can see,
Are moving at a million miles a day
In an outer spiral arm, at 40,000 miles an hour,
Of the galaxy we call the Milky Way.
posted by meehawl at 4:30 PM on November 28, 2006
Ok, but all those velocities are relative to something. There's no such thing as absolute velocity. So saying the ground is moving at 67000mph is pretty meaningless, because the ground is only moving at a few hundred mph relative to the plane. And I'm fairly certain the atmosphere rotates along with the earth, mostly, so we're not all being blasted with 1000mph winds all day long.
posted by knave at 5:05 PM on November 28, 2006
posted by knave at 5:05 PM on November 28, 2006
Stress is caused by uneven forces on a structure. If all parts of a floating structure are subjected to approximately equal forces, then there may be acceleration, but there isn't necessarily stress.
There might be stress caused by rapidly changing winds, but that's not what you're talking about.
By the way, airframes are substantially overdesigned. Like bridges and buildings, they are designed to handle considerably more stress than they are expected to have to deal with under normal situations.
posted by Steven C. Den Beste at 5:26 PM on November 28, 2006
There might be stress caused by rapidly changing winds, but that's not what you're talking about.
By the way, airframes are substantially overdesigned. Like bridges and buildings, they are designed to handle considerably more stress than they are expected to have to deal with under normal situations.
posted by Steven C. Den Beste at 5:26 PM on November 28, 2006
Ok, but all those velocities are relative to something. There's no such thing as absolute velocity. So saying the ground is moving at 67000mph is pretty meaningless
Exactly. The plane doesn't give a shit that the air it's in is moving at 67000+mph through the vacuum and 1000mph around the Earth, because it just moves along with the air.
Likewise, the plane shouldn't give a shit that the air it's swimming through is moving at 100mph crossways to its vector of travel along the ground. Except for the brief period where it's moving into the air stream, it just moves along with the air, just like it moves along with the 67000mph motion and the 1000mph motion.
posted by ROU_Xenophobe at 6:20 PM on November 28, 2006
Exactly. The plane doesn't give a shit that the air it's in is moving at 67000+mph through the vacuum and 1000mph around the Earth, because it just moves along with the air.
Likewise, the plane shouldn't give a shit that the air it's swimming through is moving at 100mph crossways to its vector of travel along the ground. Except for the brief period where it's moving into the air stream, it just moves along with the air, just like it moves along with the 67000mph motion and the 1000mph motion.
posted by ROU_Xenophobe at 6:20 PM on November 28, 2006
i think trying to think about multiple vectors just tried to explode my brain
posted by craven_morhead at 7:35 PM on November 28, 2006
posted by craven_morhead at 7:35 PM on November 28, 2006
This thread is closed to new comments.
posted by godawful at 3:19 PM on November 28, 2006