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Boeing 787 Reaches 801 MPH as a Jet Stream Packs Record-Breaking Speeds

latimes.com

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Re: Boeing 787 Reaches 801 MPH as a Jet Stream Packs Record-Breaking Speeds

#181

Post by jsjohnst »

dingaling wrote: post #129
Kye wrote: post #77

Earlier quoted context omitted.

That would be editorializing.

They have already editorialised by converting the speed from knots Anyway, still doesn't set an unofficial record by variant or type: https://groundspeedrecords.com/wof-top-3/?aircraft-manufactu... Absolute fastest I can find on that site is a 747-400 at 752 knots / 866 mph but I do have a memory of one of that type breaking 800 knots over the Pacific within the last few years.

That site only includes submissions where the pilot took a photo of the instrument panel, so yeah, definitely not the true top speed record as I’m sure that not every pilot takes a photo, let alone knows of the site.

Re: Boeing 787 Reaches 801 MPH as a Jet Stream Packs Record-Breaking Speeds

#182

Post by brianwawok »

thecopy wrote: post #74
brianwawok wrote: post #53

Earlier quoted context omitted.

For me on a trip right now, I have: 2h drive to ORD 2h airport security Theater 4h Flight to SFO 1h to deplane get an Uber to someplace So 9 hour total journey on a direct flight. A 50% faster flight would make it be 8 hours instead of 9? I don't think I would pay anything for that.

2h airport security? In Zürich im usually done in 10 or 15 minutes...

Well, parking to at my gate.

If you park at the airport - It's about a 20-30 minute journey from parking lot to the front door of the airport. If parking offsite it can even be longer.

Then going through TSA, even with pre-check, can be from 20-60 minutes. 20 minutes is about the minimum time, just due to how BIG the airport is. You can end up having to walk a mile door to gate. I can run a mile pretty fast, but that is generally frowned upon.

And if you need to somehow deal with an agent for checking bags or anything else? That can easily be another 30 minutes down the crapper.

Re: Boeing 787 Reaches 801 MPH as a Jet Stream Packs Record-Breaking Speeds

#183

Post by astrodust »

aidenn0 wrote: post #118
astrodust wrote: post #93

Earlier quoted context omitted.

Some of that thrust has to be used to generate lift.

If the engines are level, then none of the thrust is generating lift; the wings generate the lift (and with it some corresponding drag).

The engines provide the energy to keep the plane flying. It must overcome two forces: Drag and gravity.

The energy requirements are split between those two.

If the plane is not generating lift then it's on the ground or about to end up in the ground.

Re: Boeing 787 Reaches 801 MPH as a Jet Stream Packs Record-Breaking Speeds

#184

Post by fooqux »

cyberferret wrote: post #67
fooqux wrote: post #15

Earlier quoted context omitted.

Yes. Ground speed is basically airplane speed + wind speed.

Technically it would be airplane speed + wind speed vector for the same direction the airplane is heading. :)

Hey, I said 'basically'! :P

But yes, you are correct. However, the person I was replying to already said they were ignorant of this stuff, so I didn't want to get too crazy.

Re: Boeing 787 Reaches 801 MPH as a Jet Stream Packs Record-Breaking Speeds

#185

Post by asteli »

pdx_flyer wrote: post #123
asteli wrote: post #88

Earlier quoted context omitted.

Reading your comment, I thought "how bad is a high-altitude stall anyway? it's obviously undesirable, but what makes it dangerous? possibly entering a flat spin?" Doing a little digging, it seems that there's also a significant risk of entering an overspeed condition during recovery, and inducing a structural failure! Makes sense considering that we're talking about speeds near Mach 1 to begin with.

Air France 447.

That's... a bit different? AF447 is a classic case of human factors in aviation accidents. The stall would have been completely recoverable if the pilot had nosed down.

Re: Boeing 787 Reaches 801 MPH as a Jet Stream Packs Record-Breaking Speeds

#186

Post by cxseven »

jazzyjackson wrote: post #110
Bendingo wrote: post #99

Earlier quoted context omitted.

> air speed is how fast the people on the plane are going relative to themselves That makes no sense. How can people be moving relative to themselves?

relative to their own location Δt ago?

Location with respect to what?

Re: Boeing 787 Reaches 801 MPH as a Jet Stream Packs Record-Breaking Speeds

#187

Post by henvic »

jsjohnst wrote: post #178
e40 wrote: post #104

Earlier quoted context omitted.

Do you know if the rides in higher energy jet streams are less comfortable, or is it undetectable by the passengers?

I’ve had a SFO -> London flight once where the pilot intentionally flew into a very strong jet stream current (saved us a lot of flight time, think it was close to an hour). Experienced a short burst of mildly rough turbulence entering and exiting, but otherwise smooth sailing.

Just curious... How do you know that? I wonder how some nervous passengers might react if they learned the pilot decided to enter a turbulence area on purpose.

Re: Boeing 787 Reaches 801 MPH as a Jet Stream Packs Record-Breaking Speeds

#188

Post by dzhiurgis »

glitchc wrote: post #157
kgermino wrote: post #6

This is probably a stupid question, but how is "ground speed" measured? Is it how quickly the airplane moves past a fixed point at it's altitude, or along the earth's surface? I.e. the plane is effectively moving along the surface of a sphere, but if the plane is 30,000 ft up, then the radius of the plane's sphere is 30,000 ft greater than the radius of the "ground" so traveling at the same angular velocity will requ…

Ground speed is measured by GPS on modern aircraft.

Which is probably measured in it's trajectory and then recalculated as ground speed, which is sea level? Wonder if it accounts for sea levers being higher at certain parts of planet?

Re: Boeing 787 Reaches 801 MPH as a Jet Stream Packs Record-Breaking Speeds

#189

Post by jsjohnst »

henvic wrote: post #187
jsjohnst wrote: post #178

Earlier quoted context omitted.

I’ve had a SFO -> London flight once where the pilot intentionally flew into a very strong jet stream current (saved us a lot of flight time, think it was close to an hour). Experienced a short burst of mildly rough turbulence entering and exiting, but otherwise smooth sailing.

Just curious... How do you know that? I wonder how some nervous passengers might react if they learned the pilot decided to enter a turbulence area on purpose.

The pilot got on the intercom and specifically stated he was doing it. He assured everyone there was zero risk outside the brief bumpiness and it would get us there much faster. He got loud cheers of support from the cabin, so I guess those nervous just kept to themselves.

Re: Boeing 787 Reaches 801 MPH as a Jet Stream Packs Record-Breaking Speeds

#190

Post by cweiss »

jsjohnst wrote: post #178
e40 wrote: post #104

Earlier quoted context omitted.

Do you know if the rides in higher energy jet streams are less comfortable, or is it undetectable by the passengers?

I’ve had a SFO -> London flight once where the pilot intentionally flew into a very strong jet stream current (saved us a lot of flight time, think it was close to an hour). Experienced a short burst of mildly rough turbulence entering and exiting, but otherwise smooth sailing.

I wonder if the pilot got any compensation for the fuel savings? I could see that being a dangerous incentive though, forcing pilots to opt for more risky conditions for the fuel savings bonus.
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