‘Supersonic’ on a 747 - 20th Jan
Jan 21, 2019, 8:25 pm
#32
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Jan 22, 2019, 12:29 am
#33
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I remember flying into ORD on a 737 in really bad weather and watching the wings flex to a degree I would not have thought possible but apparently well below their design limits.
Jan 22, 2019, 12:41 am
#34
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When we start seeing the "how fast can this thing go" shots from passengers I am always reminded of Maj Shul's story of the pilot's version of the same game:
https://www.youtube.com/watch?v=Lg73GKm7GgI
https://www.youtube.com/watch?v=Lg73GKm7GgI
Jan 22, 2019, 2:04 am
#35
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Slightly off topic but in the ballpark - could someone explain how fuel consumption is affected by tail/headwinds? I understand that commercial aircraft have an optimum cruising speed based on the performance/efficiency curve of turbofan engines. Does the optimum cruising speed vary depending on wind conditions?
Jan 22, 2019, 4:07 am
#36
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Slightly off topic but in the ballpark - could someone explain how fuel consumption is affected by tail/headwinds? I understand that commercial aircraft have an optimum cruising speed based on the performance/efficiency curve of turbofan engines. Does the optimum cruising speed vary depending on wind conditions?
During climb, pilots typically climb at the plane's optimal indicated airspeed when above 10,000 feet until the crossover point between that and the aircraft's optimal cruise mach number, typically in the high 20,000's. Above that, planes fly at the optimal mach number. This crossover happens because mach/true airspeed is constant and not affected by air pressure, unlike indicated airspeed (i.e. 300 knots indicated airspeed at sea level = 300 knots true airspeed and is around Mach 0.45, whereas at 28,000 feet 300 knots indicated airspeed is closer to 450-500 knots true airspeed and around Mach 0.76).
As a result, flying into a headwind decreases your ground speed, which increases the air distance flown to cover the same distance over the ground, increasing fuel consumption, and vice versa for a tailwind. Therefore, flights are typically routed to minimize the air distance flown, subject to certain airspace/airway restrictions such as the NAT tracks.
Jan 22, 2019, 7:04 am
#37
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I think there are two factors that make avoiding turbulence somewhat challenging. First, weather patterns aren't completely predictable. I've been on plenty of flights where I was warned that turbulence might become severe and never did, and the reverse as well where the captain thought it was a gorgeous day for flying and the atmosphere threw us a bumpy curve ball.
Second, and something about to change, commercial air traffic control is still a ground-based activity. In this article, the author, who is a member here at FT, discusses one of the side effects of a ground-based system, essentially that all planes are generally kept in the order that they join a route stream with adequate spacing, and the impending launch of a satellite-based ATC system which will have many benefits, including decreasing the likelihood that a disaster such as the MH 370 flight would result in a plane that will never be found and increasing fuel savings. Although not discussed in the article, another potential benefit implied in the discussion would seem to be the ability to give pilots a wider latitude in changing routes to avoid severe turbulence: https://blog.wandr.me/2019/01/aireon...the-best-part/.
There was an animation NATS put out several years ago that shows a typical day along the TATL air traffic lanes--it's easy to forget when you're in that tube 35,000 feet up with virtually no other planes in sight that ATC is actually keeping track of thousands of flights across the Atlantic.
Second, and something about to change, commercial air traffic control is still a ground-based activity. In this article, the author, who is a member here at FT, discusses one of the side effects of a ground-based system, essentially that all planes are generally kept in the order that they join a route stream with adequate spacing, and the impending launch of a satellite-based ATC system which will have many benefits, including decreasing the likelihood that a disaster such as the MH 370 flight would result in a plane that will never be found and increasing fuel savings. Although not discussed in the article, another potential benefit implied in the discussion would seem to be the ability to give pilots a wider latitude in changing routes to avoid severe turbulence: https://blog.wandr.me/2019/01/aireon...the-best-part/.
There was an animation NATS put out several years ago that shows a typical day along the TATL air traffic lanes--it's easy to forget when you're in that tube 35,000 feet up with virtually no other planes in sight that ATC is actually keeping track of thousands of flights across the Atlantic.
Jan 22, 2019, 7:18 am
#38
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Did the 737 have the most flex of any plane you have flown ?
Jan 22, 2019, 12:02 pm
#40
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Turbulence - me no likey.
One memory springs to mind. Flying with Ryanair over the alps just after Christmas. Fairly bumpy over a 15 minute period. I thought to myself, if the service starts I grabbing a large whiskey. My prayers were answered and when the trolly came round I think I spent nearly £30 on two double whiskeys and coke. Best money I ever spent. As soon as I got them the service was stopped due to more turbulence. I lashed the whiskeys into me and soon felt the benefit. After a while I couldn’t have cared less about the bumps. So my tip to myself and to other self loading freight, order two large ones if turbulence is expected!!!
One memory springs to mind. Flying with Ryanair over the alps just after Christmas. Fairly bumpy over a 15 minute period. I thought to myself, if the service starts I grabbing a large whiskey. My prayers were answered and when the trolly came round I think I spent nearly £30 on two double whiskeys and coke. Best money I ever spent. As soon as I got them the service was stopped due to more turbulence. I lashed the whiskeys into me and soon felt the benefit. After a while I couldn’t have cared less about the bumps. So my tip to myself and to other self loading freight, order two large ones if turbulence is expected!!!
Jan 22, 2019, 3:06 pm
#41
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Bear in mind the wings stay still and the fuselage moves up and down relative to the wings. Otherwise if it was the wings moving relative to the fuselage (as visually perceived by the pax) then the pax cabin would be stable, save the odd mild wobble. Think about it......
Jan 22, 2019, 3:59 pm
#42
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I think there are two factors that make avoiding turbulence somewhat challenging. First, weather patterns aren't completely predictable. I've been on plenty of flights where I was warned that turbulence might become severe and never did, and the reverse as well where the captain thought it was a gorgeous day for flying and the atmosphere threw us a bumpy curve ball.
Second, and something about to change, commercial air traffic control is still a ground-based activity. In this article, the author, who is a member here at FT, discusses one of the side effects of a ground-based system, essentially that all planes are generally kept in the order that they join a route stream with adequate spacing, and the impending launch of a satellite-based ATC system which will have many benefits, including decreasing the likelihood that a disaster such as the MH 370 flight would result in a plane that will never be found and increasing fuel savings. Although not discussed in the article, another potential benefit implied in the discussion would seem to be the ability to give pilots a wider latitude in changing routes to avoid severe turbulence: https://blog.wandr.me/2019/01/aireon...the-best-part/.
There was an animation NATS put out several years ago that shows a typical day along the TATL air traffic lanes--it's easy to forget when you're in that tube 35,000 feet up with virtually no other planes in sight that ATC is actually keeping track of thousands of flights across the Atlantic.
Second, and something about to change, commercial air traffic control is still a ground-based activity. In this article, the author, who is a member here at FT, discusses one of the side effects of a ground-based system, essentially that all planes are generally kept in the order that they join a route stream with adequate spacing, and the impending launch of a satellite-based ATC system which will have many benefits, including decreasing the likelihood that a disaster such as the MH 370 flight would result in a plane that will never be found and increasing fuel savings. Although not discussed in the article, another potential benefit implied in the discussion would seem to be the ability to give pilots a wider latitude in changing routes to avoid severe turbulence: https://blog.wandr.me/2019/01/aireon...the-best-part/.
There was an animation NATS put out several years ago that shows a typical day along the TATL air traffic lanes--it's easy to forget when you're in that tube 35,000 feet up with virtually no other planes in sight that ATC is actually keeping track of thousands of flights across the Atlantic.