I was just having a look at Singapore airlines flight SIA211 at flightradar24.com and at one stage the plane was moving at a speed of 771mph at 38000 feet. 771mph!!!!!!. Ground speed, though. The plane is Boeing777 and their rated max cruise speed is 590mph. Must be a hell of a tail wind at that height. A Qantas flight, QFA32, from Heathrow, was doing 750mph at 39000.
Last edited by renormalised; 06-07-2011 at 11:50 PM.
Reason: Got a little carried away:)
It was doing 672kt airspeed (or thereabouts), which is 771mph. I was looking at a 180mph jetstream. The position of the core of the jetstream would be in accordance of where the plane was coming in from.
I'm very well aware of the differences in speeds and what they are, Steve. I'm an aircraft fanatic and I've flown often enough
It was doing 672kt airspeed (or thereabouts), which is 771mph. I was looking at a 180mph jetstream. The position of the core of the jetstream would be in accordance of where the plane was coming in from.
I'm very well aware of the differences in speeds and what they are, Steve. I'm an aircraft fanatic and I've flown often enough
<facepalm> well....for the benefit of others reading then Carl
The strongest jet streams I have experienced to date have been near Japan...around 240 knots,and I'll let you do the math.
That said, airspeed in all heavy jets in cruise is around Mach 0.79 to 0.86, so unless you were in a Concorde, the sound barrier was never even close To being busted.
An airframe section must be carefully designed and constructed to meet critical specific criteria before it is even capable of achieving and sustaining supersonic flight. In other words, atmospheric vehicles not designed to be supersonic cannot - and won't - become supersonic without very quickly falling apart.
The strongest jet streams I have experienced to date have been near Japan...around 240 knots,and I'll let you do the math.
That said, airspeed in all heavy jets in cruise is around Mach 0.79 to 0.86, so unless you were in a Concorde, the sound barrier was never even close To being busted.
Well that's what I was thinking...the speeds were unrealistic for heavies. It's probable that the reported speeds were glitches with the instrumentation that were recording them. However, if you're belting along at 400-500kts and you have a 150-250kt tailwind, your groundspeed is going to be pretty fast. So's the airspeed.
Here's one, now...a Qantas jet, flight QF582 at 39000 feet doing 648kts. He'd have to have the mother of all tailwinds to do that and I'm just wondering how a 20-25 year old 747-438 would handle that structurally. Not too well I'd imagine.
But nearly every plane I've seen flying at 37000-40000 feet today from west to east has been traveling at those high speeds.
660kt at 35000 is the speed of sound, or 760mph groundspeed.
I'd like to find out off the captains of these planes what they were really doing. That'd be the way to verify the speed of the planes.
An airframe section must be carefully designed and constructed to meet critical specific criteria before it is even capable of achieving and sustaining supersonic flight. In other words, atmospheric vehicles not designed to be supersonic cannot - and won't - become supersonic without very quickly falling apart.
That's a given....that's why I was flumoxed and wondering about these speeds...it'd have to be groundspeed and certainly not airspeed.
Interesting. I never gave it much thought at the time, but yesterday evening I was on a flight from Melbourne to Brisbane. There were gale force winds in Victoria and we must have had quite a tailwind because for a while the flight track screen was showing us travelling at 1016 km/h (Altitude = 12,000 m).
Later in the flight we had a bit of turbulence as the Captain said we were coming out of the high speed winds and the speed some time later had dropped to about 880 km/h, which I believe is about the cruising speed for a B737.
It's really easy to think of it this way: boat going up stream goes say, 20 knots relative to the bank. Downstream it gets up to a 40 knot clip. Is the boat going any faster? No it's still doing it's 30 knot speed, the river simply makes the relative speed ( to the bank or ground ) seem faster or slower.
A little known fact is heavy jets have enough sea level thrust to make orbit. The sad fact is they can't sustain that thrust at 35,000 feet.....hence no Sydney to London in 40 minutes yet......
I should think so....326000lbs of thrust at sea level (that's all 4 engines) for an A380-861 and 320000lbs for the A380-842 (which Qantas flies). Not bad...that much thrust could easily lift a relatively large rocket into space, but jets don't cut the mustard.
I should think so....326000lbs of thrust at sea level (that's all 4 engines) for an A380-861 and 320000lbs for the A380-842 (which Qantas flies). Not bad...that much thrust could easily lift a relatively large rocket into space, but jets don't cut the mustard.
Don't believe what you may read in the media
The last edition of my FCOM (sorry: Flight Crew Operating Manual) says QF trent 900's to be flat rated to 72,000 pounds of thrust.. ie. total of 288K...
..not quite sure where that 320K figure came from....
...anyway they are air breathing engines, that, unlike rockets, literally run out of puff at altitude.
The last edition of my FCOM (sorry: Flight Crew Operating Manual) says QF trent 900's to be flat rated to 72,000 pounds of thrust.. ie. total of 288K...
..not quite sure where that 320K figure came from....
...anyway they are air breathing engines, that, unlike rockets, literally run out of puff at altitude.
I was looking at the rated thrust for the Trent 972B engine (80,231lbs). The other engine was a GP7270 (81,500lbs). They were for maximum thrust. It did say that the GP7270 was normally rated at 70,000lbs for the A380. So I imagine the Trents would be rated likewise.
Yep....they need methane/LOX fuel like the Aurora spyplane That'll give them some more puff
Looking at Flightradar24, eastbound jets are doing in-excess of 1200km/h ground speed at cruising altitude of 30-40000ft all across Vic and NSW. Yesrterday, I was viewing the Boeing 747-400 of QF 64 from Johannesberg to Sydney doing about 1,240km/h above Adelaide and Mildura/ NW Victoria and SW NSW... that is well over Mach 1 at SEA LEVEL, let alone at FL 390 where the jet was crusing. IN zero wind, Mach 1 at 35,000ft equals about 1,058km.h. This aircraft was travelling inexcess of Mach 1.15 ground speed at cruising altitude, fast enough for a sonic boom to reach the ground, but thanks to the tailwinds, the airflow over the wings was no more than 900km/h, fooling the aircraft into an airspeed of 900km/h, yet doing in excess of 1200kmh groundspeed....but because the wings were doing 900km/h relative to the windspeed, there was no sonic boom to be heard.
Assuming perfectly still conditions at the same altitudes...Mach 1 (the "sound barrier" threshold) equals 1078km/h at 33,000ft, or 1220 km/h at sea level.
The typical groundspeed of commercial jets is around mach 0.85, or about 900km/h.
The jetstream is so strong, that east-bound commercial airliners are literally travelling at supersonic ground-speed. In still conditions aloft, 1200km/h would equal Mach 1.12.
Last edited by pgc hunter; 06-07-2011 at 11:25 PM.
Shows you how much thrust the engines (PW F135-100) for a F35 generate, in such a small package. Only 1.7t in weight and yet they generate 43000lbs of thrust!!!.
Guys...I think a major point is being lost here... "groundspeed" is a little irrelevant.....you will not produce a sonic boom doing M0.86 in a jetstream adding another M0.15 to your progress over terra firma....your speed through the air is still "just" M0.86.
Sure, some ground-speeds can get up to quite a clip (or just the opposite if you happen to be flying the opposite direction), but the airspeed (ie speed through the airmass) is the same...hence no sonic boom even if your ground speed is Mach 1.01
Massive jetstream!!!
