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colossus
10th Oct 2003, 01:09
What thoughts do the pprune community have in relation to the wake turbulence that the A380 will itself create? What implications this might have on separation times and distances for other aircraft?

I seem to recollect reading somewhere that the wake turbulence of significantly smaller aircraft (757?) were somewhat underestimated at the time of development, and that it's a complex issue to say the least.

What happend when the first 747's took to the skies?

747FOCAL
10th Oct 2003, 02:04
Wake Turbulence of large aircraft is a non event because they do not climb as fast as a smaller aircraft. If a 747 takes of from an airport followed by a 737 there is no way unless the 737 climbs then dives that the wake turbulence will ever encounter the 737. Wake turbulence does not stay in the same path it falls towards the ground. Do you really think that A300 N587, I think, was climbing slower than the 747 that had left before it? The wake turbulence from that 747 would have been following a path well below that A300. :8

Max Angle
10th Oct 2003, 03:28
Wake Turbulence of large aircraft is a non event because they do not climb as fast as a smaller aircraft. Why, in that case is a 2 minute separation applied between a heavy and a smaller aircraft?. You may out climb the wake on 2 engines but you will be right in it if you lose one. Also consider that a lightly loaded heavy aircraft, particularly a large twin (777, A330) will rotate at about the same place as a 737/A320 type aircraft that is heavy. Wake turbulence can be pretty scary stuff, I've had some nasty encounters even when all the distances and timings where correct.

I suspect the A380 may need another minute added to the departure timing and a little more spacing on the approach. I guess it will be looked at during certification but it's going to punch a mighty big hole in the air.

747FOCAL
10th Oct 2003, 05:16
There are turbulent forces as strong and stronger than wake turbulence at cruise level and you guys fly into them all the time and the aircraft does not break up. :confused: Yes PAX and the Stews go flying, but the tail don't come off. I have had a 727 at full thrust fly over me at about 30-40 ft and it didn't even take my hat off, are you sure these turbulents are everything the "experts" say they are?

PAXboy
10th Oct 2003, 06:06
col: I seem to recollect reading somewhere that the wake turbulence of significantly smaller aircraft (757?) were somewhat underestimated at the time of development, and that it's a complex issue to say the least. Yes it certainly is! The wake of the 757 has been discussed many times in various forums here and you should be able to find some by searching. It has an unusual wake for it's size but the reasons are now well known. I'm not sure if this means that future designs will change.

colossus
11th Oct 2003, 01:27
Thanks for all the thoughts on Wake Turbulence, hate to be a pain, but I have a further question

Given that, as PAXboy has confirmed, in the past under estimates where made in relation to the 757, has the industries knowledge of Wake Turbulence moved on enough that Airbus can realistically model what turbulence might create? Or is it more a case of as Max Angle has hinted at, wait till the certification aircraft are around?

simfly
11th Oct 2003, 01:35
747 FOCAL

I'm sure I remember watching something on TV regarding what you say about the AA A300 scenario, and I think they showed that the a/c turned earlier that the 747 before it, hence it ended up in it's wake.

Dom Joly
11th Oct 2003, 03:09
747focal

What happens when there is a wind straight down the runway. There would then be a significant chance that the lighter aircraft without sufficient separation would experience the wake of the heavier aircraft during climbout

Surely, you must be aware of this!?