Questions tagged [wake-turbulence]

Turbulence that forms behind an aircraft, which is particularly dangerous during takeoff and landing.

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What are the wake turbulence characteristics at ground level near landing aircraft?

I'm a structural engineer and I need to understand the additional forces that wake turbulence may cause on a building near a runway. I can determine the natural wind speed and associated forces on the ...
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2 votes
2 answers
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How does the wake behind a propeller blade affect the next blade if the airflow through the propeller should be clearing the wake?

Propeller or wind turbine often has only 3 blades,reason is wake behind each blade interfere with next blade. I think wind that comes to propeller must clear this wake,so faster you go the air for ...
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With a separation of 1000 feet, in flight is there any danger of severe wake turbulence?

Air Canada Flight 190 at 36600 experienced severe wake turbulence due to a Boeing 747-400 United 896 Flight at 37000. Assume the worst possible combination of civilian aircraft under standard speeds ...
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What are differences between vortex, swirl, eddies and wake?

These terms seem to have the same meanings. Can anyone differentiate them?
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Can any conclusions about aerodynamic efficiency be drawn on the basis of fly-by noise?

Edit: I'm beginning to think this is more suited to the physics stack exchange, but I'll keep this here for a while... Being bored mindless, surfing the interwebz, I came across this video, where a ...
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Why did the pilot in this EC135 crash change the throttle setting after encountering wake turbulence?

I’m confused in this accident why the Eurocopter EC135 pilot decided to manipulate the throttle after encountering wake turbulence - I can’t think of a reason for this. Could someone please explain ...
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3 votes
2 answers
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Is turbulence behind an airliner less severe during cruise?

The turbulence and tip vortices behind an airliner are a familiar hazard for smaller aircraft when near an airport. But a lightweight glider seems to have not suffered from this, when its tail was ...
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3 votes
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Is propeller wake turbulence quantifiable based on operating conditions?

I know the propeller does work on the air and thus the flow behind a propeller is higher than the airspeed. However, what is the quality of this flow? If I were doing a heat transfer analysis of an ...
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8 votes
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Wake turbulence: crossing under a final approach path VFR

Flying VFR around the Bay Area I’ve had two experiences recently that made me a bit nervous, but I haven’t been able to find recommendations that fit the situation. The first was flying (C172) north ...
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6 votes
3 answers
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What vertical separation is required in a holding stack to avoid wake turbulence?

Sometimes in my free time I play Endless ATC, a game where one acts as the approach and departure controller. In the game (as in real life) the controller is forced to put planes in a holding stack, ...
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1 vote
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Could reduced-lift wingtips allow an airplane to generate less wake turbulence?

Would it be possible to weaken the wake vortices generated by a large aircraft (which can be dangerous to smaller aircraft behind the large aircraft, and are the limiting factor determining how ...
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If a pilot's plane suddenly and unintentionally becomes inverted, what is the pilot's best course of action?

If a plane was suddenly inverted through no action of the pilot, say wake turbulence from a much large plane (think 747 vs. Learjet), should the pilot first try to right the plane or get the nose ...
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Is there a wake turbulence difference between B737s?

I've heard pilots talking about how the new 737s produce much more wake turbulence then the model historically. They described it as similar to the 757, based on anecdotal experience. Have there been ...
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would a dimpled heat shield reduce heat transfer during reentry? [closed]

Would a large ceramic golfball absorb less heat on reentry than a standard sphere? "The difference in the flowfields around a smooth sphere and a rough, or dimpled, sphere can be seen above. Since ...
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9 votes
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Why does wake turbulence seem to move upward on touchdown?

Source of the first photo I saw this photo of business jet touching down (first picture) and the smoke of tires forming wake turbulence . as I have provided other pictures (second and third) of "what ...
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Does the wake from horizontal stabilizers merge with the wing wake?

There is already a long series of questions about the downwash and tip vortexes with nice images, but I'm going to add another one... Large airliners (A380, B747-8) have horizontal stabilizers ...
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How and why do wake vortices come together to form two tip vortices?

Wake vortices are created all along the wingspan but, the vortices come together to form two tip vortices. How exacly does this happen and why does it? I know that wake vortices push air to the side. ...
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Are there areas to avoid while flying formation with a larger aircraft?

Consider a fighter jet flying formation with an airliner-size aircraft, such as during an interception or mid-air refueling. Are there areas which should be avoided by the fighter jet? I.e. are there ...
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Why isn't the Presidential 747 "Air Force One Heavy"?

Aircraft with a maximum takeoff weight of at least 300,000 pounds add the word "Heavy" to their callsign. (Example: Lufthansa 415 Heavy in this video.) The current Presidential 747's have a maximum ...
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What is the relationship between angle of attack and wake turbulence?

It is said that when the preceding airplane is heavy, clean, and slow, wake turbulence is much hazardous due to greater angle of attack is requried. However, why does increasing angle of attack result ...
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What are normal landing separation minima? [duplicate]

As far as I know we have separation minima of 10 minutes in horizontal flight, so do we have any equivalent separation minima for landing? If so, how it is possible to land two aircraft in a very ...
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What is the safe separation for landing a Cessna-172 behind a commercial airline jet?

When is it safe to land a Cessna-172 after a commercial airline jet has landed?
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What is the minimum separation between two landing A380s?

I have always assumed that landing separation depends on wake turbulence limits depending on weight class. However I see that no minimum separation needed for the A380 as trailing aircraft (and in a ...
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6 votes
2 answers
1k views

Why there is no wake turbulence right after touch down or before rotation?

It is said that wake turbulence occurs when an aircraft generates lift and there is no wake turbulence after touch down or before take off. That's how we avoid wake turbulence. However, I've thought ...
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Why aren't departures separated by minimum distance rather than minimum time?

Normally, two departures are required to be separated by a minimum amount of time depending on the weight class of the aircraft. However, I was wondering if someone could explain why departure-...
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Are most/all flights affected by a noticeable amount of turbulence?

How common is turbulence that is severe enough to feel uncomfortable? I don't mean a little shaking here and there, but a drop that lasts a second or two. Last 2 flights I was on (Paris to Singapore, ...
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1 vote
1 answer
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How should wake turbulence from aircraft on the ground be avoided during landing?

If a large jet aircraft is holding short of runway 28L while I am landing a single-engine aircraft on runway 28R, how should I proceed with such a landing?
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19 votes
2 answers
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What does it mean when an airplane has the "super" call sign? [duplicate]

What does it mean if an airplane uses the "super" designation after their call sign on the radio?
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What is the difference between Jet Wash and Jet Blast?

I was reading about Wake Turbulence in Wikipedia and got to know about Jet Wash and Wing Vortex. According to Wikipedia, Jet Blast is the movement of air from the jet exhaust. Isn't this same as Jet ...
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4 votes
1 answer
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What type of commercial aircrafts generate strong Wake Turbulence?

I know that 757, 737 generate strong Wake Turbulence and as pilots, we should always be aware of that and caution for the wake turbulence while landing and departing. I would like to know if is ...
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31 votes
5 answers
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How do aircraft refueling in-air deal with wake turbulence?

Many fighter planes have the capability to refuel in air. When a plane moves in air, turbulence is generated at its back. To refuel, the fighter plane must come near to the parent plane (which has ...
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14 votes
4 answers
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How does wake turbulence affect parachutists?

If one were to parachute out of a jumbo jetliner, would wake turbulence from the plane be an issue? A 747 for instance produces much more wake turbulence than the smaller planes usually used to drop ...
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38 votes
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How does an aircraft form wake turbulence?

This question discusses how wake turbulence can affect planes flying in formation. It got me wondering, how do aircraft (the wings in particular) form wake turbulence to begin with? It can't be as ...
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12 votes
3 answers
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How are these Airbus A350s flying in formation without being affected by wake turbulence?

The first photo in this article appears to depict three Airbus A350s flying closely in tandem at approximately the same altitude. I thought that a large jetliner would leave a trail of wake ...
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9 votes
1 answer
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Minix wingtip vortices mitigation - How does it work?

I stumbled upon this article: Minix wing tip device promises 6% gain in fuel efficiency for airliners. Such an economy is appealing and I must confess the design is "sexy". Could someone expand a ...
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11 votes
1 answer
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Do the shock waves from a supersonic plane affect general aviation planes?

Are there any considerations to take into account when flying around supersonic aircraft? I know that wake turbulence from large aircraft can pose a threat to smaller planes. Is the same true of the ...
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9 votes
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When and how can pilots waive wake turbulence holds in the US?

According to FAA rules, controllers are required to hold aircraft 2 or 3 minutes for wake turbulence under certain conditions. When is that wake turbulence hold required, and when are pilots allowed ...
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31 votes
2 answers
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What is the cause of unusually strong wake turbulence from the 757?

The Boeing 757 (at least in the US) is in a special class of its own with respect to air traffic control wake turbulence advisories and separation. This is apparently due to it producing stronger wake ...
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