Question to Mxmanic

writes:

Real people in real airplanes training to become real pilots do real
45 degree bank, constant altitude turns on a regular basis and run into
their real wake.

My research indicates that this is not possible. The wake sinks at a rate
between 150 and 500 feet per minute (roughly). Thus, it would always be well
below the airplane by the time it closes its own circle, unless the airplane
is also descending.

I've seen reports of pilots descending in a 360-degree turn and running into
their own wakes. If they can descend and encounter their own wake, then they
cannot remain at the same altitude and encounter it. It cannot be in two
places at once.

--
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In rec.aviation.piloting Mxsmanic wrote:
writes:

Real people in real airplanes training to become real pilots do real
45 degree bank, constant altitude turns on a regular basis and run into
their real wake.

My research indicates that this is not possible.

Your research at what, at your desk in front of Microsoft Flight
Simulator?

In my experience as a real pilot of real airplanes, it has happened.

In the experience of many real pilots of real airplanes, it has happened.

The altitude tolerance on a 360 degree turn is +/- 100 feet from
start to finish.

Once again, you have no context for understanding.

snip ignorant nonsense

--
Jim Pennino

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writes:

Your research at what, at your desk in front of Microsoft Flight
Simulator?

No, my survey of the literature.

In my experience as a real pilot of real airplanes, it has happened.

In the experience of many real pilots of real airplanes, it has happened.

In the course of my research, it appears to be impossible. The sources I
consulted seemed more reliable than a name on a screen.

The altitude tolerance on a 360 degree turn is +/- 100 feet from
start to finish.

If you are not descending at the same speed as your wake, I don't see how you
can run back into it.

--
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In rec.aviation.piloting Mxsmanic wrote:
writes:

Your research at what, at your desk in front of Microsoft Flight
Simulator?

No, my survey of the literature.

What does your "literature" say about the wake turbulance to be
found from a Cessna 172? How about a '47 Ercoupe?

In my experience as a real pilot of real airplanes, it has happened.

In the experience of many real pilots of real airplanes, it has happened.

In the course of my research, it appears to be impossible. The sources I
consulted seemed more reliable than a name on a screen.

I, and many, many other pilots have experienced it.

Yet another difference between simulated and real flight.

The altitude tolerance on a 360 degree turn is +/- 100 feet from
start to finish.

If you are not descending at the same speed as your wake, I don't see how you
can run back into it.

Because you have no context with which to even begin to understand it.

All your protestations do is show how unrealistic your flight simulator
and "experience" gained through playing flight simulator is.

--
Jim Pennino

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On Apr 15, 6:25 am, wrote:
In rec.aviation.piloting Mxsmanic wrote:

writes:
Your research at what, at your desk in front of Microsoft Flight
Simulator?
No, my survey of the literature.

What does your "literature" say about the wake turbulance to be
found from a Cessna 172? How about a '47 Ercoupe?

In my experience as a real pilot of real airplanes, it has happened.

In the experience of many real pilots of real airplanes, it has happened.
In the course of my research, it appears to be impossible. The sources I
consulted seemed more reliable than a name on a screen.

I, and many, many other pilots have experienced it.

Yet another difference between simulated and real flight.

The altitude tolerance on a 360 degree turn is +/- 100 feet from
start to finish.
If you are not descending at the same speed as your wake, I don't see how you
can run back into it.

Because you have no context with which to even begin to understand it.

All your protestations do is show how unrealistic your flight simulator
and "experience" gained through playing flight simulator is.


I always maintained altitude and rate of turn in steep turns with the
end result being hitting my own slipstream.
Its time mixup got into an aeroplane

george wrote:

I always maintained altitude and rate of turn in steep turns with the
end result being hitting my own slipstream.
Its time mixup got into an aeroplane

Who'd cleanup the vomit and brown runny stuff??? d:-))

On Apr 14, 4:27 pm, "george" wrote:
I always maintained altitude and rate of turn in steep turns with the
end result being hitting my own slipstream.

As have we all on nice days, and students like to brag about it. Yet
Mx is correct, in theory we should not be able to do this.

I seem to recall recent magazine (web?) articles where the idea that
you can hit your own wake while actually holding altitude, should be
downplayed nowadays. You _have_ to descend a little bit to do so,
which means that, while you might be within the +/- 100' test
scenario, you are NOT holding the same exact altitude.

Hmm. Or else it means that the wake doesn't necessarily descend as
we're taught. On a warm clear day (which is when I've hit my own
wake), I betcha that the wake is being held upward a tiny bit by the
heat from the ground.

Cheers, Kev

I seem to recall recent magazine (web?) articles where the idea that
you can hit your own wake while actually holding altitude, should be
downplayed nowadays. You _have_ to descend a little bit to do so,

How tall is the wake?

Jose
--
Get high on gasoline: fly an airplane.
for Email, make the obvious change in the address.

Kev writes:

On a warm clear day (which is when I've hit my own
wake), I betcha that the wake is being held upward a tiny bit by the
heat from the ground.

Then you must be descending through the rising column of air.

--
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On 16 Apr 2007 06:37:13 -0700, "Kev" wrote:

On Apr 14, 4:27 pm, "george" wrote:
I always maintained altitude and rate of turn in steep turns with the
end result being hitting my own slipstream.

As have we all on nice days, and students like to brag about it. Yet
Mx is correct, in theory we should not be able to do this.

I seem to recall recent magazine (web?) articles where the idea that
you can hit your own wake while actually holding altitude, should be
downplayed nowadays. You _have_ to descend a little bit to do so,
which means that, while you might be within the +/- 100' test
scenario, you are NOT holding the same exact altitude.

Hmm. Or else it means that the wake doesn't necessarily descend as
we're taught. On a warm clear day (which is when I've hit my own
wake), I betcha that the wake is being held upward a tiny bit by the
heat from the ground.

Cheers, Kev



The big question is "why does the wake turbulence descend?"
Is the air volume inside the vortices denser than surrounding air?
Probably not. So the descent is probably not due to gravitational
force.

I am no expert on fluid dynamics and have no access to texts that
answer the question (if there are any), but figure 7-3-5 in AIM is
interesting - it shows a wake sinking at several hundred fpm
immediately after an aircraft, but than stabilizing at several hunderd
feet below the flightpath, i.e. no further sink. This might indicate
that the sink is due to wing downwash.

If that is the case, than
1. Wake turbulence in steep turns will not move just downward, but
down and out, that is: opposite lift.
2. The speed at which it moves will depend on downwash - it's speed,
intensity, strength (?) I don't know which term would be appropriate
here. Whatever it is, it might be much smaller for GA aircraft than
for large aircraft.

It would be interesting to do the following flight test:
On a nice day (meaning: perfectly still air) fly turns at different
bank angles and speeds and note when you do and don't experience the
bump at the end of the turn. Do this in different aircraft - low/high
wing, small/large/...

Does anyone know whether big aircraft experience the bump at the
conclusion of their steep 360s?

- Tom