Question to Mxmanic

Thomas Borchert wrote:
Mxsmanic,


Steep turns tend to be descending turns.



Why does anyone bother arguing with this idiot? Please!

No, no, Thomas. He's right, but you have to force fit your mental
processes into a replica of his very limited ones. As everyone else but
Anthony knows, steep turns do indeed TEND to be descending turns, unless
specific action is taken to remain at a constant altitude. The fact that
any competent pilot can complete a 360 within 10 feet of the initial
altitude seems to escape him.

Unfortunately, Anthony cannot make the simple leap from assuming his
vaunted "research" is correct, even though it provides the wrong answer,
to asking himself, "Let me assume that the empirical experiments
conducted by hundreds of thousands of real world pilots provide
hypothetical proof that an aircraft, completing a 360 degree turn at a
constant altitude, can indeed run through its own wake. What new
assumptions must I make to make this so, and how can I verify those
assumptions?"

That's how science works. Anthony thinks it's done by referring to
un-quotable armchair research about very restricted, generally incorrect
assumptions on his part. Then, when he is wrong, he becomes repetitive,
pedantic, and frustrated.

Oh well. The entire thread has forced me to ask myself just what the
wake behind an aircraft looks like. Like every other pilot, I know you
can intercept your own wake during a constant altitude turn, but it
would be neat to be able to SEE all of the air masses at work. Modern
computation isn't up to the task of separating out all of the variables
involved. Which is why a simulator, any simulator, is a very limited
substitute for reality. Poor Anthony.

Rip

I don't know if he "cannot" or will not or just wants to get under
everyone's skin. What you say in this post is correct. But why do people
keep responding and arguing ad nauseum with someone who can't or won't
get it? What's the dynamic? I doubt that there has ever been a pilot who
has not flown into his own wake in a constant altitude 360. So this is
not a topic that one pilot needs to prove to another pilot with a
different opinion.

Rip wrote:


Unfortunately, Anthony cannot make the simple leap from assuming his
vaunted "research" is correct, even though it provides the wrong answer,
to asking himself, "Let me assume that the empirical experiments
conducted by hundreds of thousands of real world pilots provide
hypothetical proof that an aircraft, completing a 360 degree turn at a
constant altitude, can indeed run through its own wake. What new
assumptions must I make to make this so, and how can I verify those
assumptions?"

RomeoMike wrote:

I don't know if he "cannot" or will not or just wants to get under
everyone's skin. What you say in this post is correct. But why do people
keep responding and arguing ad nauseum with someone who can't or won't
get it? What's the dynamic? I doubt that there has ever been a pilot who
has not flown into his own wake in a constant altitude 360. So this is
not a topic that one pilot needs to prove to another pilot with a
different opinion.

The only dynamic is between the pilots on the group, certainly not with
MX. But, as I mentioned, the thread forced me to ask myself just what it
was I am "running over" when I hit my own wake turbulence. Does it
matter? Probably not, but this enquiring mind wants to know. I still
don't have the answer. Rising wingtip vortices in warm air? Prop wash?
"Burbles" from the passage of non-lifting surfaces like the fuselage?

We all know it happens. I'm just one of those weirdos that wants to know
WHY it happens. As a result of this thread, it appears that nobody
knows. It's an unstudied regime of flight. I find THAT interesting!
Perhaps it could lead to some super-terrific drag reduction technique,
like surfing on your own wake? After all, that's why geese fly in "V"
formation.

Rip

"Rip" wrote ...

We all know it happens. I'm just one of those weirdos that wants to know
WHY it happens. As a result of this thread, it appears that nobody knows.
It's an unstudied regime of flight. I find THAT interesting!

Me too ;-)

I actually tried yesterday... with poor results for the connect ;(

But the GPS track provided an explanation. It showed my 360s were not proper
full circles, i.e. at the exit I crossed the previous flight path at an
angle (more than 45 degrees in fact) instead of actually flying in the same
circle track as the entry of the 360. Not so easy to explain, but the result
was that the airplane was only in the potential wake area for a fraction of
a second. I guess you need to fly so that the flightpath is well aligned
with the original circle, in order to catch the wake.

Back to the theory:
I read some interesting basic aerodynamics of drag. According to the book,
at low speeds the induced drag (which is a side effect of the lift force) is
larger than the parasite drag (caused by frontal area, landing gear etc).
But at higher speeds (above 70 mph in the example case, a light plane)
parasite drag becomes the dominant drag component. Now, the induced drag is
creating the tip vortices, which presumably descend, but parasite drag has
no vertical component, so in theory it should stay in place. So according to
this, the higher the airplane's relative speed, the slower the wake will
descend (if at all).

I look forward to the results of the group's experiments ;-)

"Snowbird" wrote:
I actually tried yesterday... with poor results for the connect ;(

But the GPS track provided an explanation. It showed my 360s were not
proper full circles, i.e. at the exit I crossed the previous flight path at
an angle (more than 45 degrees in fact) instead of actually flying in the
same circle track as the entry of the 360.

That's probably because there was wind aloft. GPS shows your track over the
ground, not your track WRT the moving air mass.

In perfectly calm conditions, GPS track would show a circle if you flew one
properly.

--
Dan
C-172RG at BFM

Snowbird writes:

Now, the induced drag is
creating the tip vortices, which presumably descend, but parasite drag has
no vertical component, so in theory it should stay in place. So according to
this, the higher the airplane's relative speed, the slower the wake will
descend (if at all).

The entire air mass behind the aircraft is descending. The downwash descends,
and air from above moves down to replace it. While parasitic drag is not
associated with lift and thus has no vertical component of its own, any
turbulence it creates will still drift downward with the downwash, although
perhaps less quickly than the downwash itself, depending on where the
turbulence leaves the aircraft.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Mxsmanic wrote in
:

Snowbird writes:

Now, the induced drag is
creating the tip vortices, which presumably descend, but parasite
drag has no vertical component, so in theory it should stay in place.
So according to this, the higher the airplane's relative speed, the
slower the wake will descend (if at all).

The entire air mass behind the aircraft is descending.

No,m it isn't., fjukktard.

you're wrong... again..


Bertie

"Mxsmanic" wrote in message
...
The entire air mass behind the aircraft is descending. The downwash
descends,
and air from above moves down to replace it. While parasitic drag is not
associated with lift and thus has no vertical component of its own, any
turbulence it creates will still drift downward with the downwash,
although
perhaps less quickly than the downwash itself, depending on where the
turbulence leaves the aircraft.


Blazing generalizations,,,,bull****.

You can hit your wake at the same altitude, people do it everyday. The
answer is simple and right in front of you. You are just too stupid to see
it.

"Maxwell" wrote in message
...

"Mxsmanic" wrote in message
...
The entire air mass behind the aircraft is descending. The downwash
descends,
and air from above moves down to replace it. While parasitic drag is
not
associated with lift and thus has no vertical component of its own, any
turbulence it creates will still drift downward with the downwash,
although
perhaps less quickly than the downwash itself, depending on where the
turbulence leaves the aircraft.


Blazing generalizations,,,,bull****.

You can hit your wake at the same altitude, people do it everyday. The
answer is simple and right in front of you. You are just too stupid to see
it.


Thank God a few are still awake here!

The only dynamic is between the pilots on the group, certainly not with
MX. But, as I mentioned, the thread forced me to ask myself just what it
was I am "running over" when I hit my own wake turbulence. Does it
matter? Probably not, but this enquiring mind wants to know. I still
don't have the answer. Rising wingtip vortices in warm air? Prop wash?
"Burbles" from the passage of non-lifting surfaces like the fuselage?

We all know it happens. I'm just one of those weirdos that wants to know
WHY it happens. As a result of this thread, it appears that nobody
knows. It's an unstudied regime of flight. I find THAT interesting!
Perhaps it could lead to some super-terrific drag reduction technique,
like surfing on your own wake? After all, that's why geese fly in "V"
formation.

Rip

As you correctly point out, we all know that it happens because we have all
done it; and when we flew eights around pilons, we hit our own wake quite
decisively each time we crossed the center point.

Thus, clearly, it doesn't matter whether we might have found a more
impressive bump lower down; the salient point is that a portion of the wake
was above the flight path when we returned to that place in the atmosphere.

Actually, most of the writings about wakes and sinking air, insofar as I can
tell, only discuss the motion of the central portion of the wake.
Additional writings, regarding the (very reall) potential for upset discuss
the central area of the vorticies--which settle at a lesser rate and expand
as they settle. Our actual experience strongly implies that the vortices
expand at least as rapidly as they settle.

I see that Snowbird has already posted links to my favorite illustration of
this, plus quite a few more, so I'll stop.

Peter