Back in the air.

In my experience, it's a matter of how cross controlled you have the
airplane. If it's being done for landing, one uses the yoke to keep
the airplane in line with the centerline of the runway and the rudder
to keep its axis in line with that same centerline. In a sideslip for
altitude loss, one isn't concerned about that -- you want to present
the side of the airplane to the wind, making it areodynamically dirty.

If you had some sort of monitor on the contols and reviewed their
position after the flight you'd have a hard time telling the
difference, unless you noted the controls were a lot more active if it
was for a cross wind landing.



On Mar 5, 8:20 am, Jose wrote:
The difference is that when the longitudinal axis of the airplane is not
lined up with the runway centerline (forward slip), there is much more
drag.

This is true of a side slip too. I suppose if you want to lose
altitude, you cross your controls more, but again, the =airplane=
doesn't see the runway, so the =airplane= can't tell the difference.
It's just cross controlled.

The only difference between the two slips is what you are looking at out
the window.

Jose
--
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Shirl:
The difference is that when the longitudinal axis of the airplane is not
lined up with the runway centerline (forward slip), there is much more
drag.

Jose:
This is true of a side slip too. I suppose if you want to lose
altitude, you cross your controls more, but again, the =airplane=
doesn't see the runway, so the =airplane= can't tell the difference.
It's just cross controlled.

It's true that the action of the pilot is the same; however, in a
forward slip (for loss of altitude) it is cross-controlled to a greater
degree so that the airplane is actually coming down sideways (but in
line with the centerline) so as to expose more of it to the oncoming
wind. Yes, there's drag in a side slip (for crosswind correction) too,
but not as much, and the whole point of the side slip is to keep the
airplane lined up with the runway, not to lose altitude.

"Tony" wrote:
In my experience, it's a matter of how cross controlled
you have the airplane.

Exactly.
And that depends on what you're using the slip for -- to lose altitude
or for x-wind correction.

In a sideslip for altitude loss,

Side slip is used for x-wind correction, not altitude loss.

one isn't concerned about that -- you want to present
the side of the airplane to the wind, making it areodynamically
dirty.

True.

If you had some sort of monitor on the contols and reviewed their
position after the flight you'd have a hard time telling the
difference, unless you noted the controls were a lot more active if it
was for a cross wind landing.

Describe "more active"?
The controls are used to a lesser degree in a side slip for a crosswind
landing than they are in a forward slip for loss of altitude. If you
have the wing into the wind and are using full rudder and still can't
keep the axis lined up with the centerline because of the strong x-wind,
you're probably in conditions that exceed the x-wind limit of the
airplane.

The reason for pointing out the difference in the first place was to
note, for example, that if you are in an emergency where you HAVE TO
lose altitude and get the plane down quickly to a designated spot, a
"side slip" (axis lined up with the runway) isn't going to burn off
altitude like a "forward slip". Knowing the difference in the two slips
and how/when to use them in an emergency could make the difference in a
successful landing and not ending up where you wanted to.

On Mon, 05 Mar 2007 13:20:47 GMT, Jose
wrote:

The difference is that when the longitudinal axis of the airplane is not
lined up with the runway centerline (forward slip), there is much more
drag.

This is true of a side slip too. I suppose if you want to lose
altitude, you cross your controls more, but again, the =airplane=
doesn't see the runway, so the =airplane= can't tell the difference.
It's just cross controlled.

The only difference between the two slips is what you are looking at out
the window.

It may be worth noting that the controls are crossed in a skid as well
as a slip. Slips are good; skids may be the entry to the deadly
cross-controlled stall.

Don

Let me chime in... ;-)

"Shirl"wrote
Shirl:
The difference is that when the longitudinal axis of the airplane is
not
lined up with the runway centerline (forward slip), there is much more
drag.

I think this is true only in the no-crosswind case when the relative wind
has the same direction as the runway. If there is crosswind, the relative
wind direction is from a direction more or less to the side, depending on
the crosswind component. Therefore, in a crosswind side-slip approach, even
if the airplane's longitudinal axis is aligned with the runway there is some
degree of additional drag as the airplane is not aligned into the relative
wind. (In comparison, in a crabbing approach the airplane is aligned much
closer to the relative wind.)


Jose:
This is true of a side slip too. I suppose if you want to lose
altitude, you cross your controls more, but again, the =airplane=
doesn't see the runway, so the =airplane= can't tell the difference.
It's just cross controlled.

It's true that the action of the pilot is the same; however, in a
forward slip (for loss of altitude) it is cross-controlled to a greater
degree so that the airplane is actually coming down sideways (but in
line with the centerline) so as to expose more of it to the oncoming
wind. Yes, there's drag in a side slip (for crosswind correction) too,
but not as much, and the whole point of the side slip is to keep the
airplane lined up with the runway, not to lose altitude.

Yes, in a forward slip where you want maximum descent speed it's no problem
to use full opposite rudder. In a crosswind side-slip, the crosswind itself
does much of the job the opposite rudder does in a forward slip, so less
rudder is needed.

Did we reach a higher level of confusion? ;-)

The reason I suggest a "forward" slip would show more active controls
is that when I do them there are constant control adjustments to keep
the hull aligned along the runway and on the centerline.

For a slip to lose energy, however, I stomp on the rudder and use the
yoke deflection to more or less keep things OK. Rudder authority is
not that great in the Mooney.

So, if a knowledgable px was hooded, she would note I'm working a
little harder with a forward slip (using the definition of this
thread.)


On Mar 5, 10:17 am, Shirl wrote:
"Tony" wrote:
In my experience, it's a matter of how cross controlled
you have the airplane.

Exactly.
And that depends on what you're using the slip for -- to lose altitude
or for x-wind correction.

In a sideslip for altitude loss,

Side slip is used for x-wind correction, not altitude loss.

one isn't concerned about that -- you want to present
the side of the airplane to the wind, making it areodynamically
dirty.

True.

If you had some sort of monitor on the contols and reviewed their
position after the flight you'd have a hard time telling the
difference, unless you noted the controls were a lot more active if it
was for a cross wind landing.

Describe "more active"?
The controls are used to a lesser degree in a side slip for a crosswind
landing than they are in a forward slip for loss of altitude. If you
have the wing into the wind and are using full rudder and still can't
keep the axis lined up with the centerline because of the strong x-wind,
you're probably in conditions that exceed the x-wind limit of the
airplane.

The reason for pointing out the difference in the first place was to
note, for example, that if you are in an emergency where you HAVE TO
lose altitude and get the plane down quickly to a designated spot, a
"side slip" (axis lined up with the runway) isn't going to burn off
altitude like a "forward slip". Knowing the difference in the two slips
and how/when to use them in an emergency could make the difference in a
successful landing and not ending up where you wanted to.

"Tony" wrote:
The reason I suggest a "forward" slip would show more active controls
is that when I do them there are constant control adjustments to keep
the hull aligned along the runway and on the centerline.

When the hull is aligned with the centerline of the runway, that is a
*side* slip, not a forward slip. If you like, I can quote the Soaring
Flight Manual that spells out the difference and what condition each is
used for. As previously noted, it does seem they were named in reverse,
and that makes it confusing as to which is which.

So, if a knowledgable px was hooded, she would note I'm working a
little harder with a forward slip (using the definition of this
thread.)

I agree that you work harder in a *SIDE* slip (keeping the hull aligned
with the runway centerline in a crosswind), although the degree of
cross-control in a forward slip (for loss of altitude) is greater.

Shirl:
The difference is that when the longitudinal axis of
the airplane is not lined up with the runway centerline
(forward slip), there is much more drag.

"Nils Rostedt" wrote:
I think this is true only in the no-crosswind case when the
relative wind has the same direction as the runway. If there
is crosswind, the relative wind direction is from a direction
more or less to the side, depending on the crosswind component.
Therefore, in a crosswind side-slip approach, even if the airplane's
longitudinal axis is aligned with the runway there is some degree
of additional drag as the airplane is not aligned into the relative
wind. (In comparison, in a crabbing approach the airplane is aligned
much closer to the relative wind.)

Agreed.

It's true that the action of the pilot is the same; however, in a
forward slip (for loss of altitude) it is cross-controlled to a greater
degree so that the airplane is actually coming down sideways (but in
line with the centerline) so as to expose more of it to the oncoming
wind. Yes, there's drag in a side slip (for crosswind correction) too,
but not as much, and the whole point of the side slip is to keep the
airplane lined up with the runway, not to lose altitude.

Yes, in a forward slip where you want maximum descent speed it's no problem
to use full opposite rudder. In a crosswind side-slip, the crosswind itself
does much of the job the opposite rudder does in a forward slip, so less
rudder is needed.

Agreed.

Did we reach a higher level of confusion? ;-)

No confusion here. ;-)
Again, I only meant to point out the difference and their uses because
in an emergency situation where losing altitude quickly and/or fighting
a strong crosswind were paramount to getting the plane down where you
have to, knowing the difference and using the correct one could mean the
difference between success and disaster.

On Sun, 04 Mar 2007 22:30:44 GMT, Crash Lander wrote:

My instructor didn't seem phased by it, and I'm sure she would not have let
me go if she was concerned about it, but I do understand your comment.

One must take into account the personality of the instructor. We have an
old codger instructor with thousands of hours as a commercial commuter
pilot.

Despite all this experience, I won't fly with the guy. His "Bold Pilot"
approach to aviation scares the crap out of me.

--
Dallas

It's true that the action of the pilot is the same; however, in a
forward slip (for loss of altitude) it is cross-controlled to a greater
degree...

The slip is the same, just differing in degree, and only because the
purpose is different. But the airplane doesn't know the purpose.

Also, if you need to sideslip to a parallel runway that is sort of far
away, you'll slip more, and lose more altitude, just like a forward slip.

Jose
--
Humans are pack animals. Above all things, they have a deep need to
follow something, be it a leader, a creed, or a mob. Whosoever fully
understands this holds the world in his hands.
for Email, make the obvious change in the address.