Flight maneuver opinions (#2)

[Pat Russell]

Is "crabbing" a maneuver?

[Judy Ruprecht]

At 14:18 10 February 2004, Pat Russell wrote:
>Is 'crabbing' a maneuver?

Sort of... in the US Practical Test Standards for gliders,
the term 'crab' is not used. I suppose this is because
there may be instances when a flight test is performed
with little or no wind aloft, making a crab difficult/impossible
to demonstrate. There are, however, four tasks which
may involve using a crab:

- the 'Normal and Crosswind Takeoff' task for aero
tow requires that the applicant maintain 'directional
control and proper wind-drift correction throughout
the takeoff.'

- the 'Normal and Crosswind Landing' task (which is
separate from the 'Slips to Landing' task) refers to
the applicant maintaining 'crosswind correction and
directional control throughout the approach and landing.'
Arguably, a crab on downwind is in many/most instances
the preferred crosswind correction.

- similarly to the above, the 'Traffic Patterns' task
refers to the applicant recognizing and making appropriate
corrections for the effect of wind.

- the 'Straight Glides' task refers to the applicant
tracking toward a prominent landmark using smooth,
coordinated control.

Judy

[Pat Russell]

I've long held the cranky opinion that "ground reference
maneuvers" are not maneuvers at all, and that teaching them as
such only confuses the student.

For example, "circles around a point," or "S-turns across a
road" are not maneuvers in their own right, but applications of
turning flight at various bank angles.

Similarly, "crabbing" is not a true maneuver, since it is
identical to "straight and level flight."

A "true" maneuver is an aerodynamic exercise that is carried out
by proper use of the controls. It has nothing to do with the
wind or the ground.

In the real world, there are a lot of reasons, pertaining to the
wind or the ground, for performing maneuvers. This is why we
learn them. But having a new reason to perform a maneuver is
not a new maneuver.

Consequently, I believe that we are doing a disservice to our
students by calling a crab (which is really just straight
flight) a maneuver. And a slip is just a slip. There is only
one slip. We may have different reasons for doing a slip, but
it is still just a single maneuver.

-Pat

[Chris OCallaghan]

Pat Russell > wrote in message >...
> Is "crabbing" a maneuver?

maneuver: n.

any skillful change of movement or direction in driving a vehicle,
controlling a spacecraft, etc.; specif.,

a) any change of movement by a flying aircraft b) a series of
movements by an aircraft according to a specific pattern, as a roll, a
loop, etc.

navigate: vi.

to steer, or direct, a ship or aircraft

Sounds like "crabbing" is navigation. A maneuver (a turn) is required
to establish crab angle, but is not itself a maneuver... at least,
according to Webster.

[F.L. Whiteley]

Perhaps best described as an 'attitude';^) in relation to the activity.

http://tinyurl.com/2gs2s

Indeed, this was impressed upon me during my early soaring instruction.
Attitude control applies to the glider (skill set), the pilot (and the
pilot's personal safety), and perhaps somewhat to reasonable discussion
here. Crabbing may or may not be useful in a given situation. By
definition, it's a pretty inefficient soaring manuevar.

I sometimes call for an 'altitude check' on the ground when I think a
pilot's attitude is displaced. Breaks the ice when I see someone that
appears distracted, pre-occupied, or otherwise ill-focused on the task at
hand. If their personal 'altitude' seems too high or too low before getting
on the line, it's worth a short, tactful discussion to get focused.

Have a fun day,

Frank

"Chris OCallaghan" > wrote in message
om...
> Pat Russell > wrote in message
>...
> > Is "crabbing" a maneuver?
>
> maneuver: n.
>
> any skillful change of movement or direction in driving a vehicle,
> controlling a spacecraft, etc.; specif.,
>
> a) any change of movement by a flying aircraft b) a series of
> movements by an aircraft according to a specific pattern, as a roll, a
> loop, etc.
>
> navigate: vi.
>
> to steer, or direct, a ship or aircraft
>
> Sounds like "crabbing" is navigation. A maneuver (a turn) is required
> to establish crab angle, but is not itself a maneuver... at least,
> according to Webster.

[Eric Greenwell]

F.L. Whiteley wrote:

> Perhaps best described as an 'attitude';^) in relation to the activity.
>
> http://tinyurl.com/2gs2s
>
> Indeed, this was impressed upon me during my early soaring instruction.
> Attitude control applies to the glider (skill set), the pilot (and the
> pilot's personal safety), and perhaps somewhat to reasonable discussion
> here. Crabbing may or may not be useful in a given situation. By
> definition, it's a pretty inefficient soaring manuevar.
>

Since we fly in a "crab" anytime there is a wind (and ridge soaring
demands it), unless going directly upwind or downwind, perhaps you meant
something else?
--
-----
change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

[soarski]

Judy Ruprecht > wrote in message >...
> At 14:18 10 February 2004, Pat Russell wrote:
> >Is 'crabbing' a maneuver?
>
> Sort of... in the US Practical Test Standards for gliders,
> the term 'crab' is not used. I suppose this is because
> there may be instances when a flight test is performed
> with little or no wind aloft, making a crab difficult/impossible
> to demonstrate. There are, however, four tasks which
> may involve using a crab:
>
> - the 'Normal and Crosswind Takeoff' task for aero
> tow requires that the applicant maintain 'directional
> control and proper wind-drift correction throughout
> the takeoff.'
>


The Tow pilot or the glider pilot? Take off, when does it start, and
end?
One cannot crab on the ground! Once airborne only the towpilot has to
crab, the
Glider's longitudenal axis is in line with the Tug's fuselage and the
towrope?
Both of them crab as one?....Reading the above, there is no crabing
mentioned.
I teach to keep the glider on the ground, until the Tug lifts off.
(directional control) upwind wing down, slight forward pressure,
oposite rudder, as needed. Like landing in a slip! After liftoff, as
a towpilot, I do not want the glider to do any special manouvers, he
may keep me from crabing! Just hang on!

Soarski

[Nyal Williams]

At 12:48 11 February 2004, Pat Russell wrote:
>I've long held the cranky opinion that 'ground reference
>maneuvers' are not maneuvers at all, and that teaching
>them as
>such only confuses the student.
>
>For example, 'circles around a point,' or 'S-turns
>across a
>road' are not maneuvers in their own right, but applications
>of
>turning flight at various bank angles.
>
>Similarly, 'crabbing' is not a true maneuver, since
>it is
>identical to 'straight and level flight.'
>
>A 'true' maneuver is an aerodynamic exercise that is
>carried out
>by proper use of the controls. It has nothing to do
>with the
>wind or the ground.
>
>In the real world, there are a lot of reasons, pertaining
>to the
>wind or the ground, for performing maneuvers. This
>is why we
>learn them. But having a new reason to perform a maneuver
>is
>not a new maneuver.
>
>Consequently, I believe that we are doing a disservice
>to our
>students by calling a crab (which is really just straight
>flight) a maneuver. And a slip is just a slip. There
>is only
>one slip. We may have different reasons for doing
>a slip, but
>it is still just a single maneuver.
>
>-Pat

'A kiss is just a kiss; a sigh is jsut a sigh,
As <geography> goes by'

'By George! I think you've got it'

Imagine an airport with diverging runways coming to
an apex and an aircraft on approach to one of them
with a wing low and in a slip. There is no wayto tell
whether it is a forward slip or a side slip unless
you know the intended runway.
>

[Robert Ehrlich]

Nyal Williams wrote:
> ...
> Imagine an airport with diverging runways coming to
> an apex and an aircraft on approach to one of them
> with a wing low and in a slip. There is no wayto tell
> whether it is a forward slip or a side slip unless
> you know the intended runway.
> ...


Well, I am neither familiar with the terms (english
aviation vocabulary) nor with the maneuver itself which
is not used nor taught in France, but let's check and
correct if necessary my understanding of this. One of them
(forward slip) is used to steepen the glide path, the
other one (side slip) is used to keep the fuselage
aligned with the ground track, although a side effect is also
to steepen the glide path. So if the fuselage is aligned
with the ground track, we can say it is a side slip,
independently of the intended runway, otherwise it
is a forward slip. Or am I wrong?

[Pat Russell]

On 13 Feb 2004 01:21:43 GMT, Nyal Williams
> wrote:

>Imagine an airport with diverging runways coming to
>an apex and an aircraft on approach to one of them
>with a wing low and in a slip. There is no wayto tell
>whether it is a forward slip or a side slip unless
>you know the intended runway.
>>
This is true only if you take a snapshot of the situation. By
watching the ground track, you could determine the intended
runway.

-Pat

[Pat Russell]

On Mon, 16 Feb 2004 14:51:20 +0000, Robert Ehrlich
> wrote:

> Or am I wrong?
You are absolutely correct.

You are describing the two reasons to perform a slip. Two
reasons, one maneuver.