Do you crab or forward slip in X wind landings

Side slip is the easiest and most powerful form of crosswind correction. Simply use the rudder to keep the nose of the glider parallel to runway center line and lower the upwind wing enough to counter the wind. To much bank and you drift upwind of centerline. Side slip can be maintained all the way to the end of the roll out just by keeping the upwind wing low. If the cross wind is to strong for this method you shouldn't be flying or you should select a different runway.

Crab Requires a transition to a side slip just above the ground and almost guarantees a side loaded landing either from kicking to late or to soon and not getting into the side slip quick enough.

Forward slips are not really for crosswind correction they are more for glide path control.

Side slip for all the above reasons, especially for instruction. Translating from crab to slip in the flair or just at touchdown is unnecessarily complex. Establish the forward slip on final and hold that attitude until stopped.

However, I commonly "cheat" whilst flying the tug, crabbing until short final and then establishing the slip. Less pressure on the rudder foot/knee if doing lots of landing in the Pawnee.

On Sat, 25 Feb 2017 18:30:11 -0800 (PST), Citrus Soaring
wrote:

Side slip is the easiest and most powerful form of crosswind correction. Simply use the rudder to keep the nose of the glider parallel to runway center line and lower the upwind wing enough to counter the wind. To much bank and you drift upwind of centerline. Side slip can be maintained all the way to the end of the roll out just by keeping the upwind wing low. If the cross wind is to strong for this method you shouldn't be flying or you should select a different runway.

Crab Requires a transition to a side slip just above the ground and almost guarantees a side loaded landing either from kicking to late or to soon and not getting into the side slip quick enough.

Forward slips are not really for crosswind correction they are more for glide path control.




I wonder about the different methods that are taught - in Europe the
only acceptable method is crab, aligning with rhe runway heading
during the flare, and immediately touching down. Priority is to keep
the wings level all the time to reduce the chances of a ground loop in
case of an outlanding.

Is it grass strips vs. paved runways which we don't have in Europe?


Just a question (since I fly a glider where side slip would always
drag the wingtip on the ground before the main wheel touch down):

How do you cope with one wingtip lower than the other in case of an
outlanding on a field with higher crops? To me the side slip method is
a recipe for disaster in this case...
Do you teach both methods?




Cheers
Andreas

If you have altitude to burn you can do the the entire pattern using turning slips, and this can be a safer maneuver than the standard coordinated turns. Nevertheless, I prefer to crab when taking off and landing in a crosswind, even though you're performing a dreaded skid at the last moment.

On Sunday, February 26, 2017 at 6:37:23 AM UTC+3, wrote:
Side slip for all the above reasons, especially for instruction. Translating from crab to slip in the flair or just at touchdown is unnecessarily complex. Establish the forward slip on final and hold that attitude until stopped.

I don't know anyone who "transitions from crab to slip in the flair [sic]". You simply straighten up with wings level, and accept whatever minor sideways component the crosswind gives you in the two seconds before you touch down. Either you touch down going very slightly sideways, or you yaw a little past the runway heading to align with the direction the glider is actually going. Or, I guess, you could fly your final with a track slightly upwind of runway heading so that your track gets aligned by the crosswind during the flare.

It doesn't really matter on the wide lush grass runways we fly gliders from.. Maybe it's different if you're landing on a strip of concrete only a couple of meters wide.

Maintaining a slip all the way to the ground isn't a good idea in the long span low wing gliders we train in, especially if the grass is lush and/or uneven. Wings level!!! Again, it may be different in a 2-33.

On Sunday, February 26, 2017 at 1:00:51 AM UTC+3, Tango Eight wrote:
On Saturday, February 25, 2017 at 4:29:42 PM UTC-5, Martin Gregorie wrote:
On Sat, 25 Feb 2017 13:03:59 -0800, Jonathan St. Cloud wrote:

Do you crab or forward slip landing in x-winds and why? When I was
taught how to fly an airplane the crab method was used when I
transitioned to gliders my instructor emphasized forward slip over crab.
Years later I have established my procedures, but I thought this might
be a useful discussion for newer pilots.

Standard UK training, at least when I learnt and I haven't heard any
different from our instructors since, is to crab with wings level on
approach and kick the glider straight just before touchdown. Another
point is that we are taught to do fully held-off landings regardless of
the size and surface of the club field on the grounds that its the only
sensible way to land out, so we should be able to do it well. I think the
two are related because this keeps the wings level while speed bleeds off
and its fairly easy to kick the glider straight as it settles. If you
also manage a neat two-pointer you can award yourself brownie points as
well as knowing that this will help to keep the glider running straight
despite any cross-wind.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

What two seater is being used to teach fully held off landings?

I doubt people are doing *fully* held off landings i.e. with the glider actually stalling on. More likely it's "held off until the glider is in the same attitude it will have on the ground .. or a tiny bit more" and then allowed to settle in that attitude. As it slows, lift at that AoA becomes insufficient to support the glider, but there is never aerodynamic stall. Maximum AoA / CL is not reached. Once you touch the ground AoA can not be increased, so lift can't be, so you can't start flying again (absent a massive headwind gust) and the *objectives* of a "fully held off" landing are acheived..

Even nose-draggers like the ASK21 have a tail wheel and are landed main-and-tail or slightly tail first.

The only exception I know is the PW5. I've never seen anyone land a PW5 tail first. We had an informal challenge to do it when we first got ours. No one managed it.

At 04:25 26 February 2017, Andreas Maurer wrote:
On Sat, 25 Feb 2017 18:30:11 -0800 (PST), Citrus Soaring
wrote:

Side slip is the easiest and most powerful form of crosswind correction.
Simply use the rudder to keep the nose of the glider parallel to runway
center line and lower the upwind wing enough to counter the wind. To much
bank and you drift upwind of centerline. Side slip can be maintained all
the way to the end of the roll out just by keeping the upwind wing low.
If
the cross wind is to strong for this method you shouldn't be flying or
you
should select a different runway.

Crab Requires a transition to a side slip just above the ground and
almost
guarantees a side loaded landing either from kicking to late or to soon
and
not getting into the side slip quick enough.

Forward slips are not really for crosswind correction they are more for
glide path control.




I wonder about the different methods that are taught - in Europe the
only acceptable method is crab, aligning with rhe runway heading
during the flare, and immediately touching down. Priority is to keep
the wings level all the time to reduce the chances of a ground loop in
case of an outlanding.

Is it grass strips vs. paved runways which we don't have in Europe?


Just a question (since I fly a glider where side slip would always
drag the wingtip on the ground before the main wheel touch down):

How do you cope with one wingtip lower than the other in case of an
outlanding on a field with higher crops? To me the side slip method is
a recipe for disaster in this case...
Do you teach both methods?




Cheers
Andreas



I think it depends on what you are flying and the surface you are landing
on
The modern ships like Ventus 3 and arcus seem to have high wing tips as did

the early American stuff so slip makes sense
The kestrel,nimbus generation ships had low tip clearance and a crab was
the
only way.
I was once told the are only 2 types of Kestrel owners ,those who have
ground looped and those who are going to
Nice soft grass is much more forgiving of a little sideways slide than high

friction paving

On Sat, 25 Feb 2017 23:19:45 -0800, Bruce Hoult wrote:

On Sunday, February 26, 2017 at 1:00:51 AM UTC+3, Tango Eight wrote:
On Saturday, February 25, 2017 at 4:29:42 PM UTC-5, Martin Gregorie
wrote:
On Sat, 25 Feb 2017 13:03:59 -0800, Jonathan St. Cloud wrote:

Do you crab or forward slip landing in x-winds and why? When I was
taught how to fly an airplane the crab method was used when I
transitioned to gliders my instructor emphasized forward slip over
crab.
Years later I have established my procedures, but I thought this
might
be a useful discussion for newer pilots.

Standard UK training, at least when I learnt and I haven't heard any
different from our instructors since, is to crab with wings level on
approach and kick the glider straight just before touchdown. Another
point is that we are taught to do fully held-off landings regardless
of the size and surface of the club field on the grounds that its the
only sensible way to land out, so we should be able to do it well. I
think the two are related because this keeps the wings level while
speed bleeds off and its fairly easy to kick the glider straight as
it settles. If you also manage a neat two-pointer you can award
yourself brownie points as well as knowing that this will help to
keep the glider running straight despite any cross-wind.


--
martin@ | Martin Gregorie gregorie. | Essex, UK org |

What two seater is being used to teach fully held off landings?

I doubt people are doing *fully* held off landings i.e. with the glider
actually stalling on. More likely it's "held off until the glider is in
the same attitude it will have on the ground .. or a tiny bit more" and
then allowed to settle in that attitude. As it slows, lift at that AoA
becomes insufficient to support the glider, but there is never
aerodynamic stall. Maximum AoA / CL is not reached. Once you touch the
ground AoA can not be increased, so lift can't be, so you can't start
flying again (absent a massive headwind gust) and the *objectives* of a
"fully held off" landing are acheived.

Even nose-draggers like the ASK21 have a tail wheel and are landed
main-and-tail or slightly tail first.

The only exception I know is the PW5. I've never seen anyone land a PW5
tail first. We had an informal challenge to do it when we first got
ours. No one managed it.

Good description. I've never flown a PW6, but I have flown a PW5 and
suppose its also near impossible to fully hold off. Of course fully held
off landings work a treat for ASK-13s and T-21s: both have a nose skid.

In my experience my Std Libelle is the hardest glider to hold off for a
nice two-point landing, primarily because the weak airbrakes mean that if
you start raising the nose even slightly early it will balloon, but its
always a nice end to a flight when both wheels touch the floor together.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Saturday, February 25, 2017 at 4:04:02 PM UTC-5, Jonathan St. Cloud wrote:
Do you crab or forward slip landing in x-winds and why? . .

I teach both (a requirement of the FAA Pilot Test Standard), but recommend and almost always use a slip (in the US, that'd be the oxymoronically labelled "side slip", not a "forward slip") in moderate crosswinds. If the xwind is too strong, I switch to as much of a slip as is comfortable to avoid wingtips dinging the runway, then crab.

These procedures are more important on paved runways than grass, because the side loads on the gear with even a slightly botched crabbed landing on pavement can cause significant damage.

As to "why", it's because the properly executed "side slip" permits a stabilized approach that continues right down into the flare (easier to teach as well), and reduces the risk of side loads on the landing gear.

Finally, when the issue of ground loops, grass vs. pavement, or off-airport landings is raised, then the answer changes to "it depends", and the pilot should be skilled in using whatever procedure fits the circumstances.

This thread is more interesting that I would have guessed. I thought standard practice was to teach both. That's what we did when I was a student pilot. Crabbing was emphasized as the better technique for managing larger cross winds (and we students figured it out, just fine).

It's obvious to any pilot proficient with both slips and crabbing approaches that the cross wind limits of the crabbing approach are vastly higher than what you can manage with slipping alone. About 50%, I'd reckon.

see also: Peter Schiff, The Proficient Pilot.

best,
Evan Ludeman / T8