Do you crab or forward slip in X wind landings

On Sunday, February 26, 2017 at 11:43:08 PM UTC-8, POPS wrote:
Yaw string and coordination in big Xwind landings is my question, with
a real life experience that happened to me... I still wonder if I did
the right thing 3 years ago. Could someone in the know talk about the
lack of any coordination in these situations?

After returning to the field at 3500' agl, the wind had turned on
final, 90 degrees to the left across the only possible place to land,
on a plowed dirt strip. AWOS had the wind solid at 20 gusting to 28. I
lingered as long as I could but the massive cell to the east was not
moving or letting up. Nothing but rough desert landscape everywhere and
altitude winding down.

Field partially disappearing in dust at 800 ft. I set speed at 70 kts,
turned base into the wind, then final and into a deep forward slip,
windward wing down, way down, but not quite holding my target from
drifting away from me to windward. The yaw string was aligned nearly 70
degrees across the canopy which Really got me alarmed. I was calm,
pretty smooth and super focused. Out of the slip and into a huge crap,
no problem. Yaw string was now about 30-40 degrees out with my wings
level crab at maybe 30 degrees to the left. Had control of my target
now with partial spoilers. Field length maybe 500 yards long or so. I
went to the deck and released rudder and flared, lowered my left wing
tip a bit I think. Did a wheel landing at maybe 40, full spoilers and
into breaks as the field seemed to be getting short. Wind got under my
left wing and put the leeward wing down into the dirt at 15+ kts or so
on the roll out. Lost the wing tip skid but held it mostly straight with
my big rudder.
I heard conflicting advice and comments about coordination and this
landing.
Sorry for the long post.





'Martin Gregorie[_5_ Wrote:
;939235']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 |




--
POPS

if your yaw string was out 30-40 degrees, you were either turning uncoordinated with rudder only, or if you were not turning, you had some opposite aileron in, which would mean you were still slipping.

other than that, sounds about right. perhaps after you touched down, using your big rudder you could have maintained your heading and held your upwind wing down a bit to prevent the ground loop?

Sounds like you did a good job!

Don't be so concerned about uncoordinated flight so long as you keep
your airspeed up sufficiently that any gust won't cause a stall and,
should it happen, always be prepared to dump the nose (reduce angle of
attack significantly). And there's no reason not to land perpendicular
to the furrows in a plowed field. Sure, it'll be rough, but plowed dirt
is soft and you'll slow quickly. You'll also have a very low ground
speed given the wind.

Dan

On 2/26/2017 11:47 PM, POPS wrote:
Yaw string and coordination in big Xwind landings is my question, with
a real life experience that happened to me... I still wonder if I did
the right thing 3 years ago. Could someone in the know talk about the
lack of any coordination in these situations?

After returning to the field at 3500' agl, the wind had turned on
final, 90 degrees to the left across the only possible place to land,
on a plowed dirt strip. AWOS had the wind solid at 20 gusting to 28. I
lingered as long as I could but the massive cell to the east was not
moving or letting up. Nothing but rough desert landscape everywhere and
altitude winding down.

Field partially disappearing in dust at 800 ft. I set speed at 70 kts,
turned base into the wind, then final and into a deep forward slip,
windward wing down, way down, but not quite holding my target from
drifting away from me to windward. The yaw string was aligned nearly 70
degrees across the canopy which Really got me alarmed. I was calm,
pretty smooth and super focused. Out of the slip and into a huge crap,
no problem. Yaw string was now about 30-40 degrees out with my wings
level crab at maybe 30 degrees to the left. Had control of my target
now with partial spoilers. Field length maybe 500 yards long or so. I
went to the deck and released rudder and flared, lowered my left wing
tip a bit I think. Did a wheel landing at maybe 40, full spoilers and
into breaks as the field seemed to be getting short. Wind got under my
left wing and put the leeward wing down into the dirt at 15+ kts or so
on the roll out. Lost the wing tip skid but held it mostly straight with
my big rudder.
I heard conflicting advice and comments about coordination and this
landing.
Sorry for the long post.





'Martin Gregorie[_5_ Wrote:
;939235']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 |




--
Dan, 5J

And there's no reason not to land perpendicular
to the furrows in a plowed field. Sure, it'll be rough, but plowed
dirt
is soft and you'll slow quickly. You'll also have a very low ground
speed given the wind.

Dan

That is unless you happen to be flying out of Rieti in Italy.. They
use D-8 bulldozers to pull the plows through hardened clay, leaving
plowed up solid chunks about 1 foot across. The plowed fields
there were an absolute nightmare during the 1985 WGC. Loads of
off-field landing damages..

You have to know the nature of the countryside which you are flying
over.. If it's a fresh-plowed field in an area where there is some
moisture in the ground, then maybe it might work. If the area is
more arid, or if it isn't fresh plowed and has been left to sit and
harden, you will likely rip the gear off your glider - at the least....

Better to look at the edges of the field if it's large enough. There
may be furrows oriented into the wind there where the tractors
have had to change direction. Good examples are the crop circles
in the USA. They uses a circular irrigation rig, but the corners of
those fields are generally plowed straight, and are long enough for
a glider to land on.
You can also select the corner which provides the best landing
direction related to the wind...

It's always best to not be forced into only one land-out option where
you don't have a choice with crosswinds, etc. You have to make
those decisions earlier in the courses you select and the altitude
minimums which you decide that you can live with....

RO

On Monday, February 27, 2017 at 2:43:08 AM UTC-5, POPS wrote:
Yaw string and coordination in big Xwind landings is my question, with
a real life experience that happened to me... I still wonder if I did
the right thing 3 years ago. Could someone in the know talk about the
lack of any coordination in these situations?

After returning to the field at 3500' agl, the wind had turned on
final, 90 degrees to the left across the only possible place to land,
on a plowed dirt strip. AWOS had the wind solid at 20 gusting to 28. I
lingered as long as I could but the massive cell to the east was not
moving or letting up. Nothing but rough desert landscape everywhere and
altitude winding down.

Field partially disappearing in dust at 800 ft. I set speed at 70 kts,
turned base into the wind, then final and into a deep forward slip,
windward wing down, way down, but not quite holding my target from
drifting away from me to windward. The yaw string was aligned nearly 70
degrees across the canopy which Really got me alarmed. I was calm,
pretty smooth and super focused. Out of the slip and into a huge crap,
no problem. Yaw string was now about 30-40 degrees out with my wings
level crab at maybe 30 degrees to the left. Had control of my target
now with partial spoilers. Field length maybe 500 yards long or so. I
went to the deck and released rudder and flared, lowered my left wing
tip a bit I think. Did a wheel landing at maybe 40, full spoilers and
into breaks as the field seemed to be getting short. Wind got under my
left wing and put the leeward wing down into the dirt at 15+ kts or so
on the roll out. Lost the wing tip skid but held it mostly straight with
my big rudder.
I heard conflicting advice and comments about coordination and this
landing.
Sorry for the long post.

--
POPS

"Released rudder and flared" doesn't make sense.

The crab maneuver should be coordinated as previously mentioned. Rudder neutral, string centered.

The flare and landing is what isn't coordinated. Downwind rudder. Aileron into the wind as required to keep that upwind wing as low as you can.

best,
Evan Ludeman / T8

You're right, 'released rudder' doesn't make sense, I meant released the extreme crab angle returning to straight ahead alignment just before flairing. The yaw string never was straight during my 300 yard crabbing final approach. It was extremely windy with the wind 90 degrees across final approach. I was flying straight, not turning, wings level. I did get into full right rudder after touch down too, after being prompted 2 quick times by some mystery quest over the radio!

Dan M said not to worry about coordination in this configuration as long as you keep plenty of air speed, which was my though during this 60 second thrill ride as well.

Thanks for the input. Any additional comments concerning lack of coordination while on final due to big cross wind landing are welcomed.

Originally Posted by Tango Eight

On Monday, February 27, 2017 at 2:43:08 AM UTC-5, POPS wrote:
Yaw string and coordination in big Xwind landings is my question, with
a real life experience that happened to me... I still wonder if I did
the right thing 3 years ago. Could someone in the know talk about the
lack of any coordination in these situations?

After returning to the field at 3500' agl, the wind had turned on
final, 90 degrees to the left across the only possible place to land,
on a plowed dirt strip. AWOS had the wind solid at 20 gusting to 28. I
lingered as long as I could but the massive cell to the east was not
moving or letting up. Nothing but rough desert landscape everywhere and
altitude winding down.

Field partially disappearing in dust at 800 ft. I set speed at 70 kts,
turned base into the wind, then final and into a deep forward slip,
windward wing down, way down, but not quite holding my target from
drifting away from me to windward. The yaw string was aligned nearly 70
degrees across the canopy which Really got me alarmed. I was calm,
pretty smooth and super focused. Out of the slip and into a huge crap,
no problem. Yaw string was now about 30-40 degrees out with my wings
level crab at maybe 30 degrees to the left. Had control of my target
now with partial spoilers. Field length maybe 500 yards long or so. I
went to the deck and released rudder and flared, lowered my left wing
tip a bit I think. Did a wheel landing at maybe 40, full spoilers and
into breaks as the field seemed to be getting short. Wind got under my
left wing and put the leeward wing down into the dirt at 15+ kts or so
on the roll out. Lost the wing tip skid but held it mostly straight with
my big rudder.
I heard conflicting advice and comments about coordination and this
landing.
Sorry for the long post.

--
POPS

"Released rudder and flared" doesn't make sense.

The crab maneuver should be coordinated as previously mentioned. Rudder neutral, string centered.

The flare and landing is what isn't coordinated. Downwind rudder. Aileron into the wind as required to keep that upwind wing as low as you can.

best,
Evan Ludeman / T8

Well, since you asked... Consider landing diagonally or even
perpendicular (in the extreme) to the runway. Let field and weather
conditions help with the decision. Just don't be hobbled by what you
learned in training since that was conducted during favorable weather.
If you're going to fly in weather that wouldn't be allowed for a solo
student, be prepared to do whatever it takes to land safely.

And have fun!

Dan

On 2/27/2017 9:11 PM, POPS wrote:
You're right, 'released rudder' doesn't make sense, I meant released the
extreme crab angle returning to straight ahead alignment just before
flairing. The yaw string never was straight during my 300 yard crabbing
final approach. It was extremely windy with the wind 90 degrees across
final approach. I was flying straight, not turning, wings level. I did
get into full right rudder after touch down too, after being prompted 2
quick times by some mystery quest over the radio!

Dan M said not to worry about coordination in this configuration as long
as you keep plenty of air speed, which was my though during this 60
second thrill ride as well.

Thanks for the input. Any additional comments concerning lack of
coordination while on final due to big cross wind landing are welcomed.




Tango Eight;939442 Wrote:
On Monday, February 27, 2017 at 2:43:08 AM UTC-5, POPS wrote:-
Yaw string and coordination in big Xwind landings is my question,
with
a real life experience that happened to me... I still wonder if I did
the right thing 3 years ago. Could someone in the know talk about the
lack of any coordination in these situations?

After returning to the field at 3500' agl, the wind had turned on
final, 90 degrees to the left across the only possible place to land,
on a plowed dirt strip. AWOS had the wind solid at 20 gusting to 28.
I
lingered as long as I could but the massive cell to the east was not
moving or letting up. Nothing but rough desert landscape everywhere
and
altitude winding down.

Field partially disappearing in dust at 800 ft. I set speed at 70 kts,

turned base into the wind, then final and into a deep forward slip,
windward wing down, way down, but not quite holding my target from
drifting away from me to windward. The yaw string was aligned nearly
70
degrees across the canopy which Really got me alarmed. I was calm,
pretty smooth and super focused. Out of the slip and into a huge
crap,
no problem. Yaw string was now about 30-40 degrees out with my wings
level crab at maybe 30 degrees to the left. Had control of my target
now with partial spoilers. Field length maybe 500 yards long or so.
I
went to the deck and released rudder and flared, lowered my left wing
tip a bit I think. Did a wheel landing at maybe 40, full spoilers and
into breaks as the field seemed to be getting short. Wind got under
my
left wing and put the leeward wing down into the dirt at 15+ kts or so
on the roll out. Lost the wing tip skid but held it mostly straight
with
my big rudder.
I heard conflicting advice and comments about coordination and this
landing.
Sorry for the long post.-
-
--
POPS-

"Released rudder and flared" doesn't make sense.

The crab maneuver should be coordinated as previously mentioned. Rudder
neutral, string centered.

The flare and landing is what isn't coordinated. Downwind rudder.
Aileron into the wind as required to keep that upwind wing as low as you
can.

best,
Evan Ludeman / T8




--
Dan, 5J

On Saturday, February 25, 2017 at 1:04:02 PM UTC-8, 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.

Wouldn't that be a "side slip" since the glider's fuselage is aligned with the runway (hopefully) while the windward wing is a little low?

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? 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.

I have found over the years that students have a much easier time dealing with cross wind using the slip method.
The aiming point does not change. They look right over the nose as usual.
They do not have to try to kick out a crab and move to a wing low attitude while trying to time the round out to a low energy landing.
Obviously they nee to be aware of their bank angle near the ground but the reduced drift down low seems to take care of that.
UH

I always use the slip method. Since the Stemme has conventional gear, I
land on the upwind main and the tail wheel simultaneously (if I did it
right) and, as speed bleeds off, the downwind wheel comes down. The
fuselage remains aligned with the runway the whole time.

On 2/25/2017 5:13 PM, wrote:
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? 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.
I have found over the years that students have a much easier time dealing with cross wind using the slip method.
The aiming point does not change. They look right over the nose as usual.
They do not have to try to kick out a crab and move to a wing low attitude while trying to time the round out to a low energy landing.
Obviously they nee to be aware of their bank angle near the ground but the reduced drift down low seems to take care of that.
UH

--
Dan, 5J

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.