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Old February 27th 17, 03:24 PM posted to rec.aviation.soaring
Matt Herron Jr.
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Default 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?