Crosswinds & Obstacles are a funny thing

"Kyle Boatright" wrote in
news
I'm always puzzled by the impact obstacles (trees, buildings, etc)
have on a crosswind.

On the day ten years ago when I earned my tailwheel endorsement, there
was a 15 knot direct crosswind above the treeline. But, the field was
buried in a small gap between 75' trees and the crosswind effectively
disappeared once the airplane descended below the trees. Even better,
there was no turbulence. I'm still surprised at how easy it was to
land in those conditions.

As opposed to yesterday, when I was landing at a nearby field in a 10
knot, 60 degree crosswind. There was a row of 50' trees a hundred and
fifty feet upwind of the runway, and those trees (presumably) created
a nasty burble at groundlevel.

Because of my widely varied experience with obstacles interacting with
crosswinds, I struggle to pick the *best* runway or landing spot. Is
it better to bet on an obstacle reducing the crosswind, or is that
obstacle likely to cause a burble that will result in a rotten (or
exciting) landing? I'm still trying to crack the code on this one...



Depends, and it's hard to predict. I know of an airport that spend tens of
thousands on determining whether a new hangar would have a detrimental
effect on a nearby runway threshold. Wind tunnel tests, slide ules. they
built it and it's a nasty approach when the wind is coming that way.


Don't think so much. Do what needs to be done as it needs to be done.
Period.

Bertie

Kyle Boatright wrote:
I'm always puzzled by the impact obstacles (trees, buildings, etc) have on a
crosswind.

On the day ten years ago when I earned my tailwheel endorsement, there was a
15 knot direct crosswind above the treeline. But, the field was buried in a
small gap between 75' trees and the crosswind effectively disappeared once
the airplane descended below the trees. Even better, there was no
turbulence. I'm still surprised at how easy it was to land in those
conditions.

As opposed to yesterday, when I was landing at a nearby field in a 10 knot,
60 degree crosswind. There was a row of 50' trees a hundred and fifty feet
upwind of the runway, and those trees (presumably) created a nasty burble at
groundlevel.

Because of my widely varied experience with obstacles interacting with
crosswinds, I struggle to pick the *best* runway or landing spot. Is it
better to bet on an obstacle reducing the crosswind, or is that obstacle
likely to cause a burble that will result in a rotten (or exciting) landing?
I'm still trying to crack the code on this one...

Thoughts?

KB

When the winds are just right, the 4 windsocks at my home airport
will be pointing in 4 different directions and there will be an
updraft about half way down the runway.

Trying to guess where the wind is blowing at any given point at any
given time is an exercise in futility.

The center line on the runway is there for a reason.

--
Jim Pennino

Remove .spam.sux to reply.

Interesting runway environment... no trees.. but when the cross winds get
nasty here we get mechanical turbulence on final from the multi story hotel
about 1/2 mile to the offset to final.. clear that and the burble goes away
and just deal with the decreasing performance crosswind as you get closer to
the ground.
BUT !!
The runway is slightly elevated above the drainage ditch between the two
runways.. more of an easy swale than a ditch.. and the low level breeze can
create "ridge lift" in glider pilot language.. as it comes up the swale to
the runway.. low level lift right over the runway.. and you find yourself
with the power back.. wing low crosswind approach and "soaring in ridge lift
and climbing".. with the tire looking at the terra firma only mere inches
below.

The "code to be cracked"?
NEVER EVER stop flying the airplane.. tail wheel or nose tragger.. until it
is in the chocks and chained.

I experienced the same "tree line cross wind shear" when I first learned
taildraggin in a J3 more than 25yrs ago on a grassy runway just off the
beach in New Hampshire.
BT

"Kyle Boatright" wrote in message
news
I'm always puzzled by the impact obstacles (trees, buildings, etc) have on
a crosswind.

On the day ten years ago when I earned my tailwheel endorsement, there was
a 15 knot direct crosswind above the treeline. But, the field was buried
in a small gap between 75' trees and the crosswind effectively disappeared
once the airplane descended below the trees. Even better, there was no
turbulence. I'm still surprised at how easy it was to land in those
conditions.

As opposed to yesterday, when I was landing at a nearby field in a 10
knot, 60 degree crosswind. There was a row of 50' trees a hundred and
fifty feet upwind of the runway, and those trees (presumably) created a
nasty burble at groundlevel.

Because of my widely varied experience with obstacles interacting with
crosswinds, I struggle to pick the *best* runway or landing spot. Is it
better to bet on an obstacle reducing the crosswind, or is that obstacle
likely to cause a burble that will result in a rotten (or exciting)
landing? I'm still trying to crack the code on this one...

Thoughts?

KB

Kyle Boatright wrote:
I'm always puzzled by the impact obstacles (trees, buildings, etc) have on a
crosswind.

... [TRIMMED for Montblack] :-)

Thoughts?

KB


Landing the airplane is a coincidence of the approach, remember that
one? Always be prepared to go around or missed as the case may be. Lots
and lots of easy, loose corrections. Fly the center line and dance,
dance with the wind. I always think of it like when I finally learned to
ski the bumps, the bumps are your friend, work with the bumps. Likewise
with the wind, the wind is your partner, fly with the wind.

Did something yesterday I haven't done since PPL training. I went
around. Flying into Bar Harbor 22 short final, got below the tree line
and she sank like a rock. Rather than fight it and muscle it onto the
runway, power up, level off, and climb. I probably could have saved the
landing, but it was good to have the quick ADM process fire and make a
safe choice.

KC

("Kevin Clarke" wrote)
... [TRIMMED for Montblack] :-)


Mmm.... and all the trimmings. Just for me.

Thank you.


Montblack