No one can tell me
Nobody knows Where the wind comes from
Where the wind goes Wait, what? A good pilot knows where the wind
comes from. Always! Otherwise he’s going to end up stuffed in the wrong end of a windsock.
Let’s talk about this folks, this is fundamental to flight. Of course you want the wind to be coming straight up on the slope you’re going to be flying
on. Everybody knows that. It’s simple with a windsock. Just pop it up, and you get a
good idea of what the wind direction is doing. If you move slowly so that you get to the
point that you can see down the windsock, you are looking straight into wind.
Hiya! Guys are having fun. But what if you don’t have a windsock? Can
you tell what way the wind is blowing? Of course you can; very easy. If you just turn
your head. Now I’m turning it off to the side – and I’m turning it to the other
side – I can hear the wind noise in my ears. And when I can hear wind noise in both ears
at the same volume I’m looking straight into wind.
So, I’ll prove that to you. Wind direction is there! Am I right? Course I am!
So you can tell where the wind is blowing. Once you’ve established that line,
you know that the wind in this whole area is going to be blowing in the same direction.
The wind can’t be coming from over there and over there at the same time. It’s all
going to line up. If you imagine it’s like a river and everything is moving the way I’m
walking now. So the wind on that side and the wind on that side, everything is coming
in straight lines onto this ridge. So that’s pretty simple. Everybody gets that idea don’t
they? You know that. I know that. Is it really the
same in the air? And how can you tell what the wind direction is, when you’re flying.
Let’s go up and have a look. OK, so you know how this trick works: I’m
pointing straight into wind now, because I’m looking straight down the windsock. But what’s
happening down there? You see the windsock? Which way is the wind blowing? So the wind
is blowing this way for me here. Hang on a minute! What’s going on there?
Maybe if I slow down it will help. Nope, still pointing into wind. That’s odd. Let’s
do a turn. Hang on a minute, now the wind’s coming from this side! And look at the windsock
down there. The wind’s from there. No it’s from here. No it’s from there. Hang on a
minute. What’s going on there? So of course when you’re flying the paraglider
through the air you will feel a wind in your face because you’re moving through the air.
You will always be pointing into wind, the relative wind. So your wing will always be
flying forwards, your pod is kind of at right angles to your wing, hopefully, so your feet
will be pointing out straight into wind all the time. If you’re not feeling this wind
coming straight into your face, you need to put your hands up because you’re stalling
your wing. It should be flying round about 40 kilometres
an hour, between 30 and 40 depending on your brake input. But you can see, I’m always
pointing into wind. But the real wind, is blowing from the side, over there. Now to
be able to be going along this ridge I can’t fly straight along it because that wind will
push me over, so you can see I’m sitting at a slight angle, and that angle changes
depending on how strong the wind is. If the wind is really strong, I’m going to have
to sit pointing out to sea much more. Now something’s happening, I’ve got a
bit higher, now I’m doing exactly the same pass as I was doing before, what’s happened?
Well the wind must have got stronger. If you look at the windsock down there, it’s a
little stiffer, and that’s giving me more lift, so immediately I know the wind’s increasing,
the wind direction has stayed the same, the wind speed has increased a bit.
And I can tell how strong the wind is by how much I’m angling off the ridge to keep a
straight line. And if you find you’re angling more off the ridge, the wind has increased.
Right, so now I’ve settled into a nice straight soaring line, I’m not doing anything on
the brakes, and you can see, I want to fly there, but I’m pointing there, which means
the wind is coming from the left, and somewhere in between the two I’ve found a balance
point. As the wind increases, I’m going to have
to turn more out, and I’m going to go up. As the wind drops, I’m going to be lower
and needing to fly more along the cliff line. I better have this right or I’m going to
end up in the sea. Now if the wind was really blowing from over there, there would be no
lift along this ridge, the wind would just be blowing along and it would be full of turbulence.
Obviously it’s not blowing that way, because look, it can’t be blowing that way and be
blowing this way at the same time. So this windsock has nothing to do with the airflow
over the landscape. This is my little windsock, and I’m causing this wind.
Now the way to get higher on this ridge is to find the piece of ridge where the wind
is getting scooped up the most, and it will usually be perpendicular to the wind direction.
So I’m moving through the air here at 37 kilometres an hour, forwards, and that one
over there is blowing about 20. If I turn this way, the speeds are combined: you can
see I come past really quickly. So you’ve got to be really careful of going
downwind towards the ground. So now you can see the wind has dropped, because I’m lower,
and I’m having to point more along the cliff to keep my line. I’m just moving out now
because there’s a pilot approaching. I’m giving him lots of space so I don’t wake
him on the ridge. Then I can come back in again. But you can
see the wind is a bit lighter because now I’ve got a straighter line. I’m not having
to angle out so much so the wind isn’t pushing me so much.
It’s getting lighter now: I’ve got to be more careful now that I hug the ridge.
Try and use the last little bit of lift here. There’s a nice bit of lift in that bowl.
Now he’s turning there, so I’m going to use this opportunity to come in and use this
bit of lift here. Now this bowl is working better because the wind is coming in more
right angles to the ridge, which gives me more boost.
Don’t worry if this concept is doing your head in, it does everyone’s head in at the
beginning, because you think you’ve got it, and then you realise you haven’t got
it. The relative airspeed, the ‘wind of the paraglider’, and the real wind that
you are flying through: the combination of those two gives you your track over the ground.
Once you’ve been flying for a little bit, you also start building up a feeling for how
fast you’re going over the ground, and what’s normal. So just by looking over the edge here
and watching my shadow going over the ground, I can tell I am going slightly downwind. I’m
used to my speed and that’s a little bit more than my trim speed. So I know the wind
is coming in from behind me. And that’s very useful when you’re coming
in to land and you’re trying to work out which way the wind is. It’s just that appreciation
of your speed over the ground. If it looks scary fast on the ground, you’re going downwind.
If it looks comfy cosy, you can put your feet down, you’re pointing into wind. So now,
comparing that shadow speed, I’m now pointing into wind.
And that’s a more acceptable landing speed for me, that I’d be happy running the speed
off. So we’re coming up to approaching the windsock
again. Just look at that. My wind, and the real wind.
Now what’s important, is where does the wind come from? It’s only now that these two windsocks are going to match, when I’m stationary on the
ground. Otherwise, this windsock, the white one, is
totally independent to the red one. I hope that gives you a clearer idea of the
difference between your airspeed and the real wind that’s on the ground. Your airspeed
is going to create a relative wind, you’re going to feel that all the time, it’s always
blowing straight at your nose, if it’s not, you’re doing something wrong with your wing.
It doesn’t matter whether you’re pointing downwind, upwind, crosswind, sidewind, your
ground speed is just going to change, you won’t feel it. You can’t feel the difference
when you swing around and turn into wind. So try and remember that those two things
are separate, your airspeed, and the wind on the ground, and when you combine the two
vectors, you get a resultant vector which is your speed over the ground, and that will
be affected depending on which way you’re pointing. But you won’t feel any difference.
So I hope that helps you clear up one of the very difficult concepts in flying. And if
you’re flying, and you’ve been flying away and you don’t know what the wind is
doing, fly in one direction, look at your ground speed, and do a 90 degree turn, and
as soon as you do the 90 degree turn you’ll be able to see which way you’re drifting,
and that will tell you which way the wind is coming from. From that you turn into wind,
you can see where your ground speed is slowest, and that’s when you know you’re pointing
directly into wind, and that will help you with your landing setup.
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