What to do when the...

What to do when the wind gets too much  

Club Member

What to do when the wind gets strong.
My glider will go up to 85 mph, and has a really good sink rate at 50mph, but I don't fly it in winds much over 30mph. Why is that?
Drag increases with the square of airspeed, because of that turbulence also increases with the square of wind speed.
Put it this way, what is a bit bumpy in 10mph of wind, will be 4 times bumpier in 20mph of wind.
This means that there are very few places I can land safely in over 30mph of wind.
As you start to fly faster canopies, and are willing to fly in stronger winds then you must take extreme care about where you plan to land. Bumps that make you feel uncomfortable in 10 mph, probably mean losing control in 20mph.
Double the wind is 4 times the problem.
You need to be much further down wind of stuff that makes turbulence as the wind gets stronger. Places that you normally think of as safe and smooth may not be safe at your new higher top wind speed.
What exacerbates the problem is that as wind increases, then the area you can get to easily reduces, except downwind. But on many sites, particularly our club sites, down wind is not an option unless you have considerable altitude!
There are a number of places picked out as safe escapes in strong wind for our sites.
At Stanage sliding along and onto the area behind the hang gliding launch is the best option but must be done before you end up too low...
At Bradwell over the back east of the gliding club, there is a place where the footpath crosses the main Abney road, and there is a bench seat. There is good and smooth in 35-40mph, but obviously needs a fair altitude to reach. It's the wrong side of the Abney road closure currently, but the footpath goes straight back to takeoff.
At Lords Seat as well as Rowter Farm there is an option where the footpaths and green lane come out onto the road to chapel at the west end, where Rushup has flattened into a plateau ( a field we tried to negotiate many years ago but its use is shared between many farmers). This is good in strong winds. It might also be an option in southerlies that turn east and become too strong.
Rowter farm by the way has more landable fields going south along the gravel road, that road goes on and on and the gates are not locked and it's passable in any car. There is quite a networkof gravel roads in that area passable for quarry trucks.
When the wind is 20mph or more the last concern, of course, is where your car is. The most important thing is finding smooth air to land in.
Many years ago we would fly our hang gliders in 30+mph winds and feel pinned at times and start trading altitude for penetration. We found the limits then and our faster gliders mean we now have a huge safety margin for wind speed in terms of going into wind, but the limits on our control are much the same, so our upper wind speed limit is more or less the same.

I should add, obstacles unwind shed vortices that spill off and travel down wind. They vary in size and frequency and occasionally there is a bigger more violent one.... they diminish and smooth out and eventually die away. What this means is if you are a bit close to the thing that makes it rough, you might well have a nice smooth landing. But it's a game of chance, and it might eventually hit you with a big one. So you must play safe and make your judgement. If you think it would be iffy in one landing place, but you see someone have a nice landing there, they might have been lucky, you landing there in the past might have been lucky.
It is worth walking these places and feeling the wind there. You can feel.the gustiness and the sudden calms,.or even wind reversals when the rotor comes. Go and have a walk about when it's a bit too windy and you are waiting for it to drop.

This was a Facebook post parts of which have already been posted here on the Rowter farm landing post. But here it is in its entirety.

Posted : 29/08/2020 11:44

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