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Avoiding Being Blow...
 

Avoiding Being Blown Back  

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Wayne
(@wayne)
Committee

A while ago, I went through the BHPA incident reports for DSC sites. Being blown back over the Lord's \ Rushup ridge was one of the most common occurrences.

The rotor on the downwind side of the ridge can be severe - not a place you want to end up.

This article discusses strategies for avoiding this.

Fly Safe
SO 

http://skynomad.com/articles/ridge_soaring.htm

This topic was modified 6 months ago by Wayne
Quote
Posted : 01/09/2020 09:08
Andymac64 liked
Andymac64
(@andymac64)
Committee

A great article, all great tools to keep everyone safe. 

ReplyQuote
Posted : 01/09/2020 14:51
Hudson
(@Hudson)
Committee

Windier it is further forward you fly. This gives you options. Steve

ReplyQuote
Posted : 01/09/2020 18:34
Wayne liked
Chris Dervin - New Members Officer
(@chrisd)
Committee

Good article, I can see a few more useful replies and comments of FB, pity they will be lost and not contribute to this thread. Might be an idea when posting good articles to ask remind those commenting on FB to copy their thoughts here.

ReplyQuote
Posted : 01/09/2020 18:56
Chris Dervin - New Members Officer
(@chrisd)
Committee

This was Ross's incident last year, kept pushing into wind and getting into increasingly strong compression rather than bearing off right which would have taken him away from hill and worst of compression. https://youtu.be/8u13VykYj1g

Again lots of good comments were made and lost on FB but Squirty Bob nailed it - 

Hi Ross, i was flying the Artik 5 infront of you on the vid. seeing as everyone is chucking the advice out here is my 2p worth. hope it helps. The wind had picked up to over 20 mph as you arrived at the point where you put your bar on and there was some turbulence being thrown off the shoulder on the far end of Lords or maybe just rattling up the hill. hence the full bar / collapse. I had just seen 

Noe Muñoz

 making friends with the wall and turned back to check he was on his feet and Ok. I didnt see your collapse as I was looking at Noe. The line you were flying is the "usual" line pilots fly to get the boost that takes you above ridge height and over the top of Lords. Because the wind was stronger than forecast You need to start thinking of changing your line so head into wind and away from the compression.When you first put your bar on you could have turned back towards Mam and pushed out as other people have said. be aware that the other wings infront of you were higher performance and further out into the valley. well done for posting vid and glad there were no injuries. as a general rule if things start to get dodgy go back to where they wernt. 🤪👍

ReplyQuote
Posted : 01/09/2020 19:06
Chris Dervin - New Members Officer
(@chrisd)
Committee

I too had been flying that day but pushed out into the valley well before the strong area of compression. Might be useful if you see less experienced pilots moving into danger zones to give a general warning on radio.

ReplyQuote
Posted : 01/09/2020 19:10
moyesboy
(@moyesboy)
Club Member

Think of the hill as the top surface of a wing.
All the wind tries to get from A to B, but the stuff that finds the ridge in the way has to make a detour over the hill. To keep up with the rest it goes faster.
So 10 mph of wind.
45 degree slope.
Wind going up the slope has to go 14.142 mph to keep up.
At doesn't actually manage that so it carries on going faster for some distance after it reached the crest of the hill.
Now you can penetrate into 15mph, but you so have a sink rate of 2 mph.
So while you are in the lift the sink rate is adding to your speed into the angled wind. The horizontal wind is still 10mph.
Now you drop back over the summit and you have up to 14mph horizontal, and your sink rate does nothing to help. So you only have 1mph of penetration left, and it looks very iffy.

A little way up wind you are in the rising air, and your sink rate adds to your penetration.

Further up wind you are in the prevailing horizontal wind and can still penetrate the same.

ReplyQuote
Posted : 03/09/2020 14:43
Ross Mason
(@ross-mason)
Club Member

Here is a link to the Facebook discussion of my incident: https://www.facebook.com/groups/238819502809825/permalink/2642496072442144

Agree with Squirty Bobs assessment of the technicalities of my incident. Gordon also posted a really nice description of how the wind would roll along the face as it was fairly far off: 

What happened to the other guy behind the wall?
You are close in, wind off to west, close to the highest point of the spine but still below it... Probably something spilled off the top and grabbed you. Rotor. As the wind gets more along the ridge it starts to roll along the face. I notice this when I start to get tipped into the ridge as well as tipped out by the lift... Happens at about 30 degrees wind. 60 degrees off...
There were a few other gems in the thread including from Ash and Mike so it is worth taking the time to read it.

I often see the "technicalities" of incidents discussed though and very rarely the human factors and often think the human factors have at least an equal part to play.

 
Given time to digest what went off on the day I would say a significant factor was my mind was elsewhere. I had some new heated gloves, and I knew they were bulky and effected my ability to grasp my risers and control the wing. On launch I had noted how windy it was and had moved further away from the crowd so if I did get dragged I would not be being dragged into anybody else. I had also rushed out from a stressful day at work. 

My mind was 90% consumed with my new bit of kit and not getting dragged because I couldn't grasp the risers as I wanted. 

 
It should have been obvious to me that the "usual" route along the ridge wasn't the best plan. There were plenty of gliders going up in the center of the valley and the wind was fairly far off. However, I failed to take in the conditions and make a suitable flight plan. Because I didn't think about a flight plan I reverted to the usual flight plan on Lords. This was huge mistake and I was very lucky not to pay a heavy price.   
 
Having had this experience I decided to change some things that I think others could easily take on board so they don't get caught out in the same way: 
 
1) I try and spend more time soaking up the conditions before launching.
 
2) I note clearly when things are marginal or more risky than usual and pay more attention to 1) 
 
3) I am aware of how being at work and feeling like I am missing out can effect me and how it makes me want to rush to the site and get straight in the air. If I find myself in this situation. I make sure I am aware of it and I either make sure I slow down when I get to the site. Alternatively if it will be too much of a rush or it has been a particularly stressful day at work and my mind is elsewhere I make the conscious decision to leave it in the bag for another day.
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Posted : 03/09/2020 21:23
Wayne liked
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