Wind Factor for Flying Hills

Discussion about ski jumping.
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doubleffect
Posts: 52
Joined: 08 Mar 2009, 06:56
Location: Poland

Wind Factor for Flying Hills

Post by doubleffect »

I can't figure out how to count points for wind conditions on Flying Hills. The formula given out by FIS here is wrong.

It should be:

pts = wind * [(HS - 36)/20] * 1.8 for large hills

It worked for large hill in Klingenthal at least.

First let's look at this large hills parameters. They're here in a .pdf file.

According to that file::

HS = 140 m
Wind Factor = 9.36 Points per m/s

Let's try to check if the official FIS formula corrected by me really works. To get Wind Factor we just have to assume a wind of 1 m/s.

Wind Factor = wind * [(HS - 36)/20] * 1.8
Wind Factor = 1.0 * [(140 - 36)/20] * 1.8
Wind Factor = 1.0 * [104/20] * 1.8
Wind Factor = 1.0 * 5.2 * 1.8
Wind Factor = 9.36

It's alright here. Let's check one more hill to be sure. Let it be the large hill in Zakopane. I got parameters from this .pdf file.

HS = 134 m
Wind Factor = 8.82 Points per m/s

Wind Factor = wind * [(HS - 36)/20] * 1.8
Wind Factor = 1.0 * [(134 - 36)/20] * 1.8
Wind Factor = 1.0 * [98/20] * 1.8
Wind Factor = 1.0 * 4.9 * 1.8
Wind Factor = 8.82

OK. Now let's use this formula for a flying hill. Let it be the flying hill in Harrachov. I'll use a .pdf file from FIS website with results from the first competition in Harrachov for parameters. We just have to replace 1.8 multiplier with 1.2 multiplier as it's a flying hill.

HS = 205 m
Wind Factor = 10.80 Points per m/s

Wind Factor = wind * [(HS - 36)/20] * 1.2
Wind Factor = 1.0 * [(205 - 36)/20] * 1.2
Wind Factor = 1.0 * [169/20] * 1.2
Wind Factor = 1.0 * 8.45 * 1.2
Wind Factor = 10.14 ≠ 10.80

10.14 clearly isn't equal to 10.80. What's wrong?
DSJ3 Personal best: 314.0m (Slovenia)
DSJ4 Personal best: 196.5m (Planica) (what a great jump that was!...)
Thanatos
Posts: 96
Joined: 20 Mar 2011, 01:56
Location: Germany

Post by Thanatos »

The formula given out by FIS isn't wrong. It calculates the wind effect on jump in distance (m). However, your formula does work on large hills, ...

Klingenthal, HS 140
pts = wind * [(HS - 36)/20] * 1,8
pts = 1,0 * [104/20] * 1,8
pts = 9,36

That's just right. To make it work on an flying hill we've at least to change one parameter, the only one which makes sense. HS - X. 25 instead of 36 should work. I'm not sure if FIS calculates it that way, but in their official rules I found... nothin'?

Let's try. Harrachov first.

Harrachov, HS 205, Wind Factor should be 10,80 per m/s (according to FIS)
pts = wind * [(HS - 25)/20] * 1,2
pts = 1,0 * [(205 - 25)/20] * 1,2
pts = 1,0 * [180/20] * 1,2
pts = 10,80

Planica, HS 215, WF should be 11,40 per m/s
pts = wind * [(HS - 25)/20] * 1,2
pts = 1,0 * [(215 - 25)/20] * 1,2
pts = 1,0 * [190/20] * 1,2
pts = 11,40

Vikersund, HS 225, WF should be 12,00 per m/s
pts = wind * [(HS - 25)/20] * 1,2
pts = 1,0 * [(225 - 25)/20] * 1,2
pts = 1,0 * [200/20] * 1,2
pts = 12,00

Only explanation I've is that FIS uses more than one formula. One for normal and large, one for flyhing hills.
Oh and if you wanted to ask how I got that magic 25? It was the first number I had in mind, when I was recalculating your examples. xD
Ascot
Posts: 251
Joined: 26 Mar 2011, 09:48
Location: Polska , Olsztyn
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Post by Ascot »

Thanatos wrote:The formula given out by FIS isn't wrong. It calculates the wind effect on jump in distance (m). However, your formula does work on large hills, ...

Klingenthal, HS 140
pts = wind * [(HS - 36)/20] * 1,8
pts = 1,0 * [104/20] * 1,8
pts = 9,36

That's just right. To make it work on an flying hill we've at least to change one parameter, the only one which makes sense. HS - X. 25 instead of 36 should work. I'm not sure if FIS calculates it that way, but in their official rules I found... nothin'?

Let's try. Harrachov first.

Harrachov, HS 205, Wind Factor should be 10,80 per m/s (according to FIS)
pts = wind * [(HS - 25)/20] * 1,2
pts = 1,0 * [(205 - 25)/20] * 1,2
pts = 1,0 * [180/20] * 1,2
pts = 10,80

Planica, HS 215, WF should be 11,40 per m/s
pts = wind * [(HS - 25)/20] * 1,2
pts = 1,0 * [(215 - 25)/20] * 1,2
pts = 1,0 * [190/20] * 1,2
pts = 11,40

Vikersund, HS 225, WF should be 12,00 per m/s
pts = wind * [(HS - 25)/20] * 1,2
pts = 1,0 * [(225 - 25)/20] * 1,2
pts = 1,0 * [200/20] * 1,2
pts = 12,00

Only explanation I've is that FIS uses more than one formula. One for normal and large, one for flyhing hills.
Oh and if you wanted to ask how I got that magic 25? It was the first number I had in mind, when I was recalculating your examples. xD
Haha :D
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