cold wind vs warm wind

> 10 years ago
Reply
Register to post, see what you've read, and subscribe to topics.
gokid
gokid
QLD
491 posts
QLD, 491 posts
3 Oct 2013 1:40pm
is there any difference between kiting 20kt wind on a cold 5 Celius day wind vs 20 kt wind on a hot 35 Celius day
besides wearing a wetsuit
KiteBud
KiteBud
WA
1615 posts
WA, 1615 posts
3 Oct 2013 11:53am
colder winds packs denser air and therefore is more powerful. www.engineeringtoolbox.com/wind-power-d_1214.html

Almost the same power in a 20 knots hot day (30 c. +) sea breeze compared to 15-17 knots of cold winter wind.
waveslave
waveslave
WA
4263 posts
WA, 4263 posts
3 Oct 2013 11:54am
There are more bikinis on the beach in 35C.
Phoney
Phoney
NSW
608 posts
NSW, 608 posts
3 Oct 2013 2:07pm
When kite companies state that a 12m kite is suitable from 12 knots. I wonder what temperature this is based on?
Kazan
Kazan
QLD
699 posts
QLD, 699 posts
3 Oct 2013 2:18pm
They base it on the Beaufurt Index. That index is the same no matter what temperature as knots is knots in any climate.
gokid
gokid
QLD
491 posts
QLD, 491 posts
3 Oct 2013 2:23pm
waveslave said..

There are more bikinis on the beach in 35C.


gokid
gokid
QLD
491 posts
QLD, 491 posts
3 Oct 2013 2:32pm
cbulota said..

colder winds packs denser air and therefore is more powerful. www.engineeringtoolbox.com/wind-power-d_1214.html

Almost the same power in a 20 knots hot day (30 c. +) sea breeze compared to 15-17 knots of cold winter wind.


Checked it out,pretty interesting,colder wind is denser and stronger
ste
ste
WA
524 posts
ste ste
WA, 524 posts
3 Oct 2013 12:45pm
Arse wind has more smell for sure!???
Plummet
Plummet
4862 posts
4862 posts
3 Oct 2013 1:06pm
All other factors being equal the difference in force applied to the kite is 10.8% less on the 35 deg C day compared to the 5 Deg C day.

However the reality is that the cold frontal driven wind of wind packs a meaner punch because it is usually more gusty. On a 20 knot day it may gust 25+ knots.

A seabrease driven summer brease is more likely to be closer to a constant 20 knots.

In the formula to calculate force is 1/2 density(of the wind) x velocity (wind speed) squared.

Any variation in the wind speed has a far greater impact in the to the force applied to the kite.

Whats more changes in temperature affect the denisty of the air. However when we calculate the air denisty using the ideal gas law we use temperature in Kelvin not Deg C. Kelvin starts at -273 Deg C.

So.... To input the 5 Deg into the formula its 273+5. To input 35 deg into the formula its 273+35....... All of a sudden we have only really had a marginal change in temp and therefore very little change to the density of the wind over 30 deg temp change.

Confused?
Hendo84
Hendo84
QLD
110 posts
QLD, 110 posts
3 Oct 2013 6:15pm
There is a very obvious noticeable difference in the 'push' of wind as result of air temp. Up in Cairns I would ride 12m pretty much all the time. On the same wind strength, say 18knts on the Sunny Coast I would ride a 10m.
I noticed this difference when I kited at Yeppoon as well.
So in short- yep there is a difference and you will notice it.
iandvnt
iandvnt
QLD
581 posts
QLD, 581 posts
3 Oct 2013 7:37pm
sometimes we get warm ambient temp days with very cold southerly winds and they really pack a punch like nothing else. 32 knots in that is different to 32 knots in Maui.
BurkeyBoy
BurkeyBoy
QLD
549 posts
QLD, 549 posts
4 Oct 2013 7:04am
Colder air is more dense and therefore less of it is needed. In SE QLD I generally fly a 10m in 12-20 knt SE, but in a N I need 16-20 knts. I first wondered about this when I started kiting and a pilot told me that when they take off into a hotter N wind, they have to allow for it and increase speed and length of run up.
Though it's been noted here that location does effect this. When we get Northerlies, they are generally more consistent and less gusty that Southerlies.
fingerbone
fingerbone
NSW
921 posts
NSW, 921 posts
4 Oct 2013 7:26am
Defiantly...15 knotts Sydney = 20 knotts Cairns
cauncy
cauncy
WA
8407 posts
WA, 8407 posts
4 Oct 2013 6:10am
gokid said...
[br]is there any difference between kiting 20kt wind on a cold 5 Celius day wind vs 20 kt wind on a hot 35 Celius day
besides wearing a wetsuit


About 3 inches
gokid
gokid
QLD
491 posts
QLD, 491 posts
4 Oct 2013 12:17pm
cauncy said..

gokid said...

is there any difference between kiting 20kt wind on a cold 5 Celius day wind vs 20 kt wind on a hot 35 Celius day
besides wearing a wetsuit


About 3 inches


Kazan
Kazan
QLD
699 posts
QLD, 699 posts
4 Oct 2013 2:22pm
fingerbone said..

Defiantly...15 knotts Sydney = 20 knotts Cairns



You mean the other way around.
eddiemorgs
eddiemorgs
QLD
391 posts
QLD, 391 posts
4 Oct 2013 9:30pm
Don't get us from the top end started on this topic ! We are the experts on skinny wind vs heavy wind.

If 15 kts is the measure , for me (83 kgs) 17 m and nugget , the same wind in Southern South Oz 10-12 m and 5'10" sb.

Also, for the same location in Southern South oz, big difference between north wind from the hot centre and wind from the south.
Rails
Rails
QLD
1371 posts
QLD, 1371 posts
4 Oct 2013 10:00pm
Kazan said..

fingerbone said..

Defiantly...15 knotts Sydney = 20 knotts Cairns



You mean the other way around.


Got the feeling he may be defiant about this
gokid
gokid
QLD
491 posts
QLD, 491 posts
4 Oct 2013 10:40pm
Rails said..

Kazan said..

fingerbone said..

Defiantly...15 knotts Sydney = 20 knotts Cairns



You mean the other way around.


Got the feeling he may be defiant about this


I think thats right
Please Register, or first...
Topics Subscribe Reply