Power Kite Forum

Wind is not created equal

kiteballoon - 10-10-2013 at 12:37 PM

http://www.progression.me/news/2013/08/27/not-all-wind-is-cr...

A rather simple concept that I've noticed but not really thought about. Gives you all the more reason to hate those light summer breezes that lack the gusto of a good winter wind.

Since I'm in Florida flying most of the time, it's already trouble enough to find wind in the summer when you aren't at the beach, let alone have it possess the punch to get you kiting.

John Holgate - 10-10-2013 at 02:21 PM

Never heard the term 'wind density' before. But I know that cold air sinks....therefore heavier....therefore packs more punch when it's windy. I have noticed this in my location - a cold wind from the south can give a good session with a kite that would be really underpowered when flying in a warm northerly.

Txshooter38 - 10-10-2013 at 03:18 PM

It is sometimes listed on the kitesurfing sites as "boost". Colder air equals more power.

Cheddarhead - 10-10-2013 at 03:32 PM

I can totally relate to this!! Wisconsin temperatures can vary almost 100 degrees F from summer to winter and it has a dramatic effect on kiting. Winter winds here pack more punch, have more guts and are by far smoother than summer winds. We have TONS of trees in our state, winter means leaves are gone from the trees resulting in much smoother winds. Not coastal smooth, but far from the craptastic winds in the summer. Winter is bliss compared to summer! I'm getting pumped just thinking about it.

Excellent point!

skimtwashington - 10-10-2013 at 04:40 PM

Overlooked this significance as I bet many others have.

Good Post!

RedSky - 10-10-2013 at 07:37 PM

I used to think this too until I made the trip to Ivanpah last year...or was it the year before. Disappointing winds on the dry lake bed were forecast and the temperature was hot, very hot, 100f. Yet I was able to reach 48mph and my friend 52mph in a brief but smooth 14mph wind!

14mph wind back home on a hard smooth sandy surface gives me about 28-32mph max. Could it have been the wind, could the surface really have made that much difference ? Ivanpah is nowhere near as smooth as the beach even in the smoothest areas. Maybe colder air packs more punch but could the benefits be outweighed by the extra drag in denser air?

So basically I've found the opposite to be true.

skimtwashington - 10-10-2013 at 07:56 PM

This thread just got more interesting.

I feel a discussion a-blowin'

martinipro - 11-10-2013 at 06:06 AM

You also cannot neglect altitude which plays a big role in air density.
At the beach you are at sea level, whereas Ivanpah is 800m(2600ft+) above sea level.

Purely Luck - 11-10-2013 at 07:12 AM

Found this chart that is used for determining fan size required based on air temp and altitude.

http://www.greenheck.com/images/articles/air_density_chart.g...

Interesting, think it has any use for kiting?

I mean it is good to know that your kite size would have to be 4.89 times bigger (put that 9m away and grab a 44.01m!) if you decide to kite at 1000 degrees Fahrenheit at 15000 feet. Your kite would probably have to be made of ripstop carbon or something in order to stand up to the heat.

Purely Luck - 11-10-2013 at 07:13 AM

Found this chart that is used for determining fan size required based on air temp and altitude.

http://www.greenheck.com/images/articles/air_density_chart.g...

Interesting, think it has any use for kiting?

I mean it is good to know that your kite size would have to be 4.89 times bigger (put that 9m away and grab a 44.01m!) if you decide to kite at 1000 degrees Fahrenheit at 15000 feet. Your kite would probably have to be made of ripstop carbon or something in order to stand up to the heat.

kiteballoon - 11-10-2013 at 08:07 AM

Quote: Originally posted by martinipro  
You also cannot neglect altitude which plays a big role in air density.
At the beach you are at sea level, whereas Ivanpah is 800m(2600ft+) above sea level.


Excellent point! A few hundred feet might not particularly change things (say for instance you going from your home to the beach), but several thousand will ;-) I think the folks in Colorado can speak a bit about kiting a mile above sea level.

pbc - 11-10-2013 at 05:46 PM

Quote: Originally posted by RedSky  
I used to think this too until I made the trip to Ivanpah last year...or was it the year before. Disappointing winds on the dry lake bed were forecast and the temperature was hot, very hot, 100f. Yet I was able to reach 48mph and my friend 52mph in a brief but smooth 14mph wind!

14mph wind back home on a hard smooth sandy surface gives me about 28-32mph max. Could it have been the wind, could the surface really have made that much difference ? Ivanpah is nowhere near as smooth as the beach even in the smoothest areas. Maybe colder air packs more punch but could the benefits be outweighed by the extra drag in denser air?

So basically I've found the opposite to be true.


There's more rolling resistance on hardpacked beach sand than you might think. I never appreciated it 'til I took my bicycle to the beach. It has fat (2.35") smooth tires. They're just the sort of tire you think would roll well in the sand. Yet it was like riding through molasses despite riding on the freshly paved hardpack.

The surface I find ideal for buggying was a pain for cycling. The sand is just not as hard as it seems.

Philip

RedSky - 11-10-2013 at 05:59 PM

Quote: Originally posted by pbc  
Quote: Originally posted by RedSky  
I used to think this too until I made the trip to Ivanpah last year...or was it the year before. Disappointing winds on the dry lake bed were forecast and the temperature was hot, very hot, 100f. Yet I was able to reach 48mph and my friend 52mph in a brief but smooth 14mph wind!

14mph wind back home on a hard smooth sandy surface gives me about 28-32mph max. Could it have been the wind, could the surface really have made that much difference ? Ivanpah is nowhere near as smooth as the beach even in the smoothest areas. Maybe colder air packs more punch but could the benefits be outweighed by the extra drag in denser air?

So basically I've found the opposite to be true.


There's more rolling resistance on hardpacked beach sand than you might think. I never appreciated it 'til I took my bicycle to the beach. It has fat (2.35") smooth tires. They're just the sort of tire you think would roll well in the sand. Yet it was like riding through molasses despite riding on the freshly paved hardpack.

The surface I find ideal for buggying was a pain for cycling. The sand is just not as hard as it seems.

Philip


True. Even with the relative roughness of the dry lake, hardpack is not so hard compared. I guess the surface had a lot to do with our extra speed and also the space to find the perfect line or angle but I wonder if denser air has an extra drag effect that cancels out any benefit ?


skimtwashington - 11-10-2013 at 06:32 PM

Intriguing and perplexing....:dunno:

We need a Physicist to know what's going on for sure.

Feyd - 11-10-2013 at 07:58 PM

Warm air sucks, cold air trucks. :D I don't fly much in the summer but when I do I'm amazed at how little bite the wind has compared to winter.