Sorry to interrupt BUT is this not a thread, running in the GEAR REVIEWS section about the Ozone Catalyst.....

Does the thread really need derailed by having a pi$$ing contest with such an inane subject as has just been demonstrated?

FFS

Select to expand quote

rcr46401 said...
Try Jason at Westoz kiteboarding, I demo/purchased my 2014 cats from him.

Cheers

Hey dudes - would there a preference between the 2013 and 2014 cats (8m) for use with strapless surfboard?

my trusty ole 8m Ozone XC light needs replacing after lasting a good few years of abuse!!

are the recent cats much different to the light XC? (top end of this kite is insane!!!)

cheers!

I'd be looking at a 2014 7m Catalyst to fit the wind range of the 8m Light. The 2013 and 2014 Cats are more powerful than the Lights and the earlier Catalysts that replaced them.

The REOs should also be on your list and probably offer a bit more depowerability at the top end.

Select to expand quote

Kitepower Australia said..

Plummet said..

I did some maths in a thread a little while back.

Plummet said..

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 <span class="spnSearchHighlight" id="hilite">cold</span> 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 <span class="spnSearchHighlight" id="hilite">air</span>. However when we calculate the <span class="spnSearchHighlight" id="hilite">air</span> 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?

Which just means that it makes a bees dick of difference.
We all kite at sea level, so altitude makes no difference at all. Most of us kite between 15C and 25-30C temps, so the difference is actually more like 5%, and this does not equal a full kite size or 3 as some suggest.
Most people misread the wind in a new location and then begin to believe this total BS about massive differences in power delivery between a cooler location than a warmer one.
Don't be mislead, 20 knots somewhere is basically 20 knots anywhere!!!

interesting,during my last visit used to kite on the snow at greolierr in france then down to the sea in the same day same windstrengths but much different in temperature, struggle to get powered at sea level but well powered in colder climates, also for sure a colder wind here feels punchier than the same in summer, the bksa and now british kitesports constantly run warnings on colder dense air telling members to consider using a smaller kite, so but a 12 cat for the summer and a 9 for winter

Sorry to put in cat thread. This is straight from a pilots handbook

"Effects of pressure on density

Since air is a gas, it can be compressed or expanded. When air is compressed, a greater amount of air can occupy a given volume. Conversely, when pressure on a given volume of air is decreased, the air expands and occupies a greater space. That is, the original column of air at a lower pressure contains a smaller mass of air.

In other words, the density is decreased. In fact, density is directly proportional to pressure. If the pressure is doubled, the density is doubled, and if the pressure is lowered, so is the density. This statement is true only at a constant temperature.

Effect of temperature on density

Increasing the temperature of a substance decreases its density. Conversely, decreasing the temperature increases the density. Thus, the density of air varies inversely with temperature. This statement is true only at a constant pressure.

In the atmosphere, both temperature and pressure decrease with altitude, and have conflicting effects upon density. However, the fairly rapid drop in pressure as altitude is increased usually has the dominating effect. Hence, pilots can expect the density to decrease with altitude.

Effect of humidity (moisture) on density

The preceding paragraphs have assumed that the air was perfectly dry. In reality, it is never completely dry.

The small amount of water vapor suspended in the atmosphere may be almost negligible under certain conditions, but in other conditions humidity may become an important factor in the performance of an airplane. Water vapor is lighter than air; consequently, moist air is lighter than dry air. Therefore, as the water content of the air increases, the air becomes less dense, increasing density altitude and decreasing performance."



I need......and can hold down a bigger kite in Asia than I can at home at the same wind speed. That is also why you can get the same wind speed at home from a different direction and you will need or can use a different sized kite. Humidity, temperature, pressure is different.

living in the tropics i can say temperature and humidity make a BIG difference - about one kite size . winter the wind has a lot more power in it for the same wind speed .

i.e. zephyr gets going in 12 knots easily in winter , where in summer i need 14 to 15 just to get cruising. ... feel free to come up and experience if you don't believe the facts .

the difference between here and perth is HUGE ,, i ride my 10 cat easily down there in 17 knots where here i need minimum 20 .

Thanks for backing us up troops

Cheers dj, will take that on board....