What wind speed is necessary to fly my kite?

Question

I have a stunt kite that weighs X grams and has surface area Y square centimeters. What does the wind speed need to be in order to keep it in the air?

Apologies for the variables. I haven't gotten round to weighing the kite yet; I was hoping someone could give me a general answer, something I could plug future kites' weight and surface area into.

(A little bit of background: I own a stunt kite that I quite enjoy flying. Unfortunately, the thing takes a pretty stiff breeze to get off the ground, and it's hard to estimate the difference between a breezy enough day and a day too windy for flying. I'd like to be able to just measure wind speed and know when I can take it out.)

Bad Dog · Accepted Answer

There are more variables than you are considering, if you want to get a truly accurate answer.  

There are equations that you can use which you can google for.  Also, you could probably use standard Aerospace Engineering equations or a slight modification of them.  The shape of the airfoil plays a part in generating the lift, as well as the angle of attack in relation to the wind.  It is not as simple as X grams and Y surface area.  There are equations which calculate the "lift" of a flat airfoil, but few kites are actually flat in cross-section while being exposed to a wind.  If you could get an accurate drawing of the kite's airfoil shape (a side view of the 'wing' showing the curve of the kite's surface from front to back, while the kite is exposed to an airstream such as a floor fan), then find the equation which describes the curve, you can plug that into standard lift equations and calculate the wind-speed necessary to generate enough lift to fly your kite.

I once had reference materials with these equations, but have lost them over time, otherwise I would just give them to you.

What wind speed is necessary to fly my kite?

1 Answer