Simple Explanation For How Kites Fly?

Q:

How do kites fly?

Middle school students have a hard time understanding the big words. How can you put it so they understand?

A:

I'll try :-)

Let's assume the kite is a simple flat Diamond with the string attached to where the sticks cross each other. This kind of kite needs a long tail attached to the tail end.

How It Flies

1) Anything that is flat, and is held at a nose-up angle to the wind will feel a push in 2 directions. Backwards, and upwards.

2) The kite is tied to a string, so it can't go backwards! That is, in the wind's direction, away from the person flying it.

3) However, there is nothing stopping it from going upwards, except it's own weight, and the weight of the string. As the kite rises on its string, the kite's angle to the wind gets smaller. The nose comes down and the tail comes up, until the kite is at a much smaller angle to the wind than when it started. This causes the upward push on the kite to get smaller too. When the upward push is equal to the downward pull of the kite's weight plus the string's weight, the kite doesn't get any higher.

How It Stays In The Air

1) While near the ground, the tail end of the kite is free to swing left and right like a pendulum. There is more weight below where the string attaches to the kite than above this point. So the tail always tries to hang straight down. Hence the nose always tries to point straight up, letting the kite climb quickly.

2) When much higher up, the kite is still free to swing left and right around where the string attaches to it. But the tail end is not hanging straight down any more. To stay up there, the nose of the kite must point straight into the wind. The long, light tail helps to do this, by dragging the tail end of the kite back so the nose of the kite keeps pointing upwind.

Hope this helps, although I have not attempted to explain the Lift force itself in much detail. Pose another question if you need more on that...

Here is a page on this site that your keenest students might like to check out, after they 'get' the above explanations! How a kite flies in a bit more detail.