TetrahedronKites By

Elton White

Overview• Tetrahedron kite is a kite made of four 3D

triangles.• We are making them out of 24 straws and strings,

four 24 inches and four 45 inches.

What I’d like to learn

• What kind of stunts kites can do• How to build the tetrahedron kite

Basics of flight• ReleaseTo launch the kite, we have to create a lift force which is greater than the weight of the kite. The size of the lift force depends on a lot of factors, with the most important factor being the velocity of the air going by the kite. It does not matter whether the air blows over the kite, or the kite is pulled through the air; the important factor for generating lift is the relative velocity between the air and the kite.• Launch during launch we can usually stand still and the kite will fly just fine. This occurs because the velocity of the wind normally increases as we increase altitude. The change in velocity from the surface of the earth to some altitude is caused by the boundary layer of the atmosphere. Inside the boundary layer the velocity is low and may be unsteady. But with enough altitude, the velocity (and the lift force) become fairly constant.

Basics of flight (continued)

• CruiseOnce the kite has been launched, it will cruise at an altitude and in an attitude where all the forces and the torques are balanced. If the forces are changed, the kite moves until the forces are in balance once again. In particular, if we pull on the control line, we can slightly increase the velocity of the kite.• ClimbThe increased velocity increases the lift, which causes the kite to climb. If the wind velocity is even slightly higher at the new altitude, the kite remains at that altitude. Letting out line initially causes the kite to drop slightly due to the increased weight of the line, and decreased tension in the line (slight decrease in velocity). But pulling on the line can move the kite back up to a higher altitude.

Different types of kites• Single linersDelta kiteSled kiteDiamond kite• Dual linersPeter powellsParafoilsQauntums

ComparisonsName Kite Birds Heli Jet AirlinerGravity pull

Thrust Lift Cruise Launch >50 mph <50 mph Variable

Pictures