What principle keeps this bamboo dragonfly from falling

There is an inclination between the blades of the bamboo dragonfly and the horizontally rotating surface (this inclination angle can be adjusted). When the rotor rotates, the rotating blades push the air downwards to form a strong wind, and the air also gives the bamboo dragonfly an upward reaction lift, which changes with the inclination angle of the blades. When the lift force is greater than the weight of the bamboo dragonfly, the bamboo dragonfly can fly upward.

The blades and rotating surface of the bamboo dragonfly also maintain an inclination, so when we rotate the bamboo dragonfly by hand, it will get the reaction thrust of the air and fly upwards. The greater the resistance area of the wing surface, the greater the force, and therefore the greater the reaction force (and the greater the buoyancy), the higher the bamboo dragonfly flies. However, we also found that the larger the resistance area, the greater the rotational force required, so it is not practical in the actual operation of the bamboo dragonfly, and it may be necessary to find a balance point in the force and angle area to make the bamboo dragonfly effortless and easy to operate and fly high.

The non-falling of the bamboo dragonfly is due to the action of lift, which acts on the blades of the bamboo dragonfly, allowing the blades to keep rotating and generate an upward lift force so that the bamboo dragonfly does not fall. This principle is the same as the principle of lift generated by the wings of an airplane, when the blades of the bamboo dragonfly rotate, the air under the blades is under less pressure, and the air above the blades is under more pressure, so that the lift is generated, allowing the bamboo dragonfly to be suspended in the air. At the same time, the blades of the bamboo dragonfly also have a certain resistance and stability, which can maintain the balance of the bamboo dragonfly so that it will not flip or shake.

Therefore, the bamboo dragonfly does not fall down.

The principle of bamboo dragonfly is actually the same as ***, which is to use the rotation of the blades to generate lift, so as to overcome its own gravity to achieve the purpose of flight. The blades of the bamboo dragonfly are two symmetrical and angled sheets, the cross-section of the sheet is generally round-headed and pointed-tailed, the upper surface has a certain curvature, and the lower surface is generally straight, which is basically the same as the airfoil used on modern low-speed aircraft. When the blades of the bamboo dragonfly rotate, the air flow through the blades of the bamboo dragonfly will bypass the blades themselves, and because the air flow from the upper surface is longer from the lower surface (between two points, the straight-line distance is the shortest), the air flow on the upper surface is forced to move at a higher speed than the lower surface, so that the air flow converges at the tail of the blade at the same time.

In the low-velocity flow state, the higher the speed of the air flow, the lower the pressure (static pressure), which causes the pressure on the upper surface to be lower than that on the small surface, so that the pressure difference between the upper and lower surfaces is generated, which is manifested as a resultant force pointing to the upper surface on the blade, and this force is the lift force on the blade.

The flight performance of a bamboo dragonfly depends on the following:

1. The difference between lift and gravity, if the lift is less than gravity, the bamboo dragonfly cannot fly normally, which requires the blades to be as thin as possible;

2. The relationship between lift and resistance: lift increases with the increase of the angle of the blade, and the drag also increases, at a certain critical angle, the increase speed of lift is less than the increase speed of resistance, so that the size of the drag reaches an unacceptable level, that is, stall, which will seriously affect the flight performance, therefore, the angle of the bamboo dragonfly blade can not be too large, it is recommended to choose about 15 degrees;

3. The position of the center of gravity: if the position of the center of gravity is not on the geometric center line of the bamboo dragonfly, it will cause the bamboo dragonfly to fly unstable, and it is necessary to ensure the verticality between the vertical bamboo stick and the blade, otherwise it may cause the tail of the bamboo dragonfly to swing seriously when flying, and eventually lose stability and stall.

The principle of the bamboo dragonfly is that there is an inclination angle between the blades of the bamboo dragonfly and the horizontal rotation surface, when the rotor rotates, the rotating blades push the air downward, forming a strong wind, and the air also gives the bamboo dragonfly an upward reaction lift, this lift changes with the inclination angle of the blade, the inclination angle is large, the inclination angle is small, and the lift is small, when the lift is greater than the gravity of the bamboo dragonfly itself, the bamboo dragonfly can fly upward. <

The principle of the bamboo dragonfly is that there is an inclination angle between the blades of the bamboo dragonfly and the horizontal rotation surface, when the rotor rotates, the rotating blades push the air downward, forming a strong wind, and the air also gives the bamboo dragonfly an upward reaction lift, this lift changes with the inclination angle of the blade, the inclination angle is large, the inclination angle is small, and the lift is small, when the lift is greater than the gravity of the bamboo dragonfly itself, the bamboo dragonfly can fly upward.