How do bamboo dragonflies fly?

Bamboo dragonflies. In fact, the principle is 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 lead to the unstable flight of the bamboo dragonfly, and the verticality between the vertical bamboo stick and the blade should be ensured.

Otherwise, it may cause the bamboo dragonfly to swing its tail 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 the same as that of the propeller, which is a device that converts rotational power into propulsion by rotating the blades in the air. The propeller blade is a spiral surface, when it rotates, the force of air on the propeller blade can be broken down into an upward force and a force in the opposite direction of rotation, the faster it rotates, the greater the upward force of the decomposition, so that the propeller can rise. Helicopters make use of this principle.

The origin of the bamboo dragonflyThe bamboo dragonfly is an ancient Chinese folk children's toy, its shape is T-shaped, a horizontal piece like a propeller, there is a small hole in it, which inserts a straight bamboo stick, rubs this bamboo stick with both hands, the bamboo dragonfly will rotate and fly into the sky, and only fall to the ground when the lift is weakened. In the process of making and playing with bamboo dragonflies, you can appreciate the fun of ancient Chinese children's toys and the mystery of science and technology.

Dragonflies are insects that are good at flying, with thin and light wings, front and rear wings on the left and right sides, and very light weight, but can vibrate 30 to 50 times per second. The dragonfly is very flexible, it can not only fly quickly, quickly change direction and altitude, but also glide slowly at a certain altitude, or suspended in mid-air, and even fly upside down, sideways, straight up and down, it can be said that it can be said to be freewheeling, even the most modern aircraft are far from the dragonfly.

The dragon's extraordinary flying skills are due to its well-developed wing muscles, the former allowing the wings to flapp, and the air sacs, which store air, which can regulate body temperature and increase buoyancy.

Dragonflies fly so freely that the nervous system controls the angle of inclination of the wings, which subtly adapts to the flight speed and atmospheric pressure. Due to the different angles of inclination of the wings, it can generate both upward lift and forward or backward thrust, so that it can fly freely.

Antennal receptors

Dragonflies have short, bristly hairy antennae with many receptors distributed on them. The main types of receptors are cone-receptors, cavity-cone receptors, plate-shaped receptors and jar receptors. Studies have shown that different species of dragonflies have different types of receptors, and their numbers and distribution forms are also different.

The receptors of female dragonflies are stable in the same family, the same genus and the same species, while there are obvious differences between different families and genera, although the differences between different species in the same genus are small, but the differences between individual species are still very obvious, so the receptors of female dragonflies also have certain significance in the classification.

The structure of dragonfly and butterfly wings is different, the surface of butterfly wings is covered with scales, and it is not like hummingbirds with endoskeletal muscle enhancement and flexible movement tissue, so that they cannot vibrate at high frequency like hummingbird dragonflies, so the generation and use of micro-scale air vortices or small-scale unstable airflow is necessarily weaker than that of dragonfly hummingbirds, so the flight ability is necessarily weaker than that of dragonflies and hummingbirds, and it can also be said that the ability to generate and use micro-scale air vortices or small-scale unstable airflows is positively correlated with the frequency of wing vibration. However, butterflies still use small-scale air vortices or small-scale unstable air currents, which are completely different from the flight principles of large birds.

The membranous wings are used to agitate the air to fly, and the leathery wings are used to protect the membranous wings, and the two pairs of membranous wings flutter in a wavy shape to ensure the direction of the airflow, that is, the fore and hind wings are never at the highest or lowest point at the same time when flying.

Dragonfly--- dragonfly, membranous wings; Butterflies --- lepidoptera, with two pairs of membranous scales.

Basically, the vibration of the wings is caused by the formation of many tiny, low-density air cannons under the wings, which produce buoyancy and the propulsive force of the front.

The principle of flight of dragonflies is to wave their wings through the wing muscles to press down the air flow, and when the air pressure in the lower part of the wings reaches a certain level, it can take off under the interaction of forces. The dragonfly is an expert in the flight of insects, its wings are thin and light, with front and rear wings on the left and right, which can vibrate 30-50 times per second, and the flying action is very flexible, which can not only fly quickly, but also quickly change direction and altitude.

Dragonflies: are carnivorous insects. They prey on flies.

Mosquitoes, leafhoppers.

A variety of agricultural, forestry and animal husbandry pests such as midges and small butterfly moths. Dragonflies are an important class of natural enemies that are beneficial to humans. "Dragonfly dotting water" is a biological feature of dragonflies laying their eggs in water.

The larvae live in water and live for a period of different species depending on the species, ranging from 2 years to 3 to 5 years. The study of dragonfly wings focuses on the principles of mechanics and biomimicry.

Aspect. Because dragonfly wings have two special structures, wing knots and wing moles, it is an excellent flyer in nature.

In terms of mechanical research, it is found that the wings of dragonflies in the air will be affected by horizontal force, vertical force, torque, bending, and action when flying and turning, and it is found that dragonflies fly at slow speed and fly in the aircraft.

Principle: There is an inclination angle between the blades of the bamboo dragonfly and the horizontal rotation 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 bamboo dragonfly's own gravity, 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.