Paragliing paraglider

As a new type of outdoor advertising media, paramotors can fly in low-altitude circles in areas designated by customers, and can also fly in formation with several paramotors, creating a particularly spectacular sight. Paramotors generally fly at a height of 20 meters to 80 meters. The advertising area of ????the umbrella is 9.7 meters × 3.2 meters, and a promotional slogan of 20 words can be posted. When the pilot flies into the promotional airspace, the roaring motor sound and direct and eye-catching advertising slogans will It will give people a strong sense of visual and auditory impact, leaving a deep impression on the audience. It is an ideal helper for enterprises to release information and strengthen their brands. Parachuting originated in 1983, among some European people with high-altitude skydiving experience. Climbers, after reaching the top, jump down with high-altitude umbrellas and enjoy the joy of soaring. Some climbers were able to fly in the air for a period of time by taking advantage of the strong winds on the mountain ridges. So some people used hang gliding experience and improved parachute equipment to develop a new flying sport - "paragliding", which can be used on hillsides or after climbing to the top. Glide down under the parachute and soar across the sky. The performance of the flying parachute at that time was not good. The glide ratio was about 1:3, that is, it dropped one meter and slid three meters. Its shape was similar to that of the parachute used for high-altitude skydiving. However, with the development up to now, the appearance and performance of paragliders are quite different from those before. Most of its shapes are fusiform, and the sliding ratio is also increased to 1:9. A. Canopy (CANOPY)~

Also called sail. The wing shape, thickness and chord of the canopy determine the flight characteristics of the parachute. Umbrella canopies can be divided into upper canopies and lower canopies, and the material is polyester or nylon-based fabric. B. Suspension rope (LINE)~

Also known as paracord, it is divided into A/B/C/D groups and is connected to the assembly belt (assembly belt riser). Its material is bulletproof fiber (DYNEEMA or KAVLAR (two types), covered with nylon protection.

C. BRAKE CORD~

Also known as the control rope, there is one on the left and one on the left, and there is a grip ring below each. Pull it down or put it up to change the wing. The trailing edge airfoil then changes the lift/drag characteristics to achieve turning and braking actions.

D. Air hole (CELL)~

Two air chambers form an air hole, and the air hole is the connection point between the parachute and the parachute rope.

E. Air chamber (CHAMBER)~

Each air chamber has an air intake (Air intake), and there are also designs to close part of the air intake.

F. Compartment vents~

The vents inside the umbrella canopy. The number of compartments directly affects the surface flatness of the parachute and improves the performance of the umbrella. The vents inside It is used to maintain the balance of air pressure inside the umbrella.

G. Stabilizer (STABILIZER)~

Increases the stability of the parachute in unstable airflow, just like the rudder of a ship, and is designed for early flying parachutes or training parachutes/primary parachutes , but today’s parachute designs rarely include stabilizing wings. Instead, they change their different angles of attack or arcs at the wing ends to achieve the same stability.

H. RISER~

There are two groups, three groups, four groups or even five groups. It is the reinforced part that connects the paracord and the harness, and can be used for movement. It can also be attached with an adjustment strap (Trime Tab) to adjust the angle of attack.

I. Harness (sling) (HARNESS) ~

A comfortable air seat is formed by connecting shoulder straps, chest straps, and leg straps to support the weight of the human body. The hook is connected to the belt and the umbrella canopy. 1. Umbrella wing area (AREA)~

The projected area in the air, or the area of ??the flat surface, is usually measured by the projected area, expressed in square meters.

2. Leading edge (LEADING EDGE) ~

The front end of the umbrella wing, where the air separates up and down and flows on the upper and lower wing surfaces of the umbrella.

3. Trailing edge (TRAILING EDGE)~

The rear end of the umbrella wing.

4. Wing tip (WING TIP) ~

The left and right ends of the umbrella wing.

5. Wing span length (WING SPAN) ~

The full length of the umbrella wing is measured from the end of the left wing to the end of the right wing, in meters. 6. Chord LENGTH~

Like the string of a bow and arrow, the distance between the leading edge and the trailing edge.

7. Wing LOADING~

Refers to the weight of the parachute in flight (including parachute weight, weight, straps, instruments and other complete equipment), divided by The value of wing area. Generally speaking, paragliders with heavy wing loads tend to go faster.

8. Aspect ratio (ASPECT RATIO) ~

The square of the wingspan divided by the wing area. Generally speaking, the larger this value is, the larger the glide ratio is.

9. GRIDE RATIO~

The ratio of the height difference from the landing point to the flight distance when flying in a calm state.

10. Minimum sink rate (MIN. SINK RATE)~

In the umbrella wing load specification, use the lightest wing load test to slow down the umbrella speed to the minimum descent per second value, expressed in meters per second. It is one of the important parts of an umbrella.

11. Stall Speed ??(STALL SPEED)~

In the windless state, the umbrella is tested under the maximum wing load. When the umbrella speed drops to a certain value, the descent rate increases greatly. The umbrella will suddenly lose forward speed and fall in free fall. This speed is called stall speed.

12. Maximum speed (MAX SPEED) ~

In the windless state, the umbrella is tested under the maximum wing load. The fastest speed the umbrella can fly, including the use of the acceleration system. At present, the fastest speed that a high-flying parachute can achieve in the world is 55 to 60 kilometers per hour. 1. Stability of paragliding

Flying paraglider

For all moving objects, the first quality requirement is stability. The stability of a paraglider refers to its tendency or ability to return to its original state (smooth and straight flight) when it is disturbed by external forces (mostly wind gusts, turbulence or brief maneuvers by the pilot). In short, a stable paraglider can automatically return to normal flight status after encountering gust interference or it has the ability to fly "hands-off" in stable airflow.

To illustrate the stability of a paraglider, let us first take a look at its three axes of rotation: the transverse axis, the longitudinal axis, and the vertical axis. The rotation of a paraglider around the transverse axis is called pitch, that is, the front edge of the paraglider rises or falls, which is a change in the angle of attack; the rotation around the longitudinal axis is called roll, that is, the upward or downward movement of one side of the paraglider; around the vertical axis The rotation of the paraglider is called yaw, which is the forward or backward movement of one side of the paraglider, that is, the change of the paraglider's course.

The pitch stability and roll stability of a paraglider are both caused by the action of the pendulum. During normal and stable flight, the pilot hangs under the parachute (which is similar to a heavy object suspended under a string, that is, a pendulum). At this time, the aerodynamic force R and the weight W of the parachute system are equal in size and opposite in direction. The entire force system In a flat state. Due to disturbance (such as the driving force of the oncoming gust of wind), the position of the canopy and the human body deviates, and the angle of attack increases. Since R and w no longer act on the same straight line, the equilibrium state is destroyed. However, due to the deviation of the force, at this time A force couple or moment will be generated, causing the canopy to return to a non-original position. Therefore, the pitch stability of a paraglider is disturbed and the paraglider's angle of attack tends to return to its original angle of attack state. If the side of the paraglider is hit by a gust of wind, the wing tip of one side of the paraglider will rise and the other side will drop, which will also cause the balance of R and w to be destroyed, and a restoring moment will also be generated under the action of the force couple, causing the paraglider to fall. The parachute rotates around the longitudinal axis and returns to the top of our heads. This is the rolling stability of the paraglider.

The yaw and heading stability of gliding are different from those above. When the paragliding canopy yaws to the wind direction, the shadow area of ??the canopy is the area behind the center of pressure (the center of pressure is always the sum of the upward aerodynamic force R, which can also be regarded as the center of gravity also acting on this point. Click on). In the yaw state, the side of the parachute moving backward is at a higher angle of attack according to experience, while the side moving forward is at a lower angle of attack, so the former generates greater force than the latter. The force acting on the rear side combined with the gravity of the center of mass of the system produces a correction effect on the canopy, causing it to break away from the yaw state and return to the original heading.

2. Turning flight

The paraglider turns in the air by pulling down the control rope, causing the subsequent part of the parachute to bend downward, increasing the angle of attack, so the paraglider turns in the air. Under the action of airflow, the resistance on this side increases and the lift is destroyed.

One side of the paraglider decelerates and descends slightly as the brakes are applied. At the same time, the paraglider rotates around the vertical axis to change the flight direction, thereby achieving an aerial turn.

When the paraglider turns, due to the inertial force of the human body, the human body deflects outward and the paraglider is tilted. It should be pointed out that when the brakes are pulled down to turn, the inclination angle of the parachute will increase as the amount of braking increases, and the centrifugal force caused by the inertia of the human body will also change with the amount of braking and the speed of control. The faster you pull the brakes, the greater the inertial force. Therefore, the braking operation must be moderate and gentle, otherwise it will lead to serious consequences. If the pilot continues to increase the amount of braking, the paraglider's turning radius will become smaller and smaller, the angle of inclination will become steeper and it will enter a tight spiral descent. Excessive braking control may even lead to a dangerous spiral dive. The reason for this situation is that the centrifugal force combined with the total weight W of the umbrella system produces a new expressed gravity Wa. This new load is greater than w, and also greater than the aerodynamic force R. Since the lift force is not enough to balance the component force of wa, it will cause a loss of height. If this happens at low altitude, it will often lead to serious consequences of falling to the ground and causing casualties, which requires special attention. Under normal circumstances, when maneuvering a paraglider to turn, the inclination angle between the paraglider and the horizontal plane should not be greater than 30 degrees.

3. The best performance of paragliders

The performance of paragliders involves many aspects. Here we only discuss a few main indicators related to performance, namely glide ratio, Sinking rate and velocity.

The glide ratio is directly related to the glide trajectory. The so-called glide ratio refers to the ratio of the horizontal distance of the paraglider's forward movement to the vertical descent distance or the ratio of the horizontal speed to the vertical descent speed of the paraglider in unit time. The size of this ratio reflects the performance of the paraglider to a certain extent. The glide ratio of junior paragliders is between 3:1-6:1; while the glide ratio of intermediate and advanced paragliders is mostly between 5:1-9:1, and the glide ratio of some competitive high-performance paragliders is close to 10:1 (that is, advance 10 meters horizontally and drop 1 meter vertically). The glide ratio of a paraglider can also be simply regarded as the ratio of lift L to drag D. The way to improve the glide ratio of a paraglider should be to increase the lift and reduce the drag. Determining the maximum glide ratio (L/D) MAX of the paraglider mainly depends on the airfoil shape and aspect ratio. What should be noted here is: the flexible wing must not blindly pursue aerodynamic performance, increase the aspect ratio, and thin the airfoil. This will cause the umbrella wing to collapse easily and make recovery difficult. Because a powered paraglider has an engine, the powered paraglider can sacrifice some aerodynamic performance in exchange for greater wing rigidity and stability. This does not mean that the powered paraglider is inferior, but has a different focus. Compared with the two, the paramotor wing has stronger collapse resistance and better stability.

The sinking rate refers to the vertical descent distance of the paraglider in unit time, that is, the vertical descent speed Vv. Generally speaking, minimum sink rate occurs when we are flying very slowly (slightly faster than stall speed). The main factors in the Shadow Tower's sinkage rate are the canopy's airfoil shape, size and pilot weight.

In actual flight, when we want to change the flight speed, we usually use brake control to increase the camber of the canopy airfoil and increase the angle of attack. This method is similar to the function of lowering the flaps during normal flight. . When we pull down the left and right control ropes at the same time to deflect the trailing edge of the parachute downward, it will slow down the forward speed and vertical descent speed of the paraglider. The latter is what we call the sinking rate.

Here we have learned that in order to achieve different flight purposes (effects), the brake control should be used to adjust the angle of attack of the parachute and fly at the corresponding speed. For example, in order to achieve the longest flight distance, we should fly at the "optimal gliding speed", that is, without applying brake control. At this time, the gliding ratio and the lift-drag ratio are at their maximum value. If you want to achieve the purpose of staying in the air for a long time, you should fly at the "minimum sinking" speed. At this time, about 20-30% of the brakes should be applied to the parachute.

4. About Stall

What is "stall" and what impact does it have on paragliding flight? Let's discuss it as follows.

The paragliding parachute moves relative to the air at a certain angle of attack, generating aerodynamic force that allows us to fly in the air. For different flight needs, we have to control the parachute to change direction and adjust speed. However, the increase in angle of attack is not arbitrary, but has a limit. When the paraglider parachute flies at a certain angle of attack, the airflow flowing through the wing surface smoothly "closes" the upper surface.

When the angle of attack is further increased to a certain position, the airflow flowing close to the upper surface begins to separate from a certain position, thereby generating an unstable vortex behind it, which causes the drag to increase rapidly and the lift to disappear. , this phenomenon is called "stall".

After the paraglider stalls, the control will deteriorate and it will fall downward faster and faster. If the paraglider stalls near the ground, it is even more dangerous. If it is not handled well, it will be catastrophic. This situation is also very common in normal flight training and competitions. During the pilot's "sparrow landing" landing, the parachute "stalled" due to excessive control and fell heavily to the ground. Therefore, new students who are starting to learn to fly paragliders must not use the control rope to slow down the flight speed too much before they have fully mastered the complex flight control and recovery techniques. Here are some tips for stall situations:

1. Stall only occurs at a certain angle of attack;

2. For a specific pilot, his stall occurs at a certain flight speed, which is called the "stall speed".

3． Stalling is caused by excessive angle of attack, which is the result of excessive braking control or excessive control after pulling down;

4. The result of stalling will be the loss of flight speed, loss of control, loss of altitude and possible collapse of the canopy;

5. To recover from a moderate stall, the amount of braking should be immediately and smoothly reduced to shoulder level to reduce the angle of attack.

5. Flying in the Wind

The optimal gliding state of the paraglider we discussed above is assumed to be carried out in a still atmosphere, that is, no wind. However, for the atmosphere, there is generally no windless situation; the "wind" mentioned here is actually the large-scale horizontal movement of air masses, so it has both direction and a certain speed. Also includes horizontal and vertical directions. (We usually call the vertical direction, 'airflow')

First, let's take a look at the situation of a paraglider flying against the wind. For example, if a paraglider glides through the air at a speed V, the speed direction is consistent with the glide trajectory. Since the wind direction is horizontal, we also decompose the speed V into horizontal speed and two vertical wind quantities Vh and Vv. If the wind speed and Vh are equal in magnitude but opposite in direction, the result of the two canceling each other out is that the resultant speed is zero. At this time, the paraglider is in a stagnant state in the air relative to the ground. Due to the sinking speed Vv of the paraglider, , making the paraglider descend vertically like a normal parachute. If the horizontal speed Vh of the paraglider is greater than the wind speed, after the two offset, there is still a certain resultant speed, and the paraglider can still fly forward slowly when viewed from the ground. Of course, if the wind speed is greater than Vh, what we see from the ground is that the paraglider will not be able to move forward, but will be blown backwards by the wind.

We usually refer to the horizontal speed of a paraglider when it is stable in still air as "airspeed", and the speed of movement relative to the ground as "ground speed", then airspeed, ground speed and wind speed There is the following relationship between the three:

In the absence of wind: ground speed = airspeed;

In the case of headwind: ground speed = airspeed - wind speed;

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In the case of tailwind: ground speed = airspeed + wind speed;

Special note that flying in weather with parallel wind does not mean that the vertical wind (airflow) force has reached the flight standard. This is something paramotor pilots must keep in mind. 1. Are parachutes and parachutes the same thing?

Not the same thing. A parachute is a bit like a modern, controllable air glide parachute, but it has several important differences from a parachute:

(1) Structure: A parachute is a take-off and landing equipment, so There are no DROUGE umbrellas or sliding parts, and its structure is also lighter (because it does not need to bear the momentum when it suddenly opens during a high-speed landing). The parachute has more air chambers and the parachute rope is thinner.

(2) Take-off method: The parachute must take off against the wind from a hillside with a drop. The speed of running forward and the speed of the wind generate the lift that lifts the parachute wing upwards. "After that, the person will be taken off the ground. High-altitude skydiving requires aviation vehicles, such as airplanes, hot-air balloons, etc.

(3) Parachute opening procedure: Before the parachute takes off, the parachute must be opened and spread on the ground. High-altitude skydiving is to pull the parachute out of the parachute bag after a period of free fall (or immediately) after jumping away from the vehicle.

(4) Flight performance: The parachute can hover, glide, climb, cross-country, and stay in the air. The parachute can only be used for descent.

(5) Appearance: The wingspan of the parachute is longer and the shape is close to a fusiform. The high-altitude parachute is rectangular, with a small guide parachute above it, and a square shock-absorbing cloth above the skydiver's head to reduce the vibration when the parachute wings are opened.

2. What is the difference between paragliding and hang gliding?

(1) A hang glider has a rigid frame that maintains the triangular shape of the wing body. The parachute's canopy relies on air pressure to maintain its fusiform, oval, or olive shape.

(2) The aerodynamic structure of a hang glider is relatively clear, and its flying speed is much faster than that of a paraglider.

(3) The hang glider pilot usually flies in a prone position hanging under the wing body, with a hanging bag like an insect chrysalis wrapped around his body. Paraglider pilots usually sit on a chair-type saddle (sometimes in a supine position), with two suspenders on their chest connected to the parachute.

(4) Control method: The hang glider is controlled by moving the center of gravity of the body: push forward - accelerate; pull back - decelerate; move left - turn left; move right - turn right. Paragliding uses two control ropes. Pull the left hand to turn left; pull the right hand to turn right; pull both hands to slow down. The price of a paraglider together with the saddle is approximately RMB 10,000 to RMB 50,000. The prices of paragliders of different models, levels and brands vary greatly. The following is a list of possible expenses:

Tuition: 1,500-2,000 yuan

Paragliding: 10,000-25,000 yuan

Saddle: 3,000-5,000 yuan

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Backup umbrella: 3500-7000 yuan

During use, the parachute will age due to various factors such as wear, pulling (this is the main factor), wind and sun exposure. Its service life is generally about 4 years, of course, this is closely related to the use conditions and frequency of use. Flying in the air is not unrestrained, "the sky is high, let me fly". Since there are often multiple aircraft flying in the same airspace at the same time, it is necessary to follow a specific flight plan just like when driving on the ground to avoid accidents. Generally as follows:

(1) The fast one must be slowed down.

(2) The motivated should let the unmotivated.

(3) When moving in the same direction, the one with a higher height should be moved away from the one with a lower height.

(4) When they are in the same direction and at the same height, the one on the right goes first.

(5) When two parties meet, each turn right.

(6) When overtaking, you should overtake from the right.

(7) When entering the hot air flow, the direction of the person who enters the air flow first shall be the direction.

(8) Those who are leaning against the mountain wall on the right can go straight.

(9) Do not fly outside the airspace designated by the local aviation control department to avoid accidentally entering military sensitive areas, national security sensitive areas, border management areas, etc. The first commandment: Your ground training is less than ten hours

Explanation: Paragliding is a dangerous sport, and it is an activity in a three-dimensional space. You think it will be easier than a two-dimensional activity such as learning to drive. ? When you learn to drive, you have to spend ten hours practicing at the coaching center, and when you actually start driving, it takes a while to get used to it. Compare the risks of the two. Which one do you think requires longer training time? Commandment 2: Your first solo flight should be complete with complete equipment, including main parachute, harness, secondary parachute, radio, and helmet. Note: These equipment are basic requirements. Of course, the more protection the harness has, the better. , the newer the umbrella, the better, and pay attention to the safety level and weight range of the umbrella, whether the radio has power, whether the reception is good, etc.

Some people will tell you that you don’t need to use a parachute because you can’t fly high. That’s a big mistake. Let me ask you: Is it more painful to fall from 50 meters, or from 60 meters? Both are likely to result in death. The third commandment: When you are about to fly for the first time, ask your instructor. If the radio fails or is interfered with and you cannot hear the instructor's instructions, what should you do if you are alone in the air? Note: Before flying, you should be prepared for all possible situations. Radio interference or poor battery contact due to collision during takeoff may occur. Your instructor should give you how to handle this situation. For your own safety, ask before taking off! ! The fourth commandment: Observe your instructor to see if his takeoff is as smooth as other masters. Even better: before you want to learn from a master, pay attention to all pilots to see what is a good takeoff and what is not. To take off, of course, a person who is called a coach should have outstanding skills and knowledge. Are you willing to find a meaty person to be your coach? I once saw a man who claims to be the first licensed instructor in Taiwan. After letting his students fly out, he was about to take off but couldn't pull up the umbrella. I really felt sad for his students... The fifth commandment: When you are about to fly for the first time, ask yourself, can my take-off action be as good as others? Note: The take-off action must be practiced until you are very proficient, because when you really want to fly, the take-off action will usually be worse than usual practice. Moreover, the parachute will not recognize whether you are a veteran or a beginner, and the action is not pulled properly. Just fall off the cliff, so be careful! The sixth commandment: Choose the appropriate weather for flying activities. Note: Water can carry a boat or overturn it. Paragliders rely on the atmosphere to fly. Not every weather is suitable. There are also different suitable weather conditions for beginners. Before taking off, Being able to understand the danger beforehand; and then avoiding the danger is what a smart person does... Ask your instructor, what kind of weather is suitable for flying? What kind of weather is dangerous weather? The seventh commandment: Keep a humble heart. Keeping a humble heart can help you improve your skills and broaden your social circle in flying. In this way, when special situations occur or are likely to occur, you will get a lot of advice or solutions. Method The power of nature is great. Today you can skillfully use air currents to hover high over many ridges. You may be a little excited and complacent, but the power of nature is still something you cannot conquer. You are still fragile in nature.