What exactly do the two concepts of wing load and thrust to weight ratio determine the performance o

The wing load will not directly affect the maximum level flight speed of the aircraft, but the large wing load leads to a high stall speed, so it must maintain a high-speed flight to keep the speed from time to time, so it gives people the illusion that the aircraft with a large wing load is fast. On the contrary, the larger the wing load requires greater power system support and a larger wing angle of attack, so it brings greater drag and the maximum level flight speed will be lower. So the smaller the wing load, the more floating, the easier it is to fly.

The reason for the large wing load of some high-speed aircraft that we usually see is not that the weight is deliberately increased for the sake of speed, but that in order to reduce drag, the wingspan of the wing needs to be reduced, resulting in an increase in the wing load. Due to the high velocity, the lift provided per unit wing area is large, and large wing loads are also acceptable. In this case, the large wing load is a by-product.

There are also 3D planes in order to reduce roll resistance and improve the structural strength of the wing, the wingspan is generally relatively small, and the wing load is also larger. What is certain is that the lighter the plane, the lighter the plane, the faster. The thrust-to-weight ratio affects the aircraft's ability to accelerate, as well as the maximum angle of attack.

When the angle of attack of the wing exceeds the angle of attack of the stall, the aircraft is pulled up by thrust with greater gravity.

The wing load determines the stability and speed of the aircraft, the thrust-to-weight ratio determines the climbing angle of the aircraft, and the wind resistance level.

It seems that the calculation of the load is mainly based on the fact that the aircraft is equipped with some kind of power under such a wing area. Whether it can bear it or not, it generally seems that we can count the load of a level flight cruise at most. But the material must be several times higher. Otherwise, it is estimated that a dive will be broken.

Wing load refers to the average weight of a wing per unit.

According to the old man, the greater the wing load, the better!!

Wing load refers to the ratio of aircraft mass to wing area. Wing load is usually referred to as the wing load at takeoff, which is the ratio of the mass of the take-off aircraft to the wing area. Wing load is one of the main parameters of the overall design of the aircraft, which is related to the take-off and landing performance, climb performance, maneuverability performance, maximum range and ceiling of the aircraft.

In general, aircraft that require good maneuverability and small take-off and landing speeds use small wing loads, while aircraft that require high speed use large wing loads.

The thrust-to-weight ratio is a comprehensive performance index, which not only reflects the level of the jet engine in terms of aerothermal cycle, but also reflects the level of design in terms of structure. It has a direct impact on the flight performance and payload of the aircraft, among other things. The maximum level flight speed, climb rate, ceiling, maneuverability, etc. of the aircraft are all related to the thrust-to-weight ratio of the aircraft.

Leaps in the thrust-to-weight ratio of the engine often lead to the emergence of a new generation of fighters. The ratio of engine thrust to engine weight (force) or aircraft weight (force), which represents the thrust produced by the engine or aircraft per unit weight (force). The ratio of the thrust generated by the engine to the weight (force) of the engine structure under the condition of sea level stationary at the maximum state (the afterburner engine is in the full afterburner state) is called the engine thrust-to-weight ratio, which is one of the important performance indicators of the engine.

Thrust is not directly related to load.

The thrust of the aircraft is equal to the drag and the lift is equal to the gravitational force when cruising in level flight.

The greater the load, the greater the gravity and the greater the lift.

But the lift of the aircraft depends on three factors, speed, angle of attack and wing area. In order to ensure the lift of the aircraft in the case of increased load, it is necessary to increase the speed, angle of attack and wing area of the aircraft at the same flight altitude. Increasing these will increase the drag of the aircraft, so it must be compensated for by increasing thrust.

So the heavier the aircraft, the more thrust is needed.

The second impact lies in the take-off and landing of aircraft, especially take-offs.

The take-off principle of an airplane is simply to accelerate to a certain speed on a runway of a certain length to generate sufficient lift. The heavier the aircraft, the greater the lift required, and in cases where the wing area, lift coefficient, angle of attack are limited, it is necessary to reach a faster speed in order to take off. In the case of a limited lift slope and a limited runway length, to achieve a higher speed, it is necessary to increase the thrust at a greater rate.

So the same plane, the heavier, the more thrust it needs to take off, and the longer the runway it needs.

The relationship between the two is obvious.

For a model of aircraft, when it is designed and put into service, its thrust and maximum load capacity are determined.

For different types of aircraft, the greater the thrust of the aircraft, the greater its maximum load capacity, which is the relationship between thrust and load capacity, because, without enough thrust, the aircraft can not reach the speed required for take-off, and without enough speed, it cannot produce enough lift. It is not possible to transport the goods of the corresponding weight to the sky.

Therefore, the thrust of the aircraft determines its carrying capacity.

When designing an airplane, we usually apply it upside down, and we know at the beginning of the design how much we want to design an aircraft with a load capacity, and we can calculate how much take-off thrust is needed to design this kind of aircraft.

Hope it helps

Of course, the heavier the thrust, the greater the thrust, but the size of the thrust of the aircraft is also related to the weather, thrust coefficient, and outside temperature.

2- What are the types of external loads acting on the wings?

Hello dear dear, I am happy to answer for you, the wing is an important part of the aircraft, its role is to generate lift, so that the aircraft can fly in the air. The external load on the wing can have an impact on the flight performance of the aircraft, so it needs to be analyzed and designed. The external loads on the wing mainly include the following:

Aerodynamic loads: Since the wings need to generate yamsia lift during flight, the action of the air flow on the wings creates aerodynamic loads. Aerodynamic loads include lift, drag, pull, and thrust, among others.

Gravity loads: The gravity loads on the wings come from the aircraft itself and the cargo, fuel, etc. it carries. Gravity loads have an impact on the strength and stiffness of the wing.

Inertial load: An inertial load is a load that occurs due to the acceleration and deceleration of an aircraft. It can have an impact on the structure and strength of the wing.

External load: The external load includes the load generated by external factors such as wind load, temperature change, ice and snow cover, etc. These loads can all have an impact on the strength, stability and safety of the wing.

To sum up, the external load on the wing mainly includes air-started motion load, gravity load, inertial load and external load. These loads need to be considered in the design and analysis of the wing to ensure that the structure and performance of the wing can meet the requirements of the aircraft.

The characteristics of the external load of the wing are: the aerodynamic load and the mass force of the wing structure gradually increase from the wing tip to the wing root, so the wing structure gradually widens and thickens from the wing tip to the wing root; After installing the engine and adding fuel on the wing, the wing root can be reduced in flight, and this effect is called unloading.

The wing is one of the important parts of the aircraft and is mounted on the fuselage. The main function of the stool noise is to generate lift, which together with the rear wing forms good stability and maneuverability. In addition, ammunition, equipment and fuel tanks can be loaded inside the wing, and landing gear, engines, suspended missiles, auxiliary fuel tanks and other external equipment can be installed on the wing.

Structural jujube service form: skin skeleton type, integral wall plate type and mezzanine type.

Aircraft load refers to the load factor.

The components of the load factor in the direction of the three main axes of the body coordinate axis system are nx, ny, nz (see overview diagram). The ratio of the component of the total external force other than gravity in the y direction (which can be approximated as the lift force y) to the gravitational force g of the aircraft is the load factor ny in the y direction, which may or may be positive, depending on the direction of the external force. When the lift y is in the same direction as the positive direction of the y axis, it is positive, and vice versa.

In the case of flat direct flight**, the lift of the aircraft is only required to be equal to the gravity, that is, y=g, at this time, ny=y g=1. If the aircraft flies straight upside down at constant velocity, then ny=-1 (so the direction of lift is opposite to the positive direction of the y-axis). However, when flying in a curve, such as in the case of dive pulling, the lift force is greater than the radial component g·cos of the aircraft's gravity, and the difference between these two forces causes the aircraft to produce centripetal acceleration, and the flight trajectory is bent upward.

At this time, ny=y g=cos +v2 gr, when pulled up violently at a large speed and small radius, a large positive larger will be generated, indicating that the lift force is greater than the gravity of the aircraft, and the more serious the force on the aircraft.

Of course, in the x-direction of the aircraft, there is also an inertial force nx associated with tangent acceleration, i.e. (

According to the definition, in various flying conditions such as dives and pull-ups, the load coefficient of the x-square leakage deviation should be: the ratio of all external forces (components in the x-direction) in the x-direction (along the x-direction component) to gravity except gravity, and the return sum is (

Substitute the formula (substitution (get.

Because AX is generally small (the formula (which corresponds to the afterburner in the dive pull-up flight), and the strength and stiffness of the aircraft structure in the X direction are better, NX is often not considered except for special circumstances (such as landing brakes, forward impact, etc.). When flying at a straight and constant velocity, t=x, nx=0. In addition, the overload in the Z direction is generally small and is not considered, so the load factor in the Y direction is the key consideration.