RU2722597C1 - Method of aircraft braking during landing - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: method of aircraft braking during landing consists in creation of braking force by reactive braking device directed to rear hemisphere against movement of aircraft using solid propellant or powder charges, which action is directed forward and upward at angle of 30÷50° to the aircraft horizontal reference line, which are actuated when touching or in close proximity of landing gear to landing strip and pressing aircraft to landing strip with inclusion of brake system of wheels. Charges are arranged so that vector of braking reactive force passes through center of mass of aircraft or in front of it at distance of up to 0.5 m, which provides fast lowering of nose landing gear, and accordingly, inclusion of brake system of wheels.

EFFECT: invention is aimed at reduction of landing run.

1 cl, 3 dwg

Description

The invention relates to the field of studies of flight dynamics of aircraft, stability and controllability of aircraft in landing mode and can be used to implement their landing on a short runway.

Recently, harsh requirements have been placed on maneuverable aircraft for basing on short and ultra-short runways. One of the conditions for fulfilling these requirements is to ensure a short path when landing after touching the runway.

The main braking methods for modern aircraft of a normal take-off and landing pattern are:

- braking by wheels (patent RU 2469912 "A method of reducing the mean free path of an aircraft and a device for its implementation"), in which the mean free path is reduced by controlling the brake system of the wheels;

- the use of brake parachutes (patent RU 2208542 “Method for putting into operation an exhaust parachute using an air gun”), in which the path length is reduced by quickly releasing the parachute when the runway is touched;

- the use of thrust reverse (patent RU 2044912 "Reversing device"), in which using the reversing device of the power plant create a braking force acting on the aircraft during run along the runway.

При рассмотрении возможности базирования летательных аппаратов на аэродромах с короткой ВПП, длина которой существенно меньше (например, вдвое) длины ВПП класса Е - самого низшего класса по классификации аэродромов (М.Ю. Купринов, «Классификация аэродромов», Большая Российская Энциклопедия), применение указанных выше способов торможения может привести к выкатыванию летательного аппарата за пределы короткой ВПП. Предварительные оценки показывают, что для посадки летательного аппарата на короткую ВПП необходимо создать среднюю продольную перегрузку при пробеге и торможении

Using these methods or their acceptable combinations can significantly reduce the path length of aircraft and provide landing on the runway with the length of a given class of runways. However, the use of these methods, even in combination, allows you to create a longitudinal overload during braking of less than one, i.e.

When considering the possibility of basing aircraft at aerodromes with a short runway, the length of which is significantly less than (for example, half) the length of a class E runway - the lowest class in the classification of aerodromes (M.Yu. Kuprinov, “Classification of airfields”, Big Russian Encyclopedia), application the above braking methods can cause the aircraft to roll out of the short runway. Preliminary estimates show that for landing the aircraft on a short runway, it is necessary to create an average longitudinal overload during mileage and braking

Landing on a short runway, with a specified value of the longitudinal overload during braking, can be achieved through the use of ground-based aerofinisher. This method is implemented during the emergency landing of some maneuverable aircraft ("Arresting gear, Land-based systems", Wikipedia.pdf). When implementing this method, the aircraft is equipped with a brake hook, when it is approaching, it is released lead to a position suitable for grasping the cable of the aerofinisher stretched across the runway. However, this method requires the use of aerodromes with stationary aerofinisher or deployment of a mobile aerofinisher on the runway. Thus, this method of braking is not autonomous from the point of view of using devices located only on the aircraft.

From open sources (https://pikabu.ru/story/razgonnotormoznaya_reaktivnaya_sistema_dlya_sokrashcheniya_razbegaprobega_samoletov_6314789, 10/10/2019), a landing braking method was realized that was implemented in 1980 on a military transport aircraft carrying out S-130 mission. Two groups of powder charges were used to provide landing and one as boosters for takeoff. When landing, one group of charges was installed in the nose of the fuselage and their action was directed at a slight angle to the horizontal construction. Their function was to decelerate the aircraft in the air at altitudes of ≈5 m from the landing strip; after they were worked out, charges were placed on the fuselage vertically in the vicinity of the landing gear. The function of these charges was to create a vertical force acting upward to ensure the vertical landing speed permissible by the chassis strength. The actions of these charge groups were initially supposed to be synchronized electronically. Ultimately, the inclusion of the second group of charges was assigned to the operator. As a result of one of the test flights, the inclusion of the second group was not made, which led to a hard landing and destruction of the aircraft.

Closest to the proposed method is “Aircraft braking method” set forth in patent RU No. 2094329, which proposes aircraft braking using reactive lateral rotary engines, which are installed in a vertical position before touching the runway and create a compressive force in the initial run the aircraft to the runway, and then the engines are moved to a horizontal position, which act on the aircraft and create force in the direction opposite to its landing speed, i.e. in the back hemisphere. However, when implementing this method for maneuverable aircraft, the requirement for a given path length cannot be fulfilled, as well as a number of safety requirements for the movement of aircraft during landing and run along the runway, namely, not allowing the tail part to touch the runway surface or overload the nose landing gear . In addition, the use of rotary engines requires refinement of the power plant in terms of the presence of a mechanism that allows you to quickly turn the engines from horizontal to vertical position and then to a horizontal position in the opposite direction to the movement of the aircraft. Modern actuators (drives) provide rotation of aircraft structural elements (aircraft control surfaces - elevators, ailerons) with a maximum speed of 30 deg / s in the range of deviation angles of ± 30 °. If the brake engines are an auxiliary device, then their launch when the aircraft touches the runway takes a sufficiently long period of time, the process of turning the brake engines from vertical to horizontal also takes considerable time. If the engines indicated in the patent are used as the main engines, then when landing they are in the “low gas” mode and the time to reach maximum thrust when the aircraft touches the runway also takes considerable time. The thrust-weight ratio of jet engines and the sequence of actions for their use during the run cannot provide the required braking force. In addition, the location of jet engines outside the fuselage of the aircraft leads to a significant increase in drag and, consequently, high fuel consumption in flight.

Thus, even when using drives with the above characteristics, rotation of the engines from horizontal to vertical, and then to horizontal against the movement of the aircraft takes an excessively long time and does not provide the required level of longitudinal braking overload and does not provide landing on a short runway.

The technical result of the invention is the provision of braking of the aircraft during landing on a short runway.

The technical result is achieved by the fact that in the method of braking the aircraft during landing, in which they create a braking reactive force directed into the rear hemisphere against the movement of the aircraft, the braking reactive force is created using solid propellant or powder charges, the action of which is directed forward and upward at an angle of 30 ÷ 50 ° to the aircraft construction horizontal, triggered by touching or in close proximity of the landing gear to the landing strip and pressing the aircraft to the landing strip with the brake system of the wheels on. The charges are placed in such a way that the vector of the braking reactive force passes through the center of mass of the aircraft or in front of it at a distance of up to 0.5 m

на пробеге по ВПП.When the proposed method provides braking of the aircraft with longitudinal overload

on the runway run.

As a reactive braking device (RTU), powder charges can be used that were previously used during take-off of aircraft for their additional acceleration and discarded after separation of the aircraft from the runway. In the proposed braking method, it is proposed to use similar devices, but with a change in the direction of the force acting on the aircraft from these devices.

The list of figures in the drawings

In FIG. 1 shows a layout of a reactive braking device on an aircraft.

In FIG. 2 shows a diagram of the action on the aircraft of braking force and the resulting longitudinal moment from the RTU.

In FIG. 3 shows a diagram of the implementation of the proposed braking method.

In figures 1-3 are indicated:

1 - aircraft

2 - RTU (reactive brake device),

3 - the center of mass of the aircraft,

4 - the line along which the jet of powder gases and the reactive force created by the RTU are directed,

5 - the installation angle of the RTU relative to the construction horizontal,

6 - x-coordinate of the RTU in the associated coordinate system,

7 - the y-coordinate of the RTU in a connected coordinate system,

8 - the main landing gear of the aircraft,

9 - the nose landing gear of the aircraft,

10 is the velocity vector,

11 - angle of attack,

12 - reactive force created by the RTU,

13 is a longitudinal moment from the RTU,

14 - the scope of the hot gases of the RTU,

15 - runway,

16 - height measurement sensor,

17 - the height determined by the sensor 16,

18 - the height of the tail of the aircraft relative to the runway,

19 - the height of the main chassis relative to the runway,

20 - the height of the main chassis at which the inclusion of the RTU,

21 - on-board computer,

22 - force from the brake system of the wheels,

23 - trajectory of the center of mass of the aircraft.

The layout of the jet braking device in the fuselage of the aircraft near its center of mass and the line along which the gases of the jet device and the reactive force created by the RTU are directed are shown in FIG. 1.

The force from the reactive braking device is directed forward at an angle to the horizontal plane of the aircraft (Fig. 2), so that the stream of powder gases passes above its body, which ensures that no hot powder gases affect the structure of the aircraft, as well as their impact on the surface of the runway and does not lead to the entry into the air intakes of the power plant of foreign objects.

If it is not possible to install a RTU near the center of mass, either a longitudinal dive can act on the aircraft, as shown in FIG. 2, or the converting moment from the powder gases, depending on whether the force vector passes from their action above or below the center of mass. The diving longitudinal moment from the RTU provides a decrease in the pitch angle of the aircraft before touching the runway and a safe height of the tail of the aircraft relative to the runway, as well as faster lowering of the nose landing gear and, accordingly, the inclusion of the brake system of the wheels.

The effect of the longitudinal moment from the RTU on the cabling can lead to either the tail portion of the aircraft touching the runway surface when the RTU is turned on in air before contact with the runway, or to a jump during run when the RTU is turned on while the aircraft is moving in a strip.

To compensate for the unfavorable longitudinal longitudinal moment from the RTU, auxiliary powder charges can be installed in the fuselage to compensate for this moment. The simultaneous inclusion of the main and auxiliary powder charges provides, on the one hand, the creation of the required braking force, and on the other hand, a diving longitudinal moment from the combined RTU.

Since there is a time of buildup of force from the powder charges, they must be turned on either during compression of the main landing gear, or at a certain height before touching so that by the moment the aircraft touches the surface of the runway, the reactive braking device creates a longitudinal overload from the RTU during the run, close to maximum value.

The braking method is as follows (Fig. 3):

the aircraft 1 lands on a given glide path, the height sensor 16 determines the height of the aircraft from the surface of the runway 17 and the on-board calculator 21 determines the distance 19 from the lower point of the main landing gear to the surface of the runway, when reaching a height of 20 turning on the RTU, they generate a signal to activate the reactive brake device 2 , using solid propellant or powder charges of the RTU, the action of which is directed forward and upward at an angle of 30 ÷ 50 ° to the horizontal plane of the aircraft, create a reactive force 12 directed into the rear hemisphere against the movement of the aircraft, while ensuring the passage of the vector of the braking reactive force through the center of mass of the aircraft or in front of it at a distance of up to 0.5 m, thereby creating a longitudinal moment 13 leading to lowering of the nose landing gear and turning on the brake system of the wheels at the very beginning of the run of the aircraft along the runway, which is the reactive force vector directed towards the runway, press the aircraft to The runway and increase the force from the braking system of the wheels 22 and, accordingly, the longitudinal overload during braking, when the aircraft reaches a speed close to zero, cut off the jet from the RTU and stop the aircraft.

создаваемой РТУ и системой торможения колес, позволяет обеспечить требуемую длину пробега, при этом нагрузки на шасси при касании ВПП не превышают эксплуатационных значений.The validity of the achievement of the technical result is confirmed by the calculations of the braking process during landing of the aircraft, which show that the average value of the longitudinal overload

created by the RTU and the wheel braking system, allows to provide the required path length, while the load on the chassis when touching the runway does not exceed operational values.

Claims (2)

1. The method of braking the aircraft during landing, in which they create a braking reactive force directed into the rear hemisphere against the movement of the aircraft, characterized in that the braking reactive force is created using solid propellant or powder charges, the action of which is directed forward and upward at an angle of 30 ÷ 50 ° to the aircraft construction horizontal, triggered by touching or in close proximity of the landing gear to the landing strip and pressing the aircraft to the landing strip with the brake system of the wheels on. 2. The method according to p. 1, characterized in that the charges are placed in such a way that the vector of the braking reactive force passes through the center of mass of the aircraft or in front of it at a distance of up to 0.5 m

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