CN105109669A - Aircraft recovery spin improving device - Google Patents

Abstract

The invention relates to an aircraft spin recovery improving device, belongs to the aircraft industry which comprises the aircraft controllability and the stability field, and aims at improving the use safety and reaching the necessary quality of the training aircraft. The plan of the device shows that the device comprises two horizontal tail strakes in lifting surface forms. The two lifting surfaces are symmetrically arranged on the tail part of the aircraft relative to the longitudinal symmetrical surface of the aircraft and are connected with a horizontal tail near the wing root chord of the horizontal tail. In a range of 1.1-1.5b of each lifting surface along the aircraft body length, the maximum width can be reached between each lifting surface and the connection part, and the maximum width is in the range of 0.1-0.15b, wherein b is the wing root chord of the horizontal tail. The swept-back angle from the middle of each lifting surface to the horizontal tail is 90 degrees to 115 degrees. When any of the present recovery method is operated, the device provided by the invention enables the aircraft to recover the spin even when all of the control mechanism is deflected to the middle position, so as to improve the aircraft operational safety substantially.

Description

Aircraft changes tailspin improving device

Technical field

The invention belongs to aviation field, the invention of recommendation is used for making schoolaeroplane change tailspin and is improved, and can train aviator, with diverse ways, aircraft is changed tailspin, is specifically related to aircraft and changes tailspin improving device.

Background technology

Find out and improve aircraft changes characteristic scientific and technological scheme from tailspin state, first must ensure the safety in utilization of aircraft.As everyone knows, according to world's aircraft accident statistics, nearly 50% aircraft accident and accident be all occur under such conditions (" airplane aerodynamic under At High Angle of Attack. books inventory ", associating Science Press of Russian central fluid dynamic study institute, 1990; " General Aviation. the suggestion to design engineer ", В. and Г. М и к e л а д з e, Russian central fluid dynamic study institute publishes, the 2001,213rd page).

In addition, change Tail chain with schoolaeroplane and improve relevant also the comprising of problem:

On the one hand, it can be accepted the relatively less aviator's use of training;

On the other hand, on this aircraft, be generally training aviator, must demonstrate out aircraft is changed tailspin all Existing methods (" General Aviation. the suggestion to design engineer ", В. Г. М и к e л а д з e, central fluid dynamic study institute of Russia publishes, the 2001,276th page; Russian Federation patent № 2297364, М П К В 64 С 5/08,2007; CN201694385, М П К B64C17/00; B64C3/00,2011; US Patent 5,575,442, М П К B63H1/18; B64C21/00,1996).

So-called Λ shape wing edge strip device as you know, it is being equipped with sweepforward edge (" Russian central fluid dynamic study institute academic journal " with fuselage connection bit, Х Х VII volume, the № 1-2 phase, 1996, В o ж д а e в Е. С., Г o л o в к и н В. А., Г o л o в к и н М. А., Д o л ж e н к o Н. Н .).The whirlpool bundle that this Λ shape edge strip can cause afterbody and wing edge strip itself to be formed is installed be separated.Therefore, when breakking away appears in bundle below, the edge strip expanded along the leeward outer wing of wing leeward whirlpool, less negative pressure can be formed, and formation causes the less lift occurring stable rolling moment, thus improve the stalling characteristics of aircraft.

The defect of this device is that it for not having the aircraft of wing edge strip, and can not can not determine that it is on the impact changing Tail chain.

Immediate in the technical scheme be familiar with is a kind of device with edge strip, the profile of edge strip is two triangle lifting surfaces, be arranged on afterbody, symmetrical relative to the longitudinal plane of symmetry of aircraft, and dock with horizontal tail near wing root wing chord (network address: http://www.airwar.ru/enc/other/stucano.html and www.embraerdefensesystems.com/english/content/combat/tuc ano_three_view.asp).

This edge strip is installed before horizontal tail, as the test results of carrying out in vertical wind tunnel, will causes:

-under At High Angle of Attack, there will be extra underriding moment;

-increase damping due to rotation;

-due to above-mentioned two factors, aircraft can enter steep tailspin state by the horizontal tail state of revolving occurred during angle of attack α ≈ 70 °, and the angle of attack is at this moment α ≈ 50 °, and gyrofrequency can be lower.

Like this, be improved although aircraft changes Tail chain, so-called reinforcement drive manner (in this case start to be the complete anti-tailspin deflection of aileron and yaw rudder, circle---yaw rudder completely down then to cross 0.5) can only be used to change.This device and device similar with it all can not ensure to change tailspin state for additive method by aircraft, comprising all steering units deflect into simultaneously neutral and all steering units in the correct order (yaw rudder and aileron deflect into center position simultaneously, cross 0.5 ~ 1 enclose after---elevating rudder deflects into center position) situation.

Summary of the invention

Task of the present invention and technical achievement change tailspin improving device to develop a kind of aircraft, the Tail chain of aircraft can be improved and change Tail chain, guarantee the safety in utilization improving aircraft, this point is to schoolaeroplane particular importance, usually, aviator will go to school at such aircraft can the method that changes of all tailspins.

Aircraft changes tailspin improving device, changes tailspin improving device can obtain task solution and technical achievement by this aircraft.This device comprises the edge strip that profile is two lifting surfaces, and they are arranged on afterbody, symmetrical relative to the longitudinal plane of symmetry of aircraft, and is connected with horizontal tail near horizontal tail wing root wing chord.The length of each lifting surface is 1.1 ~ 1.5b along fuselage length direction, and is 0.1 ~ 0.15b with the maximum width of horizontal tail junction, and wherein b is horizontal tail wing root wing chord, and each lifting surface mid-length is 90 ° ~ 115 ° to the sweepback angle of horizontal tail.

This geometric shape of device and position be on the experimental investigation basis under the schoolaeroplane dynamic similarity model tailspin state of carrying out in vertical wind tunnel, and to have determined after this device has carried out calculating assessment to the impact of model characteristics with regard to installing.During super high-angle-of-attack flight, the fuselage cross-section installing edge strip position near horizontal tail can form extra normal force, and this normal force can cause occurring extra underriding moment.Thus, compared with initial scheme, under the tailspin of model appears in the less angle of attack.In addition, when tailspin state drag rotates, in windward side, dock formed dihedral angle by the lifting surface being arranged in windward side with fuselage and can form extra air flow resistance, thus cause rotational resistance to increase, namely damping increases, and model can rotate with less cireular frequency.With prototype unlike, the lifting surface shape of the formation horizontal tail edge strip selected, size and sweepback angle, the eddy current lifting surface lateral edges is formed windward is caused to leave vertical fin, but directly in its vicinity and form wash, these wash can promote the extra damping relying on vertical fin to produce, thus, also reduce further spin velocity.

The geometric shape that the device recommended is formed can ensure edge strip to be formed enough normal force near horizontal tail, and extra damping due to rotation.Namely this damping due to rotation depends on the lifting surface being arranged in windward side docks formed dihedral angle and formed air flow resistance with fuselage, and depend on again the eddy current that this lifting surface lateral edges is formed, formation and the vertical fin of eddy current interact well.

Accompanying drawing explanation

Fig. 1,2 gives various configuration scheme and gets off the plane and change the full view of tailspin improving device.

Fig. 3 gives the formation mechanism causing the extra underriding moment that the angle of attack reduces in tailspin, and damping rotates additional force square formation mechanism.

The eddy current that Fig. 4 gives lifting surface lateral edges is formed windward is formed, and it and vertical fin interact well, and form damping additional moment due to rotation.

What Fig. 5 provided is the test results being with the schoolaeroplane free flight dynamic similarity model of recommendation apparatus to change tailspin by reinforcement drive manner in vertical wind tunnel, and wherein t is the time, and ψ is the model rotation angle of relative vertical line; α is the angle of attack; β is angle of side slip; δ is steering unit angle of inclination.Here following abbreviation is additionally used: р. н. – yaw rudder, р. в. – elevating rudder, э л e р o н (п р .) – shows that starboard aileron deflects.

What Fig. 6 provided is same model deflects into test results when center position changes tailspin at all steering units.

Fig. 7 is the model test result in initial scheme, not with recommended device, by reinforcement drive manner when changing tailspin.

The model test result of what Fig. 8 provided is band prototype plant, by reinforcement drive manner when changing tailspin.

Fig. 9 gives the model test result of band prototype plant, when changing tailspin, all steering units is deflected into center position.

Detailed description of the invention

Aircraft changes tailspin improving device (Fig. 1) and comprises edge strip near horizontal tail, and planar view profile is two lifting surfaces 1 and 2, is arranged on afterbody 3, symmetrical relative to the longitudinal plane of symmetry 4 of aircraft, is connected near horizontal tail wing root wing chord with horizontal tail 5.Length along each lifting surface in fuselage length direction is 1.1 ~ 1.5b, is 0.1 ~ 0.15b with the maximum width of each lifting surface of horizontal tail connection location, and wherein b is horizontal tail wing root wing chord, and mid-length is 90 ° ~ 115 ° to the sweepback angle of horizontal tail.

Present research aircraft changes the service condition of tailspin improving device (Fig. 1,2).Its saddlebag is containing as follows.Aircraft is when Dare's critical angle of attack, the flight of tailspin state, install institute recommendation apparatus fuselage cross-section, on fuselage and device itself, there is the extra supercharging of air flow resistance, therefore, form extra normal force Δ N (Fig. 3) at longitudinal plane of symmetry, this normal force is impelled and is formed extra underriding moment Δ Mz and reduce the aircraft α angle of attack.Under tailspin state, that is, when there is spin velocity ω, time, form streaming of general speed vector W, this velocity vector equals speed V and is rotated the vector of the linear speed ω × r × sin α caused by model aircraft angle, and wherein r is the current distance from model center of gravity to А-А cross section.In a word, form extra air flow resistance at dihedral angle (windward lifting surface and fuselage dock), and form power P1 and damping moment of rotation M д 1 (Fig. 3).Therefore, the motion of model has less cireular frequency.With prototype unlike, size and sweepback angle selected by the lifting surface forming horizontal tail annex edge strip can cause forming Γ at the eddy current that lifting surface lateral edges occurs windward and not leave vertical fin (Fig. 4), but directly pass through in its vicinity.This eddy current formation can produce induction velocity υ i, and these induction velocitys can form power P2 and extra damping moment of rotation M д 2 at vertical fin, and correspondingly reduce spin velocity ω.The physical dimension that the device recommended is formed can ensure the recited above enough good effect produced because installing this device, therefore, the model mean angle of attack α when free flight=f (t) (Fig. 5,6) is α ≈ 45 °, rotational frequency ω=6.51/ second, namely (Fig. 5 and Fig. 6, ψ=f (t)).This just can make schoolaeroplane change tailspin with adding strong method in about 0.5 circle, that is, after the anti-tailspin action of all rudder faces, ψ (t) ≈ 180 °, and after all rudder face actions in about 2.5 circles (Fig. 6), even just can change tailspin by schoolaeroplane by all steering units being deflected into center position, so final substance raising that can ensure aircraft utilization safety.Fig. 7, in order to compare, gives original model test results when not having institute's recommendation apparatus.Can find out, the mean angle of attack of original model in tailspin is α ≈ 71 °, gyrofrequency is ω=101/ second, does not even also change tailspin (angle of attack is not reduced to acceptable about 15 ~ 20 °) when the corresponding so-called reinforcement changing ways of steering unit sequence of operation at about 5 circle inner models simultaneously.Fig. 8, Fig. 9, in order to compare with Fig. 5, Fig. 6, show the test results of band prototype plant.Can find out, the tailspin of model occurs in mean angle of attack α ≈ 50 °, and gyrofrequency is ω=6.81/ second.These parameter values are obviously less better than band institute recommendation apparatus model.Model with prototype plant can change tailspin (Fig. 8) with adding strong method, but as what can see in Fig. 9, model does not change tailspin after each rudder face action to center position.Test of many times shows, be with the model of prototype plant to only have and change tailspin with the employing of reinforcement drive manner, this is inadequate for the schoolaeroplane for training aviator.

The effect having been confirmed in the test of vertical wind tunnel the device that installation is recommended by math modeling and dynamic similarity free flight model and reached is good.

Claims (1)

1. an aircraft changes tailspin improving device, it comprises the edge strip of two lifting surface forms, these two lifting surfaces are arranged on afterbody relative to the longitudinal plane of symmetry symmetry of aircraft and are directly docking with horizontal tail close near horizontal tail wing root wing chord, it is characterized in that, along each lifting surface length of fuselage length within the scope of 1.1 ~ 1.5b, and each lifting surface reaches maximum width at the joint of itself and horizontal tail, this maximum width is within the scope of 0.1 ~ 0.15b, wherein, b is horizontal tail wing root wing chord, and each lifting surface mid-length is 90 ° ~ 115 ° to the sweepback angle of horizontal tail.