RU2102287C1 - Aircraft - Google Patents

Abstract

FIELD: aeronautical engineering; aircraft aerodynamic configuration. SUBSTANCE: aircraft has two- wing combination: one wing is located in front of CG and other located after CG and aerodynamic center of wing combination coincides with aircraft CG. EFFECT: enhanced efficiency. 7 dwg

Description

 The invention relates to aeronautical engineering, in particular to the aerodynamic design of an airplane of local air lines (MVL).

 MVL aircraft are usually operated at short unpaved airfields and are usually multi-purpose aircraft carrying passengers and various household goods. They can simultaneously be passenger, cargo-passenger and cargo.

 Therefore, for them, very important parameters are the presence of a powerful take-off and landing mechanization, which provides the characteristics of a short take-off and landing (KVP), and a wide range of flight alignments to provide any option for placing cargo in the fuselage.

MVL aircraft are known that have effective wing take-off and landing mechanization, allowing them to have the characteristics of a KVP aircraft. Closest to the proposed invention are:
1. An-2 airplane (An-2 airplane, Transport Publishing House, 1969).

 The biplane has two wings, located one above the other. The upper wing is equipped with rotary slotted flaps and slotted ailerons-flaps. The lower wing is equipped with rotary slotted flaps throughout the scope.

 The aircraft has incessant horizontal plumage and therefore has a limited range of operational alignments. The maximum allowable alignment of the aircraft is within 17.2% 33% of the MAR (average aerodynamic chord of the wing), the recommended alignment, providing the easiest control of the aircraft, is within 23% 28% of the MAR.

 In FIG. 7 is a diagram of the aircraft balancing. The diagram shows that the range of alignment of the aircraft is limited due to the limitation of the maximum front centering. For its expansion, the introduction of horizontal shifting plumage is necessary, but this complicates the design and operation of the aircraft and affects flight safety. Therefore, the aircraft is very strict and critical to the placement of goods (for centering on the aircraft, the use of centering cargo weighing up to 50 kg is provided) and the movement of passengers in flight (only with the knowledge of the crew!).

 2. Aircraft "NOMAD" (technical information N14, 1976).

 The aircraft is a high-wing aircraft with a large winged strut equipped with double-slotted rotary flaps and slotted ailerons.

 To ensure the balance of the aircraft with the take-off and landing mechanization released and to provide a range of operational alignments of 22.5% of the MAR, the aircraft is equipped with a fully rotatable controlled stabilizer, the use of which complicates, aggravates and increases the cost of aircraft construction and complicates its operation.

 In the case of using more powerful and efficient sliding take-off and landing mechanization (which creates large aerodynamic moments) and, at the same time, a wide range of operational alignments, for example, 30% of the MAR, it is practically impossible to solve the problem of balancing the aircraft in the longitudinal channel.

 The aim of the invention is to eliminate the disadvantages of these aircraft and the creation of an aircraft having a minimum size, high take-off and landing characteristics of short take-off and landing and a wide range of operational centers.

совпадает с центром тяжести самолета, а соотношение площадей взлетно-посадочной механизации крыльев

где: (фиг. 4, 5) B₁ хорда переднего крыла;
b_mex1 b_mex2- хорда переднего и заднего крыла с выпущенной механизацией;
S_mex1S_mex2- площадь механизации переднего и заднего крыла - площадь закрылка с обслуживаемой впереди него площадью крыла;
C $\genfrac{}{}{0ex}{}{\text{α}}{\text{y1}}$ , C $\genfrac{}{}{0ex}{}{\text{α}}{\text{y2}}$ производные коэффициентов подъемной силы переднего и заднего крыла;
S₁ S₂ площадь переднего и заднего крыла;
L аэродинамическое плечо комбинации крыльев расстояние между линиями 25% хорд переднего и заднего крыла;
K коэффициент торможения потока по углу атаки.This goal, according to the invention, is achieved by the fact that the proposed aircraft has a wing in the form of a combination of two wings, one of which is installed in front, the other behind the center of gravity of the aircraft so that the aerodynamic focus of the isolated combination of wings located at a distance from the front edge of the front wing ( Fig. 4),

coincides with the center of gravity of the aircraft, and the ratio of the areas of the take-off and landing mechanization of the wings

where: (Fig. 4, 5) B _{1 the} chord of the front wing;
b _mex1 b _mex2 - chord of the front and rear wing with the released mechanization;
S _mex1 S _mex2 - mechanized area of the front and rear wing - flap area with the wing area served in front of it;
C $\genfrac{}{}{0ex}{}{\text{α}}{\text{y1}}$ , C $\genfrac{}{}{0ex}{}{\text{α}}{\text{y2}}$ derivatives of the lift coefficients of the front and rear wings;
S ₁ S _{2 the} area of the front and rear wing;
L aerodynamic shoulder wing combination the distance between the lines of 25% of the chords of the front and rear wings;
K coefficient of inhibition of flow by angle of attack.

The invention is illustrated by drawings:
FIG. 1 is a plan view of the plane, FIG. 2 is a side view of the aircraft; FIG. 3 is a front view of the aircraft; FIG. 4 is a plan view of a combination of wings; FIG. 5 is a wing section, FIG. 6 is an airplane balancing circuit; FIG. 7 balancing scheme of the An-2 aircraft.

 The proposed aircraft is (Fig. 1, 2, 3) a multi-purpose aircraft for short take-off and landing, having the required length of unpaved runway 550 meters.

 It has a fuselage 1, front wing 2, rear wing 3, nonperishable horizontal tail 4, vertical tail 5. The front wing has sliding flaps 8 throughout the span of the consoles, the rear wing sliding flaps 9 and slotted ailerons 10 (Fig. 5).

 Horizontal tail 4 has a rudder 6, vertical tail 5 - rudder 7.

 The aerodynamic design of the proposed aircraft is as follows.

 When flying in cruising configuration (Fig. 5) (flaps 8 and 9 in the retracted position), the aircraft is balanced in the longitudinal channel. All actual deviations of the centering of the aircraft are compensated by deviations of the elevator 6.

 When the aircraft is flying in the take-off and landing configuration with the front and rear wings 8 and 9 sliding flaps released (Fig. 6), the chord, the area of the wings and the area of mechanization of the wings increase, the area of the wings acquires curvature (Fig. 5). In this case, the lifting forces of the front and rear wings increase, and their resultants are shifted back.

 Thus, significant aerodynamic forces and moments additionally arise on the airplane in the take-off and landing configuration, which must be balanced with the help of a horizontal tail, for which the usual aerodynamic configuration must have a movable or controllable stabilizer of a large area and with a large shoulder (Fig. 7).

 In the proposed aircraft, the aerodynamic moments arising on the wings, which are created relative to the center of gravity of the aircraft, are directed in different directions and are almost equal and therefore they balance and cancel each other (Fig. 6). Small deviations in the equality of moments that may occur in some flight modes are balanced by the elevator 6.

,
где m_z01m_z02- собственные моменты переднего и заднего крыла;
α угол атаки;
v установочный угол заднего крыла;
e^a a производная угла скоса потока.The equation of moments relative to the line 0.25 b ₁ (25% of the chord), which is the focus of the front wing in a rectilinear steady flight, can be written:

,
where m _z01 m _z02 - own moments of the front and rear wing;
α angle of attack;
v installation angle of the rear wing;
e ^a a is the derivative of the bevel angle.

можем записать:

Взяв частную производную по C_у от выражения момента, получим:

Таким образом, точка, отстоящая от линии 0,25 b₁ на расстоянии

, будет являться фокусом изолированной комбинации двух крыльев.Assuming that at small angles of attack, the lift coefficient is a linear function, we obtain:

we can write:

Taking the partial derivative of C _{at the} moment of expression, we get:

Thus, the point spaced from the line 0.25 b ₁ at a distance

, will be the focus of an isolated combination of two wings.

запишется:

.The position of the focal point from the leading edge of the front wing, given that

will be written:

.

Коэффициент "0,88" учитывает торможение и скос потока при условиях b₁≤h_кр≤2,5b₁, b₁≤l_кр≤3b₁
где h_кр высота плоскости хорд заднего крыла над плоскостью хорд переднего крыла (фиг.7 6);
l_кр расстояние между задней кромкой переднего крыла и передней кромкой заднего крыла (фиг. 4).The area of wing mechanization is selected from the conditions (Fig. 4):

Coefficient "0.88" takes into account braking and bevel flow under conditions b ₁ ≤h _cr ≤2.5b ₁ , b ₁ ≤l _cr ≤3b ₁
where h _{kr the} height of the plane of the chords of the rear wing above the plane of the chords of the front wing (Fig.7 6);
l _{cr the} distance between the trailing edge of the front wing and the leading edge of the rear wing (Fig. 4).

 Thus, the proposed aircraft has an aerodynamic configuration that provides the flight conditions of the aircraft in the take-off and landing configuration with the take-off and landing mechanics released, slightly different from the flight conditions in the main cruising configuration according to the conditions of the longitudinal balance of the plane, which allows the use of powerful sliding wing mechanics on the plane , have a simple non-interchangeable horizontal plumage of a minimum area and with a minimum shoulder, get a wide range of operational alignments and constancy of effort on the pitch control bodies.

 The use of two wings on a plane, horizontal plumage with a minimum shoulder can reduce the overall dimensions of the aircraft and its mass. YY4t

Claims (1)

An airplane comprising a wing with take-off and landing mechanization and plumage, characterized in that the wing is made in the form of a combination of two wings, one of which is installed in front, the other behind the center of gravity of the aircraft so that the aerodynamic focus of the isolated combination of wings is located from the leading edge of the front wings in the distance

coincides with the center of gravity of the aircraft, and the ratio of the areas of take-off and landing wing mechanization is

where b _{1 the} chord of the front wing;
S ₁ , S _{2 the} area of the front and rear wing;

wing chord with front and rear wing mechanization released;

area of mechanization flap area with front and rear wing area serviced in front of it;

derivatives of the lift coefficients of the front and rear wings;
L aerodynamic shoulder wing combination the distance between the lines of 25% of the chords of the front and rear wings;
K is the drag coefficient of the flow.

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