RU2177895C1 - Aerobatic trainer airplane як-54 - Google Patents

Abstract

FIELD: aviation; aerobatic trainer airplanes. SUBSTANCE: proposed airplane has fuselage, power plant for driving the propeller, tapered encumbered with which consists of half-wings with ailerons and horizontal and vertical tails; planes of profile chords of each half-wing, longitudinal datum line of fuselage and propeller axis lie in one plane. Lower surfaces of ailerons of each half-wing are provided with aerodynamic balances in center portion. Wing aspect ratio ranges from 5 to 5.3, ratio of ailerons area to wing area ranges from 20 to 25 %, ratio of distance between aircraft CG and 25-% mean aerodynamic chord of vertical tail does not exceed 2/3 of aeroplane overall length. Control system provides for downward deflection of ailerons to 15 deg. at possibility of differentiated deflection relative to extended position. Aeroplane is provided with hatch with glass in lower portion of fuselage. EFFECT: flight handling and maneuvering characteristics under all flight conditions in performing complexes of aerobatic maneuvers. 7 cl, 6 dwg

Description

 The invention relates to the field of aviation, in particular to training aerobatic aircraft.

 Known aerobatic aircraft containing the fuselage, a propeller located in the nose of the fuselage, a power plant for driving the propeller, a trapezoidal wing, which is designed so that the plane of the chord of the wing, the construction horizontal of the fuselage and the axis of the propeller are located in the same plane, ailerons located on wing, horizontal and vertical plumage, ailerons control device / Copyright certificate of the USSR 764275, B 64 C 1/26, 1982 /.

 The aircraft has limited capabilities when performing aerobatics.

 Also known is a training, two-seat, YAK-52 airplane containing a fuselage, a propeller located in the nose of the fuselage, a power unit for driving a propeller, a trapezoidal wing of an asymmetric profile, consisting of half wings with ailerons, horizontal and vertical tail, while planes of chords of profiles of each half-wing, the construction horizontal of the fuselage and the axis of the propeller are located in the same plane / Jane's. All the word's Aircraft. 1994-95, p. 281 /.

A well-known aircraft has limitations when performing reverse aerobatics according to the program of the World Championships, since the ratio of the maximum positive and negative overloads is + U _y / -U _y = 0.6, which negatively affects the performance of inverse figures.

 The minimum permissible flight speed, determined by the structural design of the aircraft, does not allow to obtain high landing characteristics.

 Low weight return of the structure negatively affects the flight performance.

 The wing is made with an asymmetric profile and a complex shape of the outer surface, and therefore has a high complexity of manufacturing.

 The objective of the invention is the creation of a training, two-seater, aerobatic aircraft with high aerobatic and maneuverable characteristics in all flight modes when performing complex complexes of aerobatics.

 Another objective of the invention is to increase the weight gain of the aircraft structure by reducing the length of the tail of the fuselage while maintaining the static moment of the vertical tail and increasing the maneuverability and aerobatic properties of the aircraft.

 The invention is also aimed at increasing the available overloads when performing reverse aerobatics due to the symmetrical profile of the wing.

 To solve these problems, a training aerobatic aircraft has been proposed, comprising a fuselage, a propeller located in the nose of the fuselage, a propulsion system for propeller drive, a trapezoidal wing, consisting of half wings with ailerons, horizontal and vertical plumage. In this case, the plane of the chord profiles of each half-wing, the construction horizontal of the fuselage and the axis of the propeller are located in the same plane.

 On the lower surface of the aileron of each wing in the middle part, aerodynamic compensators are made.

 The wing is made with a symmetrical profile with an elongation of 5-5.3.

 To increase the effectiveness of ailerons, the ratio of the area of ailerons to the area of the wing is 23-25%.

 The value of the ratio of the distance from the center of gravity of the aircraft to 25% of the average aerodynamic chord of vertical tail is not more than 2/3 of the total length of the aircraft.

 The aircraft can be equipped with a hatch in the lower part of the fuselage, in which glass is installed.

 In a preferred embodiment, the aircraft powerplant has a four-stroke air-cooled engine, a semi-monocoque type fuselage and a wing mid-relative to the fuselage.

 The aircraft has a three-blade variable pitch propeller and trapezoidal plumage.

Reducing the wingspan and reducing the length of the rear of the fuselage while maintaining a static moment B _{in the} vertical tail allows you to reduce the weight of the aircraft, and therefore increase maneuverability and aerobatic properties at a constant static moment.

In _in = (S _in L _{in to c.t} ) / (S _cr l _cr ) = const,
where S _in - the area of vertical plumage,
S _kp - wing area,
L _{vo about ts.t d} - distance from the aircraft center of gravity to 25% mean aerodynamic chord of the vertical stabilizer,
l _cr - wingspan.

When equal to the area S and S _{cr vo} by reducing the elongation relative to the prototype 5-5,3 possible to reduce the wingspan l _kr and the distance L _{to ts.t vo,} and consequently reduce the overall weight of the fuselage 20%.

 The invention is illustrated by drawings.

 FIG. 1 is a general view of the Yak-54 aircraft.

 FIG. 2 - plane, side view.

 FIG. 3 - aircraft, front view.

 FIG. 4 - plane, top view.

 FIG. 5 is a graph of the effect of wing elongation on the relative available roll speed.

 FIG. 6 is a graph of the effect of the relative aileron area on the relative available roll speed.

 The Yak-54 training aerobatic plane (Fig. 1-4) contains the fuselage 1, the propeller 2 located in the nose of the fuselage 1, the power unit for the propeller drive 2, the trapezoidal wing 3 of a symmetrical profile, consisting of half wings 4 and 5 s ailerons 6 and 7, horizontal trapezoidal plumage 8 and vertical plumage 9.

 The aircraft has a three-support landing gear fixed with hollow springs, made with a tail wheel.

 The plane of the chord profiles of each half wing 4 and 5, the construction horizontal 10 of the fuselage 1 and the axis of the propeller 2 are located in the same plane.

 On the lower surface of the aileron of each wing 4 and 5 in the middle part, aerodynamic compensators 11 and 12 are made.

 In the central part of the fuselage is a double crew cabin 13.

Wing 3 is made with extension
λ _cr = l _cr / in _sah = 5.15,
where l _cr - the wingspan,
in _sah - the average aerodynamic chord.

The wing 3 is made with a symmetrical profile relative to the chord. The ratio of the area of ailerons 6 and 7 to the area of the wing 3 is determined from the dependence of S _el = S _el / S _cr 100% = 23-25%.

The fuselage is designed so that the ratio of the distance L _in.o. from the center of gravity of the aircraft to 25% of the average aerodynamic chord of vertical tail 9 is not more than 2/3 of the total length l of the _{fuselage of the} aircraft.

 The plane is equipped at the bottom of the fuselage 1 with a hatch 14, in which glass is installed. The hatch is designed for visual orientation and observation of the lower hemisphere when piloting in a limited space of 1x1x1 km.

 The aircraft powerplant has a four-stroke air-cooled engine.

 The aircraft has a three-blade propeller 2 variable pitch, fuselage type 1 half-monocoque and mid-wing relative to the fuselage 1.

 The aircraft control system 15 has an additional control channel for ailerons 6 and 7 to “freeze”, that is, the root part down to 15 degrees, while allowing their differential deviation relative to the released position.

 In flight, when the ailerons 6 and 7 deviate in opposite directions, the angle of the wing 2 changes by an angle of ± 25 degrees so that the difference in the values of the lifting force of the wings creates a heeling moment relative to the longitudinal axis.

 Deviation of the ailerons in opposite directions leads to the fact that the increment of the lifting force on the right and left half wings is directed in opposite directions. As a result, an aerodynamic moment arises, causing the aircraft to rotate toward the elevated aileron.

 The experiments showed that the maximum roll speed is, at the indicated size ratios, 6 rad / sec. This allows you to pilot according to the program of world champions.

 The angular deviation of the ailerons to the maximum angle allows the Yak-52 aircraft to rotate at a speed of up to 3.5 rad / s.

 The lateral control efficiency of the proposed Yak-54 aircraft is 70% higher, which is confirmed by experimental studies of the model in wind tunnels (Figs. 5 and 6). The position of point A corresponds to the characteristics of the Yak-52 aircraft, and the position of point B corresponds to the characteristics of the Yak-54 aircraft.

удлинения крыла составляет 30%.The degree of influence on the relative available roll speed

wing elongation is 30%.

The optimal wing elongation λ _cr = 5 - 5.3 (Fig. 5).

относительной площади элеронов 6 и 7 составляет 40%, а оптимальная степень влияния 23-25% (фиг. 6).The greatest degree of influence on the roll speed

the relative area of ailerons 6 and 7 is 40%, and the optimal degree of influence is 23-25% (Fig. 6).

 With inverse figures, the flight properties of the aircraft are improved, with a symmetrical wing profile, due to the convergence of the available maximum and negative overloads. This allows for advanced training of pilots to participate in the world championships.

 In flight, when the ailerons 6 and 7 are deflected with the tail part down to an angle of up to 15 degrees, it is possible to perform an aerobatic complex by differential deviation relative to the released position with practically no loss of flight altitude.

 When landing, the "hang" of ailerons 6 and 7 at an angle of up to 15 degrees allows you to have a minimum permissible flight speed of 10% compared with the prototype, that is, significantly improve landing characteristics.

 The aircraft passed factory bench tests and flight design tests.

 It is supposed to conduct repeated static tests to confirm the assigned resource and control tests to obtain a certificate of airworthiness.

Claims (7)

 1. Aircraft containing the fuselage, a propeller located in the nose of the fuselage, a propulsion system for propelling the wing, a trapezoidal wing consisting of half wings with ailerons, an aileron control system, horizontal and vertical tail, while the plane of the chords of the profiles of each half wing, building horizontal the fuselage and the axis of the propeller are located in the same plane, characterized in that on the lower surface of the aileron of each wing in the middle part there are aerodynamic compensators, the wing is made with immetrichnym profile and has an elongation 5-5,3, aileron area ratio to the area of the wing is 23-25%, the ratio of the distance from the aircraft center of gravity to 25% mean aerodynamic chord of the vertical stabilizer is not more than 2/3 of the total length of the aircraft. 2. The aircraft under item 1, characterized in that the said control system is configured to deflect the ailerons down to 15 ^o with the possibility of differentiated deviations relative to the released position.  3. The aircraft under item 1, characterized in that it is equipped with a hatch in the lower part of the fuselage, in which the glass is installed.  4. The aircraft under item 1, characterized in that the power plant has a four-stroke air-cooled engine.  5. The aircraft according to claim 1, characterized in that it has a three-blade variable pitch propeller.  6. Aircraft according to claim 1, characterized in that it has a half-monocoque type fuselage and a wing located relatively to the fuselage.  7. The aircraft under item 1, characterized in that the horizontal tail is made trapezoidal.

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