WO2011064456A1

WO2011064456A1 - Flying apparatus

Info

Publication number: WO2011064456A1
Application number: PCT/FI2010/050969
Authority: WO
Inventors: Raimo Hirvinen
Original assignee: Raimo Hirvinen
Priority date: 2009-11-27
Filing date: 2010-11-26
Publication date: 2011-06-03
Also published as: EP2504228A4; EP2504228A1; FI122848B; WO2011064456A9; FI20096253A0; FI20096253A

Abstract

The invention relates to the wing of a flying apparatus and a flying apparatus, the leading edge of which wing is at least partly at a sweep, on which leading edge part at a sweep are arranged means (2, 2') which, when activated, raise controls (3) generating vortices on the upper surface of the wing and which at the same time increase the degree of curvature of the mean chord (6) of the airfoil in the leading edge area of the wing.

Description

Flying apparatus

The invention relates to a flying apparatus, comprising a wing with leading edge sweep exceeding 10° in at least a part of the wing.

■Background

The operation of the wing of a flying apparatus is mainly based on the uplift produced by the underpressure on its upper side, partly also on the uplift produced by the ram air on the lower surface. Airflow produces uplift on the upper surface of the wing, because air travels a longer distance on the upper surface and due to a higher speed, pressure falls in accordance with the Bernoulli equations. Furthermore, the downwards turning movement of the air produces a reacting force. Another known manner of generating underpres- sure is to generate vortices, and the operation of a delta wing at low speeds is based on the underpressure generated by vortices on the upper surface. Vortex generators which strengthen such vortex fields with low speeds are known, for example, from EP0999126 which discloses adjustable vortex generator ribs on the upper surface of a delta wing, and from US4739957 which describes an adjustable vortex generator in connection with a canard-wing flying apparatus. The above solutions do not, however, function with a very large angle of attack in connection with a delta wing, because the flow has already been disrupted by the effect of the leading edge of the wing before the airflow meets the vortex generator.

The variable profile of a wing is described, for example, in patents no.

US4899284 and US4285482, but the wings depicted in these are, however, of ordinary length and are not intended to be used with a large sweep.

Partly similar technology is described in the same Applicant's earlier application WO 0017046. It discloses a device which varies the airfoil and at the same time generates vortices on the upper surface in connection with an ordinary, that is, so-called straight wing. When opened, the device makes possible a larger angle of attack than a smooth or flush wing. When flying at a low speed close to stalling speed, the device stabilises the wing, but in re- lation to one axis. When flying at a greater speed with the device open, it causes the additional drag to increase.

The publication US 5094411 discloses a delta-wing supersonic military aircraft, which is typically heavy and has a high wing loading. The main aim therein is to improve the manoeuvrability of the aircraft with large angles of attack in supersonic operation to allow rapid evasive movements. This requires numerous computers and a complex mechanism required for moving the control surfaces with hydraulic and electric servos and systems, because due to the rapid and asymmetrical manoeuvres required, a human being would be unable to perform this task by manual control.

In accordance with the preamble, the aim of the present invention is a flying apparatus, comprising a wing with a leading sweep exceeding 10°, preferably at least 20° and more preferably at least 60°, in at least a part of the wing. In the present application, the leading sweep A of the wing means, in accordance with what is shown in Figure 1C, that the leading edge of the wing forms an angle with the longitudinal mean line P of the flying apparatus to the normal N. The wing may be, for example, an ordinary wing at a sweep, where the mean chord K is at an angle A' to the normal N of the lon- gitudinal mean line P, or a delta wing. Figure 1C shows an aircraft wing at a sweep without the "ram-it" means according to the invention.

Brief description of the invention The object of the invention is an aircraft or a flying apparatus which is safe and stable to fly also at the approaching stage and during landing when the plane flies at low speed and with high angle of attack values and is thus close to stalling. The aim is, therefore, to improve the flying characteristics and manoeuvrability of the flying apparatus, as well as its stability when operating with high angle of attack values.

In addition to being a conventional aeroplane, the flying apparatus which is the object of the invention may be a model plane, a glider which is controlled aerodynamically or by weight shift control and may also be motorised, a sailplane or an ultralight plane. The flying apparatus according to the invention may also take the form of, for example, a kite or a rescue device or recreational means which can be pulled by a land vehicle or watercraft and rises into the air at a relatively low speed, thus preventing passengers from being subjected to the strain caused, for example, by rough seas. A particular aim is to provide an easily controlled flying apparatus when flying at low speeds without compromising the performance of the apparatus in any way.

In order to achieve the aims of the invention, the flying apparatus according to the invention is characterised by what is disclosed in the characterising part of claim 1.

According to the invention, a "ram-it" means (= vortex-generating formed piece) mounted on the part of the wing at the leading edge sweep A is used, the vortex field thus generated being much more preferable than in the case of a straight wing. Compared with the vortex generators described in con- nection with the delta wing described above, the "ram-it" means according to the invention changes the wing profile at the same time, making it more curved at the front, which at the same time increases the uplift force and reduces flow resistance at high angle of attack values. The wing may be formed, for example, into a delta wing or a wing at a sweep or various com- binations of these. Detailed description of the invention

Embodiments of the invention are described in the following by means of the accompanying Figures.

Figure 1 shows a diagrammatic top view of an aeroplane according to the invention.

Figures 1A, IB show the cross-sectional profile of the wing of the flying apparatus according to the invention in different modes.

Figures 1C-1D show certain definitions used in this application.

Figure 2A shows a top view of a vortex field generated by the wing of a flying apparatus according to the invention.

Figure 2B shows a cross-section of a vortex field generated by the wing shown in Figure 2A.

Figure 2C shows a perspective view of a vortex field generated by a wing of a different shape with angle of attack a.

Figure 2D shows an aeroplane according to the invention in a state of descent.

Figures 3A-3C show an application of the flying apparatus according to the invention as a kite.

Figure 1 shows an aeroplane comprising a delta wing part 1 provided with the "ram-it" means 2, 2' according to the invention and a fixed tip part 100. If necessary, the tip part 100 can also be provided with the means 2. The cross-sectional profile of Figure 1A shows more closely the "ram-it" means 2 hinged on the leading edge of the wing 1, the trailing edge 3 above the wing acting as a vortex generator in the turned position (Figure IB). When the means 2 is turned downwards on its front edge, the degree of curvature of the mean chord 6 of the wing profile increases in the leading edge area. As shown in Figure ID, the mean chord 6 of the wing profile refers to the chord between the leading and trailing edges of the wing, the distance of which from the upper and lower surfaces of the wing is the same at each point. The wing profile chord PJ refers to the straight line between the leading and trailing edges of the wing. It should be noted that in Figure 1, the means 2 are arranged on the delta wing part of the wing, that is, the airflow is directed obliquely at the leading edge and the means 2 opened by a relatively large angle of attack a (e.g. 30°-50°) meets the airflow aerody- namically and does not cause harmful flow resistance, on the contrary, it guides the flow passing the edge of the wing more aerodynamically to the upper surface of the wing in such a way that the airflow is guided up to the trailing edge 3 of the means 2 to generate a vortex 5 on the upper surface of the wing. The passage remaining between the trailing edge 3 and the wing guides the vortex 5 for its part. The increased curvature of the lower edge and sides of the wing increases the uplift force for its part.

Figure IB shows spread angle C, the greatest available range of which depends on the angle of departure D determined by rear surface 8 of the means 2 and the lower edge of the wing. If the angle of departure is small, the spread angle may be quite large, preferably more than 90°. In that case, the trailing edge 3 of the means 2 may extend further than the original leading edge and a delta wing descending at a very large angle of attack will still be aerodynamic on the leading edge of the wing in the approach direction of air. At the same time, the surface area of the wing increases in the approach direction of air, because the trailing edge 3 of the means 2 extends outside the original outline of the wing. The angle of departure D is preferably sharp if the maximum spread angle is large.

The hinged point 4 may be on the lower surface of the wing rearwards from the leading edge, as shown in Figures 1A-1B. Hinging further rearwards brings a greater change of the profile, hinging close to the leading edge and the chord the change of the airfoil is smaller, , and the means 2 hinged on the leading edge of the wing in the chord line no longer changes the profile of the lower surface of the wing when turned. It is also possible to arrange the hinging in the centre of the wing, in which case a formed panel is required on the lower surface to cover the slot below the hinging which would otherwise remain open.

The means 2 of Figure 1 mounted on the edges of the delta wing part 1 form, when turned down, protrusions on the leading edges of the delta wing, the said protrusions forming, at a large angle of attack, stagnation points on the lower surface, and divide the flow between the lower surface and the vortex-generating part of the upper surface. A backwards directed flow at large angles of attack turns strongly downwards, thus generating uplift force. A flow which circulates past the means 2 above the wing generates a vortex which produces uplift force more efficiently than the prior art solutions described above, because the controlled vortical flow steered by the "ram-it" means is maintained and strengthens as the angle of attack enlarges. Therefore, when turned down, the delta wing part means according to the invention generate more uplift force than the prior art solutions as the angle of attack increases without, however, increasing disadvantageous resistance. On the edges and lower surface of the wing remains a laminar flow up to large angles of attack. On the upper surface act stable and strong vortices, which are generated by the effect of the flow guided by the trailing edge 3 of the means 2. These vortices remain stable on the upper surface of the wing and intensify the underpressure on the upper surface. At the same time, the vortex streets thus formed, while proceeding backwards and sideways following the leading edges of the delta-shaped piece, stabilise the flying apparatus with respect to all axes; the longitudinal, transverse and vertical axes. When the trailing edge means 2 are opened, this improved stability of the flying apparatus is demonstrated particularly well when flying a scale model in gusty weather.

In the opened position, the turned outer edge of the means 2 is parallel to the airflow with large angles of attack. Because of this, a prototype of the delta wing according to the invention acts in a stable manner and is controllable with the means 2 opened even with angles of attack exceeding 45°.

The delta-wing scale model according to the invention, with the means 2 opened, when lifting the nose and slowing down speed in gliding with the engine switched off, descends in almost horizontal attitude so that the angle of attack, and at the same time the angle of descent, exceeds 45°. The rate of descent is, however, slow and the plane does not lose its manoeuvrability, which is what usually happens when stalling. When engine power is in- creased, the scale model continues normal flight under control and similarly, when lowering the nose, it begins to glide in a normal manner. Thus, when gliding at a large angle of attack, the light delta-wing flying apparatus according to the invention behaves almost like a parachute, descending while remaining manoeuvrable. When the leading edge means 2 are closed, it functions like a normal delta wing.

Figure 2A shows a top view of the vortex fields above the wing of a flying apparatus according to the invention and Figure 2B shows the same wing in partial cross-section. Figure 2C shows a perspective view of a flying appara- tus of a different shape according to the invention. By activating the "ram-it" means 2 of the invention on the leading edge of the delta wing, a strong un- derpressured vortex field 5 is generated on the upper surface, which thus increases the uplift of the wing and at the same time the induced resistance. This phenomenon is well known as such. On the other side of the flying apparatus, the vortex field 5 is marked simply by With the trailing edge 3 lifted up, the means 2 according to the invention guides the flow circulating the leading edge of the delta wing to the trailing edge 3 of the means 2, whereby the generation of the vortex is intensified and the vortex remains stable at a large angle of attack. In normal flight at high speed and a small angle of attack, it is obviously better to fly with the means 2 closed. Figure 2C shows a flying apparatus in which the means 2 are made in the same way as in Figure 1 so as to have two parts 2, 2', which makes possible their efficient use as backup, that is, as secondary controls. The rudder is marked with reference numeral 101. In Figures 1 and 2C, the means 2 at the front of the wing and the means 2 at the rear of the wing can be activated separately. Furthermore, the formed parts on the left and right side can be activated separately to turn the flying apparatus. Figure 2D shows an aeroplane 110 according to the invention in a state of descent with the "ram-it" means 2 opened. The speed of descent is low, but the plane is still manoeuvrable. The upwards directed arrows depict the approach direction of air with respect to the plane and the downwards directed arrows depict the direction of flight. The plane, therefore, descends in an almost horizontal position and the angle of attack a exceeds 45°. The means 2 on the edge of the wing can be opened up to more than 120°.

The means 2 on the leading edge of the wing maintain their controlling power well in low-speed flying and at large angles of attack. They influence the incoming airflow and the vortices generated by the energy of the airflow on the leading edge. When the means 2 according to the invention were used as secondary controls, it was possible to make stable turns also during low-speed horizontal flying.

It is possible to position the means 2 according to the invention symmetri- cally with respect to the centre of gravity and the centre line. A recreational aviation device according to the invention is light and its wing loading is low. The airfoil is preferably normal or plate-like, and the leading edge sweep in the different parts of the wing may be of different magnitudes, and on the tips may be winglets or rudders which reduce the induced resistance of the wing. In such a case, the power requirement of the flying apparatus is reasonable during cruising. Performance can be further improved by making the integrated body part of the flying apparatus into the shape of an airfoil, whereby the apparatus will resemble a flying wing. The wing loading of the recreational flying apparatus according to the invention is preferably low, less than 100 kg/m², in a lightweight flying apparatus, for example, less than 30 kg/m².

The "ram-it" arrangement according to the invention is, therefore, also ex- tremely well suited for controlling a kite, a model plane or a lightweight delta wing and for improving flying performance in low-speed flying. The advantage of a delta wing is a strong and light construction with respect to the surface area and the uplift force. Therefore, in principle, from the point of view of its construction and strength, a delta wing would be a good wing for a lightweight flying apparatus. The low-speed flying properties of a delta wing have been poor. Although the delta wing normally allows a large angle of attack, its carrying capacity falls steeply and the loss of manoeuvrability is often sudden, because the controls on the trailing edge of the wing are caught in a sudden turbulent airflow, when the airflow detaches from the surface of the wing due to an excessively large angle of attack. Without the "ram-it" means according to the invention, the properties of a delta wing are ill-suited for flying by a beginner. At least on the basis of tests carried out with scale models, with the means according to the invention can be realised an easily manoeuvrable and safe lightweight flying apparatus with stalling and low-speed properties suitable for a beginner. The primary controls are preferably the traditional ones, that is, on the trailing edge of the delta wing are ailerons and elevator or control surfaces located in a canard wing.

Figures 3A-3C show an embodiment of the kite 50 in top, front and side view. The kite 50 according to the invention is able to accumulate considera- bly more gravitational and dynamic energy generated by wind from a higher and stronger upper wind area than wind generators on the ground can. The required energy kite station can easily be built in remote, even almost uninhabited areas, and the energy produced by it can be modified as necessary. The kite, the edges of which are equipped with "ram-it" means 2, 2', is stabi- lised with respect to all three axes when the "ram-it" means are open. At the same time, its manoeuvrability is improved and makes possible controlled descent of the kite without consuming energy, in order that the kite can start upwards again, to an energy-generating work phase. In connection with a heavy plane with a high wing loading, the solution according to the invention improves the low-speed flying performance of the flying apparatus and makes possible landing on even shorter runway, also over high obstacles, while maintaining manoeuvrability. A plane with a heavy wing loading is unable to land by descending slowly in a parachute-like man- ner as lightweight planes can, but it is able to land steeply and with the plane in a horizontal position. In that case, the system according to the invention makes stable and controlled descent possible, whereby it is easy for the plane's pilot to control the plane as the flying altitude decreases. From the point of view of fuel economy and noise impacts, it is advantageous if an airliner is able to perform a steep approach having left the cruising altitude for the purpose of landing. In an emergency (emergency descent) a sudden or rapid loss of altitude of an airliner according to invention can be done more safely than before, because the flying speed can be kept low. This prevents stress loads caused by high flying speeds from damaging further an aeroplane which is already structurally damaged.

Claims

1. A flying apparatus, comprising a wing (1) with leading edge sweep (A) exceeding 10° in at least a part of the wing, characterised in that the flying apparatus is provided with "ram-it" means (2, 2 mounted at the leading edge sweep area of the wing (A), which means, when activated, are arranged to turn downwards so that their trailing edge (3) rises from the upper surface of the wing as the leading edge turns downwards, the said means (2, 20 at the same time increasing the degree of curvature of the mean chord (6) of the airfoil in the leading edge area of the wing and generate controlled vortices on the upper surface of the wing which, when spreading backwards and sideways, stabilise the flying apparatus with respect to the longitudinal, transverse and vertical axes.

2. A flying apparatus as claimed in claim 1, characterised in that the flying apparatus is made into a delta wing or a flying wing.

3. A flying apparatus as claimed in claim 1-2, characterised in that on the leading edge of each wing is at least one or more "ram-it" means (2, 20, controllable separately or in groups, which are also fitted to act as backup or secondary controls.

4. A flying apparatus as claimed in claim 1, characterised in that the wing has a negative sweep in the mounting area of the "ram-it" means (2, 2¹).

5. A flying apparatus as claimed in any of the above claims, characterised in that the "ram-it" means (2, 2 on the leading edge of the wing can be turned at a spread angle (C) up to 90°, whereby the face (20) of the "ram-it" means is at a large angle of attack essentially aerodynamic in the approach direction of the airflow and the trailing edge (3) of the "ram-it" means (2, 20 extends above the wing and ends sharply to generate a strong vortex.

6. A flying apparatus as claimed in any of the claims 1-5, characterised in that the said leading edge sweep (A) of the wing is more than 20°.

7. A flying apparatus as claimed in any of the claims 1-5, characterised in that the said leading sweep (A) of the wing is more than 60°.

8. A flying apparatus as claimed in any of the claims 1-7, characterised in that the flying apparatus comprises on the tip of each wing at least one or more "ram-it" means (2, 20, controllable separately or in groups.

9. A flying apparatus as claimed in claim 8, characterised in that the flying apparatus comprises control means for controlling the leading edge "ram-it" means (2, 2¹ of the wing on the nose side and on the tail side for changing the horizontal attitude of longitudinal axis of the plane and for controlling the "ram-it"-means when turning in order to change the lateral direction.