Autogyro rotor blade for autorotatory lift generation

Abstract

A gyroplane rotor blade for autorotatory lift generation, comprising a root-side inner airfoil section (9) having a first airfoil (21c), a tip-side main airfoil section (10) having a second airfoil (21e) different from the first airfoil (21c), and an airfoil depth profile (22) that decreases monotonically in the longitudinal direction of the gyroplane rotor blade (1) from the area of ​​the blade root (2) towards the blade tip (3), characterized in that the gyroplane rotor blade (1) has a twist with a twist profile (23) that decreases monotonically from the area of ​​the blade root (2) towards the blade tip (3), and that the twist profile (23) has a variable slope in the inner airfoil section (9) and / or main airfoil section (10), such that the twist profile (23) is concavely curved in this area (9, 10).

Description

[0001] The present invention relates to a gyroplane rotor blade for autorotational lift generation. The gyroplane rotor blade comprises a root-side inner profile region having a first profile. Furthermore, the gyroplane rotor blade comprises a main profile region having a second profile different from the first profile. Furthermore, the gyroplane rotor blade comprises a profile depth profile that decreases monotonically in the longitudinal direction of the gyroplane rotor blade, starting from the blade root region and moving toward the blade tip.

[0002] Unlike a helicopter, the rotor of a gyroplane is not powered but rotates using airstream, a process known as autorotation. To generate this airstream, the gyroplane has a motor-driven propeller that generates forward motion, and the airstream is created by the gyroplane's movement through the surrounding air. Because the gyroplane's rotor is not powered, there is no need for a torque-compensating tail rotor like in a helicopter. Furthermore, the gyroplane's autorotation rotor gives it a high level of reliability. If the propeller fails, the gyroplane's rotor is still in autorotation, and landing, for example, is similar to landing a glider and is relatively safe.

[0003] To generate autorotation, the gyroplane rotor blades extract energy from the air flowing from bottom to top across the swept area of ​​the gyroplane, converting it into (auto)rotation and lift. It should be noted that an inner region of the gyroplane rotor blade, adjacent to the gyroplane rotor's axis of rotation, acts as the driving force for autorotation, thus accelerating the gyroplane rotor blade. An outer region of the gyroplane rotor blade, located away from the axis of rotation, acts as a braking force for autorotation. However, this outer region also generates the greatest lift due to the gyroplane rotor blade's higher orbital speed.The movement of the gyroplane rotor blade also induces drag, which depends on the speed of the gyroplane rotor blade through the surrounding air (effective airflow velocity) and the shape of the gyroplane rotor blade. Higher airflow velocities lead to greater drag. Drag also depends on lift. The more lift an area of ​​the gyroplane rotor blade generates, the greater the drag. Thus, the overall drag increases significantly toward the tip of the gyroplane rotor blade.

[0004] GB 452 366 A discloses a rotor blade for a gyroplane. It discloses a rotor blade with a substantially rectangular footprint. The cross-sectional profile can vary along the length of the rotor blade. A disadvantage of such a rotor blade is its high drag.

[0005] The object of the present invention is therefore to create a gyroplane rotor blade which has low air resistance.

[0006] The problem is solved by a gyroplane rotor blade for a gyroplane having the features of independent patent claim 1.

[0007] A gyroplane rotor blade for autorotational lift generation is proposed, comprising an inner profile region and a main profile region. Furthermore, the gyroplane rotor blade preferably has a radially outwardly tapered plan view. A cross-section through the gyroplane rotor blade, particularly at a 90° angle to the longitudinal direction, is referred to as the profile of the gyroplane rotor blade. A sequence of the individual profiles along a defined line and / or curve from the blade root to the blade tip is referred to as the profile pattern.

[0008] In addition, the gyroplane rotor blade has a leading edge, which runs ahead in an autorotating gyroplane rotor, and a trailing edge, which runs behind in an autorotating gyroplane rotor. The leading and trailing edges define the planar shape of the gyroplane rotor blade. The distance between the leading and trailing edges, particularly at a 90° angle to the longitudinal direction, is referred to as the profile depth.

[0009] Furthermore, the gyroplane rotor blade comprises a negative pressure side, on which a negative pressure is formed during normal flight of the gyroplane, and an overpressure side, on which an overpressure is formed during normal flight of the gyroplane. The negative pressure side can be formed as a convex surface of the gyroplane rotor blade, and the overpressure side as a substantially flat surface. In particular, however, the displacement effect of the incoming air is designed by a profile of the gyroplane rotor blade such that, during air flow around the gyroplane rotor blade, the flow on the upper side of the gyroplane rotor blade, namely the negative pressure side, is on average accelerated more than on the underside of the gyroplane rotor blade, namely the overpressure side.According to Bernoulli's law, a pressure distribution corresponding to the local airflow velocity develops, with the resulting pressure difference between the top and bottom surfaces generating lift for the gyroplane rotor blade. This leads to the lift of the entire gyroplane rotor and thus of the gyroplane. The aforementioned pressure distribution depends on the respective profile of the gyroplane rotor blade. If, for example, the profile changes in such a way that the local airflow velocity over the low-pressure side increases, lift can be increased. The aerodynamic properties of the gyroplane rotor blade, in particular its flight performance, are therefore dependent on the profile of the gyroplane rotor blade.

[0010] The gyroplane rotor blade also includes a root-side inner profile region, which has a first profile. This first profile can, for example, extend over the entire length of the inner profile region. Furthermore, the gyroplane rotor blade includes a tip-side main profile region, which has a second profile that differs from the first profile. This second profile can, for example, extend over the entire length of the main profile region. By providing at least two different profiles of the gyroplane rotor blade, different flows on the gyroplane rotor blade can be accommodated.

[0011] In addition, the gyroplane rotor blade has an inner profile region at the blade root and / or adjacent thereto, an outer profile region at the blade tip and / or adjacent thereto, and / or a main profile region between the blade root and blade tip. Thus, the inner profile, main profile, and outer profile regions are arranged sequentially from the blade root to the blade tip. The inner profile, outer profile, and / or main profile regions each have a profile, in particular a different one. As already described, the flow velocity of the surrounding air also increases around a region of the gyroplane rotor blade. The three regions allow for the different flow velocities along the gyroplane rotor blade to be accommodated.

[0012] Furthermore, the gyroplane rotor blade exhibits a profile depth gradient that decreases monotonically in the longitudinal direction of the gyroplane rotor blade, from the blade root area toward the blade tip. The profile depth gradient only decreases at a maximum profile depth. The area between the end of the gyroplane rotor blade at the blade root and the point of maximum profile depth contains only fasteners used to attach the gyroplane rotor blade to a gyroplane rotor head and therefore has no significant impact on flight performance.

[0013] The profile depth curve is the profile depth as a function of the longitudinal direction of the gyroplane rotor blade from the blade root area towards the blade tip. The profile depth curve can therefore be represented, for example, as a graph, function, map, or relation in a Cartesian coordinate system. The longitudinal direction from the blade root to the blade tip is plotted on the x-axis. For example, x=0 can be selected in the blade root area, particularly at the maximum profile depth of the gyroplane rotor blade. The longitudinal direction of the gyroplane rotor blade is then plotted in the direction of positive x-values. The profile depths can be plotted, for example, as y-values. The profile depth curve is then the function of the profile depth as a function of the x-values ​​or the longitudinal direction. The profile depth curve is therefore a graph ora diagram in the Cartesian coordinate system so that the profile depth of the gyroplane rotor blade can be read at any point, for example at certain distances from the blade root towards the blade tip.

[0014] A monotonically decreasing profile depth profile thus describes a gyroplane rotor blade, whose profile depth becomes monotonically smaller from the blade root, in particular from a maximum profile depth, towards the blade tip.

[0015] The profile depth can decrease linearly, parabolically, and / or exponentially from the blade root to the blade tip. Additionally or alternatively, the trailing edge, in particular, can have a convex and / or concave shape relative to the gyroplane rotor blade.

[0016] Since the gyroplane rotor blade rotates around a rotational axis of the gyroplane rotor, the gyroplane rotor blade exhibits different rotational speeds depending on the radius. The flow velocity of the surrounding air around an area of ​​the gyroplane rotor blade is a superposition of the airstream and the rotational speed of the area of ​​the gyroplane rotor blade. Thus, the flow velocity of the air flowing towards the gyroplane rotor blade increases with the radius. The flow velocity is lowest at a blade root and highest at a blade tip. In addition, the superposition of the airstream and the rotational speed along the gyroplane rotor blade results in different angles of attack at which the airflow hits the gyroplane rotor blade.

[0017] A non-twisted gyroplane rotor blade with a constant profile depth (rectangular blade) is not adapted to the locally varying incoming airflow. The flow around the gyroplane rotor blade creates a downwash at every position, depending on the local flow conditions. This creates a corresponding downwash field for the entire gyroplane rotor blade or rotor. With non-twisted rectangular blades, this induced downwash field is unfavorable, reducing the rotor's ability to turn and resulting in corresponding drag.

[0018] If the profile chord decreases towards the blade tip, this leads to a more advantageous downwash distribution with the local flow on the rotor blade, which increases the aerobatic ability of the gyroplane rotor and accordingly reduces the drag of the entire gyroplane rotor. The monotonically decreasing profile chord towards the blade tip results in a different distribution of the lift forces on the gyroplane rotor blade. The profile chord profile is designed in such a way that the inventive plan view of the gyroplane rotor blade with an optimized downwash field, together with the (outwardly) increasing approach flow velocity, provides on average the same lift as a gyroplane rotor blade with a constant profile chord profile, but with lower drag.

[0019] A gyroplane rotor blade with lower drag can achieve higher flight performance. For example, the gyroplane's flight duration and thus its range can be extended.

[0020] According to the invention, the gyroplane rotor blade has a twist with a twist profile that decreases monotonically from the blade root area towards the blade tip. The twist profile can be described analogously to the profile depth profile. For example, as a function, diagram, graph of the twist of the gyroplane rotor blade as a function of the longitudinal direction from the blade root towards the blade tip. The distance or longitudinal direction is again plotted on the x-axis, with the blade root area at x=0 and the blade tip assuming the largest (positive) x-value. The twist is then plotted on the y-axis. The graph thus allows the twist of the gyroplane rotor blade to be read at various points on the gyroplane rotor blade. The twist profile also indicates how the gyroplane rotor blade is twisted. The twist also indicates an angle.The twist with a blade pitch angle of the gyroplane rotor blade indicates how a profile is oriented relative to a rotation plane of the rotating gyroplane rotor blade.

[0021] The rotation plane is defined perpendicular to the rotation axis of the gyroplane rotor (flapping and slewing movements of the gyroplane rotor blade are not taken into account). If the gyroplane rotor blade has a blade pitch angle, it is rotated by an angle around the longitudinal axis, which runs in the spanwise direction (from the blade root to the blade tip). The blade pitch angle is the angle between a defined reference plane fixed to the rotor blade and the rotation plane.

[0022] The twist itself indicates the angle by which the local profile section is twisted relative to a reference plane. The blade pitch angle, together with the twist, forms the local geometric angle of attack. This angle varies locally due to the twist and is therefore defined as the angle between the profile chord and the plane of rotation. The profile chord is the connecting line between the farthest apart points on the leading and trailing edges of the profile.

[0023] The twist angle of an airfoil, at a blade pitch angle of zero degrees, is the angle that the airfoil forms with the rotational plane of the rotating gyroplane rotor blade. For example, this twist angle is zero degrees (for a given airfoil) if the airfoil is aligned parallel to the rotational plane (at a blade pitch angle of zero degrees).

[0024] Furthermore, the gyroplane rotor blade has a twist in the longitudinal direction, so that the gyroplane rotor blade is twisted about an axis in the longitudinal direction. When the individual profiles are lined up in a profile strip with a different angle, the twist is formed. By means of the twist, the airflow behavior on the gyroplane rotor blade can be changed. This makes it possible to achieve a more advantageous downwash distribution, so that the performance of the gyroplane rotor blade is increased while maintaining the same air resistance. The twist means that the geometric angle of attack of the individual profiles with respect to a plane of rotation of the gyroplane rotor blades (plane of rotation) of the gyroplane rotor varies across the longitudinal direction of the gyroplane rotor blade. If, for example, the twist angle is small, the corresponding profile is essentially parallel to the blade pitch angle.at a blade pitch angle of zero degrees essentially parallel to the orbital plane of the gyroplane rotor blades.

[0025] Similar to the depth distribution, the twist also has a significant influence on the local flow conditions, which in turn influences the local downwash and thus contributes to the overall downwash field / significantly determines the overall downwash field.

[0026] A twist according to the invention results in a more favorable downwash field, which further increases the rotor's agility and further reduces the drag of the entire gyroplane rotor. The twist is designed in such a way that it not only improves the downwash field, but also shapes / forms the resulting downwash field in such a way that the gyroplane rotor blade receives optimal airflow according to the locally used profiles. This allows the blade profiles to further increase the rotor's agility and thus further contribute to reducing the overall drag of the gyroplane rotor.

[0027] It is also advantageous if the longitudinal twist from the blade root to the blade tip is designed such that the trailing edge is twisted toward the low-pressure side and the leading edge toward the high-pressure side. During normal flight operations, the gyroplane rotor blade exhibits a blade pitch angle, meaning the leading edge is positioned higher than the trailing edge, so that the profile chord (the line connecting the leading and trailing edges) exhibits the geometric angle of attack. This means that the gyroplane rotor blade is tilted upward relative to the orbital plane.

[0028] Since the airflow velocity is lower in the root area than in the tip area, it is advantageous if the twisting in the root area increases the angle of the profiles and decreases them in the tip area or towards the tip area. This improves downwash distribution, thereby reducing the drag of the gyroplane rotor. The performance of the gyroplane rotor blade is thereby increased.

[0029] Furthermore, the twist pattern in the inner profile area and / or in the main profile area has a variable pitch. The twist pattern in this area can be concavely curved. The twist pattern therefore changes over the length of the gyroplane rotor blade, which is advantageous for the flight performance of the gyroplane rotor blade. Since the gyroplane rotor blade is exposed to different air flows along its length during flight, it is advantageous if the twist is also adapted to these different air flows. If the twist pattern is concavely curved and monotonically decreasing, the twist pattern approaches the x-axis, i.e. the twist angle approaches zero degrees towards the blade tip. A profile at the blade tip is therefore parallel to the plane of rotation of the rotating gyroplane rotor blade (with a blade pitch angle of zero degrees).This improves the flight performance of the gyroplane rotor blade because turbulence towards the blade tip is reduced. With a special shape, profile, twist and / or ground plan, the gyroplane rotor blade can be adapted to the specific requirements of the gyroplane. If, for example, the range of the gyroplane is to be increased (with the same fuel level, etc.) or a higher payload is to be transported, the profile depth curve according to the invention can be scaled by a factor which, for example, reduces or increases the profile depth. For example, the factor could be 0.8, so that the profile depth is reduced by this factor. The gyroplane rotor blade is thus narrower overall. Alternatively, the factor could also be 1.2, so that the profile depth is increased by this factor. The gyroplane rotor blade is thus wider by this factor.The factor could also be in a range between 0.8 and 1.2. The factor could also be variable over the length of the gyroplane rotor blade. For example, the inner profile area and the main profile area could have a different factor. This allows the profile chord profile to be ideally adapted to the design objectives. Furthermore, the profile chord profile can be optimally adapted to different rotor diameters. For example, if the plan view of the gyroplane rotor blade has a larger area, the lift is increased, so that the gyroplane rotor blade can carry higher loads. The plan view according to the invention always forms the basis for an optimized downwash field, which ultimately results in a reduction in drag of the gyroplane rotor. All of this increases the flight performance of the gyroplane rotor blade, which is achieved with the gyroplane rotor blade according to the invention.

[0030] It is also advantageous if the main profile section extends over a greater length than the inner profile section. Since the rotation speed of the gyroplane rotor blade is higher in the main profile section than in the inner profile section, the main profile section has a greater impact on the flight performance of the gyroplane rotor blade. Adjusting a larger main profile section can therefore be more effective.

[0031] An advantageous development of the invention is if a transition profile region is arranged between the inner profile region and the main profile region. Additionally or alternatively, the transition profile region can have a third profile. The profile geometry of the transition profile region preferably changes continuously and / or smoothly radially outwards from the first profile to the second profile. This can thus form, for example, a continuous and / or smooth transition between a different first and second profile. This can avoid points of discontinuity, for example edges and / or steps, between the first and second profile, which enables a smooth transition of the aerodynamic properties and thus increases the flight performance of the gyroplane rotor blade. In addition, more than one transition profile region could also be arranged between the inner profile region and the main profile region.These multiple transition profile areas could also each have a profile, with at least two profiles being different.

[0032] Additionally or alternatively, a second transition profile section can be arranged between the main profile section and the outer profile section. This allows for better adaptation to the airflow conditions around the gyroplane rotor blade. Furthermore, more than one second transition profile section could be arranged between the main profile section and the outer profile section. These multiple transition profile sections could each have a profile, with at least two profiles being different.

[0033] It is also advantageous if a nose is arranged in the area of ​​the trailing edge so that the gyroplane rotor blade is curved toward the low-pressure side and / or so that the low-pressure and high-pressure sides are essentially parallel in the area of ​​the nose. With the nose, which is curved particularly toward the low-pressure side, the airflow separating from the gyroplane rotor blade can be better guided behind the trailing edge of the gyroplane rotor blade, thereby reducing torsional loads.

[0034] It is also advantageous if the twist pattern in the transition profile area has a constant gradient, so that the twist pattern is straight, especially across the entire transition profile area. This enables a smooth transition of the aerodynamic properties.

[0035] It is also advantageous if the twist, in particular the twist angle, is constant in the first and / or second transition profile region in the longitudinal direction. This simplifies the design of the gyroplane rotor blade. Additionally or alternatively, the twist in the first and / or second transition profile region can be greater than in the inner and / or main profile region. This allows, for example, a twist between the profile regions to be compensated or adapted to one another over a short distance in the longitudinal direction of the gyroplane rotor blade.

[0036] It is also advantageous if the pitch and / or total twist of the transition profile section is at least half the maximum pitch and / or total twist of the inner profile section and / or main profile section. This allows the first and second profiles to be adapted to each other over a shorter length of the gyroplane rotor blade.

[0037] The twist can vary linearly from the blade root to the blade tip in the manner described above, which is advantageous because the airflow velocity around the gyroplane rotor blade also increases linearly with the outward radius. The twist could also exhibit a parabolic, exponential, polynomial, and / or logarithmic curve from the blade root to the blade tip. Furthermore, the twist can vary in each region, particularly the transition profile regions, the inner profile, the main profile, and / or the outer profile regions. Likewise, at least one of these regions could exhibit no twist. This allows the twist to be optimally adapted to the flow conditions in these regions.

[0038] A variable twist in the inner profile, the main profile, and / or the outer profile also offers advantages. This allows for particularly advantageous adaptation to the flow conditions, especially the flow velocity, which increases with the radius, reducing drag and thus increasing flight performance.

[0039] It is also advantageous if the gyroplane rotor blade has only a small twist angle in the area of ​​the blade tip, especially in the outer profile area. This outer profile area allows the gyroplane rotor blade to be better adapted to the flow conditions. If the twist angle is constant, for example, the gyroplane rotor blade is not twisted in the outer profile area, which leads to easier manufacturing of the gyroplane rotor blade.

[0040] Furthermore, it is advantageous if the twist pattern exhibits a positive twist angle throughout the entire inner profile area and / or in the transition area(s). As described above, the twist angle indicates the number of degrees by which the local profile section is twisted relative to a defined reference plane. With a blade pitch angle of zero degrees, the twist angle of a profile is the angle that a profile forms with the rotation plane of the rotating gyroplane rotor blade. With a positive twist angle, the gyroplane rotor blade is tilted upwards, meaning that the leading edge of the gyroplane rotor blade is at a greater distance from the rotation plane than the trailing edge.

[0041] Additionally, it is advantageous if the twist pattern has a positive twist angle in a first root-side section of the main profile section and a negative twist angle in a second tip-side section of the main profile section. Additionally or alternatively, the twist angle between the first and second sections is zero. For example, in this section, the profile is parallel to the rotation plane at a blade pitch angle of zero. All of this increases the flight performance of the gyroplane rotor blade.

[0042] Furthermore, it is advantageous if the twist pattern has a first bend at the transition from the inner profile area to the transition profile area. Additionally or alternatively, it is advantageous if the twist pattern has a second bend at the transition from the transition profile area to the main profile area. The first and / or second bend can be negative and / or convex, for example.

[0043] Furthermore, it is advantageous if the profile depth profile is designed as a curved curve, for example, in the transition profile area and / or the main profile area. Additionally or alternatively, the profile depth profile can be designed as a monotonically decreasing curve. The monotonically decreasing curve can also be a strictly monotonically decreasing curve.

[0044] Furthermore, it is advantageous if the inner profile area has a relative profile thickness, which indicates the ratio of the maximum profile thickness to the profile depth, between 11% and 15%, preferably 13.5%, with a relative thickness offset, which indicates the ratio of the distance of the maximum profile thickness from the leading edge to the profile depth, between 25% and 35%, preferably 29.2%. The profile thickness is the vertical distance between the overpressure and underpressure sides.

[0045] It is also advantageous if the main profile area has a relative profile thickness, which indicates the ratio of the greatest profile thickness and the profile depth, between 10% and 14%, preferably 12.1%, with a relative thickness offset, which indicates the ratio of the distance of the greatest profile thickness from the leading edge and the profile depth, between 26% and 36%, preferably 31.1%.

[0046] It is advantageous if the inner profile area has a maximum camber (the ratio of the greatest distance between the profile chord and the chord line to the profile depth) of between 3% and 4%, particularly between 3.6% and 3.8%, with a relative camber offset (the ratio between the distance of the maximum camber from the leading edge and the profile depth) of between 30% and 40%, preferably 35.3%. The profile chord is the line connecting the leading edge to the trailing edge. The chord line is the line that runs midway between the low-pressure and high-pressure sides.

[0047] It is advantageous if the main profile area has a maximum camber, which indicates the ratio of the greatest distance between the profile chord and the skeleton line and the profile depth, between 3% and 4%, in particular between 3.2% and 3.4%, with a relative camber offset, which indicates the ratio between the distance of the maximum camber from the leading edge and the profile depth, between 30% and 40%, preferably 36.8%.

[0048] Furthermore, it is advantageous if the cross-sectional profile of the inner profile area is designed to 1 standardized coordinates according to the following Table 1. Table 1 X / c Y / c 0.9999143 0.0013778 0.9096047 0.0057740 0.8094283 0.0215009 0.7018852 0.0380422 0.5942588 0.0547910 0.5069711 0.0676497 0.4086232 0.0790094 0.3009582 0.0828136 0.1957930 0.0751251 0.1002021 0.0572140 0.0000021 -0.0001393 0.0993147 -0.0268982 0.2099724 -0.0272236 0.2992137 -0.0251922 0.4082850 -0.0217272 0.4999015 -0.0184438 0.5916794 -0.0151009 0.7018578 -0.0112716 0.7933965 -0.0082416 0.9019589 -0.0051074 1.0000250 -0.0013522

[0049] The X / c and Y / c values ​​are normalized to the profile depth (c in the divisor of the values), the coordinate origin is at the leading edge and the values ​​are arranged in the table from top to bottom in such a way that starting from the trailing edge, the values ​​are described first along the low-pressure side to the leading edge and then along the high-pressure side back to the trailing edge.

[0050] In addition, it is advantageous if the cross-sectional profile of the main profile area is designed to 1 standardized coordinates according to the following Table 2. Table 2 X / c Y / c 0.9999143 0.0015200 0.9084306 0.0066846 0.7988078 0.0244418 0.7023305 0.0398598 0.6058425 0.0553892 0.4954016 0.0718163 0.4047419 0.0813044 0.3017767 0.0832083 0.1994129 0.0743986 0.1020109 0.0551867 0.0000031 -0.0001814 0.0957733 -0.0261818 0.2031406 -0.0278629 0.2994944 -0.0263669 0.3968387 -0.0235516 0.4948608 -0.0200729 0.6096461 -0.0157994 0.7080685 -0.0121285 0.8063514 -0.0085282 0.9045046 -0.0051214 1.0000250 -0.0014784

[0051] The X / c and Y / c values ​​are normalized to the profile depth (c in the divisor of the values), the coordinate origin is at the leading edge and the values ​​are arranged in the table from top to bottom in such a way that starting from the trailing edge, the values ​​are described first along the low-pressure side to the leading edge and then along the high-pressure side back to the trailing edge.

[0052] Furthermore, the Y / c values ​​of Table 1 can be scaled by a factor of 0.7 to 1.1, preferably 0.8, and / or the Y / c values ​​of Table 2 can be scaled by a factor of 0.7 to 1.1, preferably 0.9. The two tables, in particular the Y / c values, can thus be scaled by these factors.

[0053] By designing profiles of the areas (inner, main, and / or outer profile areas) of the gyroplane rotor blade in this way, the blade can be optimally adapted to the flight characteristics of the gyroplane rotor. For example, if a higher flight speed is required, the relative profile thickness can be selected to be smaller, thereby counteracting the transonic effects that occur at higher flight speeds. This not only leads to lower drag on the gyroplane rotor but also to a corresponding reduction in noise.

[0054] Further advantages of the invention are described in the following exemplary embodiments. They show: Fig. 1 a perspective view of a gyroplane rotor blade, Fig. 2 a diagram of a profile depth profile and a twist profile of a gyroplane rotor blade, Fig.3 a cross-section of the profile of the inner profile area and Fig. 4 a cross-section of the profile of the main profile area.

[0055] Fig.1 shows a perspective view of a gyroplane rotor blade 1. This extends along a longitudinal direction from a blade root 2 to a blade tip 3, which are arranged at the respective ends of the gyroplane rotor blade 1. In the area of ​​the blade root 2, the gyroplane rotor blade 1 can be attached to a rotor head of a gyroplane. The gyroplane rotor blade 1 thus rotates around the rotor head during flight of the gyroplane, with the blade root 2 lying inward during rotation and the blade tip 3 lying outward. The blade tip 3 therefore has a higher peripheral speed than, for example, an area further inward towards the blade root 2. A superposition of the peripheral speed of the gyroplane rotor blade 1 and a relative wind results in the flow velocity of the air at the gyroplane rotor blade 1.For example, in the forward-moving gyroplane rotor blade 1, the flow velocity is greater towards the outside.

[0056] Furthermore, the gyroplane rotor blade 1 has a leading edge 4, which runs ahead during flight operation of the gyroplane, and a trailing edge 5, which runs behind during flight operation of the gyroplane. The leading edge 4 and the trailing edge 5 border the gyroplane rotor blade 1, so that their border forms a plan view of the gyroplane rotor blade 1 (see. Fig. 2) form.

[0057] A section, in particular a 90° section, transverse to the longitudinal direction designates a profile 21a-f of the gyroplane rotor blade 1. The respective profiles 21a-f can change across the longitudinal direction of the gyroplane rotor blade 1, so that the respective profiles 21a-f differ. Furthermore, the profiles 21a-f can change continuously, for example, with the first profile 21c continuously and steadily transitioning into the third profile 21d. Furthermore, the gyroplane rotor blade 1 can also have significantly more different profiles 21. For example, the gyroplane rotor blade 1 can have a further, in particular different, profile 21 between the first profile 21c and the third profile 21d.

[0058] The profiles 21a-f in the various areas of the gyroplane rotor blade 1 determine the properties of the gyroplane rotor blade 1, such as lift and drag.

[0059] The first profile 21c is the cross-section of an inner profile area 9 (cf. Fig. 2 and Fig. 3). The second profile 21e is the cross-section of a main profile area 10 (cf. Fig. 2 and Fig. 4).

[0060] In addition, a distance between the leading edge 4 and the trailing edge 5 is referred to as profile depth 8. According to the invention, the profile depth 8 decreases monotonically from a region of maximum profile depth 15 toward the blade tip 3. Additionally or alternatively, the profile depth 8 can also be designed to be consistent across a region of the gyroplane rotor blade 1. The profile depth 8 can also influence the properties of the gyroplane rotor blade 1. For example, a corresponding profile depth profile results in a more favorable downwash field, which ultimately results in lower drag of the gyroplane rotor.

[0061] With an outwardly tapered gyroplane rotor blade 1 and special shapes of the profiles 21a-f, the requirements of the gyroplane can be met. If, for example, the gyroplane is to transport higher loads, the profile depth profile can be scaled by a factor that, for example, increases the local profile depth, so that lift is increased. This factor can be the same for each area of ​​the gyroplane rotor blade. Additionally or alternatively, the individual areas, for example the inner profile, main profile, outer profile, and / or the at least one transition profile area, could have different factors. In this case, at least two factors are different. Likewise, profiles 21a-f can be designed that have higher lift. On the other hand, if the gyroplane is to be used for sporting purposes, for example, the profile depth profile can be reduced by a factor that, for example,The local profile depth is reduced, allowing the profile depth profile to be ideally adapted to each gyroplane rotor radius, thus reducing drag and allowing the gyroplane to achieve higher flight speeds. This allows the overall flight performance of gyroplane rotor blade 1 to be increased and adapted to the requirements of the gyroplane.

[0062] A distance transverse to the longitudinal direction, in particular 90° to the longitudinal direction, of the gyroplane rotor blade 1 between the leading edge 4 and the trailing edge 5 is referred to as profile depth 8. The profile depth 8 decreases from a region of maximum profile depth 15 toward the blade tip 3. With a decreasing profile depth 8, a more favorable downwash field can be generated, resulting in less turbulence and reduced drag. As the profile depth 8 decreases outward, the drag of the gyroplane rotor is reduced, which is beneficial for the gyroplane's flight performance.

[0063] Fig.Figure 2 shows a diagram of a profile depth profile 22 and a twist profile 23 of a gyroplane rotor blade 1. The longitudinal extent 14 of the gyroplane rotor blade 1 is plotted on the horizontal or abscissa axis. The blade root 2 is located on the left side and the blade tip 3 on the right side of the abscissa axis. The gyroplane rotor blade 1 thus extends in a positive coordinate direction from the blade root 2 to the blade tip 3. On the vertical or ordinate axis, the profile depth 8 and the twist 13 of the gyroplane rotor blade 1, or the twist angle α, are plotted on the one hand. The two graphs thus represent the profile depth profile 22 and the twist profile 23.

[0064] The gyroplane rotor blade 1 is further divided into various profile regions 9, 10, 11, 12. An inner profile region 9 is arranged at the blade root 2 and / or adjacent thereto. An outer profile region 11 is arranged at the blade tip 3 and / or adjacent thereto. A main profile region 10 is arranged between these profile regions 9, 11. The three profile regions 9, 10, 11 can have different profiles. A profile is a section, in particular a 90° section, to the longitudinal direction of the gyroplane rotor blade 1. For example, the inner profile region 9 could be a profile, in particular the first profile 21c made of Fig. 1, according to Table 1 contained in the previous description or according to Fig. 3. The main profile area 10 could, for example, be a profile, in particular the second profile 21e from Fig. 1, according to Table 2 contained in the previous description or according to Fig.4.

[0065] In addition, a transition profile region 12 is arranged between the inner profile region 9 and the main profile region 10. Additionally, a second transition profile region can also be arranged between the main profile region 10 and the outer profile region 11. In particular, the inner profile region 9 and the main profile region 10 have different profiles 21c, 21e. A transition between the different profiles can be formed by means of the transition profile region 12.

[0066] A twist 13 in the gyroplane rotor blade 1 is a twisting of the rotor blade about an axis in the longitudinal direction. The leading edge 4 and the trailing edge 5 (cf. Fig.1) describe a helical line around the axis in the longitudinal direction when twisted 13. In particular, from the blade root 2 to the blade tip 3, the leading edge 4 is twisted toward the overpressure side 7 and the trailing edge 5 toward the underpressure side 6 (for overpressure side 7 and underpressure side 6, see Fig. 3, Fig. 4). During normal flight operation of the gyroplane, the gyroplane rotor blade 1 therefore has a larger angle to the orbital plane of the gyroplane rotor at the blade root 2 than at the blade tip 3. This larger angle at the blade root 2 is also reflected in the fact that the leading edge 4 is a greater distance from this orbital plane than the trailing edge 5. At the blade tip 3, this difference in the distances of the leading edge 4 and the trailing edge 5 to the orbital plane is smaller due to the twist 13. This leads to lower air resistance of the gyroplane rotor blade 1.

[0067] Furthermore, for example, a section on the left ordinate axis 16, which indicates the profile depth 8 of the gyroplane rotor blade 1, could be 20% of the maximum profile depth. Thus, the left ordinate axis would extend over 120% (from 0% to 120%). A section on the right ordinate axis 17, which indicates the twist 13, could be, for example, 1°. Furthermore, the right ordinate axis could range from -1° to 5°. A section on the abscissa axis 18 could be 10% of the longitudinal extent 14; thus, the gyroplane rotor blade 1 extends from 0% to 100% of the longitudinal extent 14; it is thus normalized to the longitudinal extent 14.

[0068] It should be noted here that the area in front of the inner profile area 9, from 0% to 16%, still belongs to the gyroplane rotor blade 1, but this is where the fastening elements, for example, are located and form a transition to the inner profile area. Therefore, the profile depth profile 22 and the twist profile 23 have a constant value and increase rapidly at the transition to the inner profile area 9. However, this area should be excluded when considering the function of the gyroplane rotor blade 1. The longitudinal extension 14 and the consideration of the function of the gyroplane blade 1 therefore only begin at 16% and end at 100%.

[0069] Furthermore, the gyroplane rotor blade 1 is divided into various profile regions 9, 10, 11, 12. The inner profile region 9 is arranged at the blade root 2 and / or adjacent thereto. The transition profile region 12 is arranged adjacent thereto. The main profile region 10 is arranged again adjacent thereto. Finally, the gyroplane rotor blade 1 has the outer profile region 11. Additionally or alternatively, a second transition profile region can be arranged between the main profile region 10 and the outer profile region 11.

[0070] In this exemplary embodiment, the inner profile region 9 extends over a range from 16% to 34% of the longitudinal extent of the gyroplane rotor blade 1. The profile depth 8 can be read off, for example, from the profile depth profile 22 for the inner profile region 9 and has, for example, values ​​of approximately 100% to 90% of the maximum profile depth. The distance between the leading edge 4 and the trailing edge 5 thus amounts to these values ​​of the maximum profile depth in this region. The profile depth profile 22 decreases monotonically from a range of the maximum profile depth 15 of the gyroplane rotor blade 1. Additionally or alternatively, the profile depth profile 22 can also be designed to be constant over a range of the longitudinal extent 14. A twist profile 23 also decreases monotonically in this inner profile region 9. The twist in this range is between approximately 4.5° and 2.8°, as can be read off the twist profile 23. In a section of approx.16% to 34% of the longitudinal extent 14, the twisting pattern 23 is concave, for example parabolic and / or exponentially falling.

[0071] For example, the transition profile area 12 can extend from 35% to 50% of the longitudinal extent 14. The profile depth profile 22 is approximately constant here. The twist profile 23 decreases linearly or has a constant (negative) gradient. For example, a twist angle α decreases from 2.8° to 0.8°.

[0072] For example, the main profile area 10 extends from 50% to 96% of the longitudinal extent 14 of the gyroplane rotor blade 1. In this area, the profile depth profile 22 continues to decrease monotonically. In a first section of this area, from approximately 50% to 64% of the longitudinal extent 14, the profile depth profile 22 decreases only slightly, for example, from 87% to 82%. From 64% to 96%, the profile depth profile 22 decreases more sharply, from a value of, for example, 82% to 42%.

[0073] The plan view of the gyroplane rotor blade 1 decreases monotonically from a maximum profile depth of 15 from the blade root 2 to the blade tip 3 and has the profile depths listed in Table 3 below at the listed radius positions. The maximum profile depth of 15 is normalized to 100%. All other values ​​listed in Table 3 refer to this maximum profile depth. The profile depth of 8 decreases from a maximum profile depth towards the blade tip 3, so that, for example, at 60% of the radius, the profile depth of 8 is still 85% of the maximum profile depth. Between the radius positions, the plan view has smooth transitions and / or is curved. The profile depth of 8 can also be scaled by a factor of 0.8 to 1.2 to ideally adapt the plan view to the respective design goals: Table 3 radius Tread depth of Tread depth up to % of max depth 20% 80% 120% 100% 30% 75,8% 113% 94,5% 50% 69,6% 104% 87,0% 60% 67,9% 102% 85,0% 70% 62,1% 92,8% 77,5% 90% 43,0% 64,2% 53,6%

[0074] The twist curve 23 also decreases in the main profile area 10. The value of the twist curve 23 decreases, for example, from 0.8° to -0.5° and exhibits, for example, a parabolic, polynomial, and / or exponentially decreasing curve.

[0075] Furthermore, the main profile region 10 has a first sub-region 24 on the root side, in which the twist profile 23 has positive values, in particular positive twist angles α. In addition, the main profile region 10 has a second sub-region 25 on the tip side, in which the twist profile 23 has negative values, in particular negative twist angles α. Between the first sub-region 24 and the second sub-region 25, a sign change 28 of the twist profile 23 takes place, which is arranged at approximately 70% of the longitudinal direction of the gyroplane rotor blade 1. At an angle of attack of zero degrees, the profile is arranged parallel to the plane of rotation of the rotating gyroplane rotor blade 1 at the point of the sign change 28. In the first sub-region 24, the local geometric angle of attack is increased by the twist. In the second sub-region 25, however, the geometric angle of attack is reduced.These changes in the geometric angle of attack result in a more favorable downwash distribution, resulting in less turbulence in the wake, which allows the gyroplane rotor to autorotate more easily, resulting in less drag from the gyroplane rotor.

[0076] The outer profile region 11, which terminates the gyroplane rotor blade 1, can be located between 96% and 100% of the longitudinal extent 14 of the gyroplane rotor blade 1. Here, the profile depth profile 22 decreases parabolically, convexly, polynomially, and / or nonlinearly from 42% and approaches zero. The twist profile 23 remains essentially constant in this region.

[0077] A gyroplane rotor blade 1 with such a profile depth profile 22 and twist profile 23 can be adjusted to specific flight requirements. For example, such a gyroplane rotor blade 1 can allow the gyroplane to fly at high speeds because air resistance is particularly low.

[0078] The profile depth profile 22 is formed as a curved and / or monotonically descending curve in the transition profile area 12 and / or in the main profile area 10. The profile depth profile 22 can also be determined by a strictly monotonically descending curve.

[0079] In addition, the twisting path 23 has a first kink 26 between the inner profile area 9 and the transition profile area 12 and a second kink 27 between the transition profile area 12 and the main profile area 10.

[0080] Furthermore, the gradient of the twist profile 23 in the transition profile region 12 is at least half as great as in the inner profile region 9 and / or the main profile region 10. Furthermore, the total twist in the transition profile region 12 is at least half as great as the total twist in the inner profile region 9 and / or the main profile region 10. The total twist in a region is defined as the difference between the twist profile 23 at the beginning and end of a region. For example, the total twist in the transition profile region 12 is approximately 2.0° (2.8° - 0.8°).

[0081] Fig. 3 shows a cross-section of the profile of the inner profile area 9 (cf. Fig. 2). The Fig.Figure 3 is a graphic representation of Table 1 from the previous description. The profile of the inner profile area 9 is bounded by the leading edge 4, the trailing edge 5, a low-pressure side 6, and the high-pressure side 7. The low-pressure side 6 is more curved than the high-pressure side 7, so that the displacement effect of the profile causes an acceleration of the surrounding airflow, resulting in a corresponding pressure distribution according to Bernoulli's law. This will result in lower pressure on the low-pressure side than on the high-pressure side. This leads to a force in the direction of the low-pressure side 6, which generates lift.

[0082] The tread depth 8 is in this Fig.3 is normalized to 1, whereby the leading edge 4 can be located at 0 in the coordinate system and the trailing edge 5 at 1. The X / c and Y / c values ​​contained in Tables 1 and 2 are the corresponding X and Y coordinates of the coordinate system, where c in the denominator represents the profile depth 8 (in order to normalize the coordinates).

[0083] The profile thickness 19 is also standardized to the profile depth 8. A relative profile thickness of the gyroplane rotor blade 1 is defined as the ratio of the maximum profile thickness 20a to the profile depth 8. For example, the relative profile thickness of the inner profile region 9, with a relative thickness offset between 25% and 35%, is between 11% and 15%, preferably 13.5%. The relative thickness offset is the ratio of the distance of the maximum profile thickness 20a from the leading edge 4 to the profile depth 8. The relative thickness 20a is set at 29.2% in this exemplary embodiment.

[0084] In addition, the profile of the inner profile area 9 has a maximum camber of between 3% and 4%, in particular between 3.6% and 3.8%, with a camber offset of between 30% and 40%, in particular 35.3%. The maximum camber is the ratio of the greatest distance between the profile chord and the yoke line. The profile chord is the connecting line between the leading edge 4 and the trailing edge 5. The yoke line is located midway between the low-pressure side 6 and the high-pressure side 7.

[0085] For example, if the gyroplane rotor blade 1 has a thicker profile 19, the lift is increased. With such a profile, a heavier load can be transported by the gyroplane.

[0086] If, on the other hand, the profile thickness 19 is smaller, the drag of the gyroplane rotor blade 1 is reduced. This allows the gyroplane to achieve, for example, a higher flight speed and / or a greater range, allowing the gyroplane to be used for sporting purposes.

[0087] Fig. 4 shows a cross-section of the profile of the main profile area 10. The Fig. 4 is the graphical representation of Table 2 of the previous description. Here, only the differences to the previous Fig.3. The profile of the main profile region 10 has a relative profile thickness between 10% and 14%, preferably 12.1%, with a relative thickness offset between 26% and 36%, preferably 29.2%. The profile has a maximum profile thickness 20b. Furthermore, the profile of the main profile region 10 has a maximum camber between 3% and 4%, in particular between 3.2% and 3.4%, with a relative camber offset between 30% and 40%, preferably 36.8%.

[0088] The present invention is not limited to the illustrated and described embodiments. Modifications within the scope of the patent claims are possible, as are combinations of features, even if they are illustrated and described in different embodiments. List of reference symbols 1 gyroplane rotor blade 2 leaf root 3 leaf tip 4 front edge 5 trailing edge 6 Vacuum side 7 Overpressure side 8 tread depth 9 Inner profile area 10 Main profile area 11 Outer profile area 12 first transition profile area 13 Twisting 14 Longitudinal extension 15 Maximum tread depth range 16 Section of the left ordinate axis 17 Section of the right ordinate axis 18 Section of the abscissa axis 19 Profile thickness 20 largest profile thickness 21a Profile 21b Profile 21c first profile 21d third profile 21e second profile 21f Profile 22 Tread depth profile 23 Twisting pattern 24 first section 25 second section 26 first bend 27 second bend 28 Change of sign α twist angle

Claims

[1] Gyroplane rotor blade for autorotatory lift generation with a root-side inner profile region (9) having a first profile (21c), with a tip-side main profile region (10) having a second profile (21e) different from the first profile (21c), and with a profile depth profile (22) decreasing monotonously in the longitudinal direction of the gyroplane rotor blade (1) from the area of ​​the blade root (2) towards the blade tip (3), characterized by that the gyroplane rotor blade (1) has a twist with a twist profile (23) that decreases monotonously from the area of ​​the blade root (2) towards the blade tip (3), and that the twist profile (23) has a variable pitch in the inner profile area (9) and / or main profile area (10), so that the twist profile (23) is concavely curved in this area (9, 10). [2] Gyroplane rotor blade according to the previous claim, characterized bythat the gyroplane rotor blade (1) has a transition profile region (12) which is arranged between the inner profile region (9) and the main profile region (10) and / or which has a third profile (21d) whose profile geometry preferably changes continuously and / or smoothly radially outwards from the first profile (21c) to the second profile (21e). [3] Gyroplane rotor blade according to one or more of the preceding claims, characterized by that the twisting profile (23) in the transition profile area (12) has a constant gradient, so that the twisting profile (23), in particular over the entire transition profile area (12), is straight. [4] Gyroplane rotor blade according to one or more of the preceding claims, characterized bythat the pitch and / or the total twist of the transition profile area (12) is at least half as large as the maximum pitch and / or total twist of the inner profile area (9) and / or main profile area (10). [5] Gyroplane rotor blade according to one or more of the preceding claims, characterized by that the twisting profile (23) has a positive twisting angle (α) in the entire inner profile area (9) and / or transition area (12). [6] Gyroplane rotor blade according to one or more of the preceding claims, characterized by that the twisting profile (23) has a positive twisting angle (α) in a root-side first partial region (24) of the main profile region (10) and a negative twisting angle (α) in a tip-side second partial region (25) of the main profile region (10) and / or that the twisting angle (α) between the first partial region (24) and second partial region (25) is zero. [7] Gyroplane rotor blade according to one or more of the preceding claims, characterized by that the twisting profile (23) has a first kink (26), in particular a negative and / or convex one, at the transition from the inner profile region (9) to the transition profile region (12) and / or a second kink (27), in particular a positive and / or concave one, at the transition from the transition profile region (12) to the main profile region (10). [8] Gyroplane rotor blade according to one or more of the preceding claims, characterized by that the gyroplane rotor blade (1) has an outer profile area (11) in the area of ​​the blade tip (3), over the length of which the twist angle is preferably constant. [9] Gyroplane rotor blade according to one or more of the preceding claims, characterized by that the profile depth profile (22) is designed as a curved and / or, in particular in the transition profile area (12) and / or main profile area (10), strictly monotonically falling curve. [10] Gyroplane rotor blade according to one or more of the preceding claims, characterized by that the inner profile region (9) has a relative profile thickness between 11% and 15%, preferably 13.5%, with a relative thickness reserve between 25% and 35%, preferably 29.2%. [11] Gyroplane rotor blade according to one or more of the preceding claims, characterized by that the main profile area (10) has a relative profile thickness between 10% and 14%, preferably 12%, with a relative thickness reserve between 26% and 36%, preferably 31.1%. [12] Gyroplane rotor blade according to one or more of the preceding claims, characterized by that the inner profile region (9) has a maximum curvature between 3% and 4%, in particular between 3.6% and 3.8%, with a relative curvature offset between 30% and 40%, preferably 35.3%. [13] Gyroplane rotor blade according to one or more of the preceding claims, characterized by that the main profile area (10) has a maximum camber between 3% and 4%, in particular between 3.2% and 3.4%, with a relative camber offset between 30% and 40%, preferably 36.8%. [14] Gyroplane rotor blade according to one or more of the preceding claims, characterized by that the first profile (21c) of the inner profile area (9) according to the following Table 1 Table 1 X / c Y / c 0.9999143 0.0013778 0.9096047 0.0057740 0.8094283 0.0215009 0.7018852 0.0380422 0.5942588 0.0547910 0.5069711 0.0676497 0.4086232 0.0790094 0.3009582 0.0828136 0.1957930 0.0751251 0.1002021 0.0572140 0.0000021 -0.0001393 0.0993147 -0.0268982 0.2099724 -0.0272236 0.2992137 -0.0251922 0.4082850 -0.0217272 0.4999015 -0.0184438 0.5916794 -0.0151009 0.7018578 -0.0112716 0.7933965 -0.0082416 0.9019589 -0.0051074 1.0000250 -0.0013522 is formed, wherein the X / c and Y / c coordinates are standardized to the profile depth (8), the coordinate origin is at the leading edge (4) and the values ​​in the table are described from top to bottom along the profile progression starting from the trailing edge (5), over the negative pressure side (6) to the leading edge (4) and over the positive pressure side (7) back to the trailing edge (5). [15] Gyroplane rotor blade according to one or more of the preceding claims, characterized bythat the second profile (21e) of the main profile area (10) according to the following Table 2 Table 2 X / c Y / c 0.9999143 0.0015200 0.9084306 0.0066846 0.7988078 0.0244418 0.7023305 0.0398598 0.6058425 0.0553892 0.4954016 0.0718163 0.4047419 0.0813044 0.3017767 0.0832083 0.1994129 0.0743986 0.1020109 0.0551867 0.0000031 -0.0001814 0.0957733 -0.0261818 0.2031406 -0.0278629 0.2994944 -0.0263669 0.3968387 -0.0235516 0.4948608 -0.0200729 0.6096461 -0.0157994 0.7080685 -0.0121285 0.8063514 -0.0085282 0.9045046 -0.0051214 1.0000250 -0.0014784 is formed, wherein the X / c and Y / c values ​​are standardized to the profile depth (8), the coordinate origin is at the leading edge (4) and the values ​​in the table describe the profile progression from top to bottom, starting from the trailing edge (5), over the negative pressure side (6) to the leading edge (4) and over the positive pressure side (7) back to the trailing edge (5).

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