Apparatus and method for improved stall/over-stall condition fixed wing aircraft pitch control
阅读说明:本技术 改进失速/过失速状态固定翼飞机俯仰控制的装置和方法 (Apparatus and method for improved stall/over-stall condition fixed wing aircraft pitch control ) 是由 傅崇豪 傅崇杰 于 2019-08-21 设计创作,主要内容包括:本发明涉及一种用于改进固定翼飞机的俯仰控制的装置和方法,特别是在深度机翼失速的情况下。根据本发明的装置包括至少一个旋转翼单元(14),其用于产生绕所述飞机的俯仰轴线的力矩,以有效地致动所述飞机的俯仰控制,即使是在深度失速中的情况下。计算机模拟结果表明,配备有本发明的无发动机滑翔机形式的飞机将能够容易地执行多翻转的瀑布式操纵。模拟进一步表明,本发明将使得推力重量比大于单位一的飞机能够在地面上静止时将其迎角提高到大角度,以便执行基于鹞式操纵的超短距离起飞。(The present invention relates to an apparatus and method for improving the pitch control of a fixed wing aircraft, particularly in the event of deep wing stall. The device according to the invention comprises at least one rotary wing unit (14) for generating a moment about the pitch axis of the aircraft in order to effectively actuate the pitch control of the aircraft, even in the case of deep stalls. Computer simulation results show that an aircraft equipped with the engine-less glider version of the present invention will be able to easily perform multi-turn waterfall maneuvers. Simulations have further shown that the invention will enable an aircraft with a thrust to weight ratio greater than unity to increase its angle of attack to a large angle at rest on the ground in order to perform an ultrashort distance takeoff based on rays manoeuvres.)
1. an apparatus for improving the pitch control of a fixed-wing aircraft in a stall/over-stall condition, comprising:
at least one rotary wing unit (14) for generating a moment about the pitch axis of the aircraft, each rotary wing unit (14) further comprising a plurality of rotary wings (142), the moment arm (17) of the device preferably being substantially equal to or greater than the moment arm (13) of the horizontal stabilizer (10) which the device replaces.
2. The apparatus of claim 1, wherein the horizontal stabilizer is physically absent.
3. The device according to claim 1, wherein the rotating wing (142) is variable pitch.
4. The device according to claim 1, wherein the rotary wing (142) is fixed pitch-angled and the rotary wing units (14) are preferably present in opposite pairs.
5. The device according to claim 4, wherein a proposed control scheme called "asymmetric-V" is applied to the rotary wing unit (14) so that the electric motor (144) driving the fixed pitch angle rotary wing (142) is powered to ensure that it rotates smoothly without jerks at a substantially minimum predetermined speed whenever used.
6. The arrangement of claim 1, wherein the rotary wing unit (14) is located behind the CG of an aircraft having a tail-aft layout, the axis of rotation of the rotary wing (142) being substantially parallel to the yaw axis of the aircraft.
7. The device according to claim 1, wherein the rotor unit (14) is located in front of the CG of an aircraft having a canard configuration and the rotation axis of the rotor (142) is substantially parallel to the yaw axis of the aircraft.
8. The device of claim 1, wherein the rotary wing unit (14) is located above the CG of an aircraft having an "above CG" layout, and the axis of rotation of the rotary wing (142) is substantially parallel to the roll axis of the aircraft.
9. A fixed wing aircraft comprising the apparatus of claim 6.
10. A fixed wing aircraft comprising the apparatus of claim 7.
11. A fixed wing aircraft comprising the apparatus of claim 8.
12. A method for improving the pitch control of a fixed-wing aircraft in a stalled/over-stalled condition, the fixed-wing aircraft comprising at least one rotary-wing unit (14) for generating a moment about the pitch axis of the aircraft, each rotary-wing unit (14) further comprising a plurality of rotary wings (142);
the aerodynamic thrust generated by the combination of a rotary wing unit (14) with its moment arm (17) generates a pitching moment which pitches the nose of the aircraft up or down in order to control the pitching of the aircraft during flight and at deep stalls, including the case where the aircraft is stationary on the ground and the forward airspeed is zero, to achieve a high angle of attack attitude suitable for ultra-short or vertical take-off;
the ultra-short takeoff sequence comprises:
(a) the aircraft is stationary with its nose landing gear (26) and main landing gear (28) on the ground;
(b) increasing an angle of attack of the aircraft to a large angle; and
(c) the aircraft launch involves a jet of thrust from the main propeller (20).
13. A fixed wing aircraft implementing the method of claim 12.
14. The device of claim 1, wherein the possible positions of the device are represented by a two-dimensional map comprising a virtual circle (30), wherein the center of the circle coincides with the CG of the aircraft of interest and the radius of the circle is substantially the moment arm (17) of the device; the device can be placed anywhere along the circumference (30) of the circle, and the thrust vectors (16A), (16B) are preferably substantially tangential to the circumference (30).
Technical Field
The present invention relates to an apparatus and method for improving the pitch control of a fixed wing aircraft, particularly in stall/over-stall conditions.
Background
Stabilizing the fins, known as stabilizers, is a key component in the operation of aircraft. Most of the efforts to develop stabilizers and their control surfaces were done in the 19 th century, when pioneer pilot test models of george kelly jazz in uk and army penode in france and manned gliders[1]. Today, typical fixed wing aircraft (or airplanes) still largely inherit the basic design concept developed by kelly in the first half of the 19 th century. Although fin-based stabilizers operate as expected even in the supersonic domain, the disadvantages become apparent in stall/over-stall conditions and extreme stunt flights that often operate in such conditions. A disadvantage is that the horizontal stabilizer and its elevator require sufficient airflow to effectively perform pitch control of the aircraft. For this reason, most stunt flight fixed wing aircraft are designed such that the control surfaces are submerged in the propeller wash stream so that they can perform a number of symbolic over-stall stunt flights such as "struts" (vertical hover), "helixes", "blenders", "rays", "tail spin", "waterfall" and derivatives thereof[2-5]. The stunt manoeuvres most relevant to the present invention are rays and waterfalls. This ray type of maneuver is a maneuver where the aircraft is flying at a trim condition at a high angle of attack around 45 using the lift riser. This steering relies on the lift from the wing and the vertical component of the propeller thrust to maintain horizontal level flight[5]. A significant feature of these aircraft is that the thrust-to-weight ratio exceeds unity[2]Therefore, the method can be used for manufacturing the VTOL airplane with super maneuverability.
However, the requirement to have sufficient airflow over the stabilizers places substantial limitations on the range and quality of over-stall maneuvers that can be performed by the stunt aircraft. For example, in a "waterfall" maneuver, the aircraft pivots 360 ° on its pitch axis with little forward motion, and the aircraft may involve one or more flips[6,7]. It is difficult for a stunt aircraft with a conventional horizontal stabilizer to perform a 'waterfall' maneuverLongitudinal, although it seems simple, because in order to apply a pitching moment around the pitch axis there must be a strong propeller wash and therefore a forward thrust, which inevitably pulls the aircraft forward. It would be highly desirable to overcome this disadvantage so that the propeller thrust and pitch control of the aircraft can be operated independently.
The present invention therefore proposes the concept of a "rotating stabilizer" as a viable alternative to conventional stabilizers and as an effective solution to overcome the limitations of conventional stabilizers in the over-stalled condition.
Disclosure of Invention
It is an object of the present invention to improve the pitch control of fixed wing aircraft in stall/over-stall conditions.
The device according to the invention comprises at least one rotary wing unit for generating a pitching moment about the pitching axis (transverse axis) of the aircraft, even in the over-stalled condition. The device functions as a horizontal stabilizer to control the pitch of the aircraft. The moment arm of the device should preferably be substantially equal to or greater than the moment arm of the horizontal stabilizer it replaces. The main advantage of the present invention over conventional stabilizer-riser methods is its effective and dominant pitch control capability during deep stalls, including when the aircraft's landing gear is on the ground and the aircraft's airspeed is zero. Computer simulation results show that an aircraft equipped with the engine-less glider version of the present invention will be able to easily perform multi-turn waterfall maneuvers. Simulations have further shown that the present invention will enable an aircraft to increase its angle of attack to a large angle to perform a jet-based ultra-short take-off when the ground is stationary. When the nose angle is further raised to 90 deg., a vertical take-off and landing (VTOL) can be performed. In addition, an aircraft equipped with the present invention will maintain control margins through a wide range of Center of Gravity (CG) positions. This has the obvious benefit of not requiring large fuel loads to be regularly distributed during flight to maintain CG limits, thereby simplifying design and improving flight safety. We will refer to the present invention as a "rotational stabilizer" and we believe that the concept of a rotational stabilizer will play an important role in the future of aviation.
Referring now to the drawings, in which like numerals represent like elements throughout. The foregoing disclosure is provided by way of example and not limitation.
Drawings
FIG. 1 is a perspective view of an aircraft in the form of an engine-less glider having a horizontal stabilizer and a vertical stabilizer in an aft layout.
Fig. 2(a) is a perspective view showing an exemplary glider as in fig. 1, except that its horizontal stabilizer is completely absent and replaced by a device according to the present invention.
Fig. 2(b) is a close-up view of an embodiment of the apparatus of the present invention.
Fig. 3 is a perspective view of a motorless glider employing the device according to the present invention, wherein the rotary wing units are present in opposite pairs, since a fixed pitch angle rotary wing is used. The inset shows the control scheme proposed in the present invention, called "asymmetric-V".
Fig. 4 shows an embodiment of the device of the invention, which is used on a fixed-wing aircraft in a canard configuration.
Fig. 5(a) to (c) show a series of side views of a typical ultra-short takeoff sequence. Initially, the forward airspeed V is 0km · h-1。
Fig. 6 shows a side view of a canard like aircraft as in fig. 4, and possible locations of the device of the present invention can be represented by a two-dimensional graph comprising a virtual circle, wherein the center of the circle coincides with the CG of the aircraft of interest, and the radius of the circle is substantially the moment arm of the device.
Fig. 7 is a perspective view of an exemplary aircraft having an "over CG" layout incorporating a device according to the present invention.
Detailed Description
The concept of the rotary stabilizer proposed in the present invention generally relates to the use of one or more rotary wing units as a main alternative to the stabilizer concerned. This concept is widely applicable to horizontal and vertical stabilizers, but in view of the unique advantages of horizontal stabilizers, the present invention focuses primarily on horizontal stabilizers.
The present invention (rotating stabilizer) relates to a device for improving aircraft pitch control, particularly in stall/over-stall conditions, which is useful for pitch-related trick flight applications or ultra-short take-off and landing (super-STOL). In an embodiment, the device according to the invention comprises at least one rotary wing unit for generating a moment about the pitch axis of the aircraft to effectively actuate the pitch control even in the event of deep wing stall. The
Figure 1 shows a perspective view of an engine-less glider with horizontal 10 and vertical 12 stabilizers in a tail-aft configuration. The reference numbers of the elements belonging to the
Fig. 2(a) shows the same exemplary glider, wherein its
In conventional surface-based
The flat flight simulation shows that the flight characteristics of a model glider equipped with the device of the present invention and a pitch gyroscope are hardly different from the flight characteristics of the original glider with a conventional stabilizer. The span of the simulated glider is 3.16 meters. The
According to the present invention, the
The inset in fig. 3 shows an example of a general plot of the output of the motor driving the
Fig. 4 shows an exemplary embodiment of a device according to the invention, which is used on board an aircraft in a canard configuration. The device is typically disposed toward the forward end of the fuselage. In this example, the device comprises a
Fig. 5 is a series of side views of a typical ultra-short takeoff sequence. Initially, the aircraft is at rest with its
The apparatus of the present invention can also be used as a safety redundancy in the event of failure of the elevator surface 242. On the other hand, if the apparatus of the present invention is damaged while in flight, the aircraft may make a conventional runway landing using the flight control surfaces (i.e.,
Based on the embodiments disclosed above, a summary can be drawn regarding the layout arrangement of the device in the present invention with respect to the aircraft CG in the air. Referring now to fig. 6, which shows a side view of a canard, the possible locations of the device can be represented by a two-dimensional graph including a
However, when the aircraft is stationary on the ground, the pivot point will be moved to coincide with the axis of the
Fig. 7 is a perspective view of an exemplary aircraft having an "over CG" layout incorporating a device according to the present invention. The exemplary aircraft has a thrust-to-weight ratio greater than 1 and includes at least one
The foregoing description of the invention has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit the invention to the form disclosed herein. Variations and modifications commensurate with the above teachings, and skill and knowledge of the relevant art, are therefore within the scope of the present invention. The embodiments described hereinabove are further intended to explain best modes known of practicing the invention and to enable others skilled in the art to utilize the invention in such, or other, embodiments and with the various modifications required by the particular applications or uses of the invention. It is intended that the appended claims be construed to include alternative embodiments to the extent permitted by the prior art.
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http://www.aerospaceweb.org/question/history/q0103.shtml
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3.International Miniature Aerobatic Club(2009)About IMAC.
http://www.mini-iac.com/
4.The World Air Sports Federation(2018)F3M Large Radio ControlAerobatics World Cup.http://www.fai.org/world-cups/f3m
5.Selig,M.S.(2014)Real-Time Flight Simulation of Highly ManeuverableUn-manned Aerial Vehicles.Journal of Aircraft,51,1705-1725.DOI:10.2514/1.C032370
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https://en.wikipedia.org/wiki/3D_Aerobatics
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https://www.giantscalenews.com/threads/the-3d-compiliation-facts-how-to-r eference-more.6332/
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