CN103158856B - Light airscrew flying wing aircraft capable of taking off and landing in short distance - Google Patents

Abstract

The invention discloses a light airscrew flying wing aircraft capable of taking off and landing in short distance. The light flying wing is characterized by comprising a fuselage (11), wings (6, 7), two piston type engines, and two airscrews (4) respectively driven by two piston type engines, wherein each wing comprises a straight wing inner section (6) and a backswept and dihedral wing external section (7), the two piston type engines are respectively arranged in engine cars (5) below the straight wing inner sections (6) at two sides to avoid the interference of the above airflow. The light airscrew flying wing aircraft provided by the invention has the advantages that the excellent aerodynamic performance of a flying wing type aircraft is inherited by using the wing and fuselage fusion technique, the high-speed cruise performance is guaranteed; the short-distance taking off and landing ability is realized by comprehensively using slip-flow deflection power lift augmentation technique and strake wing technique, the requirement on ground field is greatly reduced; and the layout is simple in structure, less in control surface, easy to realize and maintain, and low in cost. An engine connecting shaft and a motor-driven ducted fan/airscrew can guarantee the high reliability of the aircraft, and the air safety is guaranteed.

Description

Light propeller flying wing aircraft capable of short take-off and landing

technical field

The invention relates to a light flying-wing aircraft capable of short take-off and landing, and belongs to the technical field of fixed-wing aircraft design in aviation aircraft.

Background technique

Flying wing aircraft usually have no tail, and the fuselage and wings are integrated into one body without obvious boundaries. On the one hand, the integrated design makes the flying-wing layout have high aerodynamic efficiency, low resistance, and high cruising speed. On the other hand, it also makes the load optimal along the wingspan direction, effectively reducing the structural weight. In addition, the aircraft layout also has good stealth performance, which is of great significance for military aircraft. However, because there is no tail, the control surfaces of the aircraft are all on the wings. Viewed along the symmetrical plane of the aircraft, they are often too close to the center of gravity, resulting in low rudder efficiency, poor stability and maneuverability of the aircraft, and due to poor torque trimming ability, limited The use of the high-lift device is used, which makes the take-off and landing performance of the aircraft poor, and usually requires a longer roll distance. Although it has many advantages, the cost of overcoming its defects is often high, so that the conventional flying wing layout cannot be widely used in the field of light aircraft.

Contents of the invention

Aiming at the defects of the conventional flying wing layout, the invention designs a novel flying wing aircraft layout small aircraft capable of taking off and landing at short distances.

The layout adopts a twin-piston engine propeller thrust device, a single fuselage, a single wing, a three-point landing gear and an anti-scratch tail wheel on the tail ventral fin. The single fuselage is slender and fused with the wings. An independent lift fan or electric propeller is installed at the front of the fuselage for pitch control and torque trimming. The wing is a medium aspect ratio wing with a straight inner section and an upturned and swept outer section. The engine is installed on the leading edge of the straight section, and the upper and lower split flaps are used on the trailing edge. The straight sections are all in the slipstream of the propeller, combined with simple flaps to form a slipstream deflection power boost system, so that the aircraft can obtain a large lift coefficient even at low speeds. In addition, the use of side strips further improves the lift-drag characteristics of the aircraft at low-speed take-off and landing and high angle of attack. On the one hand, the pelvic fin at the tail enhances the directional stability of the aircraft, and on the other hand, the tail wheel below it can also prevent the aircraft from rolling backwards when it touches down at a high angle of attack. In order to avoid the dangerous situation of single-engine parking, the two engines adopt a coupling design.

The technologies adopted in the present invention are relatively mature, and while realizing short-distance take-off and landing of the flying-wing layout, the overall technical scheme has a simple and reliable structure and low cost, which is beneficial to the popularization of the flying-wing layout in the field of light and small aircraft.

According to one aspect of the present invention, a lightweight flying wing is provided, characterized in that it comprises:

body,

Wings, including a straight inner section and a swept and upturned outer section,

Two piston engines, which are respectively arranged in the engine pods below the inner section of the wing on both sides, so as to avoid interference with the air flow above them,

Two propellers driven respectively by said two piston engines.

Description of drawings

Fig. 1 is an overall view of a lightweight flying wing according to an embodiment of the present invention.

Figure 2 shows a flap that can be divided into upper and lower halves.

Figure 3A schematically shows a forwarding arrangement including a ducted fan according to one embodiment. Figure 3B schematically shows a forward launch arrangement including propellers according to another embodiment.

Detailed ways

In order to achieve short take-off and landing, as shown in Figure 1, the overall scheme of light-weight flying wings according to an embodiment of the present invention takes into account both high-speed cruise performance and short take-off and landing performance, specifically including:

powerplant

The piston engine is positioned at the straight wing inner section (6), and the engine pod (5) is positioned below the wing inner section (6) to avoid interference with the air flow above it. The two engines are connected through the transmission shaft (10) that traverses the rear of the fuselage (11) and the inner section of the wing (6), so as to avoid the uncontrollable yaw moment caused by single-engine parking during short take-off and landing and cruise flight .

propeller (4)

This embodiment adopts three large-diameter variable-pitch propellers (4) to ensure power matching at low speed and high speed, and pitch differential can be used for yaw control. Larger propeller size can generate larger propeller slipstream, thereby covering most of the straight airfoil inner section (6) airfoil, slipstream deflection can also provide more power gain.

Fuselage (11)

Viewed along the plane of symmetry of the aircraft, the fuselage (11) is longer, mainly to keep the ducted fan (1) at its head away from the center of gravity of the aircraft and increase the force arm of the ducted fan (1). The fuselage (11) is flat as a whole, and the cockpit (2) is located at the front, so the cross-sectional area of the front is relatively large, while the rear shrinks rapidly and integrates with the inner section of the wing (6). On the whole, the fuselage (11) has good aerodynamic characteristics and can enable the pilot to obtain a wide field of vision.

Front hair (1)

As shown in Figure 3, the front engine (1) is located in front of the cockpit (2), driven by an electric motor, and has high reliability. During short take-off and landing or low-speed level flight, the upward vector force generated by it is used on the one hand to match the nose-down moment brought by the smooth flow deflection power boost, and on the other hand, it also directly provides upward lift. Figure 3A schematically shows a forwarding arrangement comprising a ducted fan (18) according to one embodiment. Figure 3B schematically shows a forward launch arrangement comprising a propeller (17) according to another embodiment. The embodiment with the ducted fan (18) has a longer body length and a smoother aerodynamic shape. And the fuselage length of the embodiment with propeller type (17) is short, and the cabin is relatively more forward, and the field of view of the driver is better, and the structure is also relatively simple.

wing

In order to realize higher cruising speed, the present embodiment adopts high wing load, and the wing area is relatively small. Due to the use of slipstream to increase the lift, the medium aspect ratio is selected, the inner section of the wing (6) is straight, and the outer section of the wing (7) is swept back and reversed. The trailing edge of the straight inner section of the wing (6) is a flap (8), which is used for slipstream deflection and power increase. The high-speed slipstream passes through the downwardly deflected flap (8), which increases the wing circulation on the one hand, The inner section of the wing (6) generates more lift, and on the other hand, the downward deflection of the flap (8) directly deflects the thrust of the engine to generate an upward component. In addition, the flaps (8) will simultaneously act as elevons for pitch and roll control during flight. The outer section of the wing (7) does not have any movable rudder surface, which makes the structure simpler and more reliable, and reduces the weight. On the one hand, the sweep of the outer section of the wing (7) can reduce the resistance at high speed, and on the other hand, it has the same effect as that of the wing up, which increases the lateral stability of the aircraft. The upward reaction of the wing outer section (7) also weakens the induced drag in flight.

Flaps (8)

Flaps (8) are located on the trailing edge of the inner wing section (6). As shown in Figure 2, the flap (8) can be divided into upper and lower halves (15, 16). When the two are integrated, it is a simple flap for slipstream deflection power increase; when the two rotate independently, the lower half (16) is a split flap, which is used for aerodynamic lift, and the upper half (15) can be used as a spoiler for roll control; when it is deflected 90° up and down, it can be used as a drag plate when landing and sliding.

Side Wings (3)

The side strip wings (1) are located on both sides of the fuselage and are used to generate the detached vortex. The detached vortex sweeps the rear of the fuselage (11) and the root of the inner section of the wing (6), which can effectively improve the angle and lift at low speeds.

Pelvic fin (13) and caudal wheel (14)

The pelvic fin (13) is located at the lower part of the tail, which can effectively improve the directional stability of the aircraft. The tail wheel (14) is equipped with at the lower rear part of the pelvic fin, which can prevent the aircraft from rolling backwards when the high angle of attack touches down or lifts off the ground.

landing gear

The landing gear is tricycle type and can be retracted to ensure the high-speed performance of the aircraft. The front wheels (12) are received in the lower part of the cockpit (2) backwards, and the rear wheels (9) are received in the engine pod (5) to both sides.

Advantages and beneficial effects of the present invention include

—Using wing-body fusion technology, it inherits the excellent aerodynamic performance of flying-wing aircraft and ensures high-speed cruising performance.

—Through the comprehensive use of slipstream deflection power boosting technology and side strip wing technology, the short take-off and landing capability is realized, which greatly reduces the requirements on the ground site.

—The layout is simple in structure, less in control surfaces, easy to realize, easy to maintain, and lower in cost.

—Both the engine shaft and the electric ducted fan/propeller ensure high reliability of the aircraft and flight safety.

Claims (7)

1. A light-duty flying wing, characterized in that it comprises: fuselage (11), Wings (6, 7), comprising a straight wing inner section (6) and a swept back and upturned wing outer section (7), Two piston engines, which are respectively arranged in the engine pod (5) below the wing inner section (6) on both sides, to avoid interference with the air flow above it, two propellers (4) driven respectively by said two piston engines, forward(1), in The head of the fuselage (11) is equipped with a forward engine (1). During short take-off and landing or low-speed level flight, the upward vector force generated by it is used on the one hand to match the nose-down moment brought by the smooth flow deflection power increase. , on the other hand also directly provides upward lift, and the front hair (1) is selected from the ducted fan (18) formula front hair and the propeller (17) formula front hair, The fuselage (11) has a larger length viewed along the plane of symmetry of the aircraft, so that the ducted fan (1) is far away from the center of gravity of the aircraft, thereby increasing the force arm of the ducted fan (1), Fuselage (11) is overall flat, and the cross-sectional area of the front portion of fuselage (11) is larger, and cockpit (2) is positioned at the front portion of fuselage (11), The rear portion of the fuselage (11) shrinks rapidly and merges with the wing inner section (6). The two piston engines are connected through the transmission shaft (10) that traverses the rear portion of the fuselage (11) and the wing inner section (6), so as to avoid the failure caused by single-engine parking during short take-off and landing and cruising flight. Control yaw moment. 2. The lightweight flying wing according to claim 1, characterized in that: The two propellers (4) are three-blade large-diameter variable-pitch propellers (4) to ensure power matching at low speed and high speed, and pitch differential can be used for yaw control, Larger propeller size can generate larger propeller slipstream, thereby covering most of the straight airfoil (6), slipstream deflection can also provide more power gain. 3. The lightweight flying wing according to claim 1, characterized in that: The front engine (1) is located in front of the cockpit (2), driven by an electric motor, and has high reliability. 4. The lightweight flying wing according to claim 1, characterized in that: Described wing (6,7) is high wing load, and wing area is relatively small, Slip flow booster is adopted, medium aspect ratio is selected, The inner section of the wing (6) is straight, and the outer section of the wing (7) is swept back and upside down, The trailing edge of the inner section of the wing (6) is a flap (8), which is used to deflect the power of the slipstream to increase the lift. The high-speed slipstream passes through the flap (8) which is deflected downward. On the one hand, the circulation of the wing is increased, so that the wing The inner section (6) generates more lift, on the other hand, the downward deflection flap (8) directly deflects the engine thrust, generating an upward component, The flaps (8) will simultaneously serve as elevons for pitch and roll control during flight, The outer section of the wing (7) has no movable rudder surface, which makes the structure simpler and more reliable, and reduces the weight. On the one hand, the sweep of the outer section of the wing (7) can reduce the resistance at high speed, and on the other hand, it has the same effect as that of the wing up, which increases the lateral stability of the aircraft. The upper anti-wing outer section (7) also weakens the induced drag in flight. 5. The lightweight flying wing according to claim 4, characterized in that: The flap (8) is divided into upper and lower halves (15, 16), and when the upper and lower halves (15, 16) are integrated, it is a simple flap for slipstream deflection power increase; the upper and lower halves (15, 16) are independent When rotating, the lower half (16) is a split flap for aerodynamic lift, and the upper half (15) is used as a spoiler for roll control; the upper and lower halves (15, 16) are simultaneously deflected 90° to the back When used as a drag plate during landing roll. 6. The lightweight flying wing according to claim 1, further comprising: Side strip wings (3), which are located on both sides of the fuselage (11), are used to generate detached vortices, The detached vortex sweeps the rear portion of the fuselage (11) and the root of the wing inner section (6) thereafter, and is used to improve the lift force during high angle of attack and low-speed flight. 7. The lightweight flying wing according to claim 1, further comprising: The pelvic fin (13) is arranged below the tail of the fuselage (11) for improving the directional stability of the aircraft, The tail wheel (14) arranged at the lower rear part of the ventral fin is used to prevent the aircraft from rolling backwards when landing or taking off the ground at a high angle of attack, The front three-point retractable landing gear, the front wheel (12) of the landing gear is received in the lower part of the cockpit (2) backward, and the rear wheel (9) of the landing gear is received in the engine pod to both sides (5) inside.