Patent Application
20100213308
The present invention relates to an aircraft, and particularly to a positive-pressure flying aircraft that flies by relative air stream or positive pressure to an aircraft body.
In an aircraft, owing to difference in velocity of air stream flowing on the upper and lower surfaces of a wing, negative pressure generated on the upper surface raises the aircraft body. As an angle of attack of the wing increases, air stream is likely to leave the leading edge of the wing, so that the aircraft goes into a stall or is not stabilized to crash.
JP2004-106784A discloses a kite-type aircraft pushed by air stream or positive pressure to fly.
In the kite-type aircraft, the angle of attack of the aircraft body is nearly 60 degrees at low speed or in landing which is similar to a kite. However, a jetting device jets out a gas obliquely downward along the wing on the upper surface of the aircraft body to generate propelling force or lift. Lift is not generated by pushing air stream.
Furthermore, in low speed flight and landing or takeoff, it is necessary to increase the angle of attack of the aircraft body remarkably. Thus, it is very difficult for the aircraft to run on the ground while such a large angle of the attack is kept.
It is an object of the invention to provide a positive-pressure flying aircraft in which relative air stream pushes an aircraft body for flying, the aircraft stably flying with a large angle of attack at low speed and in landing or takeoff.
The inventor found that an aircraft body was pushed by a thrusting device such that the weight of the body was supported by a component force of a reaction from air stream, the aircraft rising and flying by a component force of a propelling force of the thrusting device while its posture is kept at optimum.
The above problem will be solved by the present invention below.
(1) A positive-pressure flying aircraft comprising:
a wing comprising an arcuate leading edge and a tapered trailing edge, an air trap being formed at least ½ of width of the wing from the leading edge to the trailing edge on a lower surface of the wing;
an elevator and a rudder at the rear end of the wing; and
a thrusting device on the wing.
(2) The aircraft of (1) wherein the air trap comprises a restricting portion projecting inward in the middle between front and rear ends such that a traverse sectional area of the restriction portion is smaller than those at the front and rear ends.
(3) The aircraft of (2) wherein the restricting portion comprises vertical restricting portion in which the wing has a lower surface gradually projecting from the front end to the middle and gradually not projecting from the middle to the rear end vertically.
(4) The aircraft of (2) or (3) wherein the restricting portion comprises right and left restricting portions gradually projecting from the front end to the middle and gradually not projecting from the middle to the rear end transversely.
(5) The aircraft of any one of (1) to (4) wherein thickness of the maximum thickness portion of the wing is 2/10 to 3/10 of chord length of the wing.
(6) The aircraft of (5) wherein the maximum thickness portion is located at a position of 3/10 to 4/10 of the chord length from the leading edge of the wing.
(7) The aircraft of any one of (1) to (6) wherein a diameter of an arc at the front end of the arcuate leading edge of the wing is less than the maximum thickness of the wing and ½ of the maximum thickness.
(8) The aircraft of any one of (1) to (7) wherein a right body and a left body are disposed at each side of the wing along the width of the wing to project downward from side edges, the right and left bodies having hemispherical or partially hemispherical front ends, side surface of a groove of the air trap being formed by downward-projecting portions of the wing.
(9) The aircraft of (8) wherein the right and left bodies are formed to be thinner gradually toward the rear ends, a horizontal stabilizer being integrally mounted to the rear end, the elevator being disposed at the rear end of the horizontal stabilizer.
(10) The aircraft of any one of (1) to (7) wherein the wing comprises a middle body in the middle of the width, the right body and the left body thicker than the wing being disposed longitudinally on each side of the middle body and projecting downward, the middle body having a hemispherical front end, the right and left bodies having a hemispherical front end, sides of the aircraft body forming sides of a groove of the air trap.
(11) The aircraft of (10) wherein the middle body, the right body and the left body are tapered rearward, the horizontal stabilizer being integrally mounted to the rear ends of the right and left bodies, the elevator being disposed at the rear end of the horizontal stabilizer.
(12) The aircraft of any one of (7) to (11) wherein the right and left bodies comprises a float for flying the aircraft body on the water.
(13) The aircraft of any one of (1) to (7) wherein the wing extends longitudinally of the aircraft body, the upper surface being equal along the width.
(14) The aircraft of any one of (1) to (7) wherein the wing includes the middle body disposed in the middle of the width of the aircraft body, the middle body having part or all of hemisphere.
(15) The aircraft of any one of (10), (12) and (14) wherein the middle body comprises a lower surface continuous with a bottom surface of the groove of the air in front of the wing.
(16) The aircraft of any one of (8) to (12) wherein the maximum thickness of the right and left bodies is 2/10 to 3/10 of the length of the right and left bodies.
(17) The aircraft of any one of (1) to (16) wherein the elevator is mounted at the back of the wing.
(18) The aircraft of (17) wherein the elevator is mounted to the rear end of the horizontal stabilizer with hinge, the upper surface of the elevator being linear, the lower surface of the elevator being curved or triangular.
(19) The aircraft of any one of (1) to (18) wherein a wheel for running on the ground is disposed on the lower surface of the wing.
Embodiments of the invention will be described with respect to the drawings.
In
An elevator 50 is mounted to the rear end of the horizontal stabilizer 56. In
The thickness of the maximum thickness portion 21 of the wing 12 is 3/10 to 4/10, preferably 35/100, of the cord length.
The diameter of an arc of the leading edge 22 is defined as ⅓ of the thickness of the maximum thickness portion 21. For example, the leading edge 22A has a diameter that is equal to the maximum thickness D in
If the maximum thickness is less than 3/10 of the chord length, the wing 12 will be too thin and air stream will be likely to leave the wing 12. If it is over 4/10, air resistance will get too large. The diameter of the arc of the leading edge 22 is larger than the maximum thickness, the wing 12 will get uneven. If it is smaller than ⅓, air stream will likely go away as described later. The maximum thickness portion 21 was determined in position by experiments to keep the most stable flight.
The right body 30A and the left body 30B are connected to the ends of the thin wing 12 respectively; extend longitudinally and are formed like a semicircle in a cross section. The leading edge 31A and the trailing edge 31B are formed as hemisphere at the right body 30A and the left body 30B respectively, and the right body 30A and the left body 30B are tapered rearward from the middle.
The thickness of the wing 12 is about ¼ of the heights of the right and left bodies 30A, 30B. The lower parts of the right and left bodies 30A,30B project downward from the wing 12. In
The bottom surface 24 and the right and left guide surfaces 32A,32B define an air trap 32 extending from the leading edge to the trailing edge of the wing 12.
In
By the structure, air that flows in from the front end of the air trap 32 is restricted by the restricting portion 33 projecting at maximum at the right guide surface 32A, the left guide surface 32B and the bottom surface 24 and flows out rearward.
The middle body 40 has a hemispherical end 42 and an elliptical cross section such that a cross sectional area gradually becomes smaller rearward from the middle of the length.
The front end of the middle body 40 projects forward from the front ends of the wing 12, and the right and left bodies 30A,30B. The projecting lower surface 41 projects downward from the wing 12 and is continuously formed with the bottom surface 24 of the air trap 32.
The rear end 26 of the wing 12 faces the front end of a horizontal stabilizer 56 at the same height about a gap 58.
The propeller 54 is provided at the rear end of the middle body 40 in the gap 58 in front of the horizontal stabilizer 56. The rudder 52 is placed in the middle of the width of the horizontal stabilizer 56 vertically at the back of the middle body 40. The elevator 50 is hinged to the rear end of the horizontal stabilizer 56. The elevator 50 is linear along the upper surface and is curved or triangular. The length of the elevator 50 along the width of the aircraft is almost equal to the width of the rear end of the air trap 32. The horizontal stabilizer 56 projects from the right body 30A and the left body 30B along the width of the aircraft.
The cross section of the horizontal stabilizer 56 is inverse to that of the wing 12. In this embodiment, the wing 12 is linear on the upper surface and convex on the lower surface. The wing 12 is not limited to the shape in
Instead of the propeller 54, a jet engine or rocket engine may be provided. If the aircraft 10 is a small plane such as an unmanned plane or a model plane, the propeller may be combined with a motor electrically driven by a battery.
If necessary, in such a positive-pressure flying aircraft 10 may have a wheel 50 running on the ground. The wheel 60 may be provided on the front lower surfaces of the right and left bodies 30A,30B and on the middle lower surface of the horizontal stabilizer 56. When the positive-pressure flying aircraft 10 is used as a flying boat, the right body 30A and the left body 30B may be a float.
When the positive-pressure flying aircraft 10 is accelerated forward by the propeller 54 from a rest on the ground or water, air runs with respect to the aircraft 10 and flows through the air trap 32 under the wing 12.
Air is trapped by the right guide surface 32A and the left guide surface 32B not to flow out beyond the width of the body, so that the bottom surface 24 of the air trap 32 are pushed up. The wing 12 is subjected to a reaction force from air via the bottom surface 24.
Flying of the aircraft 10 will be described compared with a Japanese kite.
In the Japanese kite, the front surface or wind-receiving surface is pushed by wind and tension is applied to a kite string for holding the Japanese kite. By pulling down the kite string with wind or without wind, the Japanese kite bound by the kite string will float up by reaction force when air stream impacts the wind-receiving surface and will rise to a position having a balancing angle of attack. The rising force is a component force along the wind-receiving surface of the reaction force unless the kite string extends. If the kite string extends, the rising force will be a resultant force of the above component force and a component force perpendicular to the wind-receiving surface.
In this embodiment of the present invention, it will be considered that the aircraft is accelerated with the wing 12 by the propeller 54 to push air whereby the two component forces are obtained as reaction force.
While air is pushed with the wing 12 by the propeller 54, the elevator 50 is tilted downward. Flying force on the wing 12 is restricted and the aircraft 10 flies slightly above the ground.
With increase of power of the propeller 54, if the elevator 50 is tilted upward, the front of the aircraft is raised. In proportion with increase in power of the propeller 54, the aircraft is accelerated and rises by a large reaction force.
The angle of attack of the wing 12 increases considerably. But the front ends of the wing 12, the right body 30A, the left body 30B and the middle body 40 are arcuate or hemispherical. Thus, air stream does not leave the front end of the wing 12. The aircraft does not go into a stall or does not crash.
In the process, air stream is generated from the front end to the rear end of the air trap 32. Air stream is narrowed by the restricting portion 33 of the right guide surface 32A, the left guide surface 32B and the bottom surface 24 and cross-sectional area increases rearward. By the Coanda Effect, high-viscosity slow air stream is generated along the bottom surface 24, the right guide surface 32A and the left guide surface 32B, while high-speed air stream is generated at a remote position. A large propelling force is obtained for the wing 12 by the high-speed air stream.
When the aircraft 10 flies at low speed with low output of the propeller 54, a force for pushing air by the air trap 32 is weak. Thus, the angle of attack of the whole aircraft 10 increases, and a forward component force of the propelling force by the propeller 54 is small.
With increase in power of the propeller 54, a force for pushing air in the wing 12 increases and the angle of attack decreases. A component force of the propelling force increases forward, enabling the aircraft 10 to fly at high speed.
The angle of attack of the aircraft 10 varies by power of the propeller 54 to realize stable flight. If air speed or wind velocity is equal to the forward component force, the aircraft 10 will hover.
The cross section of the horizontal stabilizer 56 is inverse to that of the wing 12. Lift is generated by negative pressure on the surface of the horizontal stabilizer 56 and is opposite to moment for raising the wing 12 forward, enabling flight posture to be stabilized.
The relationship of the body weight, wind-receiving area of the air trap 32 and output of the propeller 54 is determined by repeated trial and error, but it will be determined by computer if its theory is established.
The air trap 32 is single in this embodiment, but a plurality of air traps may be used. The ratio of the air trap 32 to the wing 12 in width may preferably be at least ½. If it is below ½, a flying force of the plane body is not enough and it is necessary to increase the power of the propeller 54. The upper limit is a value to which the widths of the right and left guide surfaces 32A,32B deducted from the whole width is equal. The depth of the air trap 32 is determined by trial and error such that the plane body does not slide laterally.
A positive-pressure flying aircraft 70 in Embodiment 2 of the present invention will be described in
The positive-pressure flying aircraft 70 is a whole-wing-type aircraft which has a wing 74 equal to the right and left bodies in Embodiment 1 in height. In an air trap 72, the sum of widths of right and left side walls 73 forming right and left guide surfaces 73A,73B is equal to the width of the wing 74. The air trap 72 is defined by the right and left guide surfaces 73A, 73B and a bottom surface 72A.
In the middle of the wing 74, a middle body 40 similar to that of Embodiment 1 is provided. The front end of the middle body 40 is positioned in front of the front end of the wing 74, and concaves 76 are formed in
With respect to other structure, the same numerals are allotted to the same elements in Embodiment 1 and its description is omitted.
In the whole wing positive-pressure flying aircraft, the area of the air trap 72 is larger than that of the whole aircraft body thereby providing a large flying force. The ends 31A,31B and a hemispherical end 42 of the middle body 40 assures attachment of air stream thereby stabilizing flight of the aircraft.
The whole wing aircraft according to the present invention does not always need to have a middle body. But the middle body can contribute stabilization of flight of the aircraft.
In Embodiments 1 and 2, a gap 58 is provided between the rear end of the wing and a horizontal stabilizer. The gap 58 will not be necessary.
A restricting portion 33 comprises right and left restricting portions 33A and upper and lower restricting portions 33B. Either of them may be provided. Furthermore, the front end of the middle portion need not project from the right and left bodies or may project less than them. The concave 76 therebetween contributes stabilation of flight.
Regardless of posture and velocity of the aircraft body, stable flight can be achieved.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-239298 | Sep 2007 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2008/064471 | 8/12/2008 | WO | 00 | 3/12/2010 |
