WO2009110651A1

WO2009110651A1 - Lift enhancer for a wig craft

Info

Publication number: WO2009110651A1
Application number: PCT/KR2008/001556
Authority: WO
Inventors: Chang-Gu Kang; Chang-Min Lee; Han-Jin Lee
Original assignee: Wing Ship Technology Co.
Priority date: 2008-03-06
Filing date: 2008-03-19
Publication date: 2009-09-11
Also published as: KR20090095928A

Abstract

Disclosed is a lift enhancer for a WIG craft, and more particularly, to a lift enhancer for a WIG craft positioned at the front and rear side of the wing which is to be expanded in the direction of the wing's chord to maximize ground effect by increasing the chord length and area of the wing and reducing the distance between the wing and the water surface. According to the present invention, when the WIG craft is flying over the water surface or taking off from or landing on the water, the trailing edge of the wing is not in contact with the water surface, such that the resistance from the water can be reduced to prevent the wing from being broken. In addition, ground effect can be maximized with a simple manipulation of the inventive lift enhancer.

Description

[DESCRIPTION]

[Invention Title]

LIFT ENHANCER FOR A WIG CRAFT

[Technical Field]

The present invention relates to a lift enhancer for a WIG craft.

[Background Art]

A WIG craft is the abbreviation of a Wing-In-Ground craft, which is often referred to as a ground effect wing craft or a wing craft. The WIG craft stands for a ship moving in a state of floating over a water surface at a super high speed. In other words, WIG refers to a craft or a ship having a state of the art technology which adopts both shipbuilding technologies to cruise on water at high speeds and aeronautical technologies to fly just over the water surface in a floating state.

The WIG moves forward with a lift (force) which is a fundamental principle for an airplane to fly as well as with 'ground effect 'in which the lift supporting the craft body becomes bigger as the wing comes closer to the water surface. The maximum speed of the WIG craft may reach up to about 550km/h. A WIG craft is generally provided with a plate under the end portion of the wing, so a phenomenon occurs whereby air gets trapped between the wing and the water surface, which enables the WIG craft to fly just above the water surface with ease.

The WIG craft, at first, brought about argumentswhether it should be classified a ship or a plane. In the late 90' s, however, the WIG craft was classified as a ship by the International Maritime Organization: IMO). The WIG craft has an advantage that it can cruise several times faster than a general ship, but it can be operated with much less fuel. Moreover, it has doublefeatures that it can move on water and fly in the air. However, since the WIG craft cannot fly over the water surface in case of high waves, typically it has been used in lakes or rivers up to now.

The former Soviet Union started to develop WIG crafts for military purposes, and since then Russia, Germany, China or other country have developed the WIG craft for maritime rescues or entertainment purposes. Only a small number of WIG crafts have actually been serviced hitherto.

In Korea, the related technologies about the WIG craft were first introduced through an exchange program on science and technology between Russia and Korea in 1993. In 2002, through cooperative research with a venture company, the Korea Ocean Research and Development Institute (KORDI) succeeded in a test cruise of a small four-seater WIG craft for entertainment purposes. That WIG craft is called 'Seagull' and it could fly at 2 meters above the sea level at a speed of 120 km/h, while consuming less than 50% fuel than of a typical motor boat.

Recently, the Ministry of Maritime Affairs and Fisheries announced that over 120 billion Won (about 100 million US dollars) would be invested to develop a large scale WIG craft having about 200-seats. In fact, a WIG craft flying at 5 meters high above the water surface is much similar to a plane in its principle of movement, even though it is classified as a ship by the treaty between the IMO and ICAO (International Civil Aviation Organization). The WIG craft appears to have no difference from a plane in the sense that it can fly at high speeds while floating in the air by means of a lift generated by the wings. The only difference is that the WIG craft makes the most use of ground effect, while a plane does not. Ground effect refers to a phenomenon whereby more lift is created than usual by the air trapped under the wing when the wing comes into close proximity with the water surface.

Without ground effect, the WIG craft cannot fly in the air floating like a plane. Of course, a plane is also able to experience ground effect like the WIG craft when it flies near the ground or water surface. This makes it possible to efficiently create more lift at the wings. The problem, however, is that it is very dangerous for a plane to be brought into contact with water surfaces except for a sea plane or a flying boat. In other words, between a WIG craft and a plane, even though their fundamental principles of flying in the air are very similar, their evolutionary directions to follow are totally different from the beginning because the WIG craft is designed to fly just over water surfaces, but the plane is designed to fly in the air.

In fact, the weakest point of the WIG craft is derived from this very phenomenon, ground effect.The front portion of the WIG craft flying at a high speed can be moved up and down like a wave due to ground effect. If such vibration movement becomes severe, the WIG craft can crash into the water or overturn in the air. In addition, the early design technologies on the WIG craft had such limitations in use that the WIG craft was serviceable in a lake or river, but it was not able to take off from or land on the sea, having high waves, due to the instability of ground effect. Fortunately, the problems described above have been solved one by one with the help of the development of control technologies. However, as to a large scale WIG craft, there still might exist difficult tasks to be solved because there has been reported no exemplary case to develop one until now.

If the KORDI succeeds in commercializing the large scale WIG craft, it is expected that transportation time and cost may be lowered remarkably. The WIG craft can fly at a speed of about 200 to 500 km/h, which conventional ships cannot attain, and its fuel cost will be half of that in a conventional plane. Since there is no need for the WIG craft to build a large facility such as an airport for the airplane, which may make it possible to bring an epoch-making change for the logistics in the Far East. There is no other carrier better than the WIG craft as a connection means for passengers and freight servicing cities in China, which have a large amount of cargo logistics with Korea but have no airport facilities, such as Weihai , Yantai , Qingdao and Dalian. If it is possible to transport passengers and freight from Korea to eastern coastal areas of China or Japan within one to three hours at half the price of the air fare, its ripple effect may not be easily assessed. While there might be lots of obstacles to get over, it should be noted that we live in an era in which one up- to-date science or technology can control the competitiveness of a nation.

However, since the wing profile of aconvent iona1 WIG craft is in a fixed form, in order to enhance ground effect its cruising altitude should be lowered or the main wing should be positioned as low as possible at a fuselage, considering it from the design stage.

The increment of lift due to ground effect is determined by a h/c ratio, wherein h is thedistance between the trailing edge of a wing and the water surface, and c is the chord length of a wing, i.e., a straight line connecting the leading edge with the trailing edge. The smaller the h/c ratio becomes, the more the lift increases exponentially. In other words, ground effect will be increased by lowering the altitude of the wing (h) or increasing the chord length (c).

When designing the WIG craft, the above mentioned aspects should be taken into consideration. If a design option to lower the position of the wing, when seen from the fuselage, is applied, i.e., with a fuselage design wherein the chord length is increased or the absolute position of the wing is lowered, the end portions of the wing willbe submerged into the water when the WIG craft is floating on the water. Accordingly, the wings might be broken due to a high resistance to water when the WIG craft is taking off from or landing on the water. Further, if the situation gets even worse, structural weakness such that the WIG craft is not able to take off from or land on the water might follow, which leads to a design limitation in lowering the position of the wing.

In addition, in case of reducing the cruising altitudeof the WIG craft to increase the lift, an accident might occur where the fuselage of the WIG craft comes in contact with the water surface, which results in another design limitation.

[Disclosure]

[Technical Problem]

In view of the above-noted drawbacks and other problems inherent in the prior art, it isan object of the present invention to provide a lift enhancer for a WIG craft each positioned at the front and rear side of a wing, which is to be expanded in such a direction of a wing's chord to increase the chord length and area of the wing and also to reduce the distance between the wing and the water surface, resulting in maximizing the ground effect of the WIG craft. [Technical Solution]

In order to accomplish the above-mentioned objects, the present invention provides a lift enhancer for a WIG craft. [Advantageous Effects]

According to the present invention, when the WIG craft is cruising over the water surface in a state of floating or taking off from or landing on water, the trailing edge of the wing is not in contact withthe water surface so that resistance from the water can be reduced to prevent the wing from being broken. In addition, ground effect can be maximized with thesimple manipulation of the lift enhancer. [Description of Drawings]

The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a drawing schematically showing a construction of the lift enhancer for a WIG craft, i.e., a cross-sectional profile of the wing of a WIG craft, in accordance with the present invention",

Fig. 2 is a drawing showing alift enhancer in accordance with the present invention in a retracted position when the WIG craft is moving on the water surface or taking off from and landing on the water surface;

Fig. 3 is a drawing showing the state in which a leading edge expansion plate 210 is expanded in a forward direction;

Fig. 4 is a drawing showing the state in which a trailing edge expansion plate 310 is expanded in a rearwarddirection;

Fig. 5 is a drawing showing thestate in which a leading edge expansion plate 210 and a trailing edge expansion plate 310 are expanded in a forward and rearward direction, respectively;

Fig. 6 is a drawing showing thestate in which a trailing edge expansion plate 310 is turned in a downward direction by a pivot device 340; and Fig.7 is a drawing showing thestate in which a trailing edge expansion plate 310 is turned in an upward direction by a pivot device 340. [Best Mode]

Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

Fig. 1 is a drawing schematically showing a construction of a lift enhancer for a WIG craft according to the present invention. The lift enhancer for a WIG craft in accordance with the present invention includes a wing body 100, a leading edge expansion section 200, and a trailing edge expansion section 300. The leading edge expansion section 200 and the trailing edge expansion section 300 operate respectively to expand the wing of the WIG craft in a chord direction, thereby increasing the chord length and area of the wing. They also shorten the distance between the wing and the water surface. Accordingly, the ground effect of the WIG craft would be maximized.

The leading edge expansion section 200 includes a leading edge expansion plate 210, a driving motor 220 for the leading edge expansion plate 210, and a connecting rod 230 for the leading edge expansion plate 210. The leading edge expansion section 200 is designed to expand the wing of the WIG craft in a forward direction of the wing.

The leading edge expansion plate 210 is a separate plate to const itutethe leading edge of the wing body 100. After the WIG craft takes off from the water surface, the leading edge expansion plate 210 is expanded in the forward direction, so that it simultaneously increases the area and chord length of the wing.

The driving motor 220 for the leading edge expansion plate 210 operates the leading edge expansion plate 210, while the connecting rod 230 for the leading edge expansion plate 210 connects the leading edge expansion plate 210 with the driving motor 220 for the leading edge expansion plate 210. Upon the activation of the driving motor 220, the leading edge expansion plate 210 moves forward to reach its expanded position or moves rearward to return to its initial position. Here, when the leading edge expansion plate 210 moves forward to expand in the direction of the front of the wing body 100, the ground effect and lift of the WIG craft increase to such an extent as well. In contrast, if the leading edge expansion plate 210 moves rearward to its initial position, the ground effect and lift of the WIG craft decrease accordingly.

The trailing edge expansion section 300 includes a trailing edge expansion plate 310, a driving motor 320 for the trailing edge expansion plate 310, and a connect ingrod 330 for the trailing edge expansion plate 310. The trailing edge expansion section 300 is designed to expand the wing of the WIG craft in the rearward direction of the wing.

The trailing edge expansion plate 310 is a separate plate which constitutes the trailing edge of the wing body 100. After the WIG craft takes off from the water surface, the trail ingedge expansion plate 310 is expanded in the rearward direction, so that it increases the area of the wing and at the same time the chord length of the wing.

The driving motor 320 for the trailing edge expansion plate 310 operates the trailing edge expansion plate 310, while the connecting rod 330 for the trailing edge expansion plate 310 connects the trailing edge expansion plate 310 with the driving motor 320 for the trailing edge expansion plate 310. Upon the activation of the driving motor 320, the trail ingedge expansion plate 310 moves rearward to reach its expanded position or moves forward to return to its initial position. Here, when the trailing edge expansion plate 310 moves rearward to expand in the direction rear of the wing body 100, the ground effect and the lift of the WIG craft increase to such an extent as well. In contrast, if the trailing edge expansion plate 310 moves forward to its initial position, the ground effect and liftof the WIG craft decrease accordingly.

Particularly, since the trailing edge expansion section 300 serves to place the trailing edge of the wing closer to the water surface, i.e., to reduce the distance between the wing and the water surface, it has a great influence on the ground effect.

Here, the trailing edge expansion section 300 is located at the point where the trailing edge expansion plate 310 is connected to the connecting rod 330 for the trailing edge expansion plate 310. It is desirablefor the trailing edge expansion section 300 further to include a pivot device 340 which is designed to adjust the angle of the trailing edge expansion plate 310 in a upward or downward direction using electronic control technologies. If the pivot device 340 turns the angle of the trailing edge expansion plate 310 in an upward direction, the lift generated at the wing of the WIG craft is decreased. On the contrary, if the pivot device 340 turns the angle of the trailing edge expansion plate 310 in a downward direction, the lift generated at the wing of the WIG craft is increased. Accordingly, the altitude of the WIG craft can be easily controlled therewith, which will be described in detail hereinbelow.

Fig. 2 shows the inventive lift enhancer in a retracted state while the WIG craft is moving on the water surface or taking off from and landing on the water surface. In the case which the WIG craft is in a state of moving on the water surface or taking off from and landing on the water surface, if the wing is brought into contact with the water surface, a large load can be delivered to the wing, which leads to increase the resistance to break the lift enhancer in accordance with the invention. Therefore, during the above mentioned states of the WIG craft, it should be noted that the inventive lift enhancer must be placed and maintained in a retracted position in advance to prevent such failures.

Fig. 3 shows thestate in which a leading edge expansion plate 210 is expanded in the forward direction. As described above, at the present state both the area and chord length of the wing areincreased due to the expansion of the leading edge expansion plate 210.

Fig. 4 shows thestate in which a trailing edge expansion plate 310 is expanded in the rearward direction. At this state, due to the expansion of the trailing edge expansion plate 310, the chord length and area of the wing are increased. In addition, the trailing edge of the wing is positioned much closer to the water surface, thereby considerably increasing ground effect of the WIG craft.

Fig. 5 shows the state in which the leading edge expansion plate 210 and the trailing edge expansion plate 310 are expanded together in the forward and rearward direction, respectively. Each role of the leading edge expansion plate 210 and the trailing edge expansion plate 310 is the same as those described hereinabove.

Fig. 6 shows thestate in which the trailing edge expansion plate 310 is turned in the downward direction by the pivot device 340. In the case which the trailing edge expansion plate 310 is turned in the downward direction like this, the lift of the wing itself is remarkably increased even without taking into consideration the ground effect. Moreover, the distance between the trailing edge and the water surface becomes far closer, resulting in increasing lift to a great extent by ground effect.

Fig.7 shows the state in which the trailing edge expansion plate 310 is turned in theupward direction by a pivot device 340. In the case which the trailing edge expansion plate 310 is turned in the upward direction like this, the lift of the wing itself is decreased and the distance between the trailing edge and the water surface becomes even farther, thereby reducing the lift due to ground effect. As a result, the altitude of the WIG craft is to be reduced accordingly.

As described above, the present invention is designed to provide a lift enhancer that is to be retracted when the WIG craft is moving on the water surface or taking off or landing on the water, and that is to be operated to increase the liftat the wing. In other words, the inventive lift enhancer is capable of introducing a lift increase phenomenon, without considering ground effect, by expanding the leading edge expansion plate 210 and trailing edge expansion plate 310 in the forward and rearward direction of the wing, respectively to increase the chord length and area of the wing. In case of considering ground effect, the present lift enhancer is able to introduce a lift increase phenomenon by way of reducing the h/c ratio through increasing the chord length (increasing the value of "c") which is a factor to determine the level of ground effect. Further, as the trailing edge becomes closer to the water surface (decreasing the value of "h"), the h/c ratio is reduced to introduce a lift increase due to ground effect. In addition, it could be appreciated that the distance (h) between the wing and the water surface can be adjusted by manipulating the angle of the trailing edge expansion plate 310, which can be utilized to control the position of the WIG craft.

The embodiments set forth hereinabove have been presented for illustrative purposes only and, therefore, the present invention is not limited to these embodiments. It will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention defined in the claims. [Industrial Applicability]

With a lift enhancer for a WIG craft described hereinabove, it is possible to prevent the increase of the resistance from the water and then the breakage of the wing since the trailing edge of the wing is not in contact with the water surface when the WIG craft is cruising on the water surface or taking off from or landing on the water. In addition, ground effect can be maximized with a simple manipulation of the inventive lift enhancer. The present invention can be broadly used in the field of shipbuilding or machine technology to achieve practical and economical values.

Claims

[CLAIMS] [Claim 1]

A lift enhancer for a WIG craft, comprising: a wing body 100 constituting the main body of a wing of the WIG craft; a leading edge expansion section 200 including a leading edge expansion plate 210, as a separate plate, to constitute a leading edge of the wing body 100, wherein the leading edge expansion plate is expanded in a forward direction to simultaneously increase the chord length and area of the wing after the WIG takes off from the water surface, a driving motor 220 for the leading edge expansion plate 210 to operatethe leading edge expansion plate 210, and a connecting rod 230 for the leading edge expansion plate 210 to connect the leading edge expansion plate 210 with the driving motor 220 for the leading edge expansion plate 210, wherein the leading edge expansion plate 210 moves forward to reach its expanded position or moves rearward to return to its initial position upon activation of the driving motor 220; and a trailing edge expansion section 300 including a trailing edge expansion plate 310, as a separate plate, to constitute a trailing edge of the wing body 100, wherein the trailing edge expansion plate is expanded in a rearward direction to simultaneously increase the chord length and area of the wing after the WIG takes off from the water surface, a driving motor 320 for the trailing edge expansion plate 310 to operate the trailing edge expansion plate 310, and a connecting rod 330 for the trailing edge expansion plate 310 to connect the trailing edge expansion plate 310 with the driving motor 320 for the trailing edge expansion plate 310, wherein the trailing edge expansion plate 310 moves rearward to reach its expanded position or moves forward to return to its initial position upon activation of the driving motor 320. [Claim 2]

The lift enhancerfor a WIG craft as recited in claim 1, wherein the trailing edge expansion section 300 further includes a pivot device 340 at a location where the trailing edge expansion plate 310is connected with the connecting rod 330 for the trailing edge expansion plate 310, wherein the pivot device 340 is electronically controlled to adjust the angle of the trailing edge expansion plate 310 in an upward or downward direction. [Claim 3]

The lift enhancer for a WIG craft as recitedin claim 1, wherein the leading edge expansion section 200 and the trailing edge expansion section 300 are separately operated from each other.