SPEEDBOAT WITH TWO CARRIER WINGS

Abstract: The invention relates to a speedboat comprising a frame (1) with a cockpit for at least one pilot for piloting the propulsion means and two surface-effect carrier wings, wherein the speedboat is equipped with a keelwing (5) which, at his bottom side, ends in the form of a ski, which speedboat is further characterized in that the propulsion means comprise two air propellers (8) which are each individually universally orientable.

Description: The invention relates to a speedboat comprising a cockpit for at least one pilot for piloting air propulsion means, two carrier wings, and a keel wing. There is known by FR-A-1 579 611 a speedboat comprising a cockpit for at least one pilot, air propulsion means, carrier wings and a main keel wing, in which the propulsion means comprises a single, non orientable propeller with control surfaces, while the carrier wings are provided with control flaps. The boat is piloted by acting on the control surfaces, while the lateral stability is controled through the flaps. The object of the invention is to realize a speedboat having a monolithic structure and, despite the absence of movable extending members influencing the piloting, such as for example so-called flaps, can be piloted at different speeds and which by increased speed is lifted up out of the water. The object of the invention is realized in that the propulsion means comprise two air propellers which are each individually orientable, and in that the relative longitudinal positions of the propellers and of the keel wing in relation with the boat are such that, when the propellers are oriented so as to provide a downwardly oriented propulsion component, this component gives rise to a change of the longitudinal attitude of the boat, namely a raising of the prow with relation to the rear border, so that the speedboat may be piloted by piloting the air propellers, without the need for air flaps. Still according to the invention, the aerodynamic centre of the boat lies, in the longitudinal direction, behind the centre of gravity of the boat. Still according to the invention, the keel wing is mounted at a distance from the prow which correspond to substantially half the length of the speedboat frame. Still according to the invention, the propulsion force generated by the air propellers grips above the centre of gravity of the speed boat. In a preferred embodiment, the carrier wings show a so-called shark profile, i.e. a delta-form which is strongly rounded at the top. In a possible alternative the carrier wings show a delta profile. Other details and advantages of the invention will be showed in the description given hereunder of a speedboat according to the invention. The description is only given by way of example and does not limit the invention. The reference numbers relate to the figures given herewith. Figure 1 is a side view of a speedboat according to the invention. Figure 2 is a top view of a speedboat according to figure 1. Figure 3 is a top view of a possible variation of the speedboat according to the figures 1 and 2. Figure 4 is a front view of the keelwing. Figure 5 is a bottom view of the keelwing. Figures 6 to 9 show schematically four successive positions of the speedboat starting from the standstill position of the speedboat and ending in a complet lift out of the water at a corresponding increased speed. The speedboat according to the figures 1 to 9 comprises a frame 1 in the middle of which the cockpit for one, and in some cases two, pilots is mounted. On both sides of the cockpit lateral wings 3 are extending. They show the well-known shark-profile, i.e. compared to the also known delta-profile, it differs by a profile which is strongly rounded-off at the top. The invention is also applicable to a speedboat with the known delta-profile, although the stability of a speedboat with such a profile does not reach the one of a speedboat having a shark-profile. The speedboat described here corresponds thus to the preferred embodiment. The figures 2 and 3 relate to two different embodiments which only differ by the fact that the edges of the carrier wings 3 extend according to the form of a pure arc (figure 2) or they are formed by two straight lines which cross each other (figure 3). The cockpit extends in length so far, and is elongated with the profiled middle wing so far, that the directional stability of the speedboat is remarkably increased. At its bottom side the speedboat is equipped with an essential element, that is the keelwing 5. This keelwing is mounted approximately at half of the length starting from the prow of the boat. The keelwing has a vertical and a horizontal component. The vertical component 6 determines the distance between the speedboat's keel and the ski 7 which forms the horizontal component of the keel wing. The keelwing shows a form which can clearly be seen in the figures 1, 4, 5 and 6 to 9. A side view of the keelwing shows a form which is rounded-off towards the ski 7 while seen in front view it is elongated sharply towards the front. The middle part of the keelwing broadens towards the backside. From an hydrodynamical point of view more alternatives of the keelwing showed in the figures can be formed. The essential function of the ski 7 of the keelwing is to lift the speedboat out of the water when the speed increases. The keelwing, at least the vertical component thereof, plays an important part in the directional stability which, in first instance, has to be assigned to the so-called shark-profile. The propulsion, the lateral stability and the handiness of the speedboat are provided due to two orientable airpropellers 8 which are mounted at the stern of the speedboat. It is essential that the propulsion force can be directed by the pilot according to several components which are independent from each other. Thanks to that essential characteristic, the speedboad, which at higher speed is lift out of the water and rests on the water by means of its ski, shows remarkable navigation qualities. The speedboat according to the invention can independently from his speed and in the first place of the direction of his air propellers take different positions : In absence of the propulsion, the speedboat floats on the water ; When the propellers are activated in order to give an horizontal propulsion, the speedboat is propulsed while still floating on the water ; By applying an oblique and downwards oriented component to the propulsion vector of the propellers, the boat directs itselfs with the prow out of the water. By enough speed the boat is lift out of the water by means of the ski which then lays down on the water ; The piloting of the airpropellers, by applying them a different vertical and downwards oriented component, is thus essential to permit the speedboat to take some curves without loosing its stability. By orienting the boat propellers as wished, the speedboat reacts immediately ; By a dropdown of the propulsion force, the speedboat immediately goes down to the water-level. At normal speed, i.e. when the speedboat has his frame out of the water, the essential pulling force is provided by the ski 7 at the bottom of the keelwing 5. The carrier wings 3 which are operating at the so-called ground-effect due to the proximity of the water-level, also supply to the pulling force. Because the pulling force originating from the ski 7, grips relatively close to the rear border 9 of the speedboad, the aerodynamical centre, i.e. the point around which the moment of the total pulling force is, at a given speed, independent of the angle of the speedboat, lies relatively close to the back of the boat. That point lies, in each case, seen in the navigation direction of the speedboat, far behind the speedboat gravity centre. This explains the longitudinal stability of the speedboat. The lateral stability is explained by the ground effect of the carrier wings 3. Between the carrier wings and the water-level an over-pressure is build up, which is more important with decreasing distance between the carrier wings and the water-level. At the upper side of the carrier wings, an under-pressure is build up, which originates from the whirling at the front side generated by the profile. By a lateral heel of the boat, the over-pressure under the carrier wings increases at the side where the distance to the water-level is the smallest and decreases at the side where the distance is the largest while the streaming at the upper side is in principle not modified. This explains the origin of the lateral stabilizing torque. Experiences have proven that the two most important phenomenons which cause the forces on the structure of the speedboat are, on the one hand the hydrodynamical effect on the keelwing, and on the other hand the aerodynamical forces on the wing profile. The aerodynamical forces which work on the structure, can be divided into the ground effect and the profile working. The pulling force on that structure due to the profile working is in fact small due to the small ratio of the span with respect to the profile depth. It is also clear that adjustment of both airpropellers plays an essential role by assuring the stability of the speedboat. The independent adjustment of both airpropellors is then also a main characteristic of the invention. Important is also that the grip point of the forces developed by those propellers on the speedboat lies above the gravity center of the boat. Finally a minor construction detail can also be mentioned which consists by the fact that the extremities of the carrier wings are either pivotable or demountable. The line according to which the hinged movement of the lateral ends of the carrier wings 3, or in case the demounting thereof, can be realized is indicated by the line 10. By temporary decreasing the carrier width of the carrier wings, certain transport problems are solved in an easy way. The presence of two hinged or mobile structures of the carrier wings does not impede that a speedboat according to the invention has a monolithic structure. It will be clear that the invention is not limited to the embodiment described hereabove and that thereto a lot of modifications could be applied without leaving the scope of the patent application.

Claims: A speedboat comprising a frame with a cockpit for at least one pilot for piloting air propulsion means, two carrier wings, and a keel wing, characterized in that the propulsion means comprise two air propellers (8) which are each individually orientable, the relative longitudinal positions of the propellers (8) and of the keel wing (5) in relation with the boat are such that, when the propellers (8) are oriented so as to provide a downwardly oriented propulsion component, this component gives rise to a change of the longitudinal attitude of the boat, namely a raising of the prow with relation to the rear border, so that the speedboat may be piloted by piloting the air propellers, without the need for air flaps. Speedboad according to claim 1, characterized in that the aerodynamic centre of the boat lies, in the longitudinal direction, behind the centre of gravity of the boat Speedboat according to any of claims 1 and 2, characterized in that said keel wing (5) is mounted at a distance from the prow which correspond to substantially half the length of the speedboat frame. Speedboat according to any of claims 1 to 3, characterized in that said propulsion force generated by the air propellers (8) grips above the centre of gravity of the speed boat. Speedboat according to any of claims 1 to 4, characterized in that said carrier wings show a shark profile, i.e. a delta form which is strongly rounded at the top. Speedboat according to any of claims 1 to 4, characterized in that said carrier wings show a delta profile.

Inventors: GIELENS, JAN
Applicants: GIELENS, JAN
Application year: 1988
Main classification: B63H7
IPC codes: B63B1, B63H7