GB2029714A - Tetrahedral flight vehicle - Google Patents

Abstract

The tetrahedral flight vehicle possesses a three dimensional geometric shape based on an irregular tetrahedron. The longest dimension of the said shape is aligned with the direction of flight and the foremost extremity is that which encloses the smallest included angle when seen in plane. Four plane triangular flight surfaces, are conjoined to form the said tetrahedral shape, and maintain the vehicle in stable and sustained flight. When in flight, the vehicle presents an undesirable surface, which meets the airflow at a positive angle of attack. The two upper surfaces meet the airflow at a negative angle of attack, which is marginally less in magnitude than the aforesaid positive angle of attack. The resolved components of force, perpendicular to the direction of flight, produce a net upthrust resulting in lift. Viewed in transverse section, the triangular juxtaposition of flight surfaces induces stability. <IMAGE>

Description

SPECIFICATION Tetrahedral flight vehicle This invention, designated by the name Tetrahedral Flight Vehicle, relates to a three dimensional shape, which provides the basis of a new type of flying vehicle, capable of sustained and stable flight.

The Tetrahedral Flight Vehicle is the fundamental and basic embodiment of a new means of achieving flight.

The shape of the flight vehicle is derived from the geometrical figure known as a tetrahedron.

More specifically the vehicle conforms to the shape of an irregular tetrahedron, whose edges comprise six lines which contain four plane triangular surfaces, as illustrated in the accompanying diagrams, which are as follows: Figure 1 is a three dimensional sketch showing longitudinal and transverse sections.

Figure 2 is a Plan View as seen from above.

Figure 3 is a Front View based on the "in flight" attitude.

Figure 4 is a Side View showing the "in flight" attitude.

Figure 5 is a Plan View as seen from below.

In the above diagrams components 1,2,3 and 4 represent plane triangular surfaces joined together as shown in order to provide a fully enclosed three-dimensional shape.

To achieve flight the vehicle should be propelled in the direction indicated by arrow A in Figure 4. Any suitable means may be used to achieve the stated motion.

With reference to the angle at which the vehicle meets the airflow as shown in Figure 4, it can be seen that components 1 and 2 on the upper surface and component 3 on the lower surface will each present a frontal area to the oncoming air.

These frontal areas are shown in Figure 3. The "in flight" attitude represents a position of equilibrium such that the frontal area due to components 1 and 2 on the upper surface is equal in area to the frontal area presented by component 3 on the lower surface.

If one considers the forces acting on the upper surface there will be a resulting down thrust arising from the inclination of that surface with respect to the airflow. However this tendency is counteracted by an opposing upthrust arising from the inclination of component 3 on the underside. If one considers the magnitude of forces acting in the aforesaid manner it will be found that the upthrust due to component 3 is greater than the down thrust due to components 1 and 2. The condition of greater upthrust is due to the differing angles of inclination, relative to the airflow, of the upper components 1 and 2 and the lower component 3, shown respectively in Figure 4 by lines XY and XZ.On account of the natural equilibrium in flight determined by the equal balancing of the frontal areas presented by the upper and lower surfaces respectively, it is found that XZ, being shorter than XY in length, inevitably meets the on-coming airflow at a steeper angle than XY, resulting in a larger component of force perpendicular to the direction of the airflow. The margin of upthrust over downthrust corresponds to the lift obtained.

The tetrahedral Flight Vehicle is inherently stable in flight. Viewed in transverse section, components 1 and 2 form the upper two sides of a triangle, while component 3 forms the base. This arrangement ensures that the forces acting on components 1 , 2 and 3 are orientated to produce lateral stability. Longitudinal stability is achieved by the correct distribution of weight considered in conjunction with aerodynamic forces acting.

1. A flight vehicle comprising an irregular tetrahedral shape; two upper surfaces joined at a central longitudinal common edge, being the longest dimension of the vehicle and aligned in the direction of flight; an underside surface forming the base of uniformly increasing triangular crosssection symmetrical about a central vertical axis, with the said two upper surfaces being joined at the said central longitudinal edge to form the apex of the said triangular cross-section, which expands uniformly from the foremost extremity until reaching a maximum area at a point approximately two-thirds along the length of the vehicle measured from the foremost extremity; thereafter a triangular cross-section, which diminishes rapidly and culminates in a point coincident with the rear extremity of the central longitudinal common edge of the said two upper surfaces; a triangular cross-section at the point of maximum area having a base line coincident with the transverse common edge of the forward triangular underside surface and the rearward underside surface; a planform delineated by the joining of the outermost edges of each of the said two upper surfaces to the outermost edges of the said forward and rearward triangular underside surfaces, which have apexes at the forward and rearward extremities of the vehicle with respect to the common transverse base line of the said underside surfaces; a central longitudinal common edge on the upper side mutually at right angles to the transverse common edge on the underside when viewed in plan, with a vertical separation between the said two common edges equivalent to the maximum vertical thickness of the flight vehicle.

2. A flight vehicle substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Tetrahedral flight vehicle This invention, designated by the name Tetrahedral Flight Vehicle, relates to a three dimensional shape, which provides the basis of a new type of flying vehicle, capable of sustained and stable flight. The Tetrahedral Flight Vehicle is the fundamental and basic embodiment of a new means of achieving flight. The shape of the flight vehicle is derived from the geometrical figure known as a tetrahedron. More specifically the vehicle conforms to the shape of an irregular tetrahedron, whose edges comprise six lines which contain four plane triangular surfaces, as illustrated in the accompanying diagrams, which are as follows: Figure 1 is a three dimensional sketch showing longitudinal and transverse sections. Figure 2 is a Plan View as seen from above. Figure 3 is a Front View based on the "in flight" attitude. Figure 4 is a Side View showing the "in flight" attitude. Figure 5 is a Plan View as seen from below. In the above diagrams components 1,2,3 and 4 represent plane triangular surfaces joined together as shown in order to provide a fully enclosed three-dimensional shape. To achieve flight the vehicle should be propelled in the direction indicated by arrow A in Figure 4. Any suitable means may be used to achieve the stated motion. With reference to the angle at which the vehicle meets the airflow as shown in Figure 4, it can be seen that components 1 and 2 on the upper surface and component 3 on the lower surface will each present a frontal area to the oncoming air. These frontal areas are shown in Figure 3. The "in flight" attitude represents a position of equilibrium such that the frontal area due to components 1 and 2 on the upper surface is equal in area to the frontal area presented by component 3 on the lower surface. If one considers the forces acting on the upper surface there will be a resulting down thrust arising from the inclination of that surface with respect to the airflow. However this tendency is counteracted by an opposing upthrust arising from the inclination of component 3 on the underside. If one considers the magnitude of forces acting in the aforesaid manner it will be found that the upthrust due to component 3 is greater than the down thrust due to components 1 and 2. The condition of greater upthrust is due to the differing angles of inclination, relative to the airflow, of the upper components 1 and 2 and the lower component 3, shown respectively in Figure 4 by lines XY and XZ.On account of the natural equilibrium in flight determined by the equal balancing of the frontal areas presented by the upper and lower surfaces respectively, it is found that XZ, being shorter than XY in length, inevitably meets the on-coming airflow at a steeper angle than XY, resulting in a larger component of force perpendicular to the direction of the airflow. The margin of upthrust over downthrust corresponds to the lift obtained. The tetrahedral Flight Vehicle is inherently stable in flight. Viewed in transverse section, components 1 and 2 form the upper two sides of a triangle, while component 3 forms the base. This arrangement ensures that the forces acting on components 1 , 2 and 3 are orientated to produce lateral stability. Longitudinal stability is achieved by the correct distribution of weight considered in conjunction with aerodynamic forces acting. CLAIMS

1. A flight vehicle comprising an irregular tetrahedral shape; two upper surfaces joined at a central longitudinal common edge, being the longest dimension of the vehicle and aligned in the direction of flight; an underside surface forming the base of uniformly increasing triangular crosssection symmetrical about a central vertical axis, with the said two upper surfaces being joined at the said central longitudinal edge to form the apex of the said triangular cross-section, which expands uniformly from the foremost extremity until reaching a maximum area at a point approximately two-thirds along the length of the vehicle measured from the foremost extremity; thereafter a triangular cross-section, which diminishes rapidly and culminates in a point coincident with the rear extremity of the central longitudinal common edge of the said two upper surfaces; a triangular cross-section at the point of maximum area having a base line coincident with the transverse common edge of the forward triangular underside surface and the rearward underside surface; a planform delineated by the joining of the outermost edges of each of the said two upper surfaces to the outermost edges of the said forward and rearward triangular underside surfaces, which have apexes at the forward and rearward extremities of the vehicle with respect to the common transverse base line of the said underside surfaces; a central longitudinal common edge on the upper side mutually at right angles to the transverse common edge on the underside when viewed in plan, with a vertical separation between the said two common edges equivalent to the maximum vertical thickness of the flight vehicle.

2. A flight vehicle substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.