This invention relates generally to aircraft and, in particular to vertical take-off and landing aircraft.
Aircraft that are capable of vertical take-off and landing fall generally into two categories. The first category consists of those with relatively low propulsive efficiency and high top speed such as the F 35 joint strike fighter and the Hawker Harrier. Because of the relatively low propulsive efficiency during vertical takeoff and landing attributable to the high-speed exhaust of their jet engines, these aircraft require a very large power to weight ratio to achieve vertical flight. The second category consists of aircraft with relatively high propulsive efficiency such as helicopters. Although helicopters are more efficient and can fly vertically with a much lower power to weight ratio, helicopters have a relatively low maximum top speed attributable to the need to prevent the advancing blade from entering the trans-sonic flight regime. Accordingly, what is needed is an aircraft having relatively high propulsive efficiency during vertical takeoff associated with a relatively modest exhaust speed while maintaining the ability to achieve supersonic flight in a horizontal flight mode.
The present invention solves the foregoing problem by providing a jet engine powered lifting-body vertical take-off and landing (VTOL) aircraft. In an illustrative embodiment, the fuselage of the lifting-body comprises a substantially triangular or delta-shaped lifting body having airfoils disposed along all three sides. In vertical flight mode the airfoils act as exhaust diverters. A flow of exhaust gas flows from a centrally located vertical flight gas diffuser over the top surface of the lifting body and then is directed downward by the airfoils to provide the vertical lift necessary for vertical take-off. In horizontal flight mode, the airfoils act as canards and ailerons in cooperation with a conventional tail that includes vertical and horizontal stabilizers, elevators and a rudder.
Power for both vertical and horizontal flight is provided by a conventional jet engine, preferably a high-bypass turbofan engine, attached below the fuselage. In vertical flight mode, the entirety of the exhaust from the engine is diverted to the vertical flight gas diffuser by means of a transition duct that sealingly engages the exhaust outlet of the engine and diverts the flow of gas through a 90° upward bend into the vertical flight gas diffuser. The exhaust gas within the transition duct powers a multi-stage turbine that slows and cools the exhaust gas before entering the vertical flight gas diffuser. Power from the turbine is used to draw additional air into the vertical flight gas diffuser to further augment the volume while reducing the temperature of the exhaust gas exiting the vertical flight gas diffuser. The transition duct itself is movable from a first position in which it diverts the entirety of the engine exhaust into the vertical flight gas diffuser to a second position in which it partially obstructs and therefore diverts a portion of the engine exhaust into the vertical flight gas diffuser and finally to a third position in which it is fully retracted which permits the entirety of the engine thrust to be directed rearward to propel the aircraft in a horizontal flight mode.
The present invention will be better understood from a reading of the following detailed description, taken in conjunction with the accompanying drawing figures in which like references designate like elements and, in which:
The drawing figures are intended to illustrate the general manner of construction and are not necessarily to scale. In the detailed description and in the drawing figures, specific illustrative examples are shown and herein described in detail. It should be understood, however, that the drawing figures and detailed description are not intended to limit the invention to the particular form disclosed, but are merely illustrative and intended to teach one of ordinary skill how to make and/or use the invention claimed herein and for setting forth the best mode for carrying out the invention.
With reference to the figures, and in particular
A conventional tail assembly 26 comprising a horizontal stabilizer, vertical stabilizer, elevators and rudder for use in horizontal flight mode extends from side 24 of the fuselage. As explained more fully hereinafter, fuselage 12 further comprises a vertical flight gas diffuser 28, which comprises a cylindrical duct 30 having a centrally mounted compressor section 32 and a plurality of laterally-facing exhaust apertures 34, 36, 38.
With additional reference to
Gas entering transition duct 48 is directed from the horizontal portion 56 of transition duct 48 through a 90° bend, into the vertical section 58 of transition duct 48, then into vertical flight gas diffuser 28. As the gas enters vertical section 58 of transition duct 48 it passes through a multi-stage axial turbine 64 comprising at least two counter-rotating turbine disks 66, 68 which, for reasons that will be more fully explain hereinafter, are mounted on telescoping shafts 60, 62. Shafts 60, 62 in turn power a multi-stage axial compressor 70 comprising at least two counter-rotating compressor wheels 72, 74. Compressor 70 draws air into vertical flight gas diffuser 28 to augment and reduce the temperature of the high-temperature gas from transition duct 48. This combined airflow is then directed radially outward from vertical flight gas diffuser 28 through exhaust apertures 34, 36, 38. A flow diverter 76 comprising a paraboloid body of revolution assists in redirecting the flow with minimal losses. The combined airflow exiting through exhaust apertures 34, 36, 38 flows outward over the top of fuselage 12 where it is directed downward by airfoils 14, 16, 18 as shown in
With additional reference to
With additional reference to
Although certain illustrative embodiments and methods have been disclosed herein, it will be apparent from the foregoing disclosure to those skilled in the art that variations and modifications of such embodiments and methods may be made without departing from the invention. For example, although in the illustrative embodiment, the aircraft comprises a delta shaped fuselage, the inventive propulsion system may be used in combination with other airframes. Accordingly, it is intended that the invention should be limited only to the extent required by the appended claims and the rules and principles of applicable law. Additionally, as used herein, references to direction such as “up” or “down” as well as recited materials or methods of attachment are intended to be exemplary and are not considered as limiting the invention and, unless otherwise specifically defined, the terms “generally,” “substantially,” or “approximately” when used with mathematical concepts or measurements mean within ±10 degrees of angle or within 10 percent of the measurement, whichever is greater. As used herein, a step of “providing” a structural element recited in a method claim means and includes obtaining, fabricating, purchasing, acquiring or otherwise gaining access to the structural element for performing the steps of the method. As used herein, the claim terms are to be given their broadest reasonable meaning unless a clear disavowal of that meaning appears in the record in substantially the following form (“As used herein the term ______ is defined to mean ______”)
Number | Date | Country | |
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62572984 | Oct 2017 | US |