Patent Application
20190351994
The invention relates to aircraft empennage design, applicable to conventional aircraft design with a horizontal stabilizer and one or more vertical stabilizer/rudder assemblies, as well as all-wing aircraft design. The invention would allow an aircraft with one or more conventional vertical stabilizer/rudder assemblies to retract the stabilizer/rudder assemblies in flight from vertical to horizontal, creating less drag, thereby increasing speed, while also improving stealth characteristics. Conversely, the invention would allow an aircraft to extend the stabilizer/rudder assemblies in flight from horizontal to vertical, providing increased control and maneuverability of the aircraft. For example, the invention would allow an all-wing aircraft, which dues not have a vertical stabilizer, to fold one or more sections of the aircraft into a position from horizontal to vertical, or to any desired angle, thereby improving its handling characteristics during takeoff and landing, and also improving maneuvering and high-performance capabilities. The vertical stabilizer/rudder assemblies described herein may have variable geometry, and vertical stabilizer/rudder assemblies may be hinged about different axes depending on the aircraft design.
U.S. Pat. No. 4,247,062 discloses a hinged vertical tail unit which allows variable wing geometry on an all-wing aircraft, specifically a glider returning from a space mission. The hinged vertical tail unit allows the pilot to better control the aircraft at large angles of attack. The hinged vertical tail units consist of the left and right outer sections of the wing itself.
U.S. Pat. No. 4,354,646 discloses an empennage assembly of a supersonic aircraft, which includes two tail control surfaces pivotally attached at the aft end of an aircraft fuselage substantially along the longitudinal axis, and which are designated “ruddervators” since their effect could be to act as a rudder, elevator, or combination of the two.
Conventional vertical stabilizers are usually part of the aircraft's structure and are referred to as the “tail section” or “empennage”. The vertical stabilizer/rudder provides control of the aircraft around the yaw axis, and it helps control the aircraft during takeoff and landing; coordinate turns; and maintain directional control during single engine operation for multiengine aircraft. However, it also creates drag during straight and level flight. For stealth aircraft, the presence of a vertical stabilizer/rudder is a great disadvantage. Therefore, it would be highly desirable to have aircraft which could be configured with vertical stabilizers/rudders in those situations where they are advantageous, but also have the capability to be configured without vertical stabilizers/rudders in those situations where they are undesirable.
According to one embodiment of the invention, provided herein is a vertical stabilizer and rudder assembly wherein the assembly may be rotated about an axis extending substantially in parallel to the longitudinal axis of the aircraft. When retracted the assembly lies approximately parallel to the lateral axis of the aircraft, and when fully extended the assembly forms an angle greater than zero degrees above or below the lateral axis of the aircraft. Another embodiment of the invention provides a vertical stabilizer and rudder assembly wherein the assembly may be rotated about an axis extending substantially in parallel to the lateral axis of the aircraft. In this configuration, the assembly may be retracted into the body of the aircraft. The assembly could be either a one-piece integral stabilizer and rudder or a stabilizer with a separate rudder section attached by means of a hinge.
When extended, the vertical stabilizer/rudder assembly is of sufficient size to fulfill any operational requirements regarding stability or control of the aircraft about the yaw axis, thereby greatly improving the pilot's ability to fly the aircraft. When retracted, the aerodynamic drag produced by the intrusion of the assembly into the airstream is eliminated, enhancing the high speed performance characteristics of the aircraft. When retracted, the radar cross-section of the aircraft is greatly reduced, enhancing the stealth characteristics of the aircraft. The vertical stabilizer/rudder assembly of the present invention may be dimensioned as needed to provide sufficient size and shape to meet performance specifications. Some situations may not require all or nothing performance versus speed/stealth; or, for example, the pilot may prefer to utilize the assembly to provide more pitch control than yaw control; therefore, the assembly could be constructed as a combination vertical stabilizer/rudder and horizontal stabilizer/elevator (“ruddervator”), having the capability of being locked at any operational angle during flight.
Due to the above features, the invention provides yaw axis control and longitudinal directional stability when needed, while also providing high speed and/or stealth performance when needed. A drive means, such as an actuator mechanism, allows the pilot to change the aircraft configuration as needed in flight. A pivotal connecting means, such as a hinge mechanism, allows the assembly to move freely and smoothly. A latching means, such as a locking mechanism, allows the assembly to be secured in whatever configuration is desired by the pilot at any time. Thus it is possible to change the aircraft configuration to optimally meet the prevailing flight requirements in real time. Other geometric parameters could also be incorporated into the design very easily and provide an even greater level of performance.
Based on the conditions described above, the aim of the invention is to achieve the following objectives either singly or in combination:
to provide a retractable vertical stabilizer and rudder assembly for conventional aircraft whereby the assemble can be folded or stored such that the aerodynamic drag of the aircraft is decreased;
to provide a retractable vertical stabilizer and rudder assembly for conventional aircraft whereby the assemble can be folded or stored such that the stealth characteristics of the aircraft are increased;
to provide a retractable vertical stabilizer and rudder assembly for all-wing aircraft whereby the aircraft configuration can be modified to improve handling characteristics;
to provide a retractable vertical stabilizer and rudder assembly for stealth aircraft whereby the aircraft configuration can be modified to improve handling characteristics;
to arrange the retractable vertical stabilizer and rudder assembly in such a manner that does not interfere with any other aircraft components;
to provide a retractable vertical stabilizer and rudder assembly which can be quickly changed from one configuration to another;
to provide a retractable vertical stabilizer and rudder assembly which can be easily adjusted at various angles about an axis essentially parallel to the aircraft longitudinal axis;
to provide a retractable vertical stabilizer and rudder assembly which can be easily adjusted at various angles about an axis essentially parallel to the aircraft lateral axis.
Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that in accordance with the standard practice in the industry various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
Referring to
Referring to
Referring to
Referring to
The embodiments displayed in the accompanying figures show the disclosure as it would generally be designed and manufactured, with an extended profile above horizontal. However, the disclosure also includes configuring the stabilizer/rudder assembly to operate at any angle relative to the horizontal. The apparatus could be hinged about a horizontal axis extending in parallel to either the longitudinal axis of the aircraft (as in
According to the present invention, a retractable vertical stabilizer/rudder assembly is obtained which allows the vertical stabilizer/rudder to be retracted out of the slipstream, reducing drag and increasing stealth, or to be extended into the slipstream, increasing yaw control of an aircraft.
Although the disclosure has been described with reference to specific examples and embodiments, it is to be understood that the invention is intended to cover all modifications and equivalents within the scope of the appended claims.
