Augmenting flight control surface actuation system and method

Details Augmenting flight control surface actuation system and method Augmenting flight control surface actuation system and method

2002-11-25

2004-09-28

Barefoot, Galen L. (Department: 3644)

Aeronautics and astronautics

Aircraft control

C244S078200

Reexamination Certificate

active

06796526

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to aircraft and more particularly to flight control surface actuation systems.
BACKGROUND OF THE INVENTION
Power Control Units (PCU) are used to apply loads for positioning and maintaining the position of aircraft flight control surfaces such as ailerons, elevators, rudders, spoilers, etc. Conventional PCUs are typically sized for stall load and a required rate. The required rate typically involves low loads, either a no-load condition, a low-load condition, or a maximum allowable time to travel from surface faired to a specified surface position under specific flight conditions. For simplicity, subsequent discussions herein shall assume a no-load rate requirement. Stall load is referred to as the maximum amount of force that the PCU actuator can exert. The maximum no-load rate refers to the fastest rate at which an actuator piston can move when the control valve is wide open and no load is on the actuator.
Sizing a PCU according to a stall load and a required rate leads to inefficiencies due to flight dynamics. That is, conventional PCUs are relatively inefficient in terms of the required horsepower and hydraulic system weight under high rate and low load conditions (e.g., near “aerodynamic neutral” or no load for the flight control surface). The term “aerodynamic neutral” refers to the position of the flight control surface at which the net air load on the surface is zero such as when the pressure below a horizontally-oriented flight control surface is equal to the pressure above the surface.
SUMMARY OF THE INVENTION
Accordingly, a need exists for a flight control surface actuation system and method that is highly efficient and well suited for use with the present day commercial aircraft. The system should substantially reduce the hydraulic fluid flow and horsepower required to provide sufficient actuation power to meet the actuation requirements during normal and emergency flight conditions of the aircraft. Ideally, the system should provide a stall load and a maximum no-load rate that are at least comparable (i.e., substantially identical) with conventional PCUs.
In one preferred form, the present invention provides an apparatus for providing actuation power to an aircraft flight control surface. The apparatus includes a first actuator and a second actuator, where the second actuator has a bypass mode and an assist mode. The mode of the second actuator is based upon the load of the first actuator. When the second actuator is in the bypass mode, the first actuator provides the actuation power for the aircraft flight control surface. But, when the second actuator is in the assist mode, both the first and second actuators provide the actuation power for the aircraft flight control surface. Accordingly, the apparatus allows the flight control surface to be operated in a more efficient manner with less hydraulic flow being required.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating at least one preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.


REFERENCES:
patent: 0 657 656 (2000-03-01), None
Article by Avtar Hayre (Northrop Corporation); Tom Dull (Northrop Corporation); Fred Meyn (GE Aircraft) published by American Institute of Aeronautics and Astronautics, Inc., with permission (92-1076 ATF YF25 Leaf4 1/31) (7 pages).
New Application of Richard T. Krantz filed simultaneouly with this application entitled “Augmenting Flight Control Surface Acutation System and Method”.
U.S. patent application No. 10/303,271 (presently allowed), titled Augmenting Flight Control Surface Actuation System and Method of Richard M. Krantz, filed Nov. 25, 2002.

Affiliated with

Also associated with

Rating

Augmenting flight control surface actuation system and method does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Augmenting flight control surface actuation system and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Augmenting flight control surface actuation system and method will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3260851