Aircraft Thrust Reverser Fixed Ramp Movable Wall
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Solution Overview
Problem
Conventional thrust reversers require large and heavy actuators and tracks for moving translating cowlings and nozzle outer wall sections, which increase weight and space requirements within the nacelle, reducing aircraft performance.
Innovation Solution
The design incorporates a cascade thrust reverser with a fixed reverser ramp and a nozzle outer wall section that moves between deployed and stowed positions, featuring a forward portion with a leading edge section and a fixed reverser ramp with varying slopes, allowing for a reduced stroke length and smaller actuators and tracks, and an increased nozzle area to minimize skin friction losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thrust reversers use large actuators and tracks to move translating cowlings and nozzle outer wall sections, then the thrust reverser can achieve reliable deployment and retraction, but the weight and space requirements within the nacelle increase, reducing aircraft performance
Solution Approach 1:
The thrust reverser system is divided into fixed components (reverser ramp, nozzle inner wall section) and movable components (nozzle outer wall section). This segmentation allows the heavy fixed components to remain stationary while only the lighter nozzle outer wall section needs to be moved for thrust reversal operation, reducing actuator and track size requirements.
Solution Approach 2:
Instead of moving the entire translating cowling and nozzle assembly as in conventional designs, this invention inverts the approach by keeping the reverser ramp fixed and only moving the nozzle outer wall section. This reversal of the conventional movement strategy significantly reduces the mass that needs to be actuated.
2Length of moving object
If conventional thrust reversers use large actuators and tracks, then the thrust reverser can achieve sufficient stroke length for complete deployment, but the space requirements for housing actuators and tracks increase, reducing aircraft performance
Solution Approach 1:
By segmenting the thrust reverser into fixed and movable portions, the required stroke length for the movable nozzle outer wall section is reduced compared to conventional designs that move entire assemblies. This shorter stroke reduces the space needed for actuator and track housing within the nacelle.
Solution Approach 2:
The translating cowling function is extracted and eliminated from the design. Only the essential nozzle outer wall section movement is retained, which requires less stroke length and smaller housing space for the actuation mechanism.
3Length of moving object
If the nozzle outer wall section is moved aft to reduce stroke length, then the actuator and track size are reduced, but the nozzle area decreases, increasing skin friction losses
Solution Approach 1:
The nozzle outer wall section is designed with varying slopes in different regions. The forward portion has a first slope while the aft portion has a second slope, optimizing both the stroke length reduction and the nozzle flow area to minimize skin friction losses while achieving compact actuation.
Solution Approach 2:
The nozzle outer wall section geometry is optimized by changing the slope parameters of different portions. This allows the design to achieve shorter stroke length while maintaining adequate nozzle area to minimize skin friction energy losses.
Data Source
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AI summary
Aircraft systems including cascade thrust reversers are disclosed herein. An aircraft system in accordance with one embodiment includes a cascade thrust reverser having a fixed reverser ramp and a nozzle outer wall section at least partially aft of the fixed reverser ramp. The nozzle outer wall section is movable between a deployed position and a stowed position. The nozzle outer wall section includes a forward portion with a leading edge section. The fixed reverser ramp has a portion forward of and adjacent to the nozzle outer wall section when the nozzle outer wall section is in the stowed position. The portion of the fixed reverser ramp has a first slope. The forward portion of the nozzle outer wall section that is aft of the leading edge section has a second slope different than the first slope.