Aircraft Pod Assembly for VTOL Transition Control

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Solution Overview

Problem

Current aircraft designs, such as fixed-wing, tiltrotor, and tiltwing, face challenges in transitioning efficiently between vertical takeoff and landing (VTOL) and forward flight modes, particularly in terms of control complexity and efficiency, especially in congested or remote areas, and suffer from downwash inefficiencies and control difficulties during hover.

Innovation Solution

Aircraft with a distributed propulsion system featuring multiple independent propulsion assemblies and a triply redundant flight control system that allows for autonomous, remote, or pilot-controlled operation, enabling efficient transitions between VTOL and forward flight modes by independently controlling each propulsion assembly for optimal thrust and lift.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tiltrotor aircraft use fixed wing and rotating proprotors for VTOL and forward flight, then vertical lift capability is achieved, but downwash inefficiencies occur during vertical takeoff and landing due to interference from the fixed wing

Engineering Contradiction:
Improvevertical lift capabilityVSAvoiddownwash inefficiencies
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The aircraft separates the lifting function from the propulsion function by using independent lift engines mounted on the fuselage for vertical lift and separate pusher propellers for forward thrust. This segmentation eliminates the downwash interference problem that occurs in tiltrotor designs where the same rotating wings provide both lift and thrust, as the lift engines' exhaust does not interact with the forward flight propellers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediate structure - a pylon or support framework - that positions the lift engines and pusher propellers at different locations and orientations. This intermediary structure allows the lift engines to operate independently below the wing while the pusher propellers operate above and behind, preventing direct interaction between their airflow paths.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If tiltwing aircraft rotate wing to vertical orientation for VTOL, then vertical thrust efficiency improves, but control during hover becomes more difficult requiring cyclic rotor control or additional thrust station

Engineering Contradiction:
Improvevertical thrust efficiencyVSAvoidcontrol during hover
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The aircraft divides the control functions by separating lift generation (vertical thrust) from directional control. Independent lift engines provide vertical thrust while separate pusher propellers provide forward motion and directional control, eliminating the need for complex cyclic rotor control systems required in tiltwing designs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pusher propellers serve multiple functions: providing forward thrust during horizontal flight, enabling directional control during hover, and assisting in vertical ascent when combined with lift engines. This multi-functionality replaces the need for separate cyclic rotor control systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Speed

If fixed-wing aircraft use wings for lift generation during forward flight, then forward airspeed is achieved, but runway of hundreds or thousands of feet is required for takeoff and landing

Engineering Contradiction:
Improveforward airspeedVSAvoidrunway length
Core Design Contradiction:
SpeedVSLength of moving object

Solution Approach 1:

The aircraft segments the flight functions by using dedicated lift engines for vertical lift during takeoff and landing, and separate pusher propellers for forward speed generation. This allows the aircraft to operate in VTOL mode without requiring long runways, while still achieving high forward speeds when the pusher propellers are engaged.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The aircraft dynamically transitions between vertical and horizontal flight modes by controlling the thrust vectors of the lift engines and pusher propellers. During takeoff, lift engines provide vertical thrust; during transition, the aircraft rotates to horizontal orientation; during forward flight, pusher propellers provide primary thrust. This dynamic adaptability eliminates runway length constraints.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3597528B1Aircraft with selectively attachable pod assembly
Publication Date: 2021.03.17 TEXTRON INNOVATIONS INC
  • EP3597528B1 patent drawingFigure 1A~1B
  • EP3597528B1 patent drawingFigure 1C~1D
  • EP3597528B1 patent drawingFigure 2A~2C

AI summary

An aircraft (10) includes a flying frame (12) having an airframe (26), a propulsion system (34) attached to the airframe (26) and a flight control system (68) operably associated with the propulsion system (34) wherein, the flying frame (12) has a vertical takeoff and landing mode and a forward flight mode. A pod assembly (70) is selectively attachable to the flying frame (12) such that the flying frame (12) is rotatable about the pod assembly (70) wherein, the pod assembly (70) remains in a generally horizontal attitude during vertical takeoff and landing, forward flight and transitions therebetween.