Tilted Propeller Arrays for Low-Lag Distributed VTOL Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing distributed propulsion systems for medium and large VTOL aircraft face challenges in achieving safe flight control due to high rotational inertia, requiring excessive power margins or complex cyclic and collective controls, which undermines the benefits of distributed propulsion.
Innovation Solution
A distributed propulsion system with propellers symmetrically arranged around the aircraft's center of gravity, each rotating in a tilted plane, allowing for lateral and longitudinal motion without rolling or pitching, and providing greater control authority with reduced lag by selectively adjusting thrust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If propellers are mounted in the same plane or parallel planes for distributed propulsion, then the system is simpler to manufacture and operate, but the aircraft experiences unacceptable control lag and requires excessive power margin due to high rotational inertia
Solution Approach 1:
The patent transitions from conventional coplanar or parallel-plane propeller arrangements to a three-dimensional distributed configuration where propellers are positioned at different vertical levels and angular orientations around the aircraft body. This spatial distribution in multiple dimensions enables independent control of lateral and longitudinal motion without requiring the aircraft to roll or pitch first, thereby eliminating control lag associated with overcoming rotational inertia.
2Reliability
If excessive power margin and cyclic/collective controls are added to enhance control authority, then flight control becomes adequate, but the benefits of distributed propulsion (coast, weight reduction, safety) are eliminated
Solution Approach 1:
The patent divides the propulsion system into multiple independently controllable propeller units distributed around the aircraft, with each propeller capable of independent thrust modulation. This segmentation eliminates the need for complex cyclic and collective control mechanisms while maintaining adequate control authority, as each propeller can be individually adjusted to achieve desired flight dynamics.
Solution Approach 2:
The patent changes the operational parameters of the distributed propellers by tilting their planes of rotation and adjusting their rotational speeds independently. By varying the thrust magnitude of individual propellers through speed control, the system achieves sufficient control authority without requiring excessive power margin or complex mechanical control linkages.
3Device complexity
If all thrust vectors are oriented vertically for lift in a conventional distributed propulsion system, then the structure is simpler, but lateral and longitudinal motion requires rolling or pitching which creates control lag
Solution Approach 1:
The patent introduces asymmetric tilt angles for different propeller planes relative to the vertical axis. Propellers are oriented at specific angles (e.g., ±15 degrees) to generate horizontal thrust components that enable direct lateral and longitudinal motion. This asymmetric configuration allows the aircraft to move in desired directions without requiring intermediate rolling or pitching maneuvers, significantly improving ease of operation and reducing control lag.
Data Source
AI summary
An aircraft comprises a fuselage, one or more support structures connected to the fuselage, one or more engines or motors disposed within or attached to the one or more support structures or the fuselage, and a distributed propulsion system. The distributed propulsion system comprising two or more propellers symmetrically distributed in an array along the one or more support structures with respect to a center of gravity of the aircraft and operably connected to the one or more engines or motors, wherein each propeller has a rotation direction within a tilted plane of rotation, and a summation of horizontal force vectors created by the tilted plane of rotation of all the propellers is substantially zero when all the propellers are creating a substantially equal thrust magnitude. Movement of the aircraft is controlled by selectively increasing or decreasing a thrust of at least one of the two or more propellers.