Tilted Propeller Arrays for Responsive VTOL Flight 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 undermine the benefits of distributed propulsion.
Innovation Solution
The implementation of a distributed propulsion system with propellers symmetrically arranged around the aircraft's center of gravity, each operating within a tilted plane of rotation, allowing for simultaneous lateral and longitudinal motion without rolling or pitching, and achieving greater control authority with reduced control lag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If propellers are mounted in the same plane or parallel planes for distributed propulsion, then the system is simpler to manufacture and operate, but flight control authority becomes unacceptable for medium and large VTOL aircraft due to high rotational inertia
Solution Approach 1:
The patent applies asymmetry by tilting the rotational planes of the propellers relative to the horizontal plane. Instead of mounting all propellers in parallel planes, each propeller's rotational plane is tilted at a specific angle, creating an asymmetric configuration that generates both vertical lift and horizontal thrust components, thereby improving flight control authority without requiring complex cyclic and collective controls
Solution Approach 2:
The patent transitions from a two-dimensional parallel plane configuration to a three-dimensional tilted plane configuration. By introducing the tilt angle dimension, the propellers can simultaneously produce vertical and horizontal thrust components, enabling direct lateral and longitudinal motion without requiring the aircraft to first roll or pitch, thus overcoming the limitations of rotational inertia
2Reliability
If excessive power margin and cyclic and collective control are added to distributed propulsion systems, then flight control authority is enhanced, but the benefits of distributed propulsion (coast, weight reduction, and safety) are eliminated
Solution Approach 1:
The patent changes the geometric parameter of propeller orientation by introducing a tilt angle relative to the horizontal plane. This parameter change allows the propulsion system to generate both vertical and horizontal thrust components from each propeller, providing adequate flight control authority for medium and large VTOL aircraft without requiring excessive power margin or complex cyclic and collective controls
3Force
If the aircraft rolls or pitches to achieve lateral or longitudinal motion, then thrust vectors remain vertical for lift, but unacceptable lag in aircraft response occurs due to rotational inertia
Solution Approach 1:
The patent introduces asymmetric tilt angles for the propeller rotational planes, allowing each propeller to generate both vertical and horizontal thrust components. This asymmetric configuration enables direct lateral and longitudinal motion without requiring the aircraft to first roll or pitch, eliminating the time lag associated with overcoming rotational inertia
Solution Approach 2:
By tilting the propeller rotational planes out of the horizontal plane, the patent adds a vertical component to the thrust vectors in addition to the horizontal component. This dimensional change allows simultaneous generation of lift and thrust, enabling direct control of lateral and longitudinal motion without the intermediate rolling or pitching maneuvers that cause response lag
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances control authority and reduces control lag, enabling efficient and responsive flight control without the need for excessive power margins or complex control systems, thereby improving the safety and efficiency of medium and large VTOL aircraft.
Implementation Method 1
each comprising at least one propeller having a rotation direction within a tilted plane of rotation... allowing for simultaneous lateral and longitudinal motion without rolling or pitching
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
An aircraft (200; 300; 400) comprises a fuselage (205; 305; 405), one or more support structures (210a-c, 215; 310a-c, 315; 410a-c, 415) 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 (500). The distributed propulsion system (500) comprising two or more propellers (220a-1; 320a-1; 420a-1; 510a-h) symmetrically distributed in an array along the one or more support structures (210a-c, 215; 310a-c, 315; 410a-c, 415) with respect to a center of gravity of the aircraft (200; 300; 400) and operably connected to the one or more engines or motors, wherein each propeller has a rotation direction (225a-1; 325a-1; 425a-1; 512a-h) within a tilted plane of rotation (235a-1; 335a-1; 435a-1; 514a-h), and a summation of horizontal force vectors (230a-1; 330a-1; 430a-1) 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 (200; 300; 400) is controlled by selectively increasing or decreasing a thrust of at least one of the two or more propellers (220a-1; 320a-1; 420a-1; 510a-h).