Aircraft Tail Unit for Pitching Moment Compensation
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Solution Overview
Problem
Electrically driven, vertical take-off and landing multicopters experience a 'pitching-up' tilting moment during forward flight due to the offset between the rotor plane's center of gravity and the force's point of action, leading to inefficient energy consumption and reduced thrust from rear rotors operating in turbulent flow.
Innovation Solution
A tail unit, comprising a tailplane and vertical stabilizers, is mounted below or above the rotor plane to counteract the tilting moment, with the tailplane designed to create lift and adjust according to flying speed and direction, reducing the need for increased rotor operation and improving yaw stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rear rotors produce more thrust to compensate the pitching-up tilting moment, then the tilting moment is compensated, but electrical energy consumption increases and flight time is limited
Solution Approach 1:
A tail unit with tailplane and vertical stabilizers is introduced as an intermediary component to compensate the pitching-up moment. The tailplane generates aerodynamic force that counteracts the tilting moment, allowing rear rotors to operate at normal thrust levels without excessive energy consumption.
Solution Approach 2:
The aircraft is segmented into functional components: the main rotor system for lift and the tail unit for moment compensation. This segmentation allows each component to perform its specific function optimally, with the tail unit handling moment compensation while rotors focus on thrust generation.
2Force
If rear rotors operate at higher rotational speed to compensate the tilting moment, then thrust is increased, but the rotors operate in turbulent flow reducing their efficiency
Solution Approach 1:
The tail unit acts as an intermediary that assumes the responsibility of moment compensation, freeing the rear rotors from the need to operate at high speeds in turbulent flow. This allows the rotors to operate efficiently at normal speeds while the tail unit handles the aerodynamic moment balance.
3Loss of energy
If a tail unit is mounted above the rotor plane, then laminar airflow is utilized for efficient operation, but the configuration is more complex
Solution Approach 1:
The tail unit is designed to exploit the local quality of airflow above the rotor plane, which remains laminar and undisturbed by rotor-induced turbulence. This local utilization of high-quality airflow optimizes the aerodynamic efficiency of the tailplane while accepting the increased structural complexity.
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
The tail unit effectively compensates the tilting moment without overloading rotors, resulting in more homogeneous thrust distribution, improved flying efficiency, and enhanced yaw stability, particularly at high speeds.
Implementation Method 1
the tailplane to be designed such that it counteracts a pitching-up tilting moment that is brought about by a blocked surface, generated by the rotors in the rotor plane, during flying operation
Implementation Method 2
the relatively large 'blocked surface' formed by the rotor plane gives rise to a resistive force during forward flight
Implementation Method 3
the blocked surface formed by the rotor plane gives rise to a resistive force during forward flight
Implementation Method 4
the rear rotors, which have to generate additional thrust, unlike the front rotors, are subject to an already swirling turbulent flow
Data Source
AI summary
An aircraft in the form of an electrically driven, vertical take-off and landing, preferably people-carrying and/or load-carrying multicopter (1) is provided, in which a multiplicity of rotors are arranged in a common rotor plane (R), in which a tail unit (6), protruding upward or downward with respect to the rotor plane (R), is provided above or below the rotor plane (R), preferably in a rear region of the aircraft (1) with respect to a forward flying direction.