Distributed Propeller Thrust Allocation for Low-Speed Landing Lift
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Solution Overview
Problem
Existing aircraft designs with distributed propulsion systems struggle to maintain sufficient lift during low airspeeds, particularly during landing, while minimizing total thrust requirements.
Innovation Solution
The method involves arranging propeller drives side by side on the leading edge of each half-wing, with propellers rotating about parallel axes, and adjusting their thrust direction and rotational speed to maximize lift and minimize total thrust by positioning propellers in front of landing flaps to generate increased forward thrust, and using aileron deflections to redistribute lift and induce drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If distributed propulsion units are arranged along the wing leading edges to increase lift at low airspeeds, then lift is improved, but total thrust requirement increases during landing
Solution Approach 1:
The patent applies local quality by differentiating the thrust generation between inner and outer propeller drives. Inner propeller drives positioned in front of landing flaps generate increased forward thrust to compensate for drag, while outer propeller drives generate less thrust. This localized differentiation optimizes the lift-to-thrust ratio during landing approach, resolving the contradiction between maximizing lift and minimizing total thrust requirement.
2Force
If propeller drives generate increased forward thrust during landing, then lift is enhanced, but drag increases due to landing flap extension
Solution Approach 1:
The patent implements preliminary anti-action by having inner propeller drives generate increased forward thrust in anticipation of and compensation for the drag increase caused by landing flap extension. This proactive thrust adjustment counteracts the harmful drag effect before it significantly impacts the landing approach, maintaining efficient flight characteristics despite flap deployment.
3Ease of operation
If all propeller drives generate equal thrust, then control is simplified, but lift distribution is suboptimal during landing
Solution Approach 1:
The patent applies local quality by making different propeller drives perform different thrust functions. Inner propeller drives are assigned increased thrust generation to compensate for flap drag, while outer propeller drives reduce thrust to optimize overall lift distribution. This localized functional differentiation improves aerodynamic efficiency during landing while maintaining manageable control complexity through automated differentiation.
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 approach ensures enhanced lift generation with minimal total thrust, particularly during landing, by decoupling lift increase from total thrust, and allows for efficient lift distribution and drag management, enhancing aerodynamic efficiency and reducing landing speed.
Implementation Method 1
at least three propeller drives 5 arranged side by side on the leading edge of each half-wing 3, 4, the propellers of which rotate about propeller axes 17 and whose propeller wakes blow on the respective half-wing
Implementation Method 2
at least one extended landing flap 7 arranged on a trailing edge of each half-wing 3, 4
Data Source
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AI summary
An aircraft (1) has a wing (2) with two half-wings (3, 4), at least three propeller drives (5) arranged side by side on a leading edge of each half-wing (3, 4), the propellers (18) of which rotate about propeller axes (17) and whose propeller wakes blow on the respective half-wing (3, 4), and a landing flap (7, 8) arranged on a trailing edge (6) of each half-wing (3, 4). When the aircraft (1) lands, the landing flaps (7, 8) are extended, and at least one of the propeller drives (5), which is arranged on the respective half-wing (3, 4) in front of the extended landing flap (7, 8), generates a primary propeller thrust in the forward direction of its propeller axis (17) that is at least 15% greater than that generated on the respective half-wing (3, 4) not in front of the extended landing flap (7, 8).