Wing and propeller aerodynamic interaction through nonlinear lifting line theory and blade element momentum theory

Abstract: In this article different wings are computed by low and high-fidelity methods to compare their aerodynamic characteristics. Thanks to the unusual properties of the wing with the bell-shaped lift distribution, several general geometrical variants of the wings were calculated and their results are presented in this work. Three general wings are assumed and their geometry is defined as rectangular, trapezoidal and elliptical. Airspeed, total lift force, shape of airfoil and root chord are defined, and bending moment is assumed as a surrogate model for wing weight. The goal of optimization is minimization of aerodynamic drag.

Abstract: In this paper, a small airplane is redesigned by using a distributed electrical propulsion (DEP) system. The design procedure is focused on the reduction of fuel consumption in cruise regime with constrained parameters of take-off/landing. In this case, a one half wing area compared to an original airplane is used. Take-off distance and minimum airspeed for landing is achieved by distributed propellers mounted on the leading edge of the wing. These propellers induce velocity on the wing and thereby increase local dynamic pressure, thus the required lift force can be reached with smaller wing area. Moreover, the distributed propellers are assumed as folded in cruise regime to minimize drag when the main combustion engine provides sufficient power.

Abstract: This paper is focused on the usage of distributed electric propulsion (DEP) in order to increase aerodynamic efficiency. A ten seats aircraft is used as a case study. New design uses the existing fuselage, tail and turboprop engine, only wing is completely redesigned. The cost function for the design procedure consists of two parts. The first one is aerodynamic efficiency, which has a primary impact on fuel consumption, and the second one is weight of the wing. Lifting line theory with blade element momentum theory is used to design a wing geometry with DEP. Optimal geometry is also verified by CFD simulation. The estimation of the wing weight is needed for the second part of the cost function. This was done by the design of elementary wing parts under CS-23 regulation. The wing is assumed as full-aluminium with two spars. The main goal of this optimization is to redesign the wing for a given range and save as much fuel as possible.

Abstract: In this paper, an aerodynamic and wing structure is investigated by low-fidelity methods Bell-shaped lift distribution was rediscovered in the last decade as a perspective alternative to traditional wing design This leads to lower aerodynamic drag than elliptical lift distribution for a given lift force and root bending moment Root bending moment is used as a surrogate model of wing structure weight It is relatively raw simplification introduced by Prandtl to estimate the weight of the spar as a main part of the wing structure For a more accurate wing weight estimation, the main parts of the wing are dimensioned under CS-23 regulation in this work The design procedure starts with defining the elementary parameters of the wing shape (chord/twist distribution, wingspan) After geometry generating a non-linear lifting line is used to calculate aerodynamic characteristics for all regime, determined from the flight envelope The dimensions of a spar, ribs and skin are calculated in the next step of the procedure for given bending moment, load and torque moment distribution The structure of the wing is assumed as a two-spar, manufactured by aluminum A target of design is to find out the shape of the wing for given weight The solution is verified by CFD calculation

Abstract: The report gives, rather briefly, in part one an introduction to hydrodynamics which is designed to give those who have not yet been actively concerned with this science such a grasp of the theoretical underlying principles that they can follow the subsequent developments. In part two there follows a separate discussion of the different questions to be considered, in which the theory of aerofoils claims the greatest portion of the space. The last part is devoted to the application of the aerofoil theory to screw propellers. A table giving the most important quantities is at the end of the report. A short reference list of the literature on the subject and also a table of contents are added.

Abstract: The author examines the current theory on the importance of reducing slip in airplane propellers. The author feels an exaggerated importance is attached to this supposition and feels that the increase in friction by an increase in propeller area or number of revolutions can't be discounted.

Abstract: This paper considers the aerodynamic modeling of a twin-engine tail-sitter unmanned air vehicle that relies on wing- and fin-mounted control surfaces submerged in the propeller slipstreams for control during low-speed vertical flight The aerodynamic forces on this vehicle are predicted using a full azimuthal blade-element solution for the propellers combined with a fixed-wake panel-method model of the vehicle itself. When the flow components determined from the propeller solution are superimposed on the external flowfield and integrated with the panel-method model, the aerodynamic forces can be determined for the full vehicle, including slipstream effects, which are dominant in low-speed flight. The modeling described in this paper has been used extensively for multidisciplinary optimization work, as well as in the construction of a comprehensive aerodynamic database for the vehicle. This database encompasses all the aerodynamic force and moment coefficients and their derivatives for over 4300 separate flight conditions and has been extensively used for vehicle simulation and control design purposes.

Abstract: A model for the propulsion system of a small-scale electric unmanned aerial system is presented. This model is based on a blade element momentum (BEM) model of the propeller, with corrections for tip losses, Mach effects, three-dimensional flow components, and Reynolds scaling. Particular focus is placed on the estimation of scale effects not commonly encountered in the full-scale application of the BEM modeling method. Performance predictions are presented for geometries representative of several commercially available propellers. These predictions are then compared with experimental wind tunnel measurements of the propellers’ performance. The experimental data support the predictions of the proposed BEM model and point to the importance of scale effects on prediction of the overall system performance.

Abstract: Report presenting an investigation of the effectiveness of a wing equipped with large-chord plain flaps and auxiliary vanes in rotating the thrust vector of two large-diameter propellers through the large angles required for vertical take off and low-speed flight. The semispan model was equipped with a 60-percent-chord flap, a 30-percent-chord flap, and two large-diameter overlapping propellers. Results regarding static thrust conditions, tests with forward speed, and application of results are provided.