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Article
Publication date: 27 September 2018

Miodrag Milenković-Babić

This paper aims to present the new information about propeller thrust force contribution to airplane longitudinal stability analysis.

Abstract

Purpose

This paper aims to present the new information about propeller thrust force contribution to airplane longitudinal stability analysis.

Design/methodology/approach

The method presented in this paper is empirical, shows how propeller thrust force derivative can be obtained and gives some additional information about misinterpretation of the propeller thrust effects that are present in the current literature.

Findings

New information about propeller thrust force contribution to airplane longitudinal stability analysis has been presented. This information should enable more precise insight in aircraft stability analysis and better understanding of the physical process that occurs during maneuver flight.

Practical implications

The information presented in this paper is new and specific to the propeller aircraft configuration. The methods used here are standard procedure to evaluating propeller thrust force derivative.

Originality/value

The information in this paper presents theoretical results. The method for calculating thrust force contribution to the airplane longitudinal stability is given depending on the propeller type and should enable good engineering results.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 9
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 5 October 2015

Kwanchai Chinwicharnam, Edgard David Gomez Ariza, Jean-Marc Moschetta and Chinnapat Thipyopas

The purpose of this paper is to investigate the influence of a propeller slipstream on the aerodynamic characteristics of a fixed-wing micro air vehicle (MAV) by simplifying a…

Abstract

Purpose

The purpose of this paper is to investigate the influence of a propeller slipstream on the aerodynamic characteristics of a fixed-wing micro air vehicle (MAV) by simplifying a propeller to an actuator disk and an actuator volume.

Design/methodology/approach

A computational fluid dynamic (CFD) approach.

Findings

The simulation flows are found and show that the propeller slipstream changes the flow field around the wing, which improves the aerodynamic performance of the wing. The aerodynamic performance is improved first, when the separation of the boundary flow at the upper surface wing is delayed. Second, the flow region of the boundary layer is boosted close to the wing surface again at a high incidence angle. And finally, the velocity inlet of the wing is increased by the propeller-induced flow.

Research limitations/implications

The incidence angle is in the range of 0-80°with an increment of 20°. The free stream velocity and RPM used are 6 m/s and 5,000 rpm, respectively.

Originality/value

A propeller is simplified to an actuator disk and an actuator volume.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 87 no. 6
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 13 December 2023

Ying-Jie Guan and Yong-Ping Li

To solve the shortcomings of existed search and rescue drones, search and rescue the trapped people trapped in earthquake ruins, underwater and avalanches quickly and accurately…

Abstract

Purpose

To solve the shortcomings of existed search and rescue drones, search and rescue the trapped people trapped in earthquake ruins, underwater and avalanches quickly and accurately, this paper aims to propose a four-axis eight-rotor rescue unmanned aerial vehicle (UAV) which can carry a radar life detector. As the design of propeller is the key to the design of UAV, this paper mainly designs the propeller of the UAV at the present stage.

Design/methodology/approach

Based on the actual working conditions of UAVs, this paper preliminarily estimated the load of UAVs and the diameters of propellers and designed the main parameters of propellers according to the leaf element theory and momentum theory. Based on the low Reynolds number airfoil, this paper selected the airfoil with high lift drag ratio from the commonly used low Reynolds number airfoils. The chord length and twist angle of propeller blades were calculated according to the Wilson method and the maximum wind energy utilization coefficient and were optimized by the Asymptotic exponential function. The aerodynamic characteristics of the designed single propeller and coaxial propeller under different installation pitch angles and different installation distances were analyzed.

Findings

The results showed that the design of coaxial twin propellers can increase the load capacity by about 1.5 times without increasing the propeller diameter. When the installation distance between the two propellers was 8 cm and the tilt angle was 15° counterclockwise, the aerodynamic characteristics of the coaxial propeller were optimal.

Originality/value

The novelty of this work came from the conceptual design of the new rescue UAV and its numerical optimization using the Wilson method combined with the maximum wind energy utilization factor and the exponential function. The aerodynamic characteristics of the common shaft propeller were analyzed under different mounting angles and different mounting distances.

Details

Aircraft Engineering and Aerospace Technology, vol. 96 no. 1
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 20 February 2023

Y. Chandukrishna and T.N. Venkatesh

Recent interest in electric aircraft has opened avenues for exploring innovative concepts and designs. Because of its potential to increase wing aerodynamic efficiency, the idea…

Abstract

Purpose

Recent interest in electric aircraft has opened avenues for exploring innovative concepts and designs. Because of its potential to increase wing aerodynamic efficiency, the idea of wing tip-mounted propellers is becoming more popular in the context of electric aircraft. This paper aims to address the question of which configuration, tractor or pusher at wing tip is more beneficial.

Design/methodology/approach

The interactions between the wing and tip-mounted propellers in tractor and pusher configurations have been studied computationally. In this study, the propeller is modeled as a disk, and the blade element method (BEM) coupled with the computational fluid dynamics (CFD)–Reynolds-averaged Navier–Stokes (RANS) solver is used to calculate propeller blade loading recursively. A direct comparison between the wing with tip-mounted propellers in tractor and pusher configurations is made by varying the direction of rotation and thrust.

Findings

Wing with tip-mounted propellers having inboard-up rotation is found to offer less drag in tractor and pusher configurations than those without propeller cases. Wing tip-mounted propeller in tractor configuration with inboard-up rotation offers higher wing aerodynamic efficiency than the other configurations. In tractor and pusher configurations with inboard-up rotating propellers, wing tip vortex attenuation is seen, whereas with outboard-up rotating propellers, the wing tip vortex amplification is observed.

Originality/value

SU2, an open-source CFD tool, is used in this study and BEM is coupled to perform RANS–BEM simulations. Both qualitative and quantitative comparisons were made between the tractor and pusher configurations, which may find its value when a question arises about the aerodynamically best propeller configuration at wing tips.

Details

Aircraft Engineering and Aerospace Technology, vol. 95 no. 6
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 28 March 2008

C.Y. Hsu, C.K. Huang and G.J. Tzou

This purpose of this study is to investigate an effective method to manufacture propellers.

1116

Abstract

Purpose

This purpose of this study is to investigate an effective method to manufacture propellers.

Design/methodology/approach

The investment casting process and injection molding process have been applied separately to the rapid prototyping/rapid tooling (RP/RT) to obtain metal (Al‐Si alloy) propellers and plastic (Acrylonitrile butadiene styrene – ABS) propellers. The two different manufacturing processes were compared following the same master model (MM). The Moldflow software is used to optimize the experimental parameters of the molding. Furthermore, a gypsum type of powder is used to produce the RP MM of the propeller according to the Pro‐E software. The RP MM then is filled with a metallic resin material (at room temperature) to obtain a wax mold. Then, this wax mold was coating by dipping the ZrO2 slurry to improve heat resistant ability, and following solidification, and then filled with metal alloy to obtain metal (Al‐Si alloy) propellers. Another process, the RP MM by dipping the ZrO2 slurry to increase the heat resistance and then is filled with aluminum alloy and an injection mold can be obtained, the plastic (ABS) propellers can be duplicated. To ensure the precision of dimension and improves the surface roughness for the RT (metallic resin mold and aluminum alloy mold), the contour of the duplicated molds were milling with the high‐speed CNC manufacturing program.

Findings

The advantage of this process is that combining the RP/RT system with the high‐speed CNC machining center enables easy production of injection molds.

Originality/value

This process provides engineers with a quick way to fabricate parts and modify the designs. This study demonstrates that this process provides a practical way to fabricate parts and saves the cost and time which increases market competition. The molds with high precision and good surface roughness were duplicated by the rapid‐prototype technique. Furthermore, this investigation demonstrates that: if the product contains special shapes? The material requires a large amount of cutting? or In the case of expensive and hard to machine materials, the proposed process is the best choice to duplicate cost‐effective mold.

Details

Rapid Prototyping Journal, vol. 14 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 19 October 2018

Jun Jiao, Bifeng Song, Yubin Li, Yugang Zhang and Jianhua Xu

The purpose of this paper is to develop a propeller performance measurement method for high-altitude platforms by analyzing of the propeller aerodynamic characteristics and…

Abstract

Purpose

The purpose of this paper is to develop a propeller performance measurement method for high-altitude platforms by analyzing of the propeller aerodynamic characteristics and application of a mobile testing system.

Design/methodology/approach

An experimental approach is adopted for this study. Considering the aerodynamic characteristics of the high-altitude propeller, the similitude of the scaled propeller model in the experiment is analyzed and determined. Then, the experimental method and procedure to obtain the propeller’s performance under different altitudes are presented, and the structure of hardware and software and the key techniques of the testing system are introduced in detail.

Findings

The applicability and effectiveness of the testing system is verified through comparison between experimental and numerical results. In addition, the performance of the 6.8-m propeller for a high-altitude airship is tested, which proves that the high-altitude propeller can meet the requirements of the propulsion system.

Practical implications

The testing methodology and the mobile testing system could be applied to aerodynamic performance evaluation of the high-altitude propellers under different altitudes.

Originality/value

This testing approach exhibits significant time and cost benefits over many other experimental methods to obtain the performance of the high-altitude propellers, which is important in the preliminary design of the propulsion system for high-altitude platforms.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 9
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 28 June 2013

Jacek Mieloszyk, Cezary Galiński, Janusz Piechna and Jacek Brzozowski

This is the second of two companion papers presenting the results of research into a contra‐rotating propeller designed to drive a super manoeuvrable micro air vehicle (MAV) and…

Abstract

Purpose

This is the second of two companion papers presenting the results of research into a contra‐rotating propeller designed to drive a super manoeuvrable micro air vehicle (MAV) and is devoted to the experimental results. The first paper presented the design process and numerical analyses.

Design/methodology/approach

Most of experiments were conducted in the wind tunnel. Both contra‐rotating and conventional propellers were tested. The test procedures and equipment are described first. The attention is focused on the design of an aerodynamic balance used in the experiment. Then, the measurement error is discussed, followed by presentation of the wind tunnel results. Finally, an initial flight test of the MAV equipped with contra‐rotating propeller is briefly described.

Findings

Wind tunnel experiment results fall between theoretical results presented in the first part of the paper. The application of contra‐rotating propeller allowed to develop the propulsion system with zero torque. Moreover, the efficiency achieved appeared to be a few percent greater than that for a standard conventional propulsion system. The concept was finally proved during the first test flight of the new MAV.

Research limitations/implications

The propeller was designed for a fixed wing aeroplane, not for helicopter rotor. Therefore, only conditions characteristic for fixed wing aeroplane flight are tested.

Practical implications

The designed contra‐rotating propeller can be used in fixed wing aeroplane if torque equal to zero is required.

Originality/value

Original design of the balance is described for the first time, as well as test procedures applied in this experiment. Most of wind tunnel test results are also new and never published before.

Details

Aircraft Engineering and Aerospace Technology, vol. 85 no. 4
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 1 February 2022

Premkumar P.S., Nadaraja Pillai S. and Senthil Kumar C.

Pusher configured turbo-prop aircraft receive inadequate ram air cooling due to the lack of propeller slipstream, particularly during ground operations. However, flow entrainment…

Abstract

Purpose

Pusher configured turbo-prop aircraft receive inadequate ram air cooling due to the lack of propeller slipstream, particularly during ground operations. However, flow entrainment can be exploited to a greater extent by placing the oil-cooler duct close to downstream of the propeller at a suitable radial location. But this method has a detrimental effect on the propeller thrust. The purpose of this paper is to discuss the results of numerical simulations carried out to simulate the performance of the propeller with and without oil cooler.

Design/methodology/approach

In this paper, three-dimensional (3D) numerical simulations are carried out to simulate the propeller in a rotating domain using an unstructured grid. A computational fluid dynamics solver is put forward to analyze the effect of thrust loss by solving 3D Navier-Stokes equations using a second-order upwind finite-volume scheme. In this study, the impact of thrust loss incurred in the propeller flow field with and without oil cooler duct for three different locations at various rotational speeds is carried out to assess the propeller performance and to identify the optimum position to get a sufficient mass flow rate.

Findings

The findings from this study are simulated thrust values of an uninstalled five-bladed propeller of light transport aircraft (LTA) match well with original equipment manufacturer propeller thrust data. The tip speed velocities simulated for different operating conditions are in good agreement with the theoretical calculations. The influence of oil-cooler effect on the propeller flow field is less in low velocity to high-velocity operating condition due to flow transition from laminar to turbulent. The presence of the oil cooler, which influences the thrust loss, is studied at propeller upstream and downstream locations in detail for 30%, 40% and 50% of propeller radius cases.

Research limitations/implications

Simulations with finer and structured hexa grids can be applied to this problem to get closer results and save solver time as future work.

Practical implications

The recommended system is installed in the production standard aircraft of LTA. After installation oil cooler performance is better compared to the previous arrangement.

Originality/value

Research work about pusher aircraft is very limited. The problem addressed in this study is unique which resolves the major issue of pusher aircraft. This work highlights the difficulty involved in LTA engine oil cooling, and solution methodologies are also provided. Numerical simulation with oil-cooler assembly is a new area of research that gave the solution for this oil-cooling issue through various oil-cooler case studies.

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 6
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 15 July 2021

Yang Liu, Qingwei Gong, Yongning Bian and Qinghui Suo

Hydrodynamic forces and efficiency of bare propeller and ducted propellers with a wide range of advance ratio (J) and attack angle (θ) are examined. The thrust and torque…

Abstract

Purpose

Hydrodynamic forces and efficiency of bare propeller and ducted propellers with a wide range of advance ratio (J) and attack angle (θ) are examined. The thrust and torque coefficients and the efficiency are presented and discussed in detail. The present results give a reliable guidance to the improvement of the hydrodynamic characteristics of ducted propellers.

Design/methodology/approach

The effect of a duct on the hydrodynamic performance of the KP458 propeller is numerically investigated in this study. Finite volume method (FVM)-based simulations are performed for a wide range of advance ratio J (0 ≤ J ≤ 0.75) and attack angle θ of the duct (15° ≤ θ ≤ 45°). A cubic computational domain is employed in this study, and the moving reference frame (MRF) approach is adopted to handle the rotation of the propeller. Turbulence is accounted for with the RNG k-ε model. The present numerical results are first compared against available experimental data and a good agreement is achieved.

Findings

The simulation results demonstrate that the hydrodynamic forces and efficiency increases and decreases with J, respectively, at the same attack angle. In addition, it is demonstrated that the hydrodynamic forces and efficiency are both improved due to the presence of the duct, which eventually leads a better hydrodynamic performance at high advance ratios. It is further revealed that as the attack angle increases, the pressure difference between the suction- and pressure-surfaces of the propeller is also augmented, which results in a larger thrust. The wake field is more uniform at θ = 30°, suggesting that a higher efficiency can be obtained.

Originality/value

The present study aims to investigate the effect of a duct on the KP458 propeller subjected to uniform inbound flow. The relationship between the uniform incoming flow and the attack angle of the duct is mainly focused, and the design of the ducted propellers for any ship hull can be improved according to this relationship.

Details

Engineering Computations, vol. 39 no. 2
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 17 May 2011

Matthew J. Traum

High autogyro accident rates prompted experimental investigation of this type of aircraft's low‐speed pitch characteristics. Pitch control is typically derived from main rotor…

Abstract

Purpose

High autogyro accident rates prompted experimental investigation of this type of aircraft's low‐speed pitch characteristics. Pitch control is typically derived from main rotor tip‐path‐plane adjustment. Thus, autogyro designers often omit horizontal tails and pitch control surfaces. The purpose of this paper is to enable autogyro low‐speed pitch control by intentionally placing elevators in the propeller wake.

Design/methodology/approach

Wind tunnel tests were conducted on a 1:10 scale teetering rotor autogyro model. The model included a horizontal tail with elevators placed in the propeller wake. Straight‐and‐level flight conditions were estimated via a scaling scheme based on the main rotor diameter. At minimum flight speed, the pitching moment induced by 30° elevator deflection was measured. This process was repeated for a range of elevator positions behind the centre of the pitching rotation.

Findings

When placed in an autogyro propeller wake, deflected elevators induce significant pitching moments. If the elevator is shadowed from free stream flow by the autogyro cowling, the pitching moment remains unchanged regardless of the distance between elevators and centre of pitch rotation. However, if the elevator is immersed in the freestream, the pitching moment increases via deflection of both propeller wake and freestream flow.

Research limitations/implications

Kinematic similarity ensures ratios between propeller wake, wind speed, and main rotor flows are representative of full scale. Without flow visualization, main‐rotor‐diameter‐based scaling does not ensure kinematic similarity. Results are therefore qualitative.

Practical implications

Elevators mounted in autogyro propeller wake are worthy of inclusion on all autogyros for pitch control at low speed.

Originality/value

Improved low‐speed pitch control arising from elevators mounted in autogyro propeller wake could potentially reduce accidents.

Details

Aircraft Engineering and Aerospace Technology, vol. 83 no. 3
Type: Research Article
ISSN: 0002-2667

Keywords

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