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You searched for subject:(Variable sweep wing). Showing records 1 – 3 of 3 total matches.

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RMIT University

1. Guo, D. Modelling and experimental investigations of a bi-modal unmanned underwater/air system.

Degree: 2019, RMIT University

The ability to perform underwater and coastal area monitoring missions without surfacing would increase submarine's safety and its combat ability. An innovative bi-modal unmanned/underwater air system (BUUAS) and its concept of operations (CONOPS) are proposed to reduce the risk of submarine's exposure. The BUUAS is firstly released from a submerged submarine and travels underwater to keep a distance from the submarine. Then it will exit the water using an innovative propulsion system that would allow a transition from water to air with the purpose of carrying out a planned air mission. When the airborne mission is finished, the BUUAS will dive back into the water and cruise to the submarine to be collected. This study aims to design and develop this system that can achieve the proposed CONOPS. The project addresses three critical aspects, namely, i) the study of an optimised configuration considering both aerodynamic and hydrodynamic performance aspects, ii) the exploration for an effective transition between water/air media and iii) the design of the water/air hybrid propulsion system. A variable-sweep wing configuration with a novel wing-deployment mechanism is considered for an efficient operation in water and air. Numerical simulation, water and wind tunnel experimental tests were conducted to assess the performance characteristics of the propulsion unit in water and the aerodynamic characteristics in air. The assessment data supports the feasibility of the bi-modal vehicle configuration and the stability analysis demonstrates the vehicle has static and dynamic stable behaviour during its flight. The water jet transition propulsion system is powered by pressurized CO2 and was developed to enable a fast take-off transition from water to air. The preliminary design covers the system sizing using an analytical model calibrated by the high-fidelity numerical simulation approach and the design of a specialized gas release mechanism adopted in the propulsion unit. The thrust and launch experiments were performed to verify the transition propulsion system design results and applicability. The air and water experimental results of the customized compact hybrid propulsion system confirm its provision of sufficient power for flight and underwater cruise.

Subjects/Keywords: Fields of Research; BUUAS; Transition propulsion system; Hybrid propulsion system; Variable sweep wing configuration; Wind tunnel test; Numerical simulation; Composite materials; Stability analysis

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Guo, D. (2019). Modelling and experimental investigations of a bi-modal unmanned underwater/air system. (Thesis). RMIT University. Retrieved from http://researchbank.rmit.edu.au/view/rmit:162852

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Guo, D. “Modelling and experimental investigations of a bi-modal unmanned underwater/air system.” 2019. Thesis, RMIT University. Accessed January 18, 2021. http://researchbank.rmit.edu.au/view/rmit:162852.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Guo, D. “Modelling and experimental investigations of a bi-modal unmanned underwater/air system.” 2019. Web. 18 Jan 2021.

Vancouver:

Guo D. Modelling and experimental investigations of a bi-modal unmanned underwater/air system. [Internet] [Thesis]. RMIT University; 2019. [cited 2021 Jan 18]. Available from: http://researchbank.rmit.edu.au/view/rmit:162852.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Guo D. Modelling and experimental investigations of a bi-modal unmanned underwater/air system. [Thesis]. RMIT University; 2019. Available from: http://researchbank.rmit.edu.au/view/rmit:162852

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


University of Pretoria

2. [No author]. Longitudinal handling characteristics of a tailless gull-wing aircraft .

Degree: 2008, University of Pretoria

A handling quality investigation was performed on the swept gull-wing configuration. The swept gull-wing configuration is tailless and has a wing with a transition in the sweep and dihedral angle. An example of this type of aircraft is the Exulans. This aircraft is currently under development at the University of Pretoria. The handling quality study was focussed on pitch axis dynamics. The Exulans is a research testbed that will be used to investigate the swept gull-wing configuration and its special controls by means of full-scale flight testing. Variable wing sweep, twisting elevons and winglets will be investigated as means of control. These control devices are configured in such a way as to have minimum impact on the performance of the aircraft. The handling qualities of the swept gull-wing configuration have to be acceptable while using these different control strategies. The study was launched to investigate whether a gull-wing configuration aircraft will have satisfactory handling qualities at CG positions associated with the most favourable aerodynamic performance. There is an aerodynamic performance gain in designing an aircraft so that the CG falls on the so-called `E-point'. The E-point is the centre of pressure for an elliptical circulation distribution. An elliptical circulation distribution is associated with the highest Oswald efficiency for an aircraft. Time domain simulation techniques and frequency domain analysis techniques were used to analyse the handling qualities of the gull-wing configuration. The C-star criterion was used to analyse handling qualities with time domain simulation data as input. Comparative time domain simulations were performed between the Exulans and other aircraft to compare handling qualities. Eigenvalue analysis was used together with the thumbprint criterion to investigate inherent gull-wing airframe dynamics. The Shomber-Gertsen and Military Specification 8785 criteria were also used for the same purpose. The Neal-Smith method was used to investigate the effect of control authority on handling qualities and the effect of a pilot. The Monnich and Dalldorff criterion was used to evaluate gust handling qualities. An analysis chart by Fremaux and Vairo was used to evaluate the tumbling susceptibility of the gull-wing configuration. The pitch handling quality investigation shows sufficient promise that the swept gull-wing configuration will have acceptable handling qualities with the CG placed at positions associated with optimised aerodynamic performance. Analysis showed that the swept gull-wing configuration is potentially prone to tumbling. With low static margins, the configuration should exhibit improved handling qualities in gusty conditions when compared to existing tailless aircraft. It is recommended that a lateral handling quality study be performed before full scale flight testing commences on the Exulans. In addition, the possibility of wingtip stall must be investigated for the case of the swept gull-wing configuration. Advisors/Committee Members: Theron, Nicolaas J (advisor).

Subjects/Keywords: Flight simulation; Tumbling; Thumbprint criterion; Neal-smith analysis; C-star criterion; Shomber-gertsen analysis; Pilot induced oscillation; Oswald efficiency; Pilot mathematical model; Variable sweep wing; Exulans; Variable static margin; Swept gull-wing configuration; O-point; E-point; Handling qualities; Gust handling qualities; Tailless aircraft; Pecking; Monnich and dalldorff criterion; UCTD

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

author], [. (2008). Longitudinal handling characteristics of a tailless gull-wing aircraft . (Masters Thesis). University of Pretoria. Retrieved from http://upetd.up.ac.za/thesis/available/etd-09182008-132941/

Chicago Manual of Style (16th Edition):

author], [No. “Longitudinal handling characteristics of a tailless gull-wing aircraft .” 2008. Masters Thesis, University of Pretoria. Accessed January 18, 2021. http://upetd.up.ac.za/thesis/available/etd-09182008-132941/.

MLA Handbook (7th Edition):

author], [No. “Longitudinal handling characteristics of a tailless gull-wing aircraft .” 2008. Web. 18 Jan 2021.

Vancouver:

author] [. Longitudinal handling characteristics of a tailless gull-wing aircraft . [Internet] [Masters thesis]. University of Pretoria; 2008. [cited 2021 Jan 18]. Available from: http://upetd.up.ac.za/thesis/available/etd-09182008-132941/.

Council of Science Editors:

author] [. Longitudinal handling characteristics of a tailless gull-wing aircraft . [Masters Thesis]. University of Pretoria; 2008. Available from: http://upetd.up.ac.za/thesis/available/etd-09182008-132941/


University of Pretoria

3. Agenbag, Daniel Sarel. Longitudinal handling characteristics of a tailless gull-wing aircraft.

Degree: Mechanical and Aeronautical Engineering, 2008, University of Pretoria

A handling quality investigation was performed on the swept gull-wing configuration. The swept gull-wing configuration is tailless and has a wing with a transition in the sweep and dihedral angle. An example of this type of aircraft is the Exulans. This aircraft is currently under development at the University of Pretoria. The handling quality study was focussed on pitch axis dynamics. The Exulans is a research testbed that will be used to investigate the swept gull-wing configuration and its special controls by means of full-scale flight testing. Variable wing sweep, twisting elevons and winglets will be investigated as means of control. These control devices are configured in such a way as to have minimum impact on the performance of the aircraft. The handling qualities of the swept gull-wing configuration have to be acceptable while using these different control strategies. The study was launched to investigate whether a gull-wing configuration aircraft will have satisfactory handling qualities at CG positions associated with the most favourable aerodynamic performance. There is an aerodynamic performance gain in designing an aircraft so that the CG falls on the so-called `E-point'. The E-point is the centre of pressure for an elliptical circulation distribution. An elliptical circulation distribution is associated with the highest Oswald efficiency for an aircraft. Time domain simulation techniques and frequency domain analysis techniques were used to analyse the handling qualities of the gull-wing configuration. The C-star criterion was used to analyse handling qualities with time domain simulation data as input. Comparative time domain simulations were performed between the Exulans and other aircraft to compare handling qualities. Eigenvalue analysis was used together with the thumbprint criterion to investigate inherent gull-wing airframe dynamics. The Shomber-Gertsen and Military Specification 8785 criteria were also used for the same purpose. The Neal-Smith method was used to investigate the effect of control authority on handling qualities and the effect of a pilot. The Monnich and Dalldorff criterion was used to evaluate gust handling qualities. An analysis chart by Fremaux and Vairo was used to evaluate the tumbling susceptibility of the gull-wing configuration. The pitch handling quality investigation shows sufficient promise that the swept gull-wing configuration will have acceptable handling qualities with the CG placed at positions associated with optimised aerodynamic performance. Analysis showed that the swept gull-wing configuration is potentially prone to tumbling. With low static margins, the configuration should exhibit improved handling qualities in gusty conditions when compared to existing tailless aircraft. It is recommended that a lateral handling quality study be performed before full scale flight testing commences on the Exulans. In addition, the possibility of wingtip stall must be investigated for the case of the swept gull-wing configuration. Advisors/Committee Members: Theron, Nicolaas J. (advisor).

Subjects/Keywords: Flight simulation; Tumbling; Thumbprint criterion; Neal-smith analysis; C-star criterion; Shomber-gertsen analysis; Pilot induced oscillation; Oswald efficiency; Pilot mathematical model; Variable sweep wing; Exulans; Variable static margin; Swept gull-wing configuration; O-point; E-point; Handling qualities; Gust handling qualities; Tailless aircraft; Pecking; Monnich and dalldorff criterion; UCTD

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Agenbag, D. (2008). Longitudinal handling characteristics of a tailless gull-wing aircraft. (Masters Thesis). University of Pretoria. Retrieved from http://hdl.handle.net/2263/28011

Chicago Manual of Style (16th Edition):

Agenbag, Daniel. “Longitudinal handling characteristics of a tailless gull-wing aircraft.” 2008. Masters Thesis, University of Pretoria. Accessed January 18, 2021. http://hdl.handle.net/2263/28011.

MLA Handbook (7th Edition):

Agenbag, Daniel. “Longitudinal handling characteristics of a tailless gull-wing aircraft.” 2008. Web. 18 Jan 2021.

Vancouver:

Agenbag D. Longitudinal handling characteristics of a tailless gull-wing aircraft. [Internet] [Masters thesis]. University of Pretoria; 2008. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2263/28011.

Council of Science Editors:

Agenbag D. Longitudinal handling characteristics of a tailless gull-wing aircraft. [Masters Thesis]. University of Pretoria; 2008. Available from: http://hdl.handle.net/2263/28011

.