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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
URL: http://researchbank.rmit.edu.au/view/rmit:162852 
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 (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
URL: http://upetd.up.ac.za/thesis/available/etd-09182008-132941/
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 Details
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Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
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
URL: http://hdl.handle.net/2263/28011
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 Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
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
. 
Open Access Theses and Dissertations