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Articles 1 - 7 of 7
Full-Text Articles in Engineering
Oxider To Fuel Ratio Shift Compensation Via Vortex Strength Control In Hybrid Rocket Motors, Max W. Francom
Oxider To Fuel Ratio Shift Compensation Via Vortex Strength Control In Hybrid Rocket Motors, Max W. Francom
All Graduate Theses and Dissertations, Fall 2023 to Present
Hybrid motors have existed as a hypothetical propulsion system for decades in a wide range of upper stage rocket motors due to their simple, robust, non-toxic, and versatile nature. However, inherent to hybrids is Oxidizer to Fuel ratio (O/F) shift over time, which results in performance losses for the majority of the rocket’s lifetime. The purpose of this study is to develop a hybrid rocket motor capable of manipulating O/F at will, resulting in an engine which eliminates the undesirable effects of O/F shift. By developing and refining a numerical simulation, a novel injector system, and an open-loop control scheme, …
Development, Modeling, Identification, And Control Of Tilt-Rotor Evtol Aircraft, Clayton T. Spencer
Development, Modeling, Identification, And Control Of Tilt-Rotor Evtol Aircraft, Clayton T. Spencer
All Graduate Theses and Dissertations, Fall 2023 to Present
This thesis includes the development, modeling, identification, and control of an electric-Vertical-Take-Off-and-Landing (eVTOL) aircraft with tiltable rotors. The front two rotors have tilting capability for transition flight from vertical-take-off to forward-level flight. This work details the development of an eVTOL aircraft and the selection of sub components such as electric motors, batteries, and controllers. After the aircraft build, mathematical model is derived to describe the motion of the aircraft. Unknown parameters in the mathematical model are identified using a Least-Squares-regression (LSR) method that can handle parameter constraints. This is done using real flight data collected from the aircraft. Lastly, this …
Development And Testing Of An 8-Bit Digitally Throttled Hybrid Rocket Motor, Trevor W. Coombs
Development And Testing Of An 8-Bit Digitally Throttled Hybrid Rocket Motor, Trevor W. Coombs
All Graduate Theses and Dissertations, Fall 2023 to Present
Hybrid rocket motors that use a solid fuel grain and liquid oxidizer are low-cost and safer alternatives to traditional rocket motors. Another benefit of hybrid rocket motors is that during a burn, the amount of oxidizer into the combustion chamber can be changed, this capability is called throttling. To take advantage of the throttling ability of hybrid rocket motors, a throttling valve made up of 8 individually controlled valves is designed, developed, and tested, which is documented in this thesis. The results of the testing campaign show that the 8-bit digital throttling valve technology is an effective throttling technology and …
Multifidelity Comparison Of Supersonic Wave Drag Prediction Methods Using Axisymmetric Bodies †, Troy Abraham, David Lazzara, Douglas Hunsaker
Multifidelity Comparison Of Supersonic Wave Drag Prediction Methods Using Axisymmetric Bodies †, Troy Abraham, David Lazzara, Douglas Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
Low-fidelity analytic and computational wave drag prediction methods assume linear aerodynamics and small perturbations to the flow. Hence, these methods are typically accurate for only very slender geometries. The present work assesses the accuracy of these methods relative to high-fidelity Euler, compressible computational-fluid-dynamics solutions for a set of axisymmetric geometries with varying radius-to-length ratios (R/L). Grid-resolution studies are included for all computational results to ensure grid-resolved results. Results show that the low-fidelity analytic and computational methods match the Euler CFD predictions to around a single drag count (~1.0 × 10–4) for geometries with R/L ≤ 0.05 …
Stick-Fixed Maneuver Points In Roll, Pitch, And Yaw And Associated Handling Qualities, Benjamin C. Moulton, Troy A. Abraham, Douglas F. Hunsaker
Stick-Fixed Maneuver Points In Roll, Pitch, And Yaw And Associated Handling Qualities, Benjamin C. Moulton, Troy A. Abraham, Douglas F. Hunsaker
Mechanical and Aerospace Engineering Student Publications and Presentations
The stick-fixed pitch maneuver point is an important measure of aircraft longitudinal dynamic response and handling quality characteristics, and includes effects of both aerodynamic and inertia properties of the aircraft about the pitch axis. In the present work, the existence of stick-fixed roll and yaw maneuver points is demonstrated, which are determined from the lateral forces, moments, and inertial properties of the aircraft. These stick-fixed roll and yaw maneuver points are directly related to the predicted lateral handling qualities. Example results are included for several aircraft that demonstrate the importance of this parameter when predicting the dynamic response of the …
Evaluation Of First-Order Actuator Dynamics And Linear Controller For A Bio-Inspired Rotating Empennage Fighter Aircraft, Benjamin C. Moulton, Matthew W. Harris, Douglas F. Hunsaker, James J. Joo
Evaluation Of First-Order Actuator Dynamics And Linear Controller For A Bio-Inspired Rotating Empennage Fighter Aircraft, Benjamin C. Moulton, Matthew W. Harris, Douglas F. Hunsaker, James J. Joo
Mechanical and Aerospace Engineering Student Publications and Presentations
This paper considers the problem of stabilizing a bio-inspired fighter aircraft variant at its Air Combat Maneuver Condition. The aircraft equations of motion are linearized, and an infinite-horizon linear quadratic regulator design is conducted for this aircraft. Included in the dynamics are first-order actuator models, which have the effect of slowing actuator responses. This is particularly important for the bio-inspired variant because it requires rotation of the empennage, which has relatively large inertia. The bio-inspired variant open-loop system is unstable in the short period and Dutch roll modes, which is mitigated in the closed-loop system. Monte Carlo simulation responses to …
On The History And Semantics Of Burble In Aerodynamic Theory, Benjamin C. Moulton, Cory D. Goates, Troy A. Abraham
On The History And Semantics Of Burble In Aerodynamic Theory, Benjamin C. Moulton, Cory D. Goates, Troy A. Abraham
Mechanical and Aerospace Engineering Student Publications and Presentations
The term burble has been in use in aerodynamic theory for over a century. While burble may be unfamiliar to most contemporary aerodynamicists, the word has a rich history based in aerodynamic theory and experimentation. The present paper outlines the fluidity of burble's meaning over time. From analyzing subsonic flow over an airfoil, to the implementation of stochastic turbulence in aircraft carrier landing simulations, the term burble has had a significant impact on the study of aerodynamics. The term burble has fallen out of use in aerodynamic engineering circles. Why did this happen? And what can be learned from the …