The Cal Poly SLO Turbo-Prop Racer project aims to design a world speed record-breaking aircraft, capable of flying more than 550 miles per hour on a 3-kilometer closed course. To further this endeavor, this thesis presents the calculations of load distributions across the aircraft’s wing and tail and preliminary structural estimates of primary structural components for verification of the loads calculations and for use in a future finite element model. The aircraft’s fundamental design characteristics effect on the structure of the aircraft, namely the unique Y-tail design, are first examined. Then, loads are calculated in accordance with the regulation dictated by CS-23. Maneuvering loads, gust loads, ground loads, and engine loads are calculated through the Vortex-Lattice Method and CS-23 to provide input for detailed structural analysis. Structural thickness estimates are found using simplified analytical stress analysis. The wing and tail’s primary spars’ spar-caps and shear-webs, the wing and tail skins, and the rear fuselage are all calculated. The loads and thicknesses found are shown to be within order of reason and to support the fundamental design characteristics of the aircraft, pushing the project to continue toward its goal.

The structural design of flight vehicles is a balancing act between maximizing loading capability while minimizing weight. An engineer must consider not only the classical static structural yielding failure of a vehicle, but a variety of ways in which structural deformations can in turn, affect the loading conditions driving those deformations. Lift redistribution, divergence, and flutter are exactly such dynamic aeroelastic phenomena that must be properly characterized during the design of a vehicle; to do otherwise is to risk catastrophe. Relevant within the university context is the design of small-scale aircraft for student projects and of particular consideration, the DBF competition hosted by AIAA. This work implements a variety of aeroelastic analysis methods: K and PK with Theodorsen aerodynamics via Matlab, NASA EZASE, and the FEMAP NX NASTRAN Aeroelasticity Package. These techniques are applied to a number of baseline test cases in addition to two representative DBF wings. Both wings considered ultimately indicated stability within reasonable flight conditions, although each for a different reason. Analysis results for the Cal Poly 2020 wing, a spar-rib construction emblematic of the collocation design approach, showed that the wing was stable within expected flight regions. The USC 2020 wing model, a composite top spar construction, exhibited unstable behavior, however this was well outside the scope of expected flight conditions. The codebase developed as a part of this work will serve as a foundation for future student teams to perform aeroelastic analyses of their own and support continued aeroelastic research at Cal Poly - SLO.

As the demand for air transportation is projected to increase, the environmental impacts produced by air travel will also increase. In order to counter the environmental impacts while also meeting the demand for air travel, there are goals and research initiatives that aim to develop more efficient aircraft. An emerging technology that supports these goals is the application of hybrid propulsion to aircraft, but there is a challenge in effectively exploring the performance of hybrid aircraft due to the time and money required for safe flight testing and due to the diverse design space of hybrid architectures and components. Therefore, computational tools that are capable of simulating the performance of a hybrid aircraft are incredibly useful in the design process and research space. Existing work on the simulation of hybrid aircraft focuses on modelling a specific hybrid propulsion system in a particular airframe, but it would be desirable to have a simulation tool that is not specific to one design. In this thesis, a simulation framework that can be easily configured for different types of hybrid structures and components is presented, and the simulator is validated using flight test data which demonstrates that the performance of the simulated aircraft is representative of a real aircraft. A design for a hybrid aircraft is also modelled and simulated over different flight profiles in order to study the performance of the hybrid propulsion system. Results indicate that the hybrid aircraft can be successfully simulated and demonstrate how the simulator can be used as a tool to study the best way to fly and operate a hybrid aircraft.

This thesis discusses a comparison of the differences in aerodynamic performance of wings designed with elliptical and bell-shaped lift distributions. The method uses a Standard Cirrus sailplane wing with a lift distribution associated with the induced drag benefits of an elliptical distribution (span efficiency = 0.96) as the basis of comparison. The Standard Cirrus is a standard class sailplane with 15-meter wingspan that was designed by Schempp-Hirth in 1969. This sailplane wing was modeled and analyzed in XFLR5, then validated against existing wind tunnel airfoil data, and Standard Cirrus flight test data. The root bending moment of the baseline wing was determined and used as the primary constraint in the design of two wings with bell-shaped lift distribution. These wings were modeled in XFLR5 by adjusting chord length and geometric twist respectively, and then they were studied using fixed speed lifting line analysis. Steady state cruise conditions for the Standard Cirrus sailplane were taken from the flight test data and applied for the analysis. The wing designed with chord variation posed incompatibilities with the lifting line method. The resulting planform was strongly tapered in the wingtip region and the reference chord length there was such that the software could not solve for a Reynolds number the magnitude resulting from two-dimensional airfoil analysis. However, the wing geometry provided insight into the design aspect of wings with bell-shaped lift distribution. Using chord variation to shape the lift distribution, the wing featured a 12% increase in wingspan but a 6.5% decrease in total wetted area when compared to the baseline. The results of the analysis of the wing designed with geometric twist indicate that induced drag decreased by 5% when compared to the baseline wing. The constraint on root bending moment resulted in a 12% increase in wingspan. Wetted area also increased by 14.8% over the baseline yielding an estimated 15% increase in skin friction.

This study demonstrates the applicability of using a modified application strategy of panel method to analyze low aspect ratio wings at preliminary design phases. Conventional panel methods fail to capture the leading edge vortex (LEV) that is shed by wings with low aspect ratios, typically below 2 depending on planform. This aerodynamic phenomenon contributes to a significant amount of the lift of these wings and the result is a drastic underestimation of the lift characteristics when analyzed by conventional panel method. To capture the effect of the leading edge vortex, a panel method code was used with an extended definition of the Kutta condition along portions of the leading edge inducing a vortex to shed from the leading edge and flow aft just inside the leading edge. To validate that this method, it was applied to 2 elliptical planforms with constant thickness where experimental force balance data was available. Additionally, the same 2 wings were analyzed using a finite volume solver to compare pressure distributions and to demonstrate the difference in magnitude of solution times. For comparison purposes, the resulting forces and moments from both computational methods and experimental testing were plotted over a range of angles of attack. Overall, the results demonstrate that a modified panel method could be used during the preliminary design phases for low aspect ratio wings. The panel method can reasonably model the lift and induced drag characteristics of low aspect ratio wings. This method loses applicability beyond the stall point where the leading edge vortex breaks down and oversimplifies pitching moment relation to angle of attack. Additionally, when compared to finite volume solutions of the same scenario, the panel method provided a result 20 to 30 times faster than the finite volume solutions. With this in mind, the modified panel method application strategy lends itself to preliminary design phases of low aspect ratio wings where the level of detail does not warrant finite volume analysis and solution speed has higher priority.

Thesis: Sc. D., Massachusetts Institute of Technology. Department of Aeronautical Engineering, 1916. / MIT Institue Archives Thesis Coll.: copy is the Smithsoniam Institution publication. / Publication 2414. Hodgkins fund. Originaly prepared by Hunsaker as his Eng. D. Thesis, Massachusetts Institute of Technology, Dept. of Aeronautical Engineering, 1916. According to the MIT Registrar's Office, this degree was changed to an Sc.D., 1923 June 12. Original thesis did not contain the three plates. / by Jerome C. Hunsaker ... assisted by T. H. Huff, S. B., D. W. Douglas, S. B., H. K. Chow, S. M., and V. E. Clark. / Sc. D.

The two-antenna problem in aeronautical mobile telemetry is created by the reception of two copies of the same RF waveform with different phases and time delays. Alamouti and Alamouti-like space time block codes can solve the two-antenna problem, but the decoder/detector needs to account for the different time delays between the signals received from the two transmit antennas. In this thesis, a comparison is made between the performance of Alamouti space-time block codes and time-reversed space-time block codes with 16-APSK to solve the two-antenna problem. The maximum likelihood decoder/detector for Alamouti-encoded 16-APSK is a sequence detector operating on a trellis with a large number of states. A practical state-reduction technique is presented. The results produce a trellis with 256 states and a small loss in bit error rate performance as long as the delay difference is not too big. The decoder/detector for the time-reversed space time block requires only waveform manipulations and channel matched filtering in the case where the two channels are simple delays. For the more general case of multipath propagation between the two transmit antennas and the receiver, the decoder/detector requires an equalizer; simulation results using a channel pair measured at a test range show that the decoder/detector is capable of achieving near AWGN performance with a modest equalizer.

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This study was designed to examine the experiences of a small group of Black males in a college of aeronautical science, a major traditionally dominated by White males. The study also considered the differences in how African American males and Caribbean black males perceived and acted upon the same experiences. Through a social learning theoretical approach, the study examined the relevant factors, processes, and experiences involved in these Black males' choice of aeronautical science as a major and piloting as a career. Eleven (11) persisters and 4 non-persisters participated in the study, which centered around a premier aeronautical university in the southeastern part of the United States. Questions guiding the study were: (1) What experiences have been influential in a small group of Black males' selection of aeronautical science as a major, piloting as a career? (2) What factors outside of and previous to the collegial environment contribute to (and detract from) persistence in pursuit of completion of a major in piloting? (3) What factors in the collegial and occupational environment contribute to persistence in a major in piloting? (4) How do patterns of persistence compare for these Black males at a college of aeronautical science? Qualitative methodology included both individual in-depth interviews and small focus groups. Participants were recruited through both purposive and snowball samplings as well as volunteering. Criteria for persisters were Black male former aviation students who had already graduated with an aeronautical science degree and pursuing a career as a pilot or Black male students currently enrolled as juniors and seniors, in good academic standing. Non-persisters in this study were Black males who left their aeronautical science major prior to completion. Findings clearly indicated that a number of factors, such as family, individual, social, and environmental, influenced this small group of Black males' persistence in aeronautical science. Additionally, this study attempted to ascertain the differences and similarities in perceptions and experiences among African American and Caribbean black males. The Caribbean black males in this study did not perceive their race as having a negative impact on their persistence, whereas most of the African American male participants felt their race was a contributing factor to their non-persistence. This study provided the groundwork for the development of a conceptual model of academic persistence with implications for recruiting, retaining, and graduating Black males from a college of aeronautical science. / Ph. D.

No / Fault management is one of the important management functions of a telecommunication network and mainly deals with fault monitoring and diagnosis. This paper applies reliability theories and methodologies for the fault management of an aeronautical communication system developed within the EU FP7 SANDRA project. The failure of the SANDRA terminal demonstrator is an undesirable event and the corresponding fault tree was built upon a reliability function analysis and was used to quickly monitor failures in the system. By using Monte Carlo simulations, the SANDRA demonstrator's reliability can be predicted and important components, which have major contributions to system failures, can be identified. The results can be used to improve the system reliability by adding parallel components in weak and important places.