The Experts below are selected from a list of 123 Experts worldwide ranked by ideXlab platform
Pedro Gamboa - One of the best experts on this subject based on the ideXlab platform.
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Aircraft Propellers is there a future
Energies, 2020Co-Authors: Pedro Alves, Miguel Silvestre, Pedro GamboaAbstract:The race for speed ruled the early Jet Age on aviation. Aircraft manufacturers chased faster and faster planes in a fight for pride and capability. In the early 1970s, dreams were that the future would be supersonic, but fuel economy and unacceptable noise levels made that era never happen. After the 1973 oil crisis, the paradigm changed. The average cruise speed on newly developed Aircraft started to decrease in exchange for improvements in many other performance parameters. At the same pace, the airliner’s power-plants are evolving to look more like a ducted turboprop, and less like a pure jet engine as the pursuit for the higher bypass ratios continues. However, since the birth of jet Aircraft, the propeller-driven plane has lost its dominant place, associated with the idea that going back to propeller-driven airplanes, and what it represents in terms of modernity and security, has started a propeller avoidance phenomenon with travelers and thus with airlines. Today, even with the modest research effort since the 1980s, advanced Propellers are getting efficiencies closer to jet-powered engines at their contemporary typical cruise speeds. This paper gives a brief overview of the performance trends in aviation since the last century. Comparison examples between Aircraft designed on different paradigms are presented. The use of Propellers as a reborn propulsive device is discussed.
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Aircraft Propellers—Is There a Future?
Energies, 2020Co-Authors: Pedro Alves, Miguel Silvestre, Pedro GamboaAbstract:The race for speed ruled the early Jet Age on aviation. Aircraft manufacturers chased faster and faster planes in a fight for pride and capability. In the early 1970s, dreams were that the future would be supersonic, but fuel economy and unacceptable noise levels made that era never happen. After the 1973 oil crisis, the paradigm changed. The average cruise speed on newly developed Aircraft started to decrease in exchange for improvements in many other performance parameters. At the same pace, the airliner’s power-plants are evolving to look more like a ducted turboprop, and less like a pure jet engine as the pursuit for the higher bypass ratios continues. However, since the birth of jet Aircraft, the propeller-driven plane has lost its dominant place, associated with the idea that going back to propeller-driven airplanes, and what it represents in terms of modernity and security, has started a propeller avoidance phenomenon with travelers and thus with airlines. Today, even with the modest research effort since the 1980s, advanced Propellers are getting efficiencies closer to jet-powered engines at their contemporary typical cruise speeds. This paper gives a brief overview of the performance trends in aviation since the last century. Comparison examples between Aircraft designed on different paradigms are presented. The use of Propellers as a reborn propulsive device is discussed.
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Aircraft Propellers, an Outdated Innovation?
KnE Engineering, 2020Co-Authors: Pedro Alves, Miguel Silvestre, Pedro GamboaAbstract:The race for speed ruled the early Jet Age on aviation. Aircraft manufacturers chased faster and faster planes in a fight for pride and capability. In the early 1970s, dreamed that the future would be supersonic, but fuel economy and not acceptable noise levels made that era never came. After the 1973 first oil crisis, the paradigm changed. The average cruise speed on newly developed Aircraft started to decrease in exchange for improvements in many other performance parameters. At the same pace, the airliner’s powerplants are evolving to look more like a ducted turboprop, and less like a pure jet engine as the pursuit for the higher bypass ratios continues. However, since the birth of jet Aircraft, the propeller-driven plane lost its dominant place in the market. Associated with the idea of going back to propeller-driven airplanes, and what it represented in terms of modernity and security, it started a propeller avoidance phenomenon on the travelers and thus on the airlines. Today, even with the modest research effort since the 1980s, the advanced Propellers are getting closer efficiencies to the jet-powered engines at their contemporary typical cruise speeds. This paper gives a brief overview of the performance trends in aviation since the last century. Comparison examples between Aircraft designed on different paradigms are presented. The use of Propellers as a reborn propulsive device is discussed. Keywords: Propeller, Aircraft, Turboprop, Flight efficiency, Flight speed
Pedro Alves - One of the best experts on this subject based on the ideXlab platform.
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Aircraft Propellers is there a future
Energies, 2020Co-Authors: Pedro Alves, Miguel Silvestre, Pedro GamboaAbstract:The race for speed ruled the early Jet Age on aviation. Aircraft manufacturers chased faster and faster planes in a fight for pride and capability. In the early 1970s, dreams were that the future would be supersonic, but fuel economy and unacceptable noise levels made that era never happen. After the 1973 oil crisis, the paradigm changed. The average cruise speed on newly developed Aircraft started to decrease in exchange for improvements in many other performance parameters. At the same pace, the airliner’s power-plants are evolving to look more like a ducted turboprop, and less like a pure jet engine as the pursuit for the higher bypass ratios continues. However, since the birth of jet Aircraft, the propeller-driven plane has lost its dominant place, associated with the idea that going back to propeller-driven airplanes, and what it represents in terms of modernity and security, has started a propeller avoidance phenomenon with travelers and thus with airlines. Today, even with the modest research effort since the 1980s, advanced Propellers are getting efficiencies closer to jet-powered engines at their contemporary typical cruise speeds. This paper gives a brief overview of the performance trends in aviation since the last century. Comparison examples between Aircraft designed on different paradigms are presented. The use of Propellers as a reborn propulsive device is discussed.
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Aircraft Propellers—Is There a Future?
Energies, 2020Co-Authors: Pedro Alves, Miguel Silvestre, Pedro GamboaAbstract:The race for speed ruled the early Jet Age on aviation. Aircraft manufacturers chased faster and faster planes in a fight for pride and capability. In the early 1970s, dreams were that the future would be supersonic, but fuel economy and unacceptable noise levels made that era never happen. After the 1973 oil crisis, the paradigm changed. The average cruise speed on newly developed Aircraft started to decrease in exchange for improvements in many other performance parameters. At the same pace, the airliner’s power-plants are evolving to look more like a ducted turboprop, and less like a pure jet engine as the pursuit for the higher bypass ratios continues. However, since the birth of jet Aircraft, the propeller-driven plane has lost its dominant place, associated with the idea that going back to propeller-driven airplanes, and what it represents in terms of modernity and security, has started a propeller avoidance phenomenon with travelers and thus with airlines. Today, even with the modest research effort since the 1980s, advanced Propellers are getting efficiencies closer to jet-powered engines at their contemporary typical cruise speeds. This paper gives a brief overview of the performance trends in aviation since the last century. Comparison examples between Aircraft designed on different paradigms are presented. The use of Propellers as a reborn propulsive device is discussed.
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Aircraft Propellers, an Outdated Innovation?
KnE Engineering, 2020Co-Authors: Pedro Alves, Miguel Silvestre, Pedro GamboaAbstract:The race for speed ruled the early Jet Age on aviation. Aircraft manufacturers chased faster and faster planes in a fight for pride and capability. In the early 1970s, dreamed that the future would be supersonic, but fuel economy and not acceptable noise levels made that era never came. After the 1973 first oil crisis, the paradigm changed. The average cruise speed on newly developed Aircraft started to decrease in exchange for improvements in many other performance parameters. At the same pace, the airliner’s powerplants are evolving to look more like a ducted turboprop, and less like a pure jet engine as the pursuit for the higher bypass ratios continues. However, since the birth of jet Aircraft, the propeller-driven plane lost its dominant place in the market. Associated with the idea of going back to propeller-driven airplanes, and what it represented in terms of modernity and security, it started a propeller avoidance phenomenon on the travelers and thus on the airlines. Today, even with the modest research effort since the 1980s, the advanced Propellers are getting closer efficiencies to the jet-powered engines at their contemporary typical cruise speeds. This paper gives a brief overview of the performance trends in aviation since the last century. Comparison examples between Aircraft designed on different paradigms are presented. The use of Propellers as a reborn propulsive device is discussed. Keywords: Propeller, Aircraft, Turboprop, Flight efficiency, Flight speed
Miguel Silvestre - One of the best experts on this subject based on the ideXlab platform.
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Aircraft Propellers is there a future
Energies, 2020Co-Authors: Pedro Alves, Miguel Silvestre, Pedro GamboaAbstract:The race for speed ruled the early Jet Age on aviation. Aircraft manufacturers chased faster and faster planes in a fight for pride and capability. In the early 1970s, dreams were that the future would be supersonic, but fuel economy and unacceptable noise levels made that era never happen. After the 1973 oil crisis, the paradigm changed. The average cruise speed on newly developed Aircraft started to decrease in exchange for improvements in many other performance parameters. At the same pace, the airliner’s power-plants are evolving to look more like a ducted turboprop, and less like a pure jet engine as the pursuit for the higher bypass ratios continues. However, since the birth of jet Aircraft, the propeller-driven plane has lost its dominant place, associated with the idea that going back to propeller-driven airplanes, and what it represents in terms of modernity and security, has started a propeller avoidance phenomenon with travelers and thus with airlines. Today, even with the modest research effort since the 1980s, advanced Propellers are getting efficiencies closer to jet-powered engines at their contemporary typical cruise speeds. This paper gives a brief overview of the performance trends in aviation since the last century. Comparison examples between Aircraft designed on different paradigms are presented. The use of Propellers as a reborn propulsive device is discussed.
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Aircraft Propellers—Is There a Future?
Energies, 2020Co-Authors: Pedro Alves, Miguel Silvestre, Pedro GamboaAbstract:The race for speed ruled the early Jet Age on aviation. Aircraft manufacturers chased faster and faster planes in a fight for pride and capability. In the early 1970s, dreams were that the future would be supersonic, but fuel economy and unacceptable noise levels made that era never happen. After the 1973 oil crisis, the paradigm changed. The average cruise speed on newly developed Aircraft started to decrease in exchange for improvements in many other performance parameters. At the same pace, the airliner’s power-plants are evolving to look more like a ducted turboprop, and less like a pure jet engine as the pursuit for the higher bypass ratios continues. However, since the birth of jet Aircraft, the propeller-driven plane has lost its dominant place, associated with the idea that going back to propeller-driven airplanes, and what it represents in terms of modernity and security, has started a propeller avoidance phenomenon with travelers and thus with airlines. Today, even with the modest research effort since the 1980s, advanced Propellers are getting efficiencies closer to jet-powered engines at their contemporary typical cruise speeds. This paper gives a brief overview of the performance trends in aviation since the last century. Comparison examples between Aircraft designed on different paradigms are presented. The use of Propellers as a reborn propulsive device is discussed.
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Aircraft Propellers, an Outdated Innovation?
KnE Engineering, 2020Co-Authors: Pedro Alves, Miguel Silvestre, Pedro GamboaAbstract:The race for speed ruled the early Jet Age on aviation. Aircraft manufacturers chased faster and faster planes in a fight for pride and capability. In the early 1970s, dreamed that the future would be supersonic, but fuel economy and not acceptable noise levels made that era never came. After the 1973 first oil crisis, the paradigm changed. The average cruise speed on newly developed Aircraft started to decrease in exchange for improvements in many other performance parameters. At the same pace, the airliner’s powerplants are evolving to look more like a ducted turboprop, and less like a pure jet engine as the pursuit for the higher bypass ratios continues. However, since the birth of jet Aircraft, the propeller-driven plane lost its dominant place in the market. Associated with the idea of going back to propeller-driven airplanes, and what it represented in terms of modernity and security, it started a propeller avoidance phenomenon on the travelers and thus on the airlines. Today, even with the modest research effort since the 1980s, the advanced Propellers are getting closer efficiencies to the jet-powered engines at their contemporary typical cruise speeds. This paper gives a brief overview of the performance trends in aviation since the last century. Comparison examples between Aircraft designed on different paradigms are presented. The use of Propellers as a reborn propulsive device is discussed. Keywords: Propeller, Aircraft, Turboprop, Flight efficiency, Flight speed
S. Pica - One of the best experts on this subject based on the ideXlab platform.
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DIRECT COMPARISON OF FSI OPTIMIZED THEODORSEN AND LARRABEE Propellers
2015Co-Authors: Luca Piancastelli, A. Castagnoli, Leonardo Frizziero, Giampiero Donnici, S. PicaAbstract:The goal of this study is the analysis of the design process of Aircraft Propellers which are coupled to a piston engine, aiming to find the best design approach. The first design step is the calculation of the initial geometry. This phase is particularly critical since it will affect the following optimization. Several theories for blade design have been proposed during the years. The most popular are the Larrabee's procedure and the Theodorsen's theory. The Larrabee theory is the most used in recent years, while the Theodorsen was most popular in the WWII era. This work focuses on the differences on the results of the two approaches for a general aviation propeller for light Aircrafts. For this aerial vehicle category both the strength and efficiency should be considered, since the production technology cannot be as refined as for larger Propellers. As it will be seen, the subsonic nature of these aerial vehicles makes it possible to use both initial design approaches. In a second phase, the evaluation of the effect of aerodynamics and centrifugal loads requires the union of the results that come from CFD (Computational Fluid Dynamics) and the ones come from the CSM (Computational Structural Mechanics), through the execution of several one way FSI (Fluid Structure Interaction) analyses. However the starting point proved to be critical for the final result. The Larrabee procedure proves to be ideal for high speed Aircraft Propellers manufactured with up-to-date materials and procedures. The “old” Theodorsen theory leads to a stronger blade that can be easily manufactured with wood or simplified technologies. The Theodorsen blade is superior for the centrifugal load bearing capacity. This geometry leads to lighter blades. The efficiency of the Larrabee blade seems to be superior. However, experience proved that the CFD analysis can be tricky and unreliable for efficiency evaluation. The pressures are better distributed along the Larrabee’s blade with better results at high airspeed. Eventually two geometrically optimized blades have been designed, which have a deformed shape (at cruise conditions) similar to the best aerodynamic geometry and comparable technological characteristics. The Larrabee and Theodorsen designs lead to different optimized blades even after the FSI simulation, demonstrating that the optimization procedure is largely influenced by the initial propeller blade design.
Pica S. - One of the best experts on this subject based on the ideXlab platform.
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Direct comparison of fsi optimized theodorsen and larrabee Propellers
2015Co-Authors: Piancastelli L., Frizziero L., Castagnoli A., Donnici G., Pica S.Abstract:The goal of this study is the analysis of the design process of Aircraft Propellers which are coupled to a piston engine, aiming to find the best design approach. The first design step is the calculation of the initial geometry. This phase is particularly critical since it will affect the following optimization. Several theories for blade design have been proposed during the years. The most popular are the Larrabee's procedure and the Theodorsen's theory. The Larrabee theory is the most used in recent years, while the Theodorsen was most popular in the WWII era. This work focuses on the differences on the results of the two approaches for a general aviation propeller for light Aircrafts. For this aerial vehicle category both the strength and efficiency should be considered, since the production technology cannot be as refined as for larger Propellers. As it will be seen, the subsonic nature of these aerial vehicles makes it possible to use both initial design approaches. In a second phase, the evaluation of the effect of aerodynamics and centrifugal loads requires the union of the results that come from CFD (Computational Fluid Dynamics) and the ones come from the CSM (Computational Structural Mechanics), through the execution of several one way FSI (Fluid Structure Interaction) analyses. However the starting point proved to be critical for the final result. The Larrabee procedure proves to be ideal for high speed Aircraft Propellers manufactured with up-to-date materials and procedures. The "old" Theodorsen theory leads to a stronger blade that can be easily manufactured with wood or simplified technologies. The Theodorsen blade is superior for the centrifugal load bearing capacity. This geometry leads to lighter blades. The efficiency of the Larrabee blade seems to be superior. However, experience proved that the CFD analysis can be tricky and unreliable for efficiency evaluation. The pressures are better distributed along the Larrabee's blade with better results at high airspeed. Eventually two geometrically optimized blades have been designed, which have a deformed shape (at cruise conditions) similar to the best aerodynamic geometry and comparable technological characteristics. The Larrabee and Theodorsen designs lead to different optimized blades even after the FSI simulation, demonstrating that the optimization procedure is largely influenced by the initial propeller blade design. © 2006-2015 Asian Research Publishing Network (ARPN)