An Examination of the Propulsion System for the Compound Helicopter

1967 ◽  
Author(s):  
Lester B. Veno
Keyword(s):  
Direct Effect ◽  
Weight Ratio ◽  
Hybrid Vehicle ◽  
Propulsion System ◽  
Design Parameters ◽  
Power Weight ◽  
Future Performance ◽  
Performance Analyses ◽  
Compound Helicopter ◽  
Engine Power

The various design parameters which affect the performance versus speed of the compound helicopter are studied, such as disk loading, solidity, and tip speed schedule. Additional variables which are part of the compound design, such as propeller diameter, wing lift, and equivalent drag, are similarly studied. The interrelationship of each parameter is shown in terms of the total lift/propulsive power required. The study further presumes a fixed mission requirement against which each parameter is evaluated and optimized based on proper sizing and fuel usage. The study includes the direct effect of engine power/weight ratio and SFC. The paper lays a foundation for future performance analyses of this hybrid vehicle.

Low Velocity Impact Response of Composite/Sandwich Structures

2016 ◽  
Vol 725 ◽  
pp. 127-131 ◽  
Author(s):  
Kumar V. Akshaj ◽  
P. Surya ◽  
M.K. Pandit
Keyword(s):  
Sandwich Structures ◽  
Weight Ratio ◽  
Impact Response ◽  
Low Velocity Impact ◽  
Core Material ◽  
Design Parameters ◽  
Low Velocity ◽  
Velocity Impact ◽  
Composite Sandwich ◽  
Set Up

Dent resistance of structures is one of the important design parameters to consider in automotive, aerospace, packaging and transportation of fragile goods, civil engineering and marine industries. It is important to study the dynamic impact response of various combinations of skin and core materials which can provide desired fracture toughness and highest strength to weight ratio for such applications. This paper discusses the low velocity impact response of sandwich structures having unique combination of mild steel as skin material bonded to thermoplastics/PU foam as core material. HDPE, LDPE and polypropylene were the choice of thermoplastics and an optimum combination of materials for the sandwich structure was evaluated using drop-weight experimental set up. It is observed that LDPE is the best choice of core material for the sandwich structures considered.

Research on Parameters Matching of Ultralight Electric Aircraft Propulsion System

2013 ◽  
Vol 732-733 ◽  
pp. 1212-1215
Author(s):  
Gui Wen Kang ◽  
Yu Hu ◽  
Ya Dong Li ◽  
Wen Hui Jiang
Keyword(s):  
Electric Propulsion ◽  
High Energy ◽  
Low Noise ◽  
Electric Power System ◽  
Propulsion System ◽  
Heat Radiation ◽  
Design Parameters ◽  
Electric Propulsion System ◽  
Electric Aircraft ◽  
Parameter Matching

The propulsion system of ultralight electric aircraft is one of the general aviation technology development directions. It has the advantages such as light pollution, low noise, high energy utilization ratio, simple structure, easy maintenance, high reliability, less heat radiation, little operation cost and so on. Combined with the certain type of ultralight aircraft design parameters, the layout of aircraft electric propulsion, the principles and steps of the parameter matching of electric propulsion system were presented. The method of parameter matching and performance verification of electric propulsion system was put forward. The feasibility of the system is verified from the point of dynamic property. The study of parameter matching of electric propulsion system could not only provide basis for the integrated optimization for electric power system, but also evaluate the performance of the system simulation as reference.

Experimental and Numerical Investigation on Radial Stiffness of Origami-inspired Tubular Structures

2021 ◽  
pp. 1-30
Author(s):  
Weijun Shen ◽  
Yang Cao ◽  
Xuepeng Jiang ◽  
Zhan Zhang ◽  
Gül E. Okudan Kremer ◽  
...  
Keyword(s):  
Circular Tube ◽  
Weight Ratio ◽  
Design Parameters ◽  
Thin Wall ◽  
Tubular Structures ◽  
Compression Tests ◽  
Element Analysis ◽  
Radial Stiffness ◽  
Paper Folding ◽  
Engineering Problems

Abstract Origami structures, which were inspired by traditional paper folding arts, have been applied for engineering problems for the last two decades. Origami-based thin-wall tubes have been extensively investigated under axial loadings. However, less has been done with radial stiffness as one of the critical mechanical properties of a tubular structure working under lateral loadings. In this study, the radial stiffness of novel thin-wall tubular structures based on origami patterns have been studied with compression tests and finite element analysis (FEA) simulations. The results show that the radial stiffness of an origami-inspired tube can achieve about 27.1 times that of a circular tube with the same circumcircle diameter (100 mm), height (60 mm), and wall-thickness (2 mm). Yoshimura, Kresling, and modified Yoshimura patterns are selected as the basic frames, upon which the influences of different design parameters are tested and discussed. Given that the weight can vary due to different designs, the stiffness-to-weight ratio is also calculated. The origami-inspired tubular structures with superior stiffness performances are obtained and can be extended to crashworthy structures, functional structures, and stiffness enhancement with low structural weight.

An HCCI Engine: Power Plant for a Hybrid Vehicle

2004 ◽  
Author(s):  
Ruonan Sun ◽  
Rick Thomas ◽  
Charles L. Gray
Keyword(s):  
Power Plant ◽  
Hybrid Vehicle ◽  
Hcci Engine ◽  
Engine Power

An adaptive Dendrite-HDMR metamodeling technique for high dimensional problems

2022 ◽  
pp. 1-38
Author(s):  
Qi Zhang ◽  
Yizhong Wu ◽  
Li Lu ◽  
Ping Qiao
Keyword(s):  
Adaptive Sampling ◽  
Clustering Algorithm ◽  
Learning Algorithm ◽  
Weight Ratio ◽  
Propulsion System ◽  
High Dimensional ◽  
High Dimensional Model Representation ◽  
K Nearest Neighbor ◽  
Metamodeling Technique ◽  
Explicit Expressions

Abstract High dimensional model representation (HDMR), decomposing the high-dimensional problem into summands of different order component terms, has been widely researched to work out the dilemma of “curse-of-dimensionality” when using surrogate techniques to approximate high-dimensional problems in engineering design. However, the available one-metamodel-based HDMRs usually encounter the predicament of prediction uncertainty, while current multi-metamodels-based HDMRs cannot provide simple explicit expressions for black-box problems, and have high computational complexity in terms of constructing the model by the explored points and predicting the responses of unobserved locations. Therefore, aimed at such problems, a new stand-alone HDMR metamodeling technique, termed as Dendrite-HDMR, is proposed in this study based on the hierarchical Cut-HDMR and the white-box machine learning algorithm, Dendrite Net. The proposed Dendrite-HDMR not only provides succinct and explicit expressions in the form of Taylor expansion, but also has relatively higher accuracy and stronger stability for most mathematical functions than other classical HDMRs with the assistance of the proposed adaptive sampling strategy, named KKMC, in which k-means clustering algorithm, k-Nearest Neighbor classification algorithm and the maximum curvature information of the provided expression are utilized to sample new points to refine the model. Finally, the Dendrite-HDMR technique is applied to solve the design optimization problem of the solid launch vehicle propulsion system with the purpose of improving the impulse-weight ratio, which represents the design level of the propulsion system.

Inlet Duct-Engine Exhaust Nozzle Airflow Matching for the Supersonic Transport

1968 ◽  
Vol 72 (690) ◽  
pp. 490-497
Author(s):  
J. B. Taylor
Keyword(s):  
Propulsion System ◽  
Operating Conditions ◽  
Design Parameters ◽  
Gas Generator ◽  
Propulsion Systems ◽  
Engine Exhaust ◽  
Supersonic Transport ◽  
Reliable Performance ◽  
Jet Nozzle ◽  
Secondary Air

Propulsion systems selected for commercial transports must provide efficient and reliable performance over a broad range of conditions. These aeroplanes are used over both short and long route segments, on non-standard days, and at a range of altitudes to meet air-line schedule requirements. This paper covers some of the design parameters that were considered in the integration of the induction system, secondary air system, jet nozzle and the basic turbojet gas generator for the SST. During recent years some of the most important gains in propulsion efficiency have resulted from the development of inlets, engines and exhaust nozzles which are matched over a broad range of operating conditions. An efficient propulsion system for a supersonic transport depends upon very close matching of these components. This, of course, requires a better understanding of the capabilities and limitations of each of these major components. For the supersonic transport, 50% or more of the gross weight will be comprised of propulsion system and fuel and less than 10% will be payload.

Performance of the Air-Cushion–Surface-Contacting Hybrid Vehicle for Overland Operation

1972 ◽  
Vol 186 (1) ◽  
pp. 613-623
Author(s):  
J-Y. Wong
Keyword(s):  
Power Consumption ◽  
Load Distribution ◽  
Road Transport ◽  
Hybrid Vehicle ◽  
Considerable Effect ◽  
Control Device ◽  
Design Parameters ◽  
Optimum Load ◽  
Air Cushion ◽  
Cross Country

The air-cushion concept has been considered for application to off-road transport ever since the early days of its development. Recently, the rapid increase in resource exploration and exploitation in remote areas has stimulated new interest in applying air-cushion technology to overland transportation. It appears to offer solutions to a wide variety of cross-country transportation problems. Although existing vehicles fully supported by an air cushion can function overland, experience to date indicates that considerable improvements in controllability and manoeuvrability are required for continuous overland operation. One practical solution is to provide some degree of surface contact. The feasibility of an air-cushion–surface-contacting hydrid vehicle has been demonstrated by the Benin Terra-plane BC7, Vickers-Armstrongs Hovertruck, etc. However, the operating performance, capabilities and limitations of this type of vehicle have not been investigated in a systematic way. This paper attempts to provide a theoretical basis for evaluating and optimizing the performance and design of the hybrid vehicle. The basic power requirements of this type of vehicle are first analysed and compared with those of the fully-air-cushion-supported vehicle. The approaches to minimizing the power consumption and to improving the economics of operation are then investigated. It is found that among other design parameters, the load distribution between the air-cushion and the ground-contacting gear of the hybrid vehicle has a considerable effect on its power requirements. For a given vehicle in a particular type of terrain, there is an optimum load distribution which minimizes the power consumption. Finally, an analytical approach to evaluating and predicting the controllability and mobility of this kind of vehicle is discussed. It is found that using the wheel as a yaw-control device for the hybrid vehicle is quite effective. It is also shown that wheeled propulsion has limitations in cross-country operation. In order to provide the hybrid vehicle with adequate off-road mobility, an auxiliary air propulsive system appears to be necessary.

A 6-DOF Ship-Borne Antenna Platform With Large Orientation Workspace

2020 ◽  
Author(s):  
Yuhang He ◽  
Weijia Li ◽  
Yaozhong Wu ◽  
Jinbo Wu ◽  
Zhiyuan Cheng
Keyword(s):  
Particle Swarm Optimization ◽  
Particle Swarm ◽  
Weight Ratio ◽  
Stewart Platform ◽  
Design Parameters ◽  
Parallel Mechanisms ◽  
Swarm Optimization ◽  
Pitch Range ◽  
Orientation Workspace ◽  
Load Weight

Abstract Compared with traditional antenna platform with two axes, Stewart platform can search airspace with no tracking blind district. And the advantages of high accuracy, high stiffness and high load-weight ratio also make it be a better solution for antenna platforms. This paper designed a 6-DOF ship-borne antenna platform based on the Stewart platform to overcome the difficulties that to realize a large orientation workspace (azimuth range is from 0° to 360°, pitch range is from 0° to 100°) under the compact dimensions of parallel mechanisms. A novel joint structure has been proposed which can provide a larger rotation angle than common Hooke joints to realize the large orientation workspace without the inter-mechanism interference. In addition, this paper defined the concept of working height and working radius then proposed a trajectory based on that to obtain the complete pose (translation and orientation) of antenna platform by azimuth and pitch angles. After that, the particle swarm optimization algorithm is employed to seek the optimal geometrical design parameters. A prototype of the 6-DOF ship-borne antenna platform adopted the particle swarm optimization results has been constructed. And the results show that it not noly meets the design requirements, but also provides a good performance.

Hardware Structures for High Precision Pneutronic Systems

2014 ◽  
Vol 658 ◽  
pp. 541-546 ◽  
Author(s):  
Mihai Avram ◽  
Victor Constantin ◽  
Constantin Bucşan ◽  
Daniel Besnea ◽  
Alina Spanu
Keyword(s):  
High Precision ◽  
Weight Ratio ◽  
Nonlinear Behavior ◽  
Compressed Air ◽  
Power Weight ◽  
Precision Positioning ◽  
Positioning Accuracy ◽  
Large Power ◽  
Pneumatic Actuators ◽  
Positioning Systems

Pneutronic systems come with a series of advantages that are natural to working with compressed air, such as the large power/weight ratio of pneumatic actuators, easy and affordable installation and maintenance as well as being clean working systems. However, due to working with compressed air, there are a series of issues, such as static and transient nonlinear behavior, mostly due to the high compressibility of air. Thus, the behavior of such systems is hard to control, especially in terms of precision positioning. The paper deals with proposing three hardware configurations of pneutronic positioning systems in order to assure the imposed positioning accuracy in the presence of disturbances and the preservation in time of the obtained position.

Sign in / Sign up

Export Citation Format

Share Document