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The influence of a large truck on the aerodynamics of a small passenger car in an overtaking manoeuvre on the motorway was considered, many years ago, during the 1970's, to be a potential problem for the vehicle aerodynamicist. The concern never became significant as vehicle architecture evolved and car weights increased. The current drive for improved fuel economy is advocating that a considerable reduction in vehicle mass is desirable and therefore it may be time to readdress the significance of the truck passing manoeuvre. A quasi-steady experiment has been undertaken at small model scale to examine the aerodynamic characteristics of a small car in proximity to a large truck. Measurements at yaw were included to crudely simulate the effects of a crosswind. The wind tunnel data is presented and the limitations of the experimental procedure are discussed.

A new control strategy for wheel slip control, considering the complete dynamics of the electro-hydraulic brake (EHB) system, is developed and experimentally validated in Cranfield University's HiL system. The control system is based on closed loop shaping Youla-parameterization method. The plant model is linearized about the nominal operating point, a Youla parameter is defined for all stabilizing feedback controller and control performance is achieved by employing closed loop shaping technique. The stability and performance of the controller are investigated in frequency and time domain, and verified by experiments using real EHB smart actuator fitted into the HiL system with driver in the loop.

The A06 test facility designed for combustor testing in altitude has been modified to be converted in an icing facility for probe testing. The objective was to be able to simulate ice crystals conditions at high altitude, high Mach number and low temperature. This facility has been upgraded in several steps extending the median size of the ice crystals produced and the ice water content range. The aero-thermal and icing capabilities have been assessed during commissioning tests. Finally, in order to prepare the calibration of the facility, some measurement techniques for cloud characterization have been selected or developed, especially for cloud uniformity measurement.

The successful completion of aerospace projects usually involves the bringing together of many different specialist skills. The need for the engineer to become multidisciplined is today's reality, but this is becoming increasingly harder to achieve naturally in the working place. Recent industrial drives towards concurrent engineering have revealed a need for just this type of engineer. The 3 year part-time MSc course in Aircraft Engineering was designed to address these needs and was launched with the first intakes of delegates in 1995. The course is modular and students are encouraged to “mix” disciplines, combining topics such as avionics and structural analysis. The course has created skilled specialists and engineering leaders for the future, with improved technical ability and career potential, albeit at the cost of hard work! The course consists of 3 elements, namely:- Lecture courses held in one-week blocks, over the 3 year period. An individual piece of research.

This paper describes a computer code for conceptual design of mission optimized twin-turboprop Commuter or Regional aircraft. Optimum configurations and flight profiles of such aircraft are determined by coupling this code to an optimization code based on Simulated Annealing. As an example, minimum DOC configurations were determined for 50-seat Regional aircraft for operation over three stage lengths. The DOC per seat-nm and DOC per trip of the optimum aircraft were found to be comparable or significantly (8 to 17 %) lower than the corresponding values for five contemporary 40 to 50 seater aircraft for short stage lengths.

A modern aircraft wing contains many complex pipes and ducts which, amongst other functions, form the fuel management and bleed air systems. These parts are often fabricated from thin sheet material using a combination of forming and welding and the manufacturing process is predominantly manual requiring highly skilled labor. Since each wing may only contain one or two of each part type the product volumes are very low, typically a few hundred per year. This means that conventional mass production approaches used in, for example the automotive industry, are not economically viable and the parts are thus disproportionately expensive. The current fabrication process involves splitting the component into parts that can be press formed from sheet, laser trimmed and then manually welded together in a fixture. This process requires a perfect fit between the parts whose quality is reliant on the initial forming process.

Millimetre wave radar sensors are being actively developed for automotive applications including Intelligent Cruise Control (ICC), Collision Warning (CW), and Collision Avoidance (CA). Knowledge of the road geometry is of fundamental importance to these future intelligent automotive systems. The interest in such systems is evidenced by manufacturers now starting to incorporate radars in production luxury vehicles. Determination of the road geometry, day and night, under all weather conditions, is a challenging problem requiring both fundamental research and systems studies. Current automotive radar systems rely heavily on the use of extrapolating yaw rate data generated within the vehicle to produce a prediction of the path of the road ahead. This use of historical data is only satisfactory if the road trajectory is uniform. Sudden discontinuities in the path, such as bends, cause this method of path prediction to produce significant errors.

This study reports aerodynamic properties of two runback ice shapes molded from a mid-span full scale B737 aerofoil leading edge together with a series of simplistic ice shapes of the type sometimes used by aircraft manufacturers to mimic performance loss due to runback ice. The runback ice shapes were taken from a study of runback ice growth which had produced flexible silicone rubber moulds. These moulds were used to produce ice shapes without curvature which, together with the “simplistic” shapes were mounted on flat plates and installed into the Cranfield University 8 by 6 foot wind tunnel. A boundary layer suction system was used to match the wall conditions more closely to what would be anticipated on a real aerofoil. The icing conditions approximate to a hold case with the two shapes representing a 4 and a 10 mm thick runback shape. The aerodynamic tests have been performed with a tunnel speed of 45 m/s.

A multivariate optimisation code has been modified to represent the application of laminar flow to transport aircraft. This has subsequently been used to obtain optimised configurations for conventional and laminar flow designs. Results are presented, demonstrating the economic benefits of introducing laminar flow technologies to subsonic transport aircraft, with passenger payloads in the 107-517 range. These benefits are seen to improve by a factor of between two and three when the designs are optimised to take maximum advantage of the laminar flow. Sensitivity studies were conducted to investigate the impact of the assumptions used within the project studies on the optimum configurations and operating economics.

Results from a series of experimental measurements are presented in order to investigate the influence of the ground-plane boundary layer on the overall characteristics of a scale model road vehicle. The wind tunnel model is a generic bluff body which has a streamlined forebody, simple wheel representation and interchangeable rear end sections. The aerodynamic forces and moments were measured via an external 3-component balance at a free stream velocity of 24 m/s. corresponding to Reynolds number of 5.5 × 105 based on model length, over a range of ride heights and yaw angles. The ground plane boundary layer thickness was varied artificially. The influence of wheels and underbody roughness were also investigated.

An accurate simulation of a ground vehicle interacting with a crosswind gust can be achieved by using a moving model mounted on a track such that it can traverse the working section of a conventional atmospheric boundary layer wind tunnel. This paper will briefly describe the facility that is being developed at Cranfield University and detail comparisons between static and dynamic data from tests on three basic model configurations. Under the same nominal wind input, data from static tests compares well with that from dynamic tests at yaw angles below 15°. At higher yaw angles, after the onset of “large scale” separation, the dynamic values of the forces and moments become larger than the static values.

The mixture formation process in a stratified-charge spark-ignition engine under moderate load conditions has been determined from fuel concentration measurements obtained from planar laser-induced fluorescence (PLIF) of a fluorescence fuel marker, 3-pentanone. A one-cylinder 4-valve engine, specifically designed to provided optical access through the walls of the combustion chamber and through a piston window, was used. In order to gain insight into the processes influencing the fuel motion and mixing, average fuel concentrations were recorded in four different planes between 0.7 mm to 15 mm below the spark plug for various crank-angle positions during the inlet and compression stroke and for two different injection timings. These measurements give a mean 3-dimensional picture of the time history of the fuel distribution.

With increasing speeds and the anticipated reduction in weight of modern cars, the issue of crosswind sensitivity is becoming increasingly important. In a previous paper by the same authors, the normal method of testing such aerodynamic characteristics at model scale, using static models at yaw to the freestream, was compared with dynamic testing, in which the model is propelled across a ‘gust’ simulated by a wind tunnel. A direct comparison using a similar gust profile for both static and dynamic tests was made with the conclusion that the simple static test technique was underestimating the true transient loads. Further tests have been carried out, on a generic squareback (or estate) model, during which the effect of varying both the vertical velocity profile and the turbulence intensity within the gust was considered.

Different feasibility studies have been carried out over several years at the Royal Military College of Science (RMCS) into medium military airlifters aimed, in essence at replacing the C-130. The studies, each occupying a nominal 1,500 manhours (but probably 50% more) formed part of the final year of the AeroMechanical B.Eng degree at RMCS. The intention of this paper is to draw together their major findings and deals predominantly with the topics of: cargo hold sizing and body aerodynamics, powerplant selection, weight and performance.

The shear size and flexibility of the larger airframe parts makes it difficult to imagine assembly without extensive use of hard tooling. Yet, the world of aerospace manufacturing is changing. It is already possible to considerably reduce the amount of external, ‘hard tooling’, especially jigs, through innovative design and the applications of advanced technologies. Jigless Aerospace Manufacture, (JAM), is not a single, mysterious, as yet undiscovered technology. Rather it is a growing number of related and linked technologies. Many of these are already well established and considered ‘robust.’ This paper sets out to review and describe some of these enabling technologies and to explain their individual roles towards achieving JAM.

Upon their arrival, Unmanned Autonomous Systems (UAS) brought with them many benefits for those involved in a military campaign. They can use such systems to reconnoiter dangerous areas, provide 24-hr aerial security surveillance for force protection purposes or even attack enemy targets all the while avoiding friendly human losses in the process. Unfortunately, these platforms also carry the inherent risk of being built on innately vulnerable cybernetic systems. From software which can be tampered with to either steal data, damage or even outright steal the aircraft, to the data networks used for communications which can be jammed or even eavesdropped on to gain access to sensible information. All this has the potential to turn the benefits of UAS into liabilities and although the last decade has seen great advances in the development of protection and countermeasures against the described threats and beyond the risk still endures.

Fuel injector performance has a direct effect on the combustion efficiency, pollutant emissions and combustion instability of internal combustion engines. Liquid fuels are normally accelerated into an elevated combustion-chamber temperature to maintain a desirable homogeneous combustible mixture - liquid vapour and air. The accelerated jet breakup may be induced by cavitation, turbulent, hydrodynamic and aerodynamic forces interactions and variation in fluid properties. The absolute majority of studies have been devoted to the extensive study on some of the effects that cause jet instability and breakup, while others are still at their infant study. In particular, relatively few researchers have studied the combined effects of jet acceleration and non-isothermal condition on jet instability and breakup, despite its practical relevance in liquid fuel spray and combustion.

Identifying the most appropriate powertrain technology for a given vehicle class and duty cycle can be beneficial to further drive down on carbon emissions. However, with a myriad of powertrain architectures that are emerging in the industry, such as those in Electric Vehicles and Hybrid Vehicles, it becomes more challenging to carry out comprehensive comparative analyses across different permutations of powertrain topologies. This has motivated the authors to research on improving the method used to compare different types of powertrain architectures, and develop a tool that can be used by practitioners for this purpose. Literature survey has indicated that whilst there have been many comparisons made between different types of powertrains, such analyses were often carried out by comparing only limited types of architectures at a time.

The aerospace manufacturing industry is, in many ways, one of the most sophisticated commercial manufacturing systems in existence. It uses cutting-edge materials to build highly complex, safety-critical structures and parts. However, it still relies largely upon human skill and dexterity during assembly. There are increasing efforts to introduce automation, but uptake is still relatively low. Why is this and what needs to be done? Some may point to part size or the need for accuracy. However, as with any complex issue, the problems are multifactorial. There are no right or wrong answers to the automation conundrum and indeed there are many contradictions and unsettled aspects still to be resolved. Unsettled Issues on the Viability and Cost-Effectiveness of Automation in Aerospace Manufacturing builds a comprehensive picture of industry views and attitudes backed by technical analysis to answer some of the most pressing questions facing robotic aerospace manufacturing.

The field of parallel kinematics was viewed as being potentially transformational in manufacturing, having multiple potential advantages over conventional serial machine tools and robots. However, the technology never quite achieved market penetration or broad success envisaged. Yet, many of the inherent advantages still exist in terms of stiffness, force capability, and flexibility when compared to more conventional machine structures. Deployment of Parallel Kinematic Machines in Manufacturing examines why parallel kinematic machines have not lived up to original excitement and market interest and what needs to be done to rekindle that interest. A number of key questions and issues need to be explored to advance the technology further. Click here to access the full SAE EDGETM Research Report portfolio.