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In-flight atmospheric icing is a significant threat to the use of unmanned aerial vehicles (UAVs) in adverse weather. The propeller of the UAV is especially sensitive to icing conditions, as it accumulates ice at a faster rate than the wings of the UAVs. Ice protection systems can be developed to counteract the danger of icing on the propeller of UAVs. In this study, the influence of different meteorological conditions on a propeller of a UAV is analyzed for a UAV with a wingspan of a few meters. The ice accretion and the performance degradation and the required anti-icing heat fluxes have been calculated using numerical methods with ANSYS FENSAP-ICE. This analysis has been used to evaluate the critical conditions for the operation of a UAV in icing conditions and the design of a thermal IPS system for a propeller. The highest ice mass has been found at a temperature of −10 °C and an MVD of 20 μm in intermittent maximum icing conditions.

Icing is a severe hazard to aircraft and in particular to unmanned aerial vehicles (UAVs). One important activity to understand icing risks is the prediction of ice shapes with simulation tools. Nowadays, several icing computational fluid dynamic (CFD) models exist. Most of these methods have been originally developed for manned aircraft purposes at relatively high Reynolds numbers. In contrast, typical UAV applications experience Reynolds numbers an order of magnitude lower, due to the smaller airframe size and lower airspeeds. This work proposes a set of experimental ice shapes that can serve as validation data for ice prediction methods at low Reynolds numbers. Three ice shapes have been collected at different temperatures during an experimental icing wind tunnel campaign. The obtained ice shapes represent wet (glaze ice, −2 °C), mixed (−4 °C), and dry (rime ice, −10 °C) ice growth regimes. The Reynolds number is between Re=5.6…6.0×105, depending on the temperature.

Atmospheric icing is a key challenge to the operational envelope of medium-sized fixed-wing UAVs. Today, several numeric icing codes exist, that all have been developed for general aviation applications. UAVs with wingspans of several meters typically operate at Reynolds numbers an order of magnitude lower than commercial and military aircraft. Therefore, the question arises to what extent the existing codes can be applied for low-Reynolds UAV applications to predict ice accretion. This paper describes an experimental campaign at the Cranfield icing wind tunnel on a RG-15 and a NREL S826 airfoil at low velocities (25-40m/s). Three meteorological icing conditions have been selected to represent the main ice typologies: rime, glaze, and mixed ice. Each case has been run at least twice in order to assess the repeatability of the experiments. Manual ice shape tracings have been taken at three spanwise locations for each icing case.

As part of the complete solution to deal with atmospheric in-flight icing on unmanned aerial vehicles (UAV), a path planner is a valuable tool for finding an optimal path for accomplishing UAV missions. When considering icing conditions, the planner manages areas with icing risk. Together with an electro-thermal ice protection system (IPS), the path planner can optimize energy consumption by comparing energy consumed flying through the cloud or around it, as the UAV can now more safely pass through the ice. The UAV’s aerodynamic stability is also considered by meeting lift requirements, producing enough thrust, and having battery capacity left. These are constraints in the planner to ensure that the UAV can complete its mission. Benchmark icing cases are constructed to validate that the path planner performs as intended.

Atmospheric in-flight icing poses a challenge to all aircraft including unmanned aerial vehicles (UAVs). Aircraft should avoid icing conditions unless they have ways of mitigating the negative effects of icing, e.g., if they are equipped with an ice protection system (IPS). When de-icing systems are used, a certain amount of ice is allowed to accumulate before it is removed. This intercycle ice deteriorates the aerodynamics by reducing the lift, adding mass, and increasing the drag. This study combines the energy that is required to compensate for the added drag of intercycle ice shapes with the energy required for a wing IPS and compares the energy needs for different IPS operations. Two different kinds of intercycle ice shapes are simulated numerically using FENSAP-ICE, one ice shape that would accrete on an unprotected wing and one ice shape that would accrete when using a parting strip, a continuously heated element at the leading edge.

In-flight icing can result in severe aerodynamic performance penalties for unmanned aerial vehicles. It is therefore important to understand to which extent ice will build up on fixed-wing unmanned aerial vehicles wings and empennages, namely rudder and elevator, and how this ice will impact the aerodynamic performance and limits the flight envelope. This work investigates numerically icing effects on wing and empennage over a wide range of icing parameters. This is conducted using the icing CFD code FENSAP-ICE on the Maritime Robotics PX-31 Falk UAV. Therefore, the 2D profiles of these airfoils, which are RG-15 for the wing and SD8020 for rudder and elevator, are investigated. The investigated angles of attack are between –5° and 14° in 0.5° increments. Furthermore, the icing conditions are chosen according to the FAA CS 25 Appendix C for continuous maximum and intermittent maximum icing.

The Nucleation In ForesTs (NIFTY) campaign was conducted in the Morgan Monroe State Forest (MMSF) during the month of May 2008. The objectives of this campaign were to understand the principal mechanisms of nucleation, the limitations of nucleation and growth, the spatial extent of nucleation events, subsequent particle growth after nucleation in MMSF, and the link between particle nucleation and breakdown of the nocturnal boundary layer which enhances vertical mixing. This paper discusses the use of a UAV to perform selected aspects of this project, mission that was accomplished by a team of students during the campaign, and analysis of a crash which concluded the mission.

New trends in aircraft design suggest that there may be a mission advantage to placing the aircraft engine in backwards for applications in Unmanned Combat Air Vehicles (UCAV’s). These aircraft use stealth as their primary defense. Stealth is, therefore, of utmost importance leaving aerodynamics to take a lower priority in the design process. The combination of a flying wing, planform shape, airfoil and stability and control of these aircraft limit the maximum lift coefficient of the vehicle to a relatively low value. Increasing the maximum lift coefficient can be achieved by use of thrust vectoring forward of the center of gravity. This suggests an internal layout that places the engine flow opposite to that of the free stream. This design is currently being developed in an Embry-Riddle Aeronautical University undergraduate design course.

The Uniform Detection Characteristic (UDC) locus circumscribes a region in front of a vehicle at which the luminance requirement for detecting a roadway obstacle is met by the vehicle's headlamp system. Algorithms take into account variables that are not typically addressed by traditional (isolux) roadway illumination methods. The variables that can be treated include: obstacle size, coloration or reflectance characteristics; a driver's state of expectancy, age-related changes in visual sensitivity, and adaptation levels elevated by ambient light. The discernibility locus defines the distance at which a detection criterion, the luminance sensitivity threshold, is satisfied for moving or stationary obstacles. The locus protocol can be used for grading the effectiveness of lighting systems on specific vehicles, or for forensic investigation of nighttime automobile accidents

In today’s automobile industry where BS6 emission is posing a high challenge for aggregate development, cost control and with limited timeline. The main target is to provide the cooling system to have less impact on the in terms of cost, weight and to meet the challenging engineering requirement. Thus, the frugal engineering comes into the picture. This paper shows the application of thermosyphon principle for UDM injector cooling thereby reducing the rotation parts and power consumption such as an electric pump. Thermosyphon is a method of passive heat exchange and is based on natural convection, which circulates a fluid without the necessity of a mechanical or electric pump. The natural convection of the liquid commences when heat transfer to the liquid gives rise to a temperature difference from one side of the loop to the other.

Legacy electronic control units are, nowadays, required to implement cybersecurity measures, but they often do not have all the elements that are necessary to realize industry-standard cybersecurity controls. For example, they may not have hardware cryptographic accelerators, segregated areas of memory for storing keys, or one-time programmable memory areas. Such systems must still be protected with a sufficient level of rigor against attackers who wish to modify their operation or extract confidential information from them. A critical interface to defend is the Unified Diagnostics Service (UDS) interface which is used in many areas across the whole vehicle lifecycle. While the UDS service $27 (Security Access) has a reputation for poor cybersecurity, there is nothing inherent in the way it operates which prevents a secure access-control from being implemented.

A technique is presented for measuring the exhaust gas recirculation (EGR) and residual gas fraction (RGF) using a fast UEGO-based O₂ measurement of the manifold or in-cylinder gases, and of the exhaust gases. The technique has some advantages over the more common CO₂-based method. In the case of an RGF measurement, fuel interference must be eliminated and special fuelling arrangements are required. It is shown how a UEGO-based measurement, though sensitive to reactive species in the exhaust (such as H₂), as a system reports EGR/RGF rates faithfully. Preliminary tests showed that EGR and RGF measurements using the O₂ approach agreed well with CO₂-based measurements.

New and upcoming exhaust emissions regulations and fuel consumption reduction requirements are forcing the development of innovative and particularly complex intake-engine-exhaust layouts. Especially in the case of Compression Ignition (CI) engines, the HC-CO-NOx-PM after-treatment system is becoming extremely expensive and sophisticated, and the necessity to further reduce engine-out emission levels, without significantly penalizing fuel consumption figures, may lead to the adoption of intricate and challenging intake-exhaust systems configurations. The adoption of both long- and short-route Exhaust Gas Recirculation (EGR) systems is one example of such situation, and the need to precisely measure (or estimate) mass flow rates in the various elements of the gas exchange circuit is one of the consequences.

This Diesel fuel injection system provides the capability of universal application to a wide range of existing engines. It also provides the injection quantities, characteristics, and timing variations which may be needed by the new high performance Diesel engines with emphasis on gaseous emissions and noise. This is an electro-hydraulic system using unit injectors which are electronically controlled and operate on the common rail principle. It features positive displacement fuel metering, hydraulic pressure amplification and nozzle valve control. The system is highly flexible and can achieve injection characteristics beyond the capability of conventional systems.

Unburned hydrocarbon (UHC) and carbon monoxide (CO) emission sources are examined in an optical, light-duty diesel engine operating under low load and engine speed, while employing a highly dilute, partially premixed low-temperature combustion (LTC) strategy. The impact of engine load and charge dilution on the UHC and CO sources is also evaluated. The progression of in-cylinder mixing and combustion processes is studied using ultraviolet planar laser-induced fluorescence (UV PLIF) to measure the spatial distributions of liquid- and vapor-phase hydrocarbon. A separate, deep-UV LIF technique is used to examine the clearance volume spatial distribution and composition of late-cycle UHC and CO. Homogeneous reactor simulations, utilizing detailed chemical kinetics and constrained by the measured cylinder pressure, are used to examine the impact of charge dilution and initial stoichiometry on oxidation behavior.

Cenex, the UK's centre of excellence for low carbon and fuel cell technologies, is currently deploying electric passenger cars and vans throughout the UK in a series of Government funded low carbon vehicle trials. This study, produced in partnership with Millbrook Proving Ground, investigates comments and concludes on energy consumption in electric vehicles with varying driving styles and driving duties. At Millbrook, the electric vehicle (EV) track cycle is designed to represent real world driving duties over city, rural, hill and high speed circuits. It is shown that the drive efficiencies over the EV track cycle vary significantly by driver and the largest variations are noted on tracks with the highest opportunities for regenerative energy capture. To further study the regenerative energy, a model is developed and the percentage of potential vehicle energy recovered during deceleration is quantified.

Cenex, the UK's first Centre of Excellence for low carbon and fuel cell technologies, reports the results from a six month fleet electric vehicle trial. The study focuses on, and refers to vehicle performance in five private sector fleets. On board telemetry and data logging record key parameters which allow monitoring and reporting of usage patterns and energy consumption. The paper demonstrates the effect of duty cycle of candidate case studied organizations and the low ambient temperatures observed during the trial on range. The study quantifies the utilization patterns of the EVs, journey statistics, range, CO2 emissions and explores the links between range, auxiliary power use and ambient temperature. A questionnaire issued to EV users during the trial quantifies perception of performance and fleet integration aspects as well as looking at the importance of different aspects of EV purchasing decisions.

It is a requirement for the British RAF that all lightning strikes are reported and for those since 1972 there is a strike database which is maintained by GAO Consultancy on behalf of QuietiQ (previously DERA) UK (The GAOC Database) This database currently contains 1065 entries which have details of height, weather conditions, attitude, damage, effect on crew etc. In addition to the database there are also two RAE Reports of a further 630 strikes which were notified between 1944 & 1957. Some of those make fascinating reading from a purely historical point but by transferring the information available in these archive records into a format compatible with the database reports it has been possible to look for similarities and differences between, for example, strike rates per month, height bands, strikes to different aircraft classifications in differing scenarios and resulting damage.

This paper describes a practical approach used within the UK contribution to the UNECE PMP study in adopting some of the recommendations stated in the draft 2007 regulations for the measurement of particulate mass emissions from heavy-duty diesel engines in the US. This approach was named “2007PM” but the intention was to align rather than fully comply with the draft requirements for the US. In the PMP test work, four main changes were made to the standard European method of particulate emissions measurement (SPM). These were adopted as the 2007PM method. These were the application of a cyclone pre-classifier to 2007PM - with a 50% cut-size at 2.5μm, the use of a single 47mm filter rather than primary and back-up filters, close control of the filter face temperature to 47°C +/-5°C by heating of the dilution air and an increased filter face velocity. Measurements were predominantly made from aerosols generated by engines equipped with Diesel Particulate Filters (DPFs).

The paper describes a closely coordinated UK research programme involving Research Establishments and Industry in hardware design, simulator tests and flight trials to investigate the interfaces and interactions between Advanced Flight Systems, the Aircrew and Air Traffic Control, Reference is made to the work of the Royal Signals and Radar Establishment (RSRE) to describe developments in Air Traffic Management. Work in the UK on Flight Deck design has centred on the Advanced Flight Deck simulator at British Aerospace, Weybridge, and an example of their work is described. The flight test programme of the Royal Aircraft Establishment (RAE) Bedford BAC 1–11 and its equipment fit are described, together with recent examples of area navigation accuracy achieved in flight using conventional ground aids. A future programme is discussed in which the integration of all these new system elements will be investigated. Some of the problems which will be addressed are discussed.