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We have assembled and demonstrated a prototype power system that uses an innovative hydrogen generator to fuel an ultra-compact PEM fuel cell that is suitable for use in small unmanned aerial system (UAS) propulsion systems. The hydrogen generator uses thermal decomposition of ammonia borane (AB) to produce hydrogen from a very compact and lightweight package. An array of AB fuel pellets inside a low pressure container is activated sequentially to produce hydrogen on demand as it is consumed by the fuel cell. The fuel cell plant utilized in the power system prototype has been flown as part of several small UAS development programs and has logged hundreds of hours of flight time. The plant was designed specifically to be readily integrated with a range of hydrogen fueling subsystems and contains the balance of plant necessary to facilitate stand-alone operation. Based on results of these tests, we produced a conceptual design for a flight system.

As a result of the increasing use of fibre reinforced plastic (FRP) components in a modern commercial aircraft, manufacturers are facing new challenges - especially with regards to the realisation of significant build rates. One challenge is the larger variation of the thickness of FRP components compared with metal parts that can normally be manufactured within a very narrow thickness tolerance bandwidth. The larger thickness variation of composite structures has an impact on the shape of the component and especially on the surfaces intended to be joined together with other components. As a result, gaps between the components to be assembled could be encountered. However, from a structural point of view, gaps can only be accepted to a certain extent in order to maintain the structural integrity of the joint. Today's state of the art technologies to close gaps between FRP structures comprise shimming methods using liquid and solid shims.

Air to Air refueling (AAR) operations are typically performed with dedicated tanker A/C. Most existing tankers are derived from civil airliners like the A330MRTT from Airbus Military or from military transport A/C with permanent modifications for the tanker role. For being able to refuel in flight some type of receivers like medium and light turboprops, helicopters and certain UAVs, the tanker aircraft should be able to fly at low speeds. For that role medium/small size turboprop military transport aircraft, like the C295 from Airbus Military are ideally suited. This paper proposes a new palletized AAR kit for conversion of a transport A/C into a tanker. The kit includes all the needed air refueling systems, and can be installed on an existing military transport aircraft with rear cargo door ramp without big permanent modifications to the base platform.

We live in an era of increasing twin-engine commercial airplane operations, with large and very quiet high bypass ratio engines. At the same time, due to several decades of increased attention to the environment, we have large and increasing hazardous species bird populations. These trends, when combined, are not a prescription for continued assurance of a remarkable and enviable safety record for commercial aviation. Therefore, greater diligence must be placed on the evaluation of the current and future aviation wildlife hazard. We have some new weapons in this fight for greater capability to live with this situation. The basic problem is that different databases are populated independently from one another and often contain conflicting, contradictory, and erroneous data. Databases that were used individually, but not necessarily combined, are being utilized in a conjoined methodology to give us a better picture of the actual risk involved.

The renewed interest in the fuel efficient and low CO2 emission CROR (contra-rotating open rotor) propulsion system for future commercial aircrafts has recently led to a series of isolated and installed CROR wind tunnel test campaigns performed in close collaboration between Airbus and the engine manufacturers. These tests aim at better understanding the potentials and limitations of the CROR configuration, as well as at generating reference data for the development and calibration of numerical tools for both industry and research centers. One of these tested CROR concepts is the AI-PX7 CROR propeller designed by Airbus. In this context, this paper presents multidisciplinary design features of modern high-speed contra-rotating propellers for commercial aircrafts. The influence of main CROR design parameters like blade number, propeller tip speed, rotor diameter, etc. on the propeller aerodynamics, acoustics and structures is described.

This paper focuses on the virtual integration and test approach used for the evaluation of an automation system developed for the multifunctional operation of fuel cells in commercial aircraft. In order to accomplish the virtual integration a model of the overall automation system is linked with a dynamic model of the complete fuel cell system. For this purpose a modeling approach for complex physical systems is described in this paper. During virtual testing various simulation runs are executed based on automatically generated test cases, which cover a complete flight mission. For this reason a flight mission is modeled as a Statechart that includes next to time- based flight phases also potential events and malfunctions (e.g. engine flame-out, cargo fire). An algorithm is described, which can find all possible state combinations including parallel event sequences.

Following the introduction of Head-Up Displays (HUD) into commercial airplanes over 30 years ago, many aircraft manufacturers are now installing HUDs as baseline or as a selectable option on their latest designs. Most pilots that have used the HUD in difficult flying conditions prefer it to classic flight deck configurations with head-down displays only. This paper describes the features and benefits of the HUD that allow the pilot to remain head-up and eyes-out throughout the flight, especially in the crowded skies around an airport. This is achievable because the HUD provides all the primary flight information needed to fly the airplane. Some of the information is conformal to the outside world and the whole image is focused at optical infinity, eliminating the need for the pilot to refocus between the HUD symbology and real world features viewed through the HUD.

Since Automated Fiber Placement (AFP) is used to manufacture twin-aisled commercial aircraft parts, extremely large envelope machines are often required and appropriate. Additionally, for very large parts, the average AFP course length may be on the order of one to two meters, and the part may have numerous contours. With courses of this length, a high acceleration machine is necessary to achieve fast laydown rates because the machine is frequently starting and stopping. Part contour also requires high acceleration machine axes to accurately maintain the AFP tow path at high feedrates. Large machines with high accelerations result in very large loads on bearings. Large loads and the long, high speed axis travels associated with large envelope machines make achieving a long service life difficult. Designing efficient, lightweight machine structures becomes critical to provide long machine service life.

The European project MAAT (Multi-body Advanced Airship for Transport) is producing the design of a transportation system for transport of people and goods, based on the cruiser feeder concept. This project defined novel airship concepts capable of handling safer than in the past hydrogen as a buoyant gas. In particular, it has explored novel variable shape airship concepts, which presents also intrinsic energetic advantages. It has recently conduced to the definition of an innovative design method based on the constructal principle, which applies to large transport vehicles and allows performing an effective energetic optimization and an effective optimization for the specific mission.

An aerodynamic analysis methodology which makes efficient use of ANSA and FLUENT software's in the aerodynamic design of tractor-trailer class heavy commercial road vehicles is presented. The aerodynamic drag coefficient of the truck is used as the main control parameter to evaluate the performance of the methodology. Analysis methodology development activities include determining optimal FLUENT software analysis parameters for the defined problem (RANS based turbulence models, wall boundary layer models, solution schemes) and the necessary ANSA mesh generation parameters (boundary layer number and growth rate, wall surface mesh resolution, total mesh resolution). Proposed methodology is first constructed based on CFD simulations for the zero-degree yaw angle case of the 1/8 sized GCM geometry. The present results are within 1% of the experimental data.

Locked wheel protection is an important part of antiskid control for aircraft brake control system. Locked wheel protection compares the wheel speed of two or more wheels, if one of the wheels is too slow, locked wheel protection releases the brake pressure on the slow wheel. This work aims to study the control logic for locked wheel protection. Locked wheel protection control logic consists of 3 key factors: paired wheels, active threshold and inhibit velocity. Focus on comparison different options of these 3 factors, all aspects of control logic for locked wheel protection had been expounded in this study. Simulation and calculation analysis is applied for different locked wheel strategies to evaluate the effect. One conclusion is that the greatest wheel speed of the wheel under control shall be set as a reference speed for locked wheel protection. This study provide the basis to design a proper locked wheel protection function of aircraft brake control system.

Direct injection (DI) and jet ignition (JI), plus assisted turbocharging, have been demonstrated to deliver high efficiency, high power density positive ignition (PI) internal combustion engines (ICEs) with gasoline. Peak efficiency above 50% and power density of 340 kW/liter at the 15,000 rpm revolution limiter working overall λ=1.45 have been report-ed. Here we explore the further improvement in power density that may be obtained by replacing gasoline with ethanol or methanol, thanks to the higher octane number and the larger latent heat of vaporization, which translates in an increased resistance to knock, and permits to have larger compression ratios. Results of simulations are proposed for a numerical engine that uses rotary valves rather than poppet valves, while also using mechanical, rather than electric, assisted turbocharging. While with gasoline, the power density is 410-420 kW/liter, the use of oxygenates permits to achieve up to 475 kW/liter working with methanol.

Nowadays, E- commerce and logistics business model is booming in India with road transport as a major mode of delivery system using containers. As competition in such business are on rise, different ways of improving profit margins are being continuously evolved. One such scenario is to look at reducing transportation cost while reducing fuel consumption. Traditionally, aero dynamics of commercial vehicles have never been in focus during their product development although literature shows major part of total fuel energy is consumed in overcoming aerodynamic drag at and above 60 kmph in case of large commercial vehicle. Hence improving vehicle exterior aerodynamic performance gives opportunity to reduce fuel consumption and thereby business profitability. Also byproduct of this improvement is reduced emissions and meeting regulatory requirements.

Labor costs rank second only to fuel in expenses for commercial air transports. Labor issues are a growing concern in the airline industry, with an impending worldwide pilot shortage. One solution proposed and requested by some of the industry leaders is to allow a single flight crew member to operate the aircraft. Safety concerns represent the dominant barrier to single-pilot Part 121 operations. The FAA and Congress consistently demonstrate a bias toward conservatism in their regulation of airlines and commercial aircraft. Bureaucrats and the general public fall prey to isolated news stories that highlight pilot error and anchor their viewpoint on further regulating a two-person crew. Yet, in an alarming spate of recent airline accidents, the presence of multiple crewmembers did nothing to prevent, and actually may have contributed to, the crash. Technology is not the problem.

Fault-tolerance in commercial aircraft applications is typically achieved by redundancy. In such redundant systems the primary component is checked before the start of a flight to see if it operates correctly. The aircraft will not take off unless the primary is functioning. Airplane manufacturers must certify the airplane systems to be safe for flight. One means of safety certification is by safety analysis which shows that the probability of failure in a typical flight is bounded. The probability bound requirement for a system is based on the criticality of system failure. Usually backup components are checked at intervals that span multiple flights. The first backup may be checked more frequently than the second or higher levels. This leads to flights where the system may have latent faults in the backup components. The probability of failure in such cases varies from flight to flight due to the different exposure times for components in the system.

Developing the most advanced wing panel assembly line for very high production rates required an innovative and integrated solution, relying on the latest technologies in the industry. Looking back at over five decades of commercial aircraft assembly, a clear and singular vision of a fully integrated solution was defined for the new panel production line. The execution was to be focused on co-developing the automation, tooling, material handling and facilities while limiting the number of parties involved. Using the latest technologies in all these areas also required a development plan, which included pre-qualification at all stages of the system development. Planning this large scale project included goals not only for the final solution but for the development and implementation stages as well. The results: Design/build philosophy reduced project time and the number of teams involved. This allowed for easier communication and extended development time well into the project.

Butanol, a four-carbon alcohol, is considered in the last years as an interesting alternative fuel, both for Diesel and for gasoline application. Its advantages for engine operation are: good miscibility with gasoline and diesel fuels, higher calorific value than ethanol, lower hygroscopicity, lower corrosivity and possibility of replacing aviation fuels. Like ethanol, butanol can be produced as a biomass-based renewable fuel or from fossil sources. In the research project, DiBut (Diesel and butanol) addition of butanol to Diesel fuel was investigated from the points of view of engine combustion and of influences on exhaust aftertreatment systems and emissions. One investigated engine (E1) was with emission class “EU Stage 3A” for construction machines, another one, engine (E2) was HD Euro VI. The most important findings are: with higher butanol content, there is a lower heat value of the fuel and there is lower torque at full load.

This document covers recommendations for the application of existing qualified and approved in-service fixed wing aircraft tires, wheels and brakes to military and commercial rotorcraft. NOTE: This document does not address the use of radial tires due to insufficient data to support their approved use on rotorcraft, see paragraph 4.3.14 for specific impact on ground resonance.

This specification covers one type of cushion tread (semi-pneumatic) wheels for use on mobile ground support equipment.

This specification covers one type of cushion tread (semi-pneumatic) wheels for use on mobile ground support equipment.