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Technical Paper

X-36 Tailless Agility Aircraft Subsystems Integration

1997-10-01
975505
The X-36 is a remotely piloted 28% scale model of a two-axis-unstable notional future fighter aircraft with canards, a mid-wing and features the absence of any vertical control surfaces, Figure 1. The aircraft was jointly developed by the NASA Ames Research Center and McDonnell Aircraft & Missile Systems and flight tested at the NASA Dryden Flight Research Center. Objectives of this program were to demonstrate fighter aircraft agility for a vertical tailless configuration and to demonstrate the development of a low cost alternative to full size prototype aircraft. This paper presents some aspects of the subsystem integration methodology used to develop the X-36 Tailless Agility Research Aircraft.
Technical Paper

X-Ray - A Necessary Tool for Detecting Incipient Structural Failures in Service Aircraft

1964-01-01
640510
X-ray is an indispensable aid in locating and determining the extent of incipient failures in structure which is inaccessible by position or covered by multiple layers of metal. It is also the most feasible method for checking oil coolers for contamination; bonded honeycomb panels for water; fuel lines for erosion; and with a 360 deg emission tube, fuselage frames for structural integrity without removing the interior upholstery and panels from the passenger compartment or cargo compartments.
Technical Paper

X-Ray Curing of Carbon Fiber Composites for Structural Automotive Components

2017-03-28
2017-01-0504
Having demonstrated the feasibility of using X-rays derived from high current industrial electron beam accelerators (EB) to cure the matrices of carbon fiber composites and then scaled this up to cure large sized, non-structural automobile components, performance car hoods, the New York State Vehicle Composites Program had a chassis designed, a cured epoxy mold made and then the chassis matrix cured using X-rays with a formulated radiation responsive matrix material. A feasibility study had shown how X-rays could cure through materials embedded within the composite layers, such as metal inserts that could be used for mechanical fastening without fracturing the composite. In producing X-ray cured hoods, the power consumption for X-ray curing was found to be more than 20% lower than that needed for autoclave curing the same sized hoods using conventional thermosetting pre-pregs. More significant was the time-to-cure.
Technical Paper

X-Ray Determination of Residual Stresses and Hardness in Steel Due to Thermal, Mechanical, and Fatigue Deformations

1962-01-01
620053
Residual stress and hardness in steel due to thermal, mechanical, and fatigue deformations are determined by an X-ray diffraction method. The sharp temperature rise associated with electrical discharge machining causes austenitizing, rehardening, and tempering, and results in high tensile residual stress. Shot-peening quality is evaluated from residual stress and hardness induced by the peening. Rolling contact fatigue of carburized and hardened bearings causes a transformation of austenite to martensite, and thereby generates more residual compression, and also causes permanent fatigue softening. Less softening is observed in inner races of consutrode and cross-forged steels than in air-melted steel, and the former steels exhibit greater fatigue life at early and mean failure levels.
Technical Paper

X-Wing: A Low Disc-Loading V/STOL for the Navy

1985-10-01
851772
The X-Wing concept employs a single lifting system for all modes of flight. The lifting system is comprised of four very rigid, circulation control wings with blowing for lift modulation and control. For hover and low speed flight, the wings rotate such as the rotor of a helicopter. For high speed flight, the wings are stopped in an “X” configuration across the fuselage - from which the name of the concept is derived - with two forward-swept wings and two aft-swept wings. Such a vehicle is also envisioned to have an integrated gas turbine propulsive system for all flight modes. At low speeds, the gas generators) would drive a shaft to turn the wings and the circulation control compressor as well as a set of propulsive fans. For high-speed flight, the shaft would drive only the compressor and accessories as the fans propel the vehicle. The X-Wing concept has been underdevelopment for over 15 years.
Journal Article

X-ray Imaging of Cavitation in Diesel Injectors

2014-04-01
2014-01-1404
Cavitation plays a significant role in high pressure diesel injectors. However, cavitation is difficult to measure under realistic conditions. X-ray phase contrast imaging has been used in the past to study the internal geometry of fuel injectors and the structure of diesel sprays. In this paper we extend the technique to make in-situ measurements of cavitation inside unmodified diesel injectors at pressures of up to 1200 bar through the steel nozzle wall. A cerium contrast agent was added to a diesel surrogate, and the changes in x-ray intensity caused by changes in the fluid density due to cavitation were measured. Without the need to modify the injector for optical access, realistic injection and ambient pressures can be obtained and the effects of realistic nozzle geometries can be investigated. A range of single and multi-hole injectors were studied, both sharp-edged and hydro-ground. Cavitation was observed to increase with higher rail pressures.
Technical Paper

XB-70A Laboratory for Progress

1966-02-01
660276
The development of the XB-70 research aircraft produced advancements in many fields of technology. This paper covers a few of these advancements in the areas of materials, equipment, and manufacturing. These include honeycomb construction, PH 15-7 alloy steel, vacuum melted H-11 steel, equipment capable of withstanding high temperatures, chemical milling of many different alloys, miniaturized welding equipment, and exothermic brazing techniques.
Technical Paper

XV-15 Tilt Rotor Test Progress Report

1977-02-01
770953
In a continuing effort to expand the versatility of their aircraft, VTOL designers have for many years tried to combine the desirable features of various concepts into a single aircraft. This is a formidable task and most efforts have met with limited success. This paper explores the need for an aircraft combining the efficient VTOL capability of a helicopter with the efficient high speed characteristics of a fixed wing turboprop. The ability of the tilt rotor concept to fill this requirement and examples as to its potential usefulness in both military and civil missions, is discussed. The history of the concept and the status of the current Army/NASA/Bell XV-15 program and its role in proving the viability of the concept are reviewed.
Technical Paper

Xenon Light for Main and Dipped Beam

1998-02-23
980005
Xenon (HID) technology is one of the mile-stones in developing process of car lighting. The first step was to combine this technology with free-form reflector technology. The result was a high performance dipped beam beam-pattern with three times more light output compared to a halogen system. The next step of improvement is “Bi-Xenon”. It makes sense to use the enormous light output of a Xenon light source for two light functions (Main beam and dipped beam) in a single pocket headlamp system. This leads to new lighting performance and design freedom in headlamp technology. In this paper the technological aspects of system realization will be described. New solutions in lighting strategy including modern actuators which handle optical elements to switch between two light functions had to be found.
Technical Paper

Xenon with Integrated Starter – The Powerful Way for Improved HID Headlighting

2000-03-06
2000-01-0805
HID as lightsource in the automotive world has been proven as the most efficient way to satisfy the main user's requirements on a headlighting bulb: Realize a broad beam pattern with superior performance on visibility, safety and comfort on the one hand, and the fulfillment of long lifetime requirements on the other hand. In the second step, the logical integration of functions and the improvement of automotive system requests such as size and EMC has to be covered. An integrated bulb with starter is the appropriate way to combine these features: Optimized fine tuning between the entire lightsource and the starter to reach optimal electrical and EMI performance on the one side on the other side combined with very compact sizes leads to an automotive source perfectly suiting to the modern trends in headlighting applications.
Technical Paper

X—31A

1987-07-01
871346
MBB and Rockwell, under DARPA/NAVAIR and GMOD contract, are currently designing an experimental aircraft which will be dedicated to demonstrate “enhanced fighter maneuverability” (EFM) and supermaneuverability in particular. The aircraft is designed to break one of the last barriers left in aviation, the stall barrier. It will be able to perform tactical maneuvers up to 70° angle of attack and thus achieve very small radii of turn. Such highly instantaneous 3-dimensional maneuvers are of significant tactical value in future air combat with all aspect weapons. Key to the penetration into this unexplored flight regime is thrust vectoring in pitch and yaw. This feature is also used to enhance agility in critical flight conditions and to enhance the decoupling of fuselage aiming and flight path control as required for head-on gun firing.
Technical Paper

Yaw Effects on the Narrowband Spectra Above a Delta Wing in Turbulent Flow

2016-09-20
2016-01-2056
Combat aircraft maneuvering at high angles of attack or in landing approach are likely to encounter conditions where the flow over the swept wings is yawed. This paper examines the effect of yaw on the spectra of turbulence above and aft of the wing, in the region where fins and control surfaces are located. Prior work has shown the occurrence of narrowband velocity fluctuations in this region for most combat aircraft models, including those with twin fins. Fin vibration and damage has been traced to excitation by such narrowband fluctuations. The narrowband fluctuations themselves have been traced to the wing surface. The issue in this paper is the effect of yaw on these fluctuations, as well as on the aerodynamic loads on a wing, without including the perturbations due to the airframe.
Technical Paper

Yield Mapping of Soybeans and Corn Using GPS

1995-09-01
952112
Data obtained when harvesting with a combine equipped with a yield monitor were used to develop yield maps. A prototype yield monitor was developed that uses a combination of light emitters and receivers mounted in a rectangular frame. The monitor was mounted in the combine in the top of the clean grain elevator. As grain flows through the monitor, a voltage change proportional to light reduction was recorded. This voltage was then correlated to grain flow rate. At the same time, site-specific location was recorded using the global positioning satellites (GPS) system. The location data, yield monitor output, cutting width, and combine forward speed were stored in a spreadsheet format. The data were then used to prepare the yield maps.
Technical Paper

Yielding Strengh Analysis for Self Supported Pressure Vessels

2002-11-19
2002-01-3479
The hazardous bulk chemical liquid cargo transportation is usually made through highways, using special automotive devices, named semitrailer tank, a kind of mobile tank specially developed to perform this task, manufactured with many types of steel, selected according to the chemical characteristics of the product to be transported. Equipment sizing is made based on specific standards which include specified formulas, loading, and safety factors representing the design criteria of this type of device. Despite of the detailed design criteria for semitrailer tank, it has been observed failure of some pieces of equipment during operation, in a shorter effective life than that one considered in the design phase itself. Considering a detailed study of the stress distribution in this type of equipment, this paper shows a verification of the possibility of yielding failure in the semitrailer tank structure.
Technical Paper

Zinc Coated Press-Hardening Steel - Challenges and Solutions

2015-04-14
2015-01-0565
Press-hardening steels get more and more popular for body in white applications as an approach to meet the demands of passenger safety and CO2 reduction. Unlike the larger part of the structure that is typically zinc coated, the majority of the PHS parts is either uncoated or aluminum silicon coated. This paper shall give an overview of press-hardening steels with zinc coatings with detailed results for corrosion resistance, weldability and mechanical properties for strength levels of 490 to 1800 MPa. Furthermore as for zinc coated material maintaining a robust press-hardening process is of even higher importance than for uncoated or AlSi coated material. A range of different processes including indirect and direct process are shown in detail. Especially the topic of micro-cracks, mechanisms and avoidance of micro-cracks in the direct process will be discussed. Results from industrial and semi industrial production are shown.
Technical Paper

Zinc Coating Influence on Spot-Weldability of Hot-Dip Galvanized Steel Sheets

1985-02-01
850273
HOT-DIP galvanized steel sheets have been increasingly used in the automotive industry. However, two major problems occur during spot-welding because of the presence of zinc: 1/ Welding parameters differ from those used for bare sheets 2/ Electrodes life span often decreases. Two products have been thoroughly tested: 1/ Usinor MONOGAL® sheet 2/ Two-sides hot-dip galvanized sheet with various zinc-coating thicknesses. Welding parameters have been optimized by the determination of weldability lobes. Both products present a wide range of intensities, provided that weld current and electrode force are increased. The effect of an enventual variation of zinc-coating thickness is negligible. Electrodes life satisfies the FORD 2000 spot welds acceptance test. At last, temperature measurements inside the electrodes have shown the interest in increasing the electrodes tip diameter.
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