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Technical Paper

1953 Paper Jet Operations in Retrospect with Connotations for the Supersonic Transport

1965-02-01
650231
A first attempt to study civil aircraft operations comprehensively, prior to having the airplane, occurred before the initial operation of U.S. subsonic jets. One airline carried out a manual-simulated “paper jet” operation lasting fifteen months. Today, computerized simulation of machines, methods, and operations has become commonplace, and replaces the slide rule and tedious day-by-day inputs of aircraft operational criteria. Computerized simulations are also applied to every aspect of the SST design and operations. These are important, but the results being should be used with caution and judgement.
Technical Paper

1998/1999 AIAA Foundation Graduate Team Aircraft Design Competition: Super STOL Carrier On-board Delivery Aircraft

2000-10-10
2000-01-5535
The Cardinal is a Super Short Takeoff and Landing (SSTOL) aircraft, which is designed to fulfill the desire for center-city to center-city travel by utilizing river “barges” for short takeoffs and landings to avoid construction of new runways or heliports. In addition, the Cardinal will fulfill the needs of the U.S. Navy for a Carrier On-board Delivery (COD) aircraft to replace the C-2 Greyhound. Design requirements for the Cardinal included a takeoff ground roll of 300 ft, a landing ground roll of 400 ft, cruise at 350 knots with a range of up to 1500 nm with reserves, payload of 24 passengers and baggage for a commercial version or a military version with a 10,000 lb payload, capable of carrying two GE F110 engines for the F-14D, and a spot factor requirement of 60 feet by 29 feet.
Technical Paper

2-Stroke Diesel Engine for Light Aircraft: IDI vs. DI Combustion Systems

2010-10-25
2010-01-2147
The paper presents a numerical study aimed at converting a commercial lightweight 2-Stroke Indirect Injection (IDI) Diesel aircraft engine to Direct Injection(DI). First, a CFD-1D model of the IDI engine was built and calibrated against experiments at the dynamometer bench. This model is the baseline for the comparison between the IDI and the DI combustion systems. The DI chamber design was supported by extensive 3D-CFD simulations, using a customized version of the KIVA-3V code. Once a satisfactory combustion system was identified, its heat release and wall transfer patterns were entered in the CFD-1D model, and a comparison between the IDI and the DI engine was performed, considering the same Air-Fuel Ratio limit. It was found that the DI combustion system yields several advantages: better take-off performance (higher power output), lower fuel consumption at cruise conditions, improved altitude performance, reduced cooling requirements.
Journal Article

2-Stroke High Speed Diesel Engines for Light Aircraft

2011-09-11
2011-24-0089
The paper describes a numerical study, supported by experiments, on light aircraft 2-Stroke Direct Injected Diesel engines, typically rated up to 110 kW (corresponding to about 150 imperial HP). The engines must be as light as possible and they are to be directly coupled to the propeller, without reduction drive. The ensuing main design constraints are: i) in-cylinder peak pressure as low as possible (typically, no more than 120 bar); ii) maximum rotational speed limited to 2600 rpm. As far as exhaust emissions are concerned, piston aircraft engines remain unregulated but lack of visible smoke is a customer requirement, so that a value of 1 is assumed as maximum Smoke number. For the reasons clarified in the paper, only three cylinder in line engines are investigated. Reference is made to two types of scavenging and combustion systems, designed by the authors with the assistance of state-of-the-art CFD tools and described in detail in a parallel paper.
Technical Paper

210 Ft Medium Endurance Cutters

1966-02-01
660466
The U. S. Coast Guard has recently put into service new 210 ft cutters designed for search and rescue work, law enforcement, oceanographic work, and possible future ASW. This paper outlines the structure and capabilities of the vessel. An important feature of the cutter is its helicopter handling facilities, which have greatly increased the cutter's search and rescue capability by extending the area it can cover. The cutter is the first in Coast Guard service to be powered by a combination diesel engine and gas turbine installation. The combination gives a top speed of 18 knots and a cruising range of 5000 miles.
Technical Paper

21st Century Aircraft Potable Water Systems

1999-10-19
1999-01-5556
Aircraft potable (drinking) water systems haven’t changed significantly in the last half-century. These systems consist of cylindrical water tanks pressurized by bleed air from the jet engines, with insulated stainless steel distribution lines. What has changed recently is the increase in the possibility of aircraft picking up contaminated drinking water at foreign and domestic stops. Customer awareness of these problems has also changed - to the point where having reliable drinking water is now a competitive issue among airlines. Old style potable water systems that are used on modern aircraft are high maintenance and exacerbate the growth of microbes because the water is static much of the time. The integrity of some pressurized water tanks are also a concern after years of use. Cost-effective mechanical and biological solutions exist that can significantly reduce the amount of chemicals added and provide good potable water.
Technical Paper

26 X 6.6 Radial-Belted Aircraft Tire Performance

1991-09-01
912157
Preliminary results from testing of 26 X 6.6 radial-belted and bias-ply aircraft tires at NASA Langley's Aircraft Landing Dynamics Facility (ALDF) are reviewed. These tire tests are part of a larger, on going joint NASA/FAA/Industry Surface Traction and Radial Tire (START) Program involving three different tire sizes. The 26 X 6.6 tire size evaluation includes cornering performance tests throughout the aircraft ground operational speed range for both dry and wet runway surfaces. Static test results to define 26 X 6.6 tire vertical stiffness properties are also presented and discussed.
Technical Paper

270-Vdc/Hybrid 115-Vac Electric Power Generating System Technology Demonstrator

1991-09-01
912051
Sundstrand is investigating 270-Vdc/hybrid 115-Vac electrical power generating and distribution systems technology so as to be well prepared to offer such systems for future aircraft applications. The approach taken has been to design, build, and test a representative system that meets or exceeds the tightest of the performance standards as defined by miliary standards. This paper describes a single-channel, 120-kW hybrid system and presents some typical performance data. The dc bus supplies a 30-kVA, 400-Hz, 115-Vac inverter; constant power load banks of up to 150 kW; and a resistive load bank of up to 90 kW. System simulation studies indicated the potential for unstable operation due to the negative impedance of the constant power load in conjunction with the source ripple filter and the load EMI filters. Unstable voltage and current were observed in system testing when the magnitude of the source impedance was not sufficiently below that of the load impedance.
Technical Paper

270-Vdc/Hybrid 115-Vac Electric Power Generating System Technology Demonstrator Evolution to a Dual-Channel, More Electric Aircraft Technology Development Testbed

1991-09-01
912183
Sundstrand has been investigating 270-Vdc/hybrid 115-Vac electrical power generating systems (EPGS) technology in preparation for meeting the electrical power generating system (EPGS) requirements for future aircraft (1). Systems such as the one being investigated are likely to be suitable for the More-Electric Aircraft (MEA) concepts presently under industry and military study. The present Sundstrand single-channel testbed is being further expanded to better understand the electrical system performance characteristics and power quality requirements of an MEA in which traditional mechanical subsystems are replaced by those of a “more-electric” nature. This paper presents the most recent Sundstrand 270-Vdc system transient performance data, and describes the modifications being made to the 270-Vdc/hybrid 115-Vac testbed.
Technical Paper

2D Ice Shape Scaling for Helicopter Blade Profiles in Icing Wind Tunnel

2015-06-15
2015-01-2129
Different Airbus Helicopters main rotor blade profiles were tested in different icing wind tunnels and for different icing conditions. One of the objectives of the accretion tests was to validate the use of 2D icing scaling laws established for fixed wing aircraft on helicopter blade profiles. Therefore, ice shapes resulting from tests with the same icing similarity parameters are compared to each other allowing the assessment of icing scaling laws for helicopter applications. This paper presents the icing scaling laws used at Airbus Helicopters on blade profiles, the different test set ups and test models and it presents the comparison of the ice shapes collected during the icing wind tunnel test campaigns.
Technical Paper

2D Polar Assessment in Icing Wind Tunnel for iced Helicopter Blade Profiles

2015-06-15
2015-01-2127
A helicopter blade profile was tested in the DGA Aero-engine Testing's icing altitude test facility S1 in Saclay, France during the winter of 2013/2014. The airfoil was a helicopter main rotor OA312 blade profile made out of composite material and with a metallic erosion shield. Dry air and ice accretion tests have been performed in order to assess the iced airfoil's aerodynamic behaviour. Several icing conditions were tested up through Mach numbers around 0.6. This paper presents the test setup, the test model and some of the test results. The test results presented in this paper include the ice shapes generated as well as dry air and iced airfoil lift and drag curves (polars) which were obtained with the real ice shapes on the airfoil.
Technical Paper

4-Sensor 2-Channel Anti-Lock System for FWD Cars

1986-02-01
860511
The possibility of 2 Channel anti-lock system, which controls each of two independent hydraulic circuits of diagonal split braking system of FWD car seperately, were studied. Theoretical investigation suggested two out of four possible control logics to be promising and they were proved to be practically satisfactory through vehicle test. This system is almost as effective as expensive 3-channel or 4-channel system, when the braking force distribution between front and rear axles is correct as required by EEC Braking regulation. Under extreme condition that rear wheels lock earlier than fronts, the compromise between stopping distance and stability is necessary.
Journal Article

400Hz High Speed Static Transfer Switch

2008-11-11
2008-01-2877
The objective of this project was to replace electromechanical power line contactors with a Static Transfer Switch (STS) to improve the transfer of electrical power between aircraft generators and decrease required maintenance. The switch requirements include high reliability, lightweight, and high speed (less than 15mS) power transfer. An STS can shorten the bus transfer time to less than the “ride-through” of aircraft electronic loads and therefore have the ability to control and transfer electrical power while maintaining critical mission requirements. The content of this paper and presentation will discuss the initial problem, the research and development approach, design, and initial testing of the STS.
Technical Paper

48V Boost Recuperation Systems - Golden Gate into the Future

2019-04-02
2019-01-0391
The transformation of the automotive industry will be shaped mainly by the markets North America, Europe and China, which account for more than two thirds of the yearly global car production. All three markets have challenging fuel consumption, CO2 and emission regulations in place and under discussion, which are forcing the automotive industry to make their power train technology more efficient. But not only governmental regulations are driving the change, increasing urbanization intensifies local environmental pollution from vehicles and strains the acceptance of today’s car centric mobility. Electrification is the highly touted magic solution, but is it fast and comprehensive enough to solve above mentioned problems? Is society - car owners, automotive industry and governments - willing to pay the high cost for electrified car technology and infrastructure within a short timeframe of 10 to 15 years?
Technical Paper

5-Axis Flex Track Drilling Systems on Complex Contours: Solutions for Position Control

2013-09-17
2013-01-2224
Previous Flex Track drilling systems move along two parallel tracks that conform to the contour of a work piece surface. Until recently, applications have been limited to relatively simple surfaces such as the cylindrical mid-body fuselage join of a commercial aircraft. Recent developments in the state of the art have introduced the 5-axis variant which is capable of precision drilling on complex contours. This paper presents solutions to two positioning challenges associated with this added functionality: the ability to align the spindle axis normal to an angled drilling surface while maintaining accuracy in tool-point position, the ability to maintain synced motion between dual drives on complex track profiles.
Technical Paper

50 Development of Measurement Method for Airborne Sound Emitted by Personal Watercraft

2002-10-29
2002-32-1819
The personal watercrafts (PWC's) are operated in various ways; going around on certain course again and again, repeating acceleration and deceleration, or prolonged idling operation, for instance. The procedure of ISO 14509 has been applied in the traditional sound measurement for powered recreational craft. However, the standard is designed to measure the sound from the typical small crafts, on the assumption that they run straight in a constant speed. It is believed to be inappropriate to use this procedure for the measurement of PWC sound. In trying to establish the suitable procedure for PWC, evaluation by the auditory sense of 15 raters was carried out in parallel with the traditional sound pressure level measurement. As the candidate, four (4) measurement methods were employed in this test. 5 models of PWC's including modified crafts were used. Correlation between the results of traditional sound measurement and the auditory sense ratings was examined.
Technical Paper

50 KVA High Temperature Bi-directional Converter for On-Engine Application in More Electric Aircraft

2014-09-16
2014-01-2111
The transition towards More Electric Aircraft (MEA) architectures has challenges relating to integration of power electronics with the starter generator system for on-engine application. To efficiently operate the power electronics in the hostile engine environment at high switching frequency and for better thermal management, use of silicon carbide (SiC) power devices for a bi-directional power converter is examined. In this paper, development of a 50 kVA bi-directional converter operating at an ambient temperature of about 2000C is presented. The design and operation of the converter with details of control algorithm implementation and cooling chamber design are also discussed.
Technical Paper

50 YEARS OF MARINE GEAR EVOLUTION

1972-02-01
720280
A colorful series of 150 slides was presented tracing 5 HP to 1200 HP marine gear design evolution beginning in 1906, followed by pre-WWI developments, Liberty Aircraft engine usage and a 1924 to 1972 series of pleasure boat and work boat marine gear photographs. The entire slide presentation is available in 35 m.m. film strip and may be ordered (at cost) from the author, R. C. McRoberts, Twin Disc, Incorporated, Racine, Wisconsin, 53403, U.S.A. For short time usage, a loan film is available. This history of U. S. marine gear development includes information contributed by the Snow-Nabstedt Gear Corp., Capitol Gears, Inc., Paragon Gears, Inc., The Walter Machine Co., Inc., Detroit Diesel Allison Div. of General Motors Corp., Caterpillar Tractor Co., Warner Gear Div. Borg-Warner Corp. and Twin Disc, Incorporated.
Technical Paper

50 to 100-Ah Lithium Ion Cells for Aircraft and Spacecraft Applications

1997-06-18
971230
As a part of a program jointly supported by the USAF and Canada's Department of National Defense, BlueStar is developing large (50 to 100-Ah)lithium ion cells for aircraft and spacecraft applications. Presently, 20-Ah cells are being developed as the first stage of the scale-up process and the design of these cells involves several tradeoffs related to the specific nature of this application. This paper will present the design of this first generation cell in the context of these tradeoffs as well as presenting the results of the performance and life testing of these cells.
Technical Paper

5G Network Connectivity Automated Test and Verification for Autonomous Vehicles Using UAVs

2022-03-29
2022-01-0145
The significance and the number of vehicle safety features enabled via connectivity continue to increase. OnStar, with its automatic airbag notification, was one of the first vehicle safety features that demonstrate the enhanced safety benefits of connectivity. Vehicle connectivity benefits have grown to include remote software updates, data analytics to aid with preventative maintenance and even to theft prevention and recovery. All of these services require available and reliable connectivity. However, except for the airbag notification, none have strict latency requirements. For example, software updates can generally be postponed till reliable connectivity is available. Data required for prognostics use cases can be stored and transmitted at a later time. A new set of use cases are emerging that do demand continuous, reliable and low latency connectivity. For example, remote control of autonomous vehicles may be required in unique situations.
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