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Technical Paper

Hole Quality Study in High Speed Drilling of Composite and Aluminum Sheet Metal

1999-04-20
1999-01-1564
Drilling is one of the most widely applied manufacturing operations. Millions of holes are drilled today in manufacturing industries especially in aerospace industry where high quality holes are essential. Rejection and rework rate of the products because of the bad hole is quite high. In this research graphite/honeycomb composite material and aluminum sheet metal has been used. The results show that drill geometry, speed and feed rate have substantial effects on the hole quality and also there was gradual variation of the thrust and lateral forces with feed rates.
Technical Paper

Flying Qualities Evaluation of a Commuter Aircraft with an Ice Contaminated Tailplane

2000-05-09
2000-01-1676
During the NASA/FAA Tailplane Icing Program, pilot evaluations of aircraft flying qualities were conducted with various ice shapes attached to the horizontal tailplane of the NASA Twin Otter Icing Research Aircraft. Initially, only NASA pilots conducted these evaluations, assessing the differences in longitudinal flight characteristics between the baseline or clean aircraft, and the aircraft configured with an Ice Contaminated Tailplane (ICT). Longitudinal tests included Constant Airspeed Flap Transitions, Constant Airspeed Thrust Transitions, zero-G Pushovers, Repeat Elevator Doublets, and, Simulated Approach and Go-Around tasks. Later in the program, guest pilots from government and industry were invited to fly the NASAT win Otter configured with a single full-span artificial ice shape attached to the leading edge of the horizontal tailplane.
Technical Paper

Boeing 757/767 Commonality Design Philosophy

1981-08-01
810845
The 757 and 767 airplanes provide maximum commonality in equipment, flight deck configuration and handling characteristics. Pilots with three-crew ratings will be qualified to fly either airplane with a three-crew requirement, and those with two-crew ratings will have the same flexibility. In addition to crew qualification, over 80% of the LRUs in the Flight Management System are interchangeable between similar crew configurations of the 757 and 767, i.e., they have the identical part number. Seventy-five percent of the LRUs are common to both the two-and three-crew configurations. Components that have engine-related software (the Thrust Management and Flight Management Computers) will be interchangeable between 757 and 767 aircraft powered by engines from the same manufacturer.
Technical Paper

Operational Aspects of the Integrated Vertical Flight Path and Speed Control System

1983-10-03
831420
Operational aspects of a functionally integrated automatic flight path and speed control autopilot are discussed. A system is described using point mass energy principles to develop coordinated elevator and thrust commands and provide decoupled flight path and speed control for all the traditional autopilot and autothrottle functions. Various aspects of this integrated multi-input/multi-output system design on performance, operational capability, system architecture and redundancy requirements, hardware and software requirements are described. Also, possible mode control panel functional design improvements are discussed. Feedback signal normalization into energy related quantities is shown to be the key to achieving natural control decoupling with desired energy management features and consolidation of all computations for fully automatic control, computer augmented manual control and flight director thrust/elevator control guidance displays.
Technical Paper

A Design Approach to Integrated Flight and Propulsion Control

1983-10-03
831482
A decentralized, multivariable controls methodology is being developed for the functional integration of a fighter's aerodynamic controls with those of its propulsion system (inlet, engine, and thrust vectoring/reversing nozzle). Integrated controls account for, and take advantage of the significant cross-coupling between these system elements. A high-fidelity, six-degrees-of-freedom (6 DOF) aircraft simulation has been developed, incorporating advanced tactical fighter features such as variable cycle engines, variable geometry inlets, 2D-CD TV/TR nozzles, canards and a propulsive lift concept. A comprehensive evaluation test plan, including a piloted simulation, has been developed to validate this integrated-controls design methodology. Preliminary results show significant benefits of integrated control in terms of enhanced aircraft maneuverability, precise flight path control, reduced pilot workload, and fault tolerant system design.
Technical Paper

Uncertainty Methodology for In-Flight Thrust Determination

1983-10-03
831438
The Society of Automotive Engineers technical committee E-33 for In-Flight Propulsion Measurement is preparing an Aerospace Information Report on Uncertainty of In-Flight Thrust Determination (AIR-1678). The proposed methodology for evaluating uncertainty provides traceability of errors to a national standards laboratory, and is independent of the procedure used to calculate or measure thrust in-flight. This results in a consistent means of evaluating different in-flight thrust measurement capabilities. This paper summarizes Che proposed methodology. A companion paper, “Application of In-Flight Thrust Determination Uncertainty Methodology” presents an example application of the methodology based on the US Air Force Air Launched Cruise Missile (ALCM) program.
Technical Paper

Application of In-Flight Thrust Determination Uncertainty

1983-10-03
831439
The Society of Automotive Engineers technical committee E-33 for In-Flight Propulsion Measurement is preparing an Aerospace Information Report on Uncertainty of In-Flight Thrust Determination (AIR-1678). The proposed methodology for evaluating uncertainty provides trace-ability of errors to a national standards laboratory, and is independent of the procedure used to calculate or measure thrust in-flight. This results in a consistent means of evaluating different in-flight thrust measurement capabilities. A companion paper, “Uncertainty Methodology for In-Flight Thrust Determination”, summarizes this proposed methodology. This paper presents an example application of the methodology based on the US Air Force Air Launched Cruise Missile (ALCM) program.
Technical Paper

VTOL Controls for Shipboard Operations

1983-10-03
831428
Piloted, moving-base simulations have been performed in the evaluation of several VTOL control system concepts during landings on a destroyer in adverse weather conditions. All the systems incorporated attitude control augmentation; most systems incorporated various types of translational control augmentation implemented either through aircraft attitude or, more directly, through the propulsion system (thrust magnitude and deflection). Only one of the control systems failed to provide satisfactory handling qualities in calm seas. Acceptable handling qualities in sea state 6 seem to require a system with control augmentation in all translational degrees of freedom.
Technical Paper

STOL and Maneuver Technology Program

1983-10-03
831425
The STOL and Maneuver Technology Program, formally titled the “STOL Fighter Technology Program” has as its objective to demonstrate through flight test a short takeoff and landing capability on a supersonic fighter while enhancing its performance capability in all other segments of the air-to-air mission. Specific task is to takeoff and land on a 1500 by 50 foot runway at night and during ad verse weather conditions. To accomplish this task without sacrificing performance requires the integration of advanced technologies into the aircraft. The technologies included in this effort are: a two dimensional thrust vectoring/reversing exhaust nozzle; integrated flight/propulsion control; cockpit displays and controls for all weather STOL operations; and rough/soft field landing gear. As presently structured, the program will modify an existing fighter like the F-15, F-16, or F-18. A contract will be awarded in late summer of 1983 and first flight is scheduled for the fall of 1987.
Technical Paper

Inlet Design for High-Speed Propfans

1982-02-01
821359
A two-part study was performed to design inlets for high-speed propfan installation. The first part was a parametric study to select promising inlet concepts. A wide range of inlet geometries was examined and evaluated - primarily on the basis of cruise thrust and fuel burn performance. Two inlet concepts were then chosen for more detailed design studies - one appropriate to offset engine/gearbox arrangements and the other to in-line arrangements. In the second part of this study, inlet design points were chosen to optimize the net installed thrust, and detailed design of the two inlet configurations was performed. An analytical methodology was developed to account for propfan slipstream effects, transonic flow effects, and three-dimensional geometry effects. Using this methodology, low drag cowls were designed for the two inlets.
Technical Paper

The Electric Orbiter

1982-02-01
821419
The current design base of the Space Shuttle Orbiter employs hydraulic actuation for control of aerosurfaces, engine thrust, engine thrust vector, brakes, and landing gear functions. As early as 1972, electromechanical actuation (EMA) was considered as an alternative system. As a result of continued advances in technology development, studies now indicate that EMA is a more attractive alternative. Major advantages are weight reduction, striking improvement in energy efficiency, easier maintenance, and a cleaner vehicle. The results of a system study advocating EMA for the Orbiter are presented. Emphasis is placed on a clear understanding of the relationships between mission requirements and design parameters. EMA system energy requirements are compared with those of the existing hydraulic system. Detailed discussion of the synthesized EMA system is limited to the aerosurface actuators. The design is consistent with the Orbiter “fail operational,” “fail safe” redundancy requirement.
Technical Paper

Development of Thrust Augmentation Technology for the Pegasus Vectored Thrust Engine

1982-02-01
821390
Front nozzle thrust augmentation, on lift/cruise engines like the Pegasus, could greatly improve the range and load carrying capacity of Harrier/AV-8B type VTOL aircraft and is essential for supersonic derivations. However its introduction requires several new technologies to be developed for the augmentor itself, for the augmentor and engine control system and to cater for various potentially adverse ground effects and related matters. These are the subject of a number of current research and development programmes which will lead to an engine demonstration of an advanced augmentor.
Technical Paper

A Computer Model of a Pulsejet Engine

1982-02-01
820953
This paper deals with the performance prediction of one member of a family of thrust producing intermittent combustion engines, namely the pulsejet. The first part is concerned with formulating basic concepts of how pulsejets work. It describes the different methods of providing intake valving action and derives theory to demonstrate the operation of the aerodynamic tuned valve in particular. The second part is concerned with devising a computer program to simulate and predict the performance of valveless pulsejets. The program is based on the method of characteristics for calculating unsteady gas flow. Theories and techniques are given to handle the major problems associated with this application. These problems include the large range of discontinuous temperature and entropy, flow through an area discontinuity and the calculation of mean thrust.
Technical Paper

Investigation of a Flight Test Method for the Measurement of Propeller Thrust

1981-02-01
810603
A full scale wind tunnel test was performed with a general aviation aircraft to investigate the use of the slipstream momentum survey method as a means of measuring propeller thrust in flight. Aircraft angle of attack is shown to have significant influence on the momentum measurements. Thrust values obtained from the slipstream momentum correlated well with overall aircraft force measurements; however, insufficient data regarding the slipstream static pressure variation resulted in a systematic error in the results. The need for detail static pressure measurements in the slipstream is demonstrated.
Technical Paper

How to Involve Younger Members and Non-North Americans in Standards Development - an Imperative for U.S. Business

2000-10-10
2000-01-5617
To properly Involve Younger Associates and Non-North Americans in Standards Development, a joint responsibility between companies and SAE is required: Recruit appropriate representatives who represent the diversity of the company. Create an attractive environment in which to work. Lead representatives but do not breathe down their necks. Prepare them properly, including training and mentoring (tagging along). Create attrition plans. Engage in the principles of Strategic Standardization Management. Tie committee work with member company's business, technology and project plans. Make the process more efficient. Facilitate electronic communication and web-based tools. Carefully weigh alternative projects; choose the ones with the highest potential. Recognize the standards development phases. Provide credit (rewards and awards) when credit is earned.
Technical Paper

Augmentation for Synthetic Vision Displays – An Energy Based Approach

2000-10-10
2000-01-5518
To provide information about the position and orientation of the aircraft relative to the required flight path, several experimental synthetic vision display formats include a depiction of this path by means of a so-called highway-or tunnel-in-the-sky, sometimes augmented with a position predictor. To accurately track both a vertical path and a commanded velocity, energy management is required. The conventional position predictor supports path tracking but requires the pilot to use the resulting velocity error for thrust control. This paper discusses the development of an enhancement to the position predictor based on energy management considerations. The enhanced predictor provides the information needed to maintain energy awareness and allows an anticipatory thrust control strategy to be applied.
Technical Paper

Residual Error for In-Flight Thrust Determination

2000-12-01
2000-01-3251
Forces acting on the installed propulsion system are difficult to be defined and even more difficult to be evaluated. The fundamental problem of any in-flight thrust computation is that the methodology employed is always indirect, that is measurements are made of indicators of thrust. This paper discusses the necessity of in-flight thrust determination (IFTD) and methods of thrust calculation as well as the reasons for the choice of a method. The residual error (RERR) method is a variant of the gas-path/nozzle method, which does not require an ATF test, and can be used for turbofan engines to extrapolate sea level static (SLS) data to higher pressure ratios found during flights. The RERR method is described and applied to data expansion and thrust calculation of turbofan engine.
Technical Paper

Electric 30,000 RPM Shave Spindle for C Frame Riveter and High Performance Compact Aerospace Drill

2000-09-19
2000-01-3017
Two spindles are discussed in this paper. The first spindle was installed on nine C-frame riveters on the 737/757 wing line at the Boeing Renton facility. Due to discontinuing the use of Freon coolant and cutting fluid, the C-frame riveters had difficulty shaving 2034 ice box rivets with the existing 6000 RPM hydraulic spindles. The solution was to install electric 30,000 RPM shave spindles inside the existing 76.2 mm (3 in.) diameter hydraulic cylinder envelope. The new spindle is capable of 4 Nm (35 in. lbs.) of torque at full speed and 110 kgf (250 lbs.) of thrust. Another design of interest is the Electroimpact Model 09 spindle which is used for 20,000 RPM drilling and shaving on wing riveting systems. The Model 09 spindle is a complete servo-servo drilling system all mounted on a common baseplate. The entire spindle and feed assembly is only 6.5″ wide.
Technical Paper

UCAV Backwards Engine Configuration

1999-04-13
1999-01-1448
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.
Technical Paper

DC-DC Converter for Hall Thruster Plasma Discharge

1999-04-06
1999-01-1382
A Hall Thruster discharge power converter breadboard was successfully developed. The converter is rated at 400 Watts, with a maximum output of 350 Volts or 1.25 Amps. Both voltage and current are real time continuously adjustable from zero to their respective maximums. An arbitrary number of these converters can be paralleled, offering modularity, redundancy and power scaling for application on a range of Hall thrusters from few a hundred watts to several kilowatts. Operational stability and an overall efficiency of 92% was demonstrated over a broad power range, first on a resistive load and then on Busek's 200 Watt Hall thruster. The design, construction and test results are described in this paper with particular attention to the dynamic interaction of the converter and the thruster.
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