SAWE Technical Papers

@inproceedings{2101,

title = {2101. An Expanded Role for the Mass Properties Engineer},

author = {Richard Boynton},

url = {https://www.sawe.org/product/paper-2101},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {29},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {Many mass properties engineers limit their responsibility to calculating and measuring mass properties. In this paper I propose that mass properties engineers should expand their role in their company to include the following: Calculate mass properties. Measure mass properties (or at least know what the sources of measurement error are). Be active and aggressive in creating the mass properties specification for a payload. Define the coordinate system for the payload and encourage other parties such as the flight dynamics engineers to use the same coordinate system. Insure that the original design of the payload includes hard points such as precision rings so there is an unambiguous mechanical reference coordinate system. Be a major influence in the early design phase, so it won't be necessary to use large tungsten ballast weights to compensate for a poor design. Have a good understanding of flight dynamics. The first response I have gotten from fellow mass properties engineers when I suggested these ''proposed responsibilities'' was that they had more work than they could handle right now, and the last thing they wanted was additional responsibility. However, my point is that sooner or later you get involved with all these issues. It is much better to be in control of the situation, rather than to be the victim of poor decisions.},

keywords = {17. Weight Engineering - Procedures},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2098,

title = {2098. Developing the Mass Properties for the HL-20},

author = {Ian O. MacConochie},

url = {https://www.sawe.org/product/paper-2098},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {25},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {A small shuttle in the form of a lifting body is proposed for the assured return of eight astronauts from a space station. The Spacecraft, designated HL-20, is delivered to the station with wings folded in the Shuttle orbiter cargo bay. Subsystems are sized for a 24-hour flight duration and are configured so that the vehicle can remain docked to the space station unattended for long periods of time in a ready state for the return of the space station crew on demand. The HL-20 is also being studied as an alternative means for manned access to space when delivered on an expendable launch vehicle such as a Titan. For these missions, flight times are increased from 24 to 72 hours, or enough time to go to the space station, changeout the crew, and return to Earth. Operational simplicity for subsystems was emphasized in the study. This paper is primarily a survey of subsystem options and concepts with discussions of the weight and operational benefits and penalties associated with some of the concepts. A weight breakdown based on conventional components is given for two baseline vehicles with an explanation as to the weight reductions or penalties for state-of-the-art alternatives.},

keywords = {18. Weight Engineering - Spacecraft Design},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2093,

title = {2093. Using the ''Moment of Inertia Method'' to Determine Product of Inertia},

author = {K Wiener and Richard Boynton},

url = {https://www.sawe.org/product/paper-2093},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {27},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {Product of inertia is generally measured using a spin balance machine. In this type of machine, the object is rotated at a speed of about 100 RPM, and the reaction forces against the upper and lower spindle bearings are measured. Product of inertia is then calculated automatically by the machine's on line computer, using formulas that involve the vertical spacing between the upper and lower bearings and the height of the object above the mounting surface of the machine. Objects such as control fins and satellites with extended solar panels cannot be measured using this method because of the large, non-repeatable errors which are introduced by the entrained and entrapped air and turbulence. This paper outlines a method of determining product of inertia by making a series of moment of inertia measurements with the object oriented in six different positions. Product of inertia can then be calculated using formulas which involve the rotation angles of the different fixture positions. Moment of inertia is measured by oscillating the object on a torsion pendulum. Since the object moves very slowly during this measurement, there are negligible centrifugal and windage forces exerted on the object Furthermore, the mass of the entrapped and entrained air can be compensated for by making a second set of measurements in helium and extrapolating the data to predict the mass properties in a vacuum. This paper gives step-by-step instructions on how to measure product of inertia on a torsion pendulum. Special fixtures must be constructed to move the object to the six positions while keeping both the object and the fixture CG near the center of oscillation. We have included design details of such a fixture. Since vacuum data was required, measurements were made in a chamber which could be filled with helium. The design of this chamber is also explained in detail. To illustrate this method, we have used as an example real measurements which were made of airfoil control fins manufactured by one of our customers. For this example, we determined all mass properties: weight, center of gravity along three axes, moment of inertia about three axes, and product of inertia in three planes, all referred to vacuum conditions.},

keywords = {06. Inertia Measurements},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2090,

title = {2090. Advanced Composites Sizing Guide for Preliminary Weight Estimates},

author = {J W Burns},

url = {https://www.sawe.org/product/paper-2090},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {37},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {During the preliminary design and proposal phases, it is necessary for the mass properties engineer to make weight estimates that require preliminary rough estimates to improve or verify Level I and Level II estimates and to support trade studies for various types of construction, materials substitution, wing t/c, and design criteria changes. The purpose of this paper is to provide a simple and easy to understand, preliminary sizing guide and present some numeric examples that will aid the mass properties engineer that is inexperienced with advanced composites analysis.},

note = {L. R. 'Mike' Hackney Award},

keywords = {23. Weight Engineering - Structural Estimation, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2089,

title = {2089. Finite Element Model Weight Estimation},

author = {M Droegkamp},

url = {https://www.sawe.org/product/paper-2089},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {14},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {Weight is a primary criterion of aircraft performance and is frequently used as the basis for estimating aircraft cost. Weight and cost of future aircraft will be influenced by changes in design requirements and by new technologies incorporated to meet the goals set by our customers. To control and optimize the weight of aircraft structure and reduce cost, estimation procedures must be developed to reflect the weight effects of new materials and innovative configurations. This requires that weight estimation be performed at greater levels of detail than conventional weight estimation methods. The finite element model (FEM) is well suited for such detailed studies. This paper presents the technology MCAIR is developing to estimate weight from the structural FEM and distribute both structural and non-structural weight back into the FEM. Ibis technology is providing the capability to estimate and control the weight of detail parts such as individual spars, ribs, and skins. FEM weight estimates also reflect the weight impact of configuration details included in the model such as spar spacing, material properties, and construction techniques. The weight estimate can be distributed back into the FEM so that inertial loads, mode shapes, natural frequencies, flutter, and divergence speed can be calculated more accurately.},

keywords = {23. Weight Engineering - Structural Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2087,

title = {2087. Smart Materials and Structures: A Weight Saving Proposition},

author = {S P Joshi},

url = {https://www.sawe.org/product/paper-2087},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {11},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {In the early days, structural integrity was ensured by overdesigning. As safety margins have decreased, requirements for preventive inspection and maintenance have increased. Structures in the near future will be able to prevent damage to a certain extent, able to sense the damage, and survive the damage by incorporating adaptive control. They will also be able to alert us to proper maintenance. These structures are termed as ''smart structures.'' Remarkable inventions in sensor technology, discoveries of new materials, and increase in computing capabilities have made it possible for the first time to build smart structures. These structures have to be highly redundant, self testing, damage survivable, and fault tolerant.},

keywords = {22. Weight Engineering - Structural Design},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2086,

title = {2086. Probabilistic Design of Advanced Composite Structure},

author = {P M Gray},

url = {https://www.sawe.org/product/paper-2086},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {18},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {Advanced composite technology offers potentials for sizable improvements in many areas: weight savings, maintainability, durability, and reliability. However, there are a number of inhibitors to these improvements. One of the biggest inhibitors is the imposition of traditional metallic approaches to design of composite structure. This is especially detrimental in composites because new materials technology demands new design approaches. Of particular importance are the decisions made regarding structural criteria. Significant changes cannot be implemented without careful consideration and exploration. This new approach is to implement changes on a controlled, verifiable basis. Probabilistic design is the methodology and the process to accomplish this. Its foundation is to base design criteria and objectives on reliability targets instead of arbitrary factors carried over from metallic structural history. This paper discusses the background of probabilistic design and presents the results of a side-by-side comparison to generic aircraft structure designed the ''old'' way and the ''new.'' Activities are also defined that need to be undertaken to evolve available approaches to probabilistic design followed by summary and recommendations.},

keywords = {22. Weight Engineering - Structural Design},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2066,

title = {2066. Farid Program: Streamlines Spreadsheet Database to Satisfy All Required Weight Section Output},

author = {F Bergmann},

url = {https://www.sawe.org/product/paper-2066},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {29},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {The stage is set. The contract has been awarded and the preliminary design accelerates. Technical reviews and presentations abound while timely weight reporting remains as a sustaining requirement - unfettered by additional time restrained requirements. Time management becomes crucial for completing each managerial milestone. Time management becomes crucial for finding time needed to effectively control weight reflected in all output. This paper presents a ''case study'' solution for this early design challenge. The solution presented is an automated LOTUS spreadsheet macro program called FARID combined with linked spreadsheet worksheets and charts. It has become a successful tool in achieving all weight resource goals and objectives. This paper will show an effective way of producing report tables and charts, viewgraphs, output to other disciplines, and output for internal weight optimization studies. Each is derived from a single database and the tool to achieve this is orchestrated with minimal effort and will eliminate error which could be created from repetitive work. This paper is not a solution to controlling weight but a tool to allow better command of it. The paper will not provide a definitive method but will open a series of possibilities for the time constrained engineer.},

keywords = {12. Weight Engineering - Computer Applications},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2065,

title = {2065. Electronic Weight Management System (EWMS) Cradle to Grave Weights: an Automated Approach},

author = {M A Wood},

url = {https://www.sawe.org/product/paper-2065},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {17},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {Weight engineering has come a long way in the last decade. Calculation sheets have been replaced by weight databases. Manual methods are now accomplished with computer applications. Engineering, in general, is now becoming less and less paper dependent and becoming more electronically diversified in many ways. To stay effective in this constantly changing environment, weight engineers must have the right tools that will allow them to do their job. The weight engineer must receive information from a wide variety of Engineering Design and Management applications and drawing release systems and provide information to an extremely diversified customer list, both internal and external. The Electronic Weight Management System (EWMS) is a series of programs designed to provide the mass properties tools needed to do the day-to-day work; however, EWMS does not stop with mass properties applications. The EWMS philosophy is to integrate all mass properties software and to create interfaces with CAD/CAM systems, other engineering software and systems, drawing release systems, management applications, and internal and external networks. EWMS will provide the capability for weight engineers to have a common or standard method for communicating between disparate weight systems. In the new marketplace, no one company will be solely responsible for a product. A quality product will depend on successful communication between primary and support companies and their customer. EWMS is an automated total mass properties system to support the mass properties effort from the cradle to the grave.},

keywords = {12. Weight Engineering - Computer Applications},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2062,

title = {2062. A Construction Method for Latin Squares},

author = {P A Coartney and J M Dr. Moser},

url = {https://www.sawe.org/product/paper-2062},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {15},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {Most textbooks cover simple ANOVA techniques that handle factorial designs, but few give methods for reducing the number of trials. The most salient part of ''Real World'' statistical analysis is that sample size is dictated by budget and schedule. The method of Latin Squares is an experimental design which allows for a significant reduction in trials for a factorial experiment if certain conditions are met. This paper presents a construction method for Latin Squares of prime order. Development of the technique is done through an example of the 5x5 case. Equations necessary to complete the technique are given in general form to facilitate program coding.},

keywords = {12. Weight Engineering - Computer Applications},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2055,

title = {2055. Reversible Bonding of Composite Aircraft Structures},

author = {T Schneider},

url = {https://www.sawe.org/product/paper-2055},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {13},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {In 1989 and 1990, LTV Aerospace and Defense Company, Aircraft Division supported an independent research and development program titled Lightweight Structures. This program focused on developing innovative design and manufacturing concepts which have the potential to reduce aircraft structural weight. Reversible bonding is one such concept that emerged from the lightweight structures program. It is capable of reducing future aircraft acquisition and support costs as well as decreasing weight.},

keywords = {22. Weight Engineering - Structural Design},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2054,

title = {2054. The Ten-Percent Rule for Preliminary Sizing of Fibrous Composite Structures},

author = {L J Dr. Hart-Smith},

url = {https://www.sawe.org/product/paper-2054},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {28},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {Simple, reliable methods are presented for calculating the fiber-dominated in-plane strengths of well designed fibrous composite laminates. This is accomplished by a simple rule of mixtures, the Ten Percent Rule. The primary fibers for each uniaxial load condition are considered to develop 100 percent of the reference strength of the composite material for each environment, while the secondary (transverse) fibers are credited with only 10 percent of this strength and stiffness, whether they be inclined at 90' to the primary fibers or at ?45 deg. The procedure is applied to uniaxial loads, to biaxial loads of the same sign, and to biaxial loads of opposite signs (which is equivalent to in-plane shear with respect to rotated axes). A worked example for a wing skin is included to show how very rapidly this method converges on the most suitable design to withstand a set of loads, whether applied simultaneously or separately. Since neither this nor any other method less complicated than micromechanics is capable of identifying structurally inferior (matrix-dominated) fiber patterns that should be avoided, the preferred fiber patterns within the O deg, ?45 deg, and 90 deg family are established by other analyses and empirically acquired wisdom. Various other simple formulae suitable for calculating the laminate strengths and elastic constants are included. Differences between the predictions of this failure model and those of better publicized models are attributed to the failure of other authors to recognize that homogenizing the fibers and resin matrices into a single ''equivalent'' orthotropic material is permissible only for calculating elastic properties and is scientifically incorrect for predicting the strength of distinctly heterogeneous conventional fiber-polymer composites.},

keywords = {27. Weight Reduction - Materials},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2053,

title = {2053. Benefits of IHPTET Technology in Advanced Engine Turbomachinery},

author = {D F Garcia},

url = {https://www.sawe.org/product/paper-2053},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {8},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {The Integrated High Performance Turbine Engine Technology (IHPTET) initiative is a joint Department of Defense / NASA / Industry effort to develop and demonstrate revolutionary and innovative technologies that will double propulsion system capability). The technologies that result from this initiative, once transitioned, will ensure the superiority of U.S. Military Aircraft. The approach Pratt & Whitney (P&W) has taken in the development of advanced propulsion system technologies is to initiate and develop innovative concepts that allow a timely transition into advanced military products required by the U.S. Government. P&W's Advanced Turbo Pulsion Plan (ATPP) identifies the program necessary for the development of advanced technologies. The plan is a result of a three task process with Task I consisting of establishing weapon system requirements based on mission and desired performance. Task II involves conceptual design studies to establish engine weight performance, durability, and cost that result from concept application. In Task III, development plans are established for those high payoff technologies identified in Task II. P&W's Advanced Turbo Pulsion Plans are now grouped by IHPTET phase. Each IHPTET phase write-up contains a description of the plans for the six major component disciplines: fan (compressor, combusters/augmenters), turbines, mechanical components and systems, controls, and nozzles. Issues covered for each discipline include: component goals, critical path, structures, and material roadmaps.},

keywords = {27. Weight Reduction - Materials},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2051,

title = {2051. New Developments in Interconnection Technology},

author = {L P Stuart},

url = {https://www.sawe.org/product/paper-2051},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {11},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {Reliability and weight consideration are important criteria of every avionics design engineer. This paper concentrates on three specific ways in which new developments in interconnection technology are increasing the reliability of the equipment while decreasing its weight: Substitution of metallic parts by composite material. Development of advanced technology. Converting electronic systems to optical. This paper shows details of each method with practical examples of application.},

keywords = {27. Weight Reduction - Materials},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2050,

title = {2050. The Boeing Model 360 Advanced Technology Demonstrator Helicopter},

author = {J S Wisniewski},

url = {https://www.sawe.org/product/paper-2050},

year  = {1992},

date = {1992-05-01},

booktitle = {51st Annual Conference, Hartford, Connecticut, May 18-20},

pages = {30},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {Hartford, Connnecticut},

abstract = {The Model 360 all-composite demonstrator helicopter was developed by Boeing Helicopters over several years. It was company funded by Boeing to validate advanced technologies that could be applied to the company's other rotorcraft programs. Major efforts have been directed at the integration of new technology in structures, aerodynamics, flight controls, avionics and cockpit design. High Strength, lightweight composite materials make up almost all of the aircraft's primary and secondary structure. Four graphite covered rotor blades with tapered tips are attached to a composite rotor hub for increased speed with reduced noise and vibration. A retractable tricycle landing gear and buried aft fuselage engines also improved the aircraft's performance. Pilot's workload is reduced with a digital automatic flight control system and an integrated avionics system. It incorporates a glass enclosed Cockpit with six multi-function displays. The Model 360 Development Program included over 5000 hours of wind tunnel tests and an extensive simulator assessment of the helicopter's handling and flying qualities. First flight of the Model 360 took place on June 10,1987, in suburban Philadelphia. The new helicopter has demonstrated airspeeds at 214 knots and a maximum design speed of 235 knots. The current helicopter world speed record is held -by a Westland Lynx at 214.4 knots. The aircraft is currently in overhaul at the Boeing Helicopters Flight Test Center near Wilmington, Delaware.},

keywords = {10. Weight Engineering - Aircraft Design},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2046,

title = {2046. Aircraft Weight Confidence Assessment},

author = {M Anderson},

url = {https://www.sawe.org/product/paper-2046},

year  = {1991},

date = {1991-05-01},

booktitle = {50th Annual Conference, San Diego, California, May 20-22},

pages = {14},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {San Diego, California},

abstract = {The purpose of this paper is to present a technique that determines confidence levels of estimated weight data. The paper outlines a procedure and applies it to a fuel system weight breakdown. Using the fuel system example as a guide, determining confidence in an estimated aircraft weight could be found. The initial background and analysis for the method is presented with results of a confidence analysis using a ''bottoms-up'' system estimated weight. This method provides the foundation of a plan for tracking confidence of estimated aircraft weight throughout development Confidence levels can be updated continually and reviewed with management during design development. Design maturity is reflected in the possible variation of the itemized weight used in the models. By combining weight variations of each item and using simulation software, confidence levels for the total group weight can be determined. The paper concludes that confidence levels help set realistic goals, identify areas for possible weight reduction, and identify problem areas in parametric estimates or design/technology maturity.},

keywords = {21. Weight Engineering - Statistical Studies},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2043,

title = {2043. Exceling at Spreadsheet Development for Mass Properties Analysis},

author = {F Gruman},

url = {https://www.sawe.org/product/paper-2043},

year  = {1991},

date = {1991-05-01},

booktitle = {50th Annual Conference, San Diego, California, May 20-22},

pages = {14},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {San Diego, California},

abstract = {The main thrust of this paper is to show how the Microsoft Excel spreadsheet program can be used to perform-n mass properties analysis and the use of it as an alternative to developing custom FORTRAN, Pascal, or C programs. The paper begins with a brief overview of the Microsoft Excel program and its features. It then describes basic techniques for developing spreadsheets using a weight loading page as an example. It provides programming tips such as using the array function to calculate centers of gravity. The paper then discusses some rules for designing spreadsheets such as documentation, using notes, and dating. The paper further expands on the basic spreadsheet by introducing the concept of multiple spreadsheets which can be linked to one another. It then introduces the concept of macros and the ability to develop self contained interactive applications within Excel using customized menus and dialog boxes. It summarizes with some observations on Excel and lists some mass properties problems which have been solved using Excel.},

keywords = {12. Weight Engineering - Computer Applications},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2040,

title = {2040. 777 Weight Control in the Digital Environment},

author = {B Miller},

url = {https://www.sawe.org/product/paper-2040},

year  = {1991},

date = {1991-05-01},

booktitle = {50th Annual Conference, San Diego, California, May 20-22},

pages = {23},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {San Diego, California},

abstract = {It is Boeing Commercial Airplane Group's initiative to design the new 777 airplane digitally, using Dassault Systemes' Computer graphics Aided Three-dimensional Interactive Application (CATIA). This software is one of many sophisticated Computer Aided Design (CAD) packages currently in use within the aerospace industry. Our goal is to define each part of the airplane by a 3D solid (mass in space). Design engineers will use the 3D solids to perform Digital Pre-Assembly (DPA), commonly referred to as electronic mockup, ensuring that parts fit together before the design is released to manufacturing. This initiative is one of many vast departures from the Boeing business as usual scenario. Weight engineering, as well as all other disciplines within the 777 are, faced with operating in a new environment. Design definition which once was found in mounds of paper is now found through digital datasets. Designs that in the past took days to change are now evolving daily. Datasets can be shared from one site to another in seconds through the mainframe. A team comprised of weight engineers from various areas of Boeing evaluated the impact of the CAD environment on weight engineering. The team concluded that the 777 weight staff could conduct weight control on an equal or higher level than that encountered on past Boeing programs. However, change was eminent if weights was to fulfill their program responsibilities and implement any process improvements offered through the new digital environment Two actions were taken to help implement change. First, guidelines for weight control in the new environment were documented and distributed to the weight control groups. Secondly, two members of the team became full time consultants, providing on site support and training. This paper relays the major findings of the aforementioned team activity. These issues form the basis of the 777 Weight Control Plan. The CAD related issues which are addressed are: - How company computing business practices influence the overall operation of the weights staff, including the five required privileges that allow weights to perform at full potential in a digital environment. - The effect of CAD on the internal operations of a weights staff, including the recommended procedures required to ensure a smooth transition from the old ways of doing business. - How CAD has influenced the weight control process itself, addressing both the benefits and drawbacks. A section on how to utilize the digital definition for weight control efforts is also included.},

keywords = {12. Weight Engineering - Computer Applications},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2038,

title = {2038. A USAF Assessment of STOVL Fighter Options},

author = {D Hammond and R Fredette and G Tamplin and R Ashby},

url = {https://www.sawe.org/product/paper-2038},

year  = {1991},

date = {1991-05-01},

booktitle = {50th Annual Conference, San Diego, California, May 20-22},

pages = {25},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {San Diego, California},

abstract = {The US Air Force is in the early stages of defining the next generation multi-role fighter. It is anticipated that this aircraft will begin to replace the F-16 in the 2000-2010 time period. Wright Laboratory (WL) is identifying potential technologies that could have a significant impact on this aircraft. Some of these technologies are aimed at improving the operational flexibility of such an aircraft. The addition of short takeoff and vertical landing (STOVL) capability to fighter aircraft is one of these technology options. WL has invested a substantial in-house effort and contracted studies to define the possible attributes of a STOVL fighter and the required technology base. This is being done to give the US Air Force the option of fielding such an aircraft in the 2000-2010 time frame. The in-house study emphasized the air-to-air role of this multi-role fighter by designing to high levels of maneuverability, dry power supersonic cruise, and low observables. Some findings from the Advanced Fighter Technology Integration STOVL (AFTI STOVL) contracted studies are also summarized.},

keywords = {10. Weight Engineering - Aircraft Design},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2036,

title = {2036. The Effect of Composite Material Allowable Changes on VTOL Airframe Weights},

author = {R L Foye and R J Peyran},

url = {https://www.sawe.org/product/paper-2036},

year  = {1991},

date = {1991-05-01},

booktitle = {50th Annual Conference, San Diego, California, May 20-22},

pages = {34},

publisher = {Society of Allied Weight Engineers, Inc.},

address = {San Diego, California},

abstract = {This paper describes and demonstrates a method of predicting the weight change of any VTOL aircraft structure as a result of construction material design allowable changes (with emphasis on composite materials). This analysis is needed because the bulk of the composite airframe preliminary design experience and data base was accumulated at a time when less conservative allowables were used (and the same allowables were applied to all load cases). The weight savings reported in earlier composite program have generally eroded in the decade of the 80's as a result of the application of hot/wet property reductions, open hole allowables, impact damage reduction factors, and new failure and design criteria. Also, improvements in the specific properties of light alloys have reduced composite weight savings potential (by reducing metal aircraft component baseline weights). The analysis assumes small changes in the design allowables which do not affect vehicle configuration, structural concepts, or degree of dependence on bonding or mechanical fastening. The selection and application of specific materials throughout the structure remain unchanged. The design criteria for each structural element is held constant. Also, no reduction in safety margins is permitted and internal load levels are presumed to remain constant These assumptions make the analysis most appropriate where material properties change incrementally. Gross changes in material properties ultimately result in structural design changes to the vehicle. These types of cascading effects are not addressed by this analysis.},

keywords = {23. Weight Engineering - Structural Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}