SAWE Technical Papers

@inproceedings{3660,

title = {3660. Development of a Conceptual Flight Vehicle Design Weight Estimation Method Library},

author = {Andy Walker},

url = {https://www.sawe.org/product/paper-3660},

year  = {2016},

date = {2016-05-01},

booktitle = {75th Annual Conference, Denver, Colorado},

pages = {171},

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

address = {Denver, Colorado},

abstract = {The state of the art in estimating the volumetric size and mass of flight vehicles is held today by an elite group of engineers in the Aerospace Conceptual Design Industry. This is not a skill readily accessible or taught in academia. To estimate flight vehicle mass properties, many aerospace engineering students are encouraged to read the latest design textbooks, learn how to use a few basic statistical equations, and plunge into the details of parametric mass properties analysis. Specifications for and a prototype of a standardized engineering 'tool-box' of conceptual and preliminary design weight estimation methods were developed to manage the growing and ever-changing body of weight estimation knowledge. This also bridges the gap in Mass Properties education for aerospace engineering students. The Weight Method Library will also be used as a living document for use by future aerospace students. This 'tool-box' consists of a weight estimation method bibliography containing unclassified, open -source literature for conceptual and preliminary flight vehicle design phases. Transport aircraft validation cases have been applied to each entry in the AVD Weight Method Library in order to provide a sense of context and applicability to each method. The weight methodology validation results indicate consensus and agreement of the individual methods. This generic specification of a method library will be applicable for use by other disciplines within the AVD Lab, Post- Graduate design labs, or engineering design professionals.},

note = {Mike HackneyBest Paper Award - 2016},

keywords = {10. Weight Engineering - Aircraft Design, 11. Weight Engineering - Aircraft Estimation, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3639,

title = {3639. Weights Engineering of Historic Vessels},

author = {S Kery},

url = {https://www.sawe.org/product/paper-3639},

year  = {2015},

date = {2015-05-01},

booktitle = {74th Annual Conference, Alexandria, Virginia},

pages = {22},

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

address = {Alexandria, Virginia},

abstract = {Weights engineering feeds into hydrostatic trim and stability analysis and hydrodynamic analyses of many sorts. It is an important task that requires attention to detail and hours spent carefully reviewing drawings and manufacturers cut sheets to develop data at the necessary level of detail. What do you do when the ship was built far in the past and few or no drawings exist? What if there are a few drawings and references but they conflict on critical details? Will we ever be able to do an adequate weights analysis? This paper describes several such analyses and the detective work and re-engineering that has gone into developing reasonable weights and centers information for these historic vessels. These analyses were used to support sinking analyses in several cases and the problem is significantly different for a wooden vessel than a iron or steel vessel. The just-submerged analysis is significantly different from the surface analysis. Many tricks of geometry and integrating the results from different software can be used to further the understanding of the missing data.},

note = {Mike Hackney Best Paper Award, 2015},

keywords = {13. Weight Engineering - Marine, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3620,

title = {3620. Inertia Uncertainty Coordinate Transformation},

author = {Adam M. Tahir and J H Nakai},

url = {https://www.sawe.org/product/paper-3620},

year  = {2014},

date = {2014-05-01},

booktitle = {73rd Annual Conference, Long Beach California},

pages = {18},

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

address = {Long Beach, California},

abstract = {The nominal values and uncertainties of inertia tensor elements (moments and products of inertia) are dependent on the coordinate frame in which they are described. In many mass properties applications, there is a need to perform coordinate transformations in order to describe moments and products of inertia and their uncertainties in different coordinate frames. Coordinate transformation methods and algorithms for nominal moments and products of inertia are well known, but to date there are no agreed-upon procedures and algorithms to perform coordinate transformations on inertia uncertainties. This paper proposes a method to consistently express inertia uncertainties in different coordinate frames. This method addresses the problem as a linear optimization problem. The method's accuracy is being tested using a probabilistic model. Early results look promising.},

note = {Mike Hackney Best Paper Award},

keywords = {05. Inertia Calculations, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3569,

title = {3569. Revisiting Seawater Density and its Impact on Submarine Design},

author = {David Tellet},

url = {https://www.sawe.org/product/paper-3569},

year  = {2013},

date = {2013-05-01},

booktitle = {72nd Annual Conference, St. Louis, Missouri},

pages = {88},

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

address = {Saint Louis, Missouri},

abstract = {This paper presents an analysis of seawater density data and relates the findings to submarine design impacts. Oceanographic temperature, depth, and salinity data from all the Earth's oceans and seas were analyzed to test the hypothesis that the standard heavy density value used by the US Navy could be reduced for certain submarine designs. The data support the hypothesis. Design impacts of reducing water density requirement are noted. The paper includes a summary table of all the data and detailed summary sheets for each of the 100 separate datasets used in the analysis.},

note = {Mike Hackney Best Paper Award},

keywords = {13. Weight Engineering - Marine, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3547,

title = {3547. Implementation of a Tool Chain for Extended Physics-Based Wing Mass Estimation in Early Design Stages},

author = {Felix Dorbath and Björn Nagel and Volker Gollnick},

url = {https://www.sawe.org/product/paper-3547},

year  = {2012},

date = {2012-05-01},

booktitle = {71st Annual Conference, Bad Gögging, Germany},

pages = {21},

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

address = {Bad Gögging, Germany},

abstract = {The state-of-the-art methods in preliminary wing design are using models employing physics-based methods for primary structures while using empirical correlations for secondary structures. Using those methods, detailed optimization as e.g. rear spar positions or flap size is only possible within a limited design space. Novel structural concepts such as multi-spar flap layouts or the introduction of composite materials cannot be analyzed using statistical methods and require extended higher level structural modeling. Therefore an interdisciplinary tool chain is developed for extended physics-based wing mass estimation. The tool chain consists of the following components: one central model generator, a structural finite element model, a structural sizing algorithm and loads models for aerodynamic, fuel, landing gear and engine loads. The structural finite element wing model consists of the following main parts: wing box, fixed trailing edge devices, movable trailing edge devices, spoilers, landing gears and engine pylons. The model generator is able to create several different kinds of track kinematics, covering most of the track types used in state-of-the-art aircrafts. To make the complexity of the model generation process feasible for one aircraft designer, a knowledge based approach is chosen. Therefore the central model generator requires a minimum set of easy-to- understand input parameters. This enables the aircraft designer to focus on the design and not on calculating input parameters. To include the tool chain in a wider multidisciplinary aircraft design environment, the aircraft parameterization CPACS (Common Parametric Aircraft Configuration Scheme) is used as central data model for input and output. The developed tool chain is implemented as flexible as possible to enable the designer to analyze also novel structural concepts or wing configurations. On wing configurational level, the tool chain can handle most types of different wing concepts, such as e.g. blended wing bodies, strut-braced wings and box wings. On the structural concepts side, the tool chain is able to handle various different rib and spar layouts and different materials (incl. composites).},

note = {Mike Hackney Best Paper Award},

keywords = {10. Weight Engineering - Aircraft Design, 23. Weight Engineering - Structural Estimation, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3521,

title = {3521. Mass Properties and Automotive Vertical Acceleration},

author = {B P Wiegand},

url = {https://www.sawe.org/product/paper-3521},

year  = {2011},

date = {2011-05-01},

urldate = {2011-05-01},

booktitle = {70th Annual Conference, Houstion, Texas},

pages = {112},

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

address = {Houston, Texas},

abstract = {The mass properties of a vehicle affect its' motion in all directions, translational and rotational. Previously this author has dealt with how mass properties affect automotive longitudinal acceleration1 and automotive lateral acceleration2. Now a consideration is in order of how mass properties affect automotive vertical acceleration. Of course, lateral or longitudinal inputs can lead to vertical responses, etc., every aspect of a vehicle's dynamics is interconnected with every other aspect, but it is convenient to divide up automotive dynamics as if the subject were purely a matter of independent accelerations in the longitudinal, lateral, and vertical directions. Initially, this paper will investigate the significance of mass properties with regard to automotive ride (transmission of road shock & vibration) and road-holding (maintaining contact at the tire/road interface) through the use of simple, undamped, 1 DOF models. Later, the full story of how mass properties influence the bounce and pitch motions of the sprung mass will necessitate recourse to more complex 2 DOF models. The mass properties of greatest relevance to this investigation will prove to be the 'sprung' mass, the 'unsprung' masses, the 'sprung' mass distribution (longitudinal, lateral, and vertical c.g. location), the rotational inertias of the rotating portions of the 'unsprung' masses, and the 'sprung' mass longitudinal and lateral mass moments of inertia. The basic intent of this paper is to counter the commonly held simplistic concept of the role mass properties play in determining ride and road-contact. For those that have never undertaken any study of the matter, the general presumption seems to be that all that is required to achieve optimum performance is to minimize the weight and to obtain a balanced mass distribution. The reality is that there are many aspects to automotive performance, and what constitutes an optimum mass properties condition is generally a very complex matter which often necessitates difficult compromises. Tailoring some mass property parameters so as to achieve a desirable level of behavior with regard to one performance criteria will often adversely affect other performance criteria. Although this paper is restricted to mass properties issues related to performance resulting from motion in the vertical direction, occasional reference will be made to those mass properties requirements necessitated by performance considerations associated with the longitudinal (acceleration, braking) and lateral (maneuver, roll-over, and directional stability) directions, as revealed in the previous investigations noted earlier. To do otherwise would be to work in a vacuum; the nature of reality tends to be such that all things are ultimately interrelated. To the fullest extent possible, the greater intent herein is to approach reality through the totality of the papers and articles written by this author on the subject of mass properties and automotive performance. 

Rev B - 2023},

note = {Mike Hackney Best Paper Award},

keywords = {31. Weight Engineering - Surface Transportation, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3501,

title = {3501. Simulation-based Transitional Stability Criteria for Submarines},

author = {David Tellet},

url = {https://www.sawe.org/product/paper-3501},

year  = {2010},

date = {2010-05-01},

booktitle = {69th Annual Conference, Virginia Beach, Virginia},

pages = {54},

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

address = {Virginia Beach, Virginia},

abstract = {This paper documents the analysis of simulation-based submarine roll data pursuant to the development of new submarine stability criteria for the transition between submerged and surfaced conditions. A matrix of ship, environmental, and simulator conditions was developed resulting in 137 different run conditions, each of which was repeated 50 times for a period of 200 seconds at a sample rate of 1Hz. This resulted in 6850 data files and 1.37 million data points for each of the seventeen channels of data recorded (e.g., speed, depth, roll, pitch). The data was processed semi-automatically through a custom document process program designed by the author using the R statistical environment for statistical analysis and data graphics, and LATEX for typesetting detailed and summary reports for each condition and each run. This paper looks at roll angles only, and mainly for the most extreme 34 of the 137 conditions used in the simulation matrix (six conditions in lower sea states were also included). In Part I the effects of varying BG, inertia, depth and speed, wind, wave height, wave direction, phase, and sail configuration are analyzed in condition to condition comparisons. Part II proposes new transitional stability criteria based on traditional static stability calculations and also on dynamic roll probabilities based on the results of Part I. The static criteria is based on a minimum GM of 0.15 feet, minimum levels and times for stability restitution, and energy comparison. The dynamic criteria is based on the probabilities of exceeding 30, 45, and 60roll angles in beam seas corresponding to sea states 6, 7, and 8.},

note = {Mike Hackney Best Paper Award},

keywords = {13. Weight Engineering - Marine, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3468,

title = {3468. Quantifying Uncertainty and Risk in Vehicle Mass Properties Throughout the Design Development Phase},

author = {William Boze and Patrick Hester},

url = {https://www.sawe.org/product/paper-3468},

year  = {2009},

date = {2009-05-01},

booktitle = {68th Annual Conference, Wichita, Kansas},

pages = {17},

address = {Wichita, Kansas},

abstract = {In the acquisition of any new vehicle program, whether it be a marine, space, aircraft or ground transportation vehicle, there is the need throughout the life-cycle development phases to periodically assess the level of uncertainty and risk in the estimated or calculated prediction of the delivered vehicle mass properties characteristics (such as weight, center of gravity, or mass moment of inertia). Published industry standards for control of mass properties characteristics identify the components necessary for a desired outcome, yet occasionally there is a vehicle acquisition program which falls short of that desired mark. There can be many causes for this occurrence, and the causes can even appear within a program having a robust mass properties control plan. The focus of this research is on the unpredictability in the uncertainty of the reported values and associated risks, and the application of a hybrid approach to quantify that uncertainty and risk. Using current mass properties control techniques integrated with management science risk analysis approaches, the process is evaluated on an existing vehicle acquisition program covering a span of several years.},

note = {Mike Hackney Best Paper Award},

keywords = {21. Weight Engineering - Statistical Studies, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3460,

title = {3460. Using a Two-Plane Spin Balance Instrument to Balance a Satellite Rotor About Its Own Bearings},

author = {Paul Kennedy and Daniel Otlowski and Brandon Rathbun and Kurt Wiener},

url = {https://www.sawe.org/product/paper-3460},

year  = {2008},

date = {2008-05-01},

booktitle = {67th Annual Conference, Seattle, Washington},

pages = {21},

address = {Seattle, Washington},

abstract = {This paper addresses the problem of statically and dynamically balancing a satellite, mounted antenna rotor supported on its own bearings, and driven by a motor in the satellite body. The satellite body is considered a stationary platform, (stator) for this procedure and is not part of the balancing problem. The antenna rotor is isolated and balanced independently while spinning on its own bearings. In order to measure the unbalance, a method is developed to utilize a two-plane vertical axis spin balance machine. Rather than using the gas bearing rotor of the measuring instrument and spinning the entire satellite, the satellite body (stator) is attached to the balancing machine table, which is held stationary, and the satellite 'rotor' is spun on its own bearings. Forces due to the unbalance are measured by the Spin Balance Machine force transducers. The method is compared to a similar procedure using a single plane spin balancer and to methods using 'work reversal' methods to balance the rotor by spinning the entire satellite. The accuracy of this procedure is compared to the basic balance capability of the spin balance instrument when used in the conventional manner.},

note = {Mike Hackney Best Paper Award},

keywords = {06. Inertia Measurements, 18. Weight Engineering - Spacecraft Design, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3430,

title = {3430. Systems Weight Estimation Enhanced Method for Early Project Phases},

author = {Isabelle Banel-Caule},

url = {https://www.sawe.org/product/paper-3430},

year  = {2007},

date = {2007-05-01},

booktitle = {66th Annual Conference, Madrid, Spain},

pages = {28},

publisher = {Society of Allied Weight Engineers},

address = {Madrid, Spain},

organization = {Society of Allied Weight Engineers},

abstract = {From the beginning, the A380 was identified as a challenge in many fields: market, configuration, performance, environment, costs, etc. Many innovations in aircraft systems were studied for the A380 with the objective to reduce weight. An aircraft of such size benefits from any weight savings on the systems, hence new architectures and new technology investigations were encouraged. This approach is extended to subsequent Airbus aircraft programs. On a new aircraft, more and more different architectures and technologies are possible for a given system. Our objective is to identify the best possible configuration early in the project life cycle. The choice of the architecture and the technology is done following analysis of numerous key criteria: performance, reliability, cost, technical feasibility, mass, etc. Airbus weight department is associated with systems department to perform the mass parameter analysis. Doing this supports the constant objective of aircraft weight reduction for better aircraft performance. In this context, it became apparent that our systems mass and center of gravity estimation methods for early project phases should be improved in terms of sensitivity and accuracy. This would enable the right decision to be made on systems architecture and technology more rapidly and therefore deliver a more mature configuration earlier in the aircraft project. Support from the systems organization was solicited to develop rule-based methods which reflect its existing sizing process and methodology. These methods accurately predict the mass of a system and provide the correct sensitivity to key design parameters in all early project phases. They enable the assessment of the impact of different architectures and technologies on mass and allow rapid weight estimation of various configurations from the earliest project phases, reinforcing the position of mass as a key parameter for systems configuration and architecture choice. This paper describes the generic process used to develop these methods. The process is applied to the hydraulics systems for more concrete understanding. Finally, use cases are presented to illustrate which type of studies can be carried out. It will be demonstrated how the evolution of the aircraft geometry will affect the mass of the hydraulic system, followed by a comparison of the mass of two different flight controls configurations. They provide clear examples of the sensitivity studies that can be carried out with these methods to obtain better systems, and even aircraft configuration selection, at an earlier stage.},

note = {Mike Hackney Best Paper Award},

keywords = {25. Weight Engineering - System Estimation, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3384,

title = {3384. Measuring Weight And Center Of Gravity Using Load Cells},

author = {Brad Hill},

url = {https://www.sawe.org/product/paper-3384},

year  = {2006},

date = {2006-05-01},

booktitle = {65th Annual Conference, Valencia, California},

pages = {19},

publisher = {Society of Allied Weight Engineers},

address = {Valencia, California},

organization = {Society of Allied Weight Engineers},

abstract = {Today?s load cells are capable of an accuracy of +-0.05%, or better, under ideal conditions. But ideal conditions are expensive to obtain and, because ?you get what you pay for,? these high accuracies are not always possible or even required. Given sufficient time and money most anything can be weighed to a high degree of accuracy. More often we are asked to measure the weight and center of gravity of an object when the design and building of specialized fixtures and laboratory conditions is not practical or warranted. To meet the needs of a customer without exceeding his budget we are often required to be creative in how we use the equipment available while keeping in mind the accuracy and validity of the data we are gathering. Many things will affect the accuracy of the information we get from a test, especially the quality of the equipment, the physical arrangement, our procedures and the calibration uncertainty of the load cells. There are just as many areas where confidence can be built into a test. To obtain the best value for the dollar from our test we must consider things like the set-up of the test, weight and dimensional measurements, environmental factors and equipment shortcomings. For the purpose of this paper the term ?load cell? refers to stand alone canister-type cells, like those in a standard aircraft weighing kit, that are not part of a permanent fixture. This type of equipment is commonly used to measure the weight and center of gravity of large parts, assemblies, tooling, missiles and other items where a unique set-up is required for each.},

note = {Mike Hackney Best Paper Award},

keywords = {08. Weighing, 09. Weighing Equipment, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3360,

title = {3360. Are You Sure? - Uncertainty in Mass Properties Engineering},

author = {Robert L. Zimmerman and Nakai},

url = {https://www.sawe.org/product/paper-3360},

year  = {2005},

date = {2005-05-01},

booktitle = {64th Annual Conference, Annapolis, Maryland},

pages = {36},

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

address = {Annapolis, Maryland},

abstract = {The Mass Property Engineer?s role in the engineering organization is ultimately to report the mass properties of the organization?s vehicle, so that the vehicle?s performance can be characterized. It is insufficient merely to report the mass properties as a discrete entity ? the characterization of performance requires the possible variations of the vehicle?s mass properties also be determined and reported by the Mass Property Engineer to the team. Mass Property Engineers have an expectation, based on precision computerized drafting and manufacturing equipment, electronic mass property tallying, and high accuracy measurement equipment, that the reported mass properties will be very close to the vehicle?s actual mass properties. This paper will unveil the proposition that the carefully determined mass properties reported by the Mass Properties group has far greater dispersions about the reported values than that expectation. The paper is divided into three parts. Part One expands on basic statistical concepts required to determine mass property parameter dispersions. Part Two derives the algorithms necessary to determine overall vehicle mass property uncertainties. Part Three illustrates Parts One and Two using an example, and produces some representative computer code to implement the algorithms.},

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

keywords = {12. Weight Engineering - Computer Applications, 21. Weight Engineering - Statistical Studies, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3325,

title = {3325. Mass Properties Measurement in the X-38 Project},

author = {Wayne L. Peterson},

url = {https://www.sawe.org/product/paper-3325},

year  = {2004},

date = {2004-05-01},

booktitle = {63rd Annual Conference, Newport, California},

pages = {26},

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

address = {Newport, California},

abstract = {This paper details the techniques used in measuring the mass properties for the X-38 family of test vehicles. The X-38 Project was a NASA internal venture in which a series of test vehicles were built in order to develop a Crew Return Vehicle (CRV) for the International Space Station. Three atmospheric test vehicles and one spaceflight vehicle were built to develop the technologies required for a CRV. The three atmospheric test vehicles have undergone flight-testing by a combined team from the NASA Johnson Space Center and the NASA Dryden Flight Research Center. The flight-testing was performed at Edwards Air Force Base in California. The X-38 test vehicles are based on the X-24A, which flew in the ?60s and ?70s. Scaled Composites, Inc. of Mojave, California, built the airframes and the vehicles were outfitted at the NASA Johnson Space Center in Houston, Texas. Mass properties measurements on the atmospheric test vehicles included weight and balance by the three-point suspension method, four-point suspension method, three load cells on jackstands, and on three in-ground platform scales. Inertia measurements were performed as well in which Ixx, Iyy, Izz, and Ixz were obtained. This paper describes each technique and the relative merits of each. The proposed measurement methods for an X-38 spaceflight test vehicle will also be discussed. This vehicle had different measurement challenges, but integrated vehicle measurements were never conducted. The spaceflight test vehicle was also developed by NASA and was scheduled to fly on the Space Shuttle before the project was cancelled.},

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

keywords = {06. Inertia Measurements, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3310,

title = {3310. SumMassProps - An Excel VBA Solution for Summing Mass Properties},

author = {Robert L. Zimmerman},

url = {https://www.sawe.org/product/paper-3310},

year  = {2003},

date = {2003-05-01},

booktitle = {62nd Annual Conference, New Haven, Connecticut},

pages = {45},

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

address = {New Haven, Connecticut},

abstract = {Microsoft Excel is a general-purpose spreadsheet program that lends itself to mass properties calculations. There have been many papers written and presented to the SAWE showing differing techniques to use in determining assembly and vehicle mass properties. The problem with these techniques is that they require a portion of the spreadsheet to be used for storage of intermediate results and the equations used become complex and confusing using Excel?s native symbology. This paper introduces a comprehensive solution set for mass property summation using the built-in Visual Basic for Applications macro language extant in Excel. The solution set, ?SumMassProps.xla,? is embedded in an Excel Add-in. SumMassProps is comprised of three increasingly comprehensive custom functions: CCOG, a function to compute Center of Gravity; CMPROP, a function to compute the complete 10 by X mass property tensor; and CMUP, a function that extends CMPROP by also computing the combined independent uncertainty properties of all ten mass property terms in the mass property tensor. The Add-in also includes facilities to aid in setting up and using the functions in a spreadsheet. By using the Add-in paradigm, the solution set becomes available for use in any spreadsheet that is on the user?s computer. By using SumMassProps, the mass property engineer is freed from spending time debugging spreadsheets and re-inventing the wheel to determine a composite body?s mass properties. This solution set ensures that the proper equations are used and implemented in a consistent manner and speeds up production of reports and ?what-if? scenarios.},

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

keywords = {10. Weight Engineering - Aircraft Design, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3237,

title = {3237. Obtaining Optimal Results with Filar Pendulums for Moment of Inertia Measurements},

author = {David P. Lyons},

url = {https://www.sawe.org/product/paper-3237},

year  = {2002},

date = {2002-05-01},

booktitle = {61st Annual Conference, Virginia Beach, Virginia, May 18-22},

pages = {29},

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

address = {Virginia Beach, Virginia},

abstract = {A common experimental problem in engineering is determining the mass moment of inertia (MOI) of a non-homogeneous rigid body with complicated geometry, which does not lend itself to analytical methods. In recent years the labs at Lockheed Martin Aeronautics Company-Marietta (LMAC-M) have developed improved methods for MOI testing. Initially, a quadrifilar pendulum was built. This apparatus produced quick MOI test results with accuracies as good as 1-2% for objects with large MOI, but only 5-7% accuracy for objects with a small MOI. A requirement for improved accuracy on a recent program provided the incentive to ensure better-than-1% accuracies. Initially, it was believed the existing ?simple? theory on filar pendulums, available in the engineering texts, was inadequate to produce the desired results. A higher order solution was developed. Hardware improvements were made. The existing simple theory was reviewed rigorously, and an exhaustive investigation of alternative analytical methodologies was conducted. Finally, refinements to the measurement process were implemented. In the process of identifying a superior solution, the existing textbook simple theory was validated, based on a certain criterion. A concept for treating viscous damping analytically, and hence windage effects, was developed, but not proven. The latest generation MOI test capabilities developed at LMAC-M, which guarantee better than 1% accuracy, are the filar pendulums. Testing with these pendulums is done with little to no fixturing, enabling high accuracy, low cost, quick turnarounds. These pendulums are designed for a class of test objects with not-to-exceed weights and dimensions that do not produce significant windage effects. Though this project utilized the trifilar design, these refinements could also be used for bifilar and quadrifilar configurations.},

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

keywords = {05. Inertia Calculations, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3156,

title = {3156. ''Standard'' SAWE Mass Properties Calculation Software and Algorithms},

author = {Richard Boynton and Nakai and Wiener and Strom},

url = {https://www.sawe.org/product/paper-3156},

year  = {2001},

date = {2001-05-01},

booktitle = {60th Annual Conference, Arlington, Texas, May 19-23},

pages = {70},

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

address = {Arlington, Texas},

abstract = {Although most CAD programs now include routines for calculating the mass properties of the various elements of a system or vehicle, there is still a use for basic mass properties calculation software. If such software were written in JAVA, then it could be easily shared by all members of the SAWE and would run on any type of computer. This software could be used when estimating the mass properties of new designs, or it could be used to make quick simplified mass properties calculations to verify that the results of the CAD programs are reasonable. In addition to describing the software, this paper is a tutorial on the calculation of mass properties (moment of inertia, centerof gravity, product of inertia). We have included a discussion of the coordinate transformation of inertias using tensors and have provided a number of simple mathematical tests that can be used to verify the reasonableness of calculated values. There are numerous textbooks on dynamics that devote a few pages to the theory of these properties. However, these textbooks quickly jump from a very brief description of these quantities to some general mathematical formulas without giving adequate examples or explaining in enough detail how to use these formulas. The purpose of this paper is to provide a detailed procedure for the calculation of mass properties for an engineer who is inexperienced in these calculations. This paper will also provide a convenient reference for those who are already familiar with this subject. This paper contains a number of specific examples with emphasis on units of measurement. The examples used are rockets and re-entry vehicles. The paper then describes the techniques for combining the mass properties of sub-assemblies to yield the composite mass properties of the total vehicle. Errors due to misalignment of the stages of a rocket are evaluated numerically. Methods for calculating mass property corrections are also explained. It was hoped that an outcome of this paper will be the generation of SAWE standard mass properties utility software written in JAVA that is available on the SAWE web site. Tutorial booklets could also be downloaded which would explain the use of the software and describe the process of making mass properties calculations. Unfortunately, due to concerns regarding United States export restrictions, the JAVA software described in this paper is currently only available for distribution and licensing to United States companies and citizens.},

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

keywords = {12. Weight Engineering - Computer Applications, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3001,

title = {3001. Technology Evaluation Via Loss Managment Models Formulated in Terms of Vehicle Weight or Wither a Scheme for Vehicle Fuel},

author = {B Roth and D Dr. Mavris},

url = {https://www.sawe.org/product/paper-3001},

year  = {2000},

date = {2000-06-01},

booktitle = {59th Annual Conference, St. Louis, Missouri, June 5-7},

pages = {25},

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

address = {St. Louis, Missouri},

abstract = {Mass properties engineering is today an established field and an indispensable part of the aerospace vehicle design process. Detailed bookkeeping schemes have been developed to track constituent component weights in extreme detail, down to the last rib and rivet. Given this situation, i t may be more accurate to refer to this field as 'empty weights engineering 'because the focus has always been primarily on management and tracking of vehicle empty weight. Meanwhile, one of the largest weight fractions, fuel weight, is bookkept in a single lump and largely ignored (except inasmuch as it impacts vehicle size and growrh factor). Itis intuitively obvious that the aerothermodynamic losses due to the engine, airframe systems, and aerodynamic drag of the vehicle are the fundamental drivers on fuel weight and should therefore be expressible as increments in fuel weight chargeable to each loss mechanism. The sum of all chargeable fuel weights is equal to the total fuel weight required to complete a prescribed mission. The intent of this paper is to formulate a method for quantifying thermodynamic performance in terms of mission fuel chargeable to each thermodynamic loss mechanism. This is then used in conjunction with known vehicle zero fuel weight groups to estimate the gross weight chargeable to each functional component of the vehicle. The results show that chargeable vehicle gross weight canbe used as a common figure of merit linking mass properties and performance aspectsof vehicle design. This method is then demonstrated for a Northrop F-5E aircraft, and the fuel weight breakdown is analytically calculated for the design mission. The results of this analysis show that 37.3% of the F-5E subsonic mission fuel requirement is due to propulsion system losses, 36.8% is chargeable to aerodynamicdrag,and 24.3% is chargeable to vehicle empty weight.This translates into a chargeable fuel cost of roughly $173.90, $171.76, and $113.53 for each of these three loss mechanisms, respectively. Finally, the usefulness of this technique as a means of technology evaluation is considered. The strengths of this method are that it allows quantification of both weight and performance aspects of technology benefits in a single figure of merit. and also enables one to ascertain the benefits of individual technologies even when applied as part of a suite of technologies.},

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

keywords = {10. Weight Engineering - Aircraft Design, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2459,

title = {2459. The Moment of Inertia of Fluids},

author = {Richard Boynton},

url = {https://www.sawe.org/product/paper-2459},

year  = {1999},

date = {1999-05-01},

booktitle = {58th Annual Conference, San Jose, California, May 24-26},

pages = {24},

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

address = {San Jose, California},

abstract = {This paper describes a first step in trying to measure the MOI of fluids in tanks. The results I measured were not what most mass properties engineers would expect to find. There is a common assumption among mass properties engineers that a tank rotates independently of the fluid contained within it, so that the mass of the fluid has a small effect on the MOI. For this reason, they ignore the mass of the fluid when calculating moment of inertia, even though the mass of the fluid often is a large percentage of the total mass of the vehicle. Although this is often a safe assumption when rotating about the cylindrical axis, the effect of fluid mass on rotation about a transverse axis is usually large enough to be a major contributor to MOI. For a straight walled tank with an aspect ratio of about 3 filled with hydrazine, the MOI is 72% of the value the fluid would have if it were solid. Since the weight of fuel is as much as 85 % of the entire vehicle weight of a rocket, this means that the pitch and yaw MOI of the fuel is more than four times as large as the MOI of the entire rocket before filling it with fuel. If the effect of rocket fuel had been ignored, then the calculated pitch and yaw MOI would be less than 20% of true MOI. The results of a number of different types of experiments are summarized in this paper. It appears that the roll MOI of a rocket can be predicted by knowing the viscosity of the fuel. Additional experiments are necessary to establish a numerical relationship. Also additional work is needed to establish formulas which define the pitch and yaw moment of inertia of fluid-filled tanks of different aspect ratios. I hope that someone reading this paper will take up this cause.},

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

keywords = {06. Inertia Measurements, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2444,

title = {2444. Mass Properties Measurement Handbook},

author = {Richard Boynton and K Wiener},

url = {https://www.sawe.org/product/paper-2444},

year  = {1998},

date = {1998-05-01},

booktitle = {57th Annual Conference, Wichita, Kansas, May 18-20},

pages = {55},

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

address = {Wichita, Kansas},

abstract = {There has been some discussion at recent SAWE International Conferences regarding the creation of a SAWE sponsored mass properties seminar, with the ultimate goal being the certification of Mass Properties Engineers by the SAWE. This paper presents a review of the methods used to measure Center of Gravity Location, Moment of Inertia, Product of Inertia, and Weight. The authors have attempted to discuss all the elements of mass properties measurement, so that this paper can be used as a textbook. This will be condensed and edited at a later date for incorporation into the SAWE Weight Engineering Handbook. Much of the material in this paper has been gleaned from previous papers written by the senior staff engineers at Space Electronics (Boynton, Wiener, and Bell). We have provided a bibliography at the end of this paper which references some of these papers, so that readers wishing to delve further into these subjects can obtain information on mathematical derivations of error sources, etc.},

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

keywords = {03. Center Of Gravity, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2352,

title = {2352. Hidden Errors in Turbine Blade Moment Measurement and How to Avoid Them},

author = {Richard Boynton},

url = {https://www.sawe.org/product/paper-2352},

year  = {1997},

date = {1997-05-01},

booktitle = {56th Annual Conference, Bellevue, Washington, May 19-21},

pages = {26},

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

address = {Bellevue, Washington},

abstract = {By first measuring the static moment of the individual blades and then sorting them into the ideal order, jet engine manufacturers have found that they can greatly reduce the time and effort required to balance the rotor of an engine. More recently a new concept has emerged: if a computer record is kept of the moment of every blade in every engine manufactured, then a damaged blade can be replaced with one of identical moment without the need to disassemble the engine and rebalance the rotor. This saves both money and time, but it places new demands on the accuracy of the moment measurement. If blade moments are in error, then the engine will be unbalanced, resulting in premature wear, or possibly a fatal accident. The concept of blade replacement by matching blade moment requires that the blade be measured with a high degree of accuracy. For example, a 35 pound fan blade might have nominal moment of 17,000 oz-inch and need to be balanced to within 0.5 oz-inch. This represents a required measurement accuracy of 0.003 % of value! Space Electronics manufactures instruments to measure turbine blade moment (these instruments are often called ''moment weight scales''). Our instruments use a new technology which is as much as 40 times more accurate than the conventional knife-edge and load-cell technology that has been employed for the last 30 years. As a result, the moment measurement error of our instruments can be considered insignificant. This has led us to more clearly identify other sources of measurement error which appear to be widespread throughout the industry. The problems show up in two ways: (1) a blade is replaced in the field with one of supposedly identical moment, and the engine is then found to be unbalanced ; (2) a set of blades is measured at Plant A and then sent to Plant B for installation in the engine. If the blades are remeasured at Plant B before they are installed, the data differs from the original set of measurements. However, it often isn't just a simple change in scale factor (i.e. the blades aren't just 0.5% higher in moment at Plant B). There are several factors involved, resulting in what appears to be random differences. I believe I have identified the sources of these errors. This paper identifies each type of error, and gives recommendations for their elimination.},

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

keywords = {03. Center Of Gravity, Mike Hackney Best Paper Award},

pubstate = {published},

tppubtype = {inproceedings}

}