%0 Conference Paper %B 72nd Annual Conference, St. Louis, Missouri %D 2013 %T 3603. Mass Property Measurements Of The Mars Science Laboratory Rover %A Keith Fields %K 06. Inertia Measurements %K 07. Section Properties %X The NASA/JPL Mars Science Laboratory (MSL) spacecraft mass properties were measured on a spin balance table prior to launch. This paper discusses the requirements and issues encountered with the setup, qualification, and testing using the spin balance table, and the idiosyncrasies encountered with the test system. The final mass measurements were made in the Payload Hazardous Servicing Facility (PHSF) at Kennedy Space Center on the fully assembled and fueled spacecraft. This set of environmental tests required that the control system for the spin balance machine be at a remote location, which posed additional challenges to the operation of the machine. %B 72nd Annual Conference, St. Louis, Missouri %I Society of Allied Weight Engineers, Inc. %C Saint Louis, Missouri %P 16 %8 05/2013 %U https://www.sawe.org/papers/3603/buy %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE3603 %0 Conference Paper %B 70th Annual Conference, Houstion, Texas %D 2011 %T 3530. Confidence Of Mass Properties (COMP) Tool %A Smith, James %K 07. Section Properties %K 12. Weight Engineering - Computer Applications %X This paper serves to outline and discuss the practices and methods used to check the mass distribution properties of airframe conceptual aircraft. This paper will show the type and fidelity of the information gathered, collation technique, and what pertinent information was utilized. Finally, it will show how calculations can draw conclusions to the viability and the integrity of the data proposed. In addition, it will show how basic geometric equations can be applied to ensure further that the data is within the magnitude of acceptance. %B 70th Annual Conference, Houstion, Texas %I Society of Allied Weight Engineers, Inc. %C Houston, Texas %P 14 %8 05/2011 %U https://www.sawe.org/papers/3530/buy %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE3530 %0 Conference Paper %B 68th Annual Conference, Wichita, Kansas %D 2009 %T 3475. Mass Distribution, Weight, and Center of Gravity application using CATIA V5 %A Edmounson, Scott %A Papanastasiou, Angelo %K 07. Section Properties %K 12. Weight Engineering - Computer Applications %X Inertia 360, software to automate mass distribution calculations and reporting with CATIA V5, has been developed. The software has been used successfully on very large CATIA V5 assemblies to extract mass properties, create flexible volume sections and extract these mass properties and then output accurate weight, mass and fuel distribution reports. The software provides for more accurate reports, reduces the potential for human error and greatly reduces the time required to generate reports. %B 68th Annual Conference, Wichita, Kansas %C Wichita, Kansas %P 9 %8 5/16/2009 %U https://www.sawe.org/papers/3475/buy %9 7. Section Properties ; 12. Weight Engineering - Computer Applications %M 3436 %L 7 ; 12 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE3475 %0 Conference Paper %B 47th Annual Conference, Plymouth, Michigan, May 23-25 %D 1988 %T 1830. Vought High Speed - High Temperature Rotor Test %A J Banks %K 07. Section Properties %X One of the frontiers of composite application lies in its use in very high temperature environments. This paper gives an overview of an ultra high temperature, high speed turbine rotor test system. The design goal of this project was to develop a test system that would provide rotor temperatures in excess of 3000 degrees Fahrenheit and centrifugal loads to the test rotor in excess of 200,000 g's. This test system will be used to develop a carbon composite turbine rotor and will culminate in full-scale ground testing of a carbon based, hot section turbojet. Successful development of this material could result in a doubling of current thrust to size ratios for jet engines. %B 47th Annual Conference, Plymouth, Michigan, May 23-25 %I Society of Allied Weight Engineers, Inc. %C Plymouth, Michigan %P 25 %8 5/23/88 %G eng %U https://www.sawe.org/papers/1830/buy %9 7. SECTION PROPERTIES %M 1830 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE1830 %0 Conference Paper %B 45th Annual Conference, Williamsburg, Virginia, May 12-14 %D 1986 %T 1723. A Fully Automatic Mass Properties Machine %A Boynton, Richard %A Green, D %K 07. Section Properties %X This paper describes a fully automated mass properties machine which measures center of gravity, product of inertia, and moment of inertia. All three measurements can be made from a remote location without the need for any operator interaction with the machine. Furthermore, the machine then produces an illustrated report of test data, complete with a drawing of the test part which shows the datum reference points. This machine is also probably the most accurate mass properties machine in the world. Although originally designed to have unbalance reduction ratios of 97%, ratios better than 99% are generally achievable, so that the object under test can usually be balanced in a single run. Center of gravity measurement is typically better than 0.001 inch. The machine has numerous special features, including the calculation of principal axis tilt, the ability to map the available locations for unbalance correction weights (so that the machine will not specify a disallowed location), prediction of unbalance force at the selected operating speed from measurements made at a slow speed, and the safeguarding of secret data. %B 45th Annual Conference, Williamsburg, Virginia, May 12-14 %I Society of Allied Weight Engineers, Inc. %C Williamsburg, Virginia %P 35 %8 5/12/86 %G eng %U https://www.sawe.org/papers/1723/buy %9 7. SECTION PROPERTIES %M 1723 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE1723 %0 Conference Paper %B 44th Annual Conference, Arlington, Texas, May 20-22 %D 1985 %T 1667. Considerations for the Design of Spin and Static Balance Fixtures %A Boynton, Richard %A Hollenbeck, L G %K 07. Section Properties %X This paper discusses several practical matters relating to the measurement of mass properties which are often overlooked in the literature. These are: 1. Making certain the test article has the necessary precision interfaces so it can be fixtured accurately 2. Defining the datum points on the test article 3. Designing the ballast system on the test article so all anticipated conditions of unbalance can be corrected for without rework of the test article 4. Fixture design 5. Fixture accuracy verification 6. Selection of a balancing machine This paper emphasizes the need for the mass properties engineer to become intimately involved with the design of the test article from the early stages to the final design, and to warn management if the mass properties requirements are unrealistic in sight of manufacturing tolerances on the fixture interface. Traditionally the mass properties engineer often is called upon to balance a test article which is almost impossible to fixture accurately and which does not contain adequate locations for balance correction weights (ballast). It is our hope to start a trend which will change that situation. Balancing machine technology has reached the point where the limiting factor in the accuracy of mass properties measurement is the accuracy of fixturing rather than the accuracy of the balancing machine. Surprisingly, very little effort appears to be underway to improve fixturing accuracy. Other than Space Electronics, very few balancing machine companies offer precision fixtures as standard products. Furthermore, fixturing is often handled as an afterthought, the design either being delegated to a junior draftsman, or the available funding for the design woefully inadequate. This paper lists the factors to consider when designing custom fixtures. Several types of self-adjusting fixtures are illustrated. %B 44th Annual Conference, Arlington, Texas, May 20-22 %I Society of Allied Weight Engineers, Inc. %C Arlington, Texas %P 26 %8 5/20/85 %G eng %U https://www.sawe.org/papers/1667/buy %9 7. SECTION PROPERTIES %M 1667 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE1667 %0 Conference Paper %B 44th Annual Conference, Arlington, Texas, May 20-22 %D 1985 %T 1670. Dynamic Balancing Without Spinning : A New Method for Unwieldy Satellites %A Woolley, R P %K 07. Section Properties %X The Ball Dynamic Balancing Machine, Mark III/ employing a principle not used before, balances objects that would be aerodynamically intractable on a conventional balancing machine. A conventional machine uses spin to excite the effects of imbalance so they can be measured. It also excites windage noise. The noise, which can be large, can look just like an imbalance signal. The new machine uses gentle angular oscillation to excite the effects of imbalance. It excites little windage noise, and that little is out of phase with the signal so the two can be distinguished. This paper presents the theory of both classes of machine and compares their windage errors. It then describes in detail the oscillating balancer that we have built, a portable machine sized for loads up to ten tons. Aerodynamically smooth objects are best balanced on a spin balancer. But even though we don't have enough experience with the new machine to assess its ultimate sensitivity, we have shown it to be vastly superior to a spin balancer in difficult cases. We used it to balance the Earth Radiation Budget Satellite, a very ungainly 5000-pound object, and the beautiful performance of ERBS in orbit shows that the dynamic imbalance is surely less than five kilogram meter squared. We expect to beat one kilogram-meter squared on the Combined Release and Radiation Effects Satellite. Ball has applied for a patent on this new class of balancing machine. %B 44th Annual Conference, Arlington, Texas, May 20-22 %I Society of Allied Weight Engineers, Inc. %C Arlington, Texas %P 24 %8 5/20/85 %G eng %U https://www.sawe.org/papers/1670/buy %9 7. SECTION PROPERTIES %M 1670 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE1670 %0 Conference Paper %B 43rd Annual Conference, Atlanta, Georgia, May 21-23 %D 1984 %T 1611. A Dynamic Balancing Primer %A J Banks %K 07. Section Properties %X Dynamic balancing is the process of physically adding, removing, or moving a portion of a rotating object's mass to eliminate vibration during rotation. The term "dynamic" is generally used to describe all spin balance efforts but actually applies to only one of four modes of rotational unbalance. Unnecessary vibration during rotation is a source of damage and energy loss. It produces increased maintenance requirements, decreased equipment life, greater inaccuracies where precision functioning is needed, increased weight due to higher fatigue loads, and additional acoustical pollution in an already noisy world. Reduction of unnecessary vibration will save money, time, natural resources, and health. The information presented in this paper will contain the following: • identification of each of the four modes of unbalance, • common methods used to correct each mode of unbalance, • details on constructing and using an elementary balancer from equipment normally found in an electronics lab and a relatively inexpensive transducer, • and a computer program, written in BASIC, to aid use of the budget balancer. Since this paper is written for the novice, balancing techniques will be limited to balancing at rotational speeds below excitation of natural bending modes. Balancing near or above natural bending modes requires equipment, techniques, time, and money outside the scope of the novice. Natural bending mode rates are often unknown when balance work is being performed and represent only a small percentage of the balancing spectrum. However, a discussion of the phenomenon observed when balancing speeds approach or pass natural bending modes is included. Thus, the reader may identify when a balancing effort is nearing such a region and take appropriate action. %B 43rd Annual Conference, Atlanta, Georgia, May 21-23 %I Society of Allied Weight Engineers, Inc. %C Atlanta, Georgia %P 65 %8 5/21/84 %G eng %U https://www.sawe.org/papers/1611/buy %9 7. SECTION PROPERTIES %M 1611 %1 Non-Member Price: $32.50; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 32.5 %4 SAWE1611 %0 Conference Paper %B 41st Annual Conference, San Jose, California, May 17-19 %D 1982 %T 1474. Mass Properties of Solids Using Third Moments %A Strom, G J %K 07. Section Properties %X This paper presents a mathematical method of determining all of the three-dimensional mass properties of two classes of solids. The first class is bodies of revolution - a cross-sectional area of any shape revolved about an axis through any angle up to 360 degrees. The second class is prisms - a cross-sectional area of any shape that is bounded in the third dimension by two non-parallel (in general) planes. There are no restrictions at all on the complexity of the cross-sectional area. If the cross-section defines a thin shell, then the properties of a revolved or prismatic surface can be determined. The advantages of this method are: 1) complex shapes that are usually broken into several simple parts can be done in one piece, 2) it works on about 95 percent of the shapes in the SAWE handbook, and 3) it gives results for all six moments and products of inertia. It is ideally suited to be integrated into a computerized drawing system. The method requires knowledge of all of the standard section properties of the cross-sectional area plus four new higher-order properties which I call third moments. The equations for these third moments and rules for translation and rotation will be presented. This method is essentially an extension of Pappus' theorem for volumes of bodies of revolution. %B 41st Annual Conference, San Jose, California, May 17-19 %I Society of Allied Weight Engineers, Inc. %C San Jose, California %P 16 %8 5/17/82 %G eng %U https://www.sawe.org/papers/1474/buy %9 7. SECTION PROPERTIES %M 1474 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE1474 %0 Conference Paper %B 23rd National Conference / Sheraton, Dallas Hotel, Southland Center, Dallas, Texas May 18-21 %D 1964 %T 416. Volumes, Surfaces Areas, and Centroids of Prismoidal and Revolved Surfaces %A Howland, J A %K 07. Section Properties %X At times, considerable improvement in calculation results can be obtained by a more thorough understanding of, and the proper use of existing calculation methods, new “short-cut” methods and approximations. Slight rearrangement of existing formulas make them much easier to use, and applicable to more situations At times, considerable improvement in calculation results can be obtained by a more thorough understanding of, and the proper use of existing calculation methods, new "short-cut" methods and approximations. Slight rearrangement of existing formulas make them much easier to use, and applicable to more situations that occur in weight work. When to use, and when not; to use, an "End Averaging Method" in lieu of a "Prismoidal Method", is often a problem, depending on the accuracy desired. This paper goes into this problem, and gives examples. This paper not only presents in one place, useful formulas and graphs, but by development, illustration, and discussion goes into "Prismoidal Methods", and Revolved Shells, and Solids detail, so that a comprehensive, and instructive guide is available for weight personnel. Both mathematical, and pictorial proofs are presented for easy understanding. Examples are given. The paper is presented in order to help weight and design people improve the results of some of the most difficult volume, area, and centroidal calculations, in less time. It is also written in order to bring about a better understanding, and use, of some formulas not yet found any of the S.A.W.E. weight handbooks. These formulas, calculation methods, and graphs, with examples of their use, are given. Development of the general "Prismoidal Formula", "Prismoid Formula", and "Lateral Surface Area Formula" have been placed in Appendix I so that the body of the paper would be easier to read. Related useful formulas are contained in Appendix II for the same reason. Also a special page, giving a direct comparison of the "Prismoidal Method" to the "End Averaging Method”, is given in Appendix II, where it can be easily removed and used as a"Designer-Reminder" page. Reproductions of this one page maybe very useful to the weight engineer, if passed out to the design group before they are required to make a weight calculation involving a Prismatoid. %B 23rd National Conference / Sheraton, Dallas Hotel, Southland Center, Dallas, Texas May 18-21 %I Society of Allied Weight Engineers, Inc. %C Dallas, Texas %P 28 %8 5/18/64 %G eng %U https://www.sawe.org/papers/0416/buy %9 7. SECTION PROPERTIES %M 0416 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE0416 %0 Conference Paper %B 23rd National Conference / Sheraton, Dallas Hotel, Southland Center, Dallas, Texas May 18-21 %D 1964 %T 422. Application of Regression and Correlation Techniques in Mass Properties Engineering %A Strickler, W J %K 07. Section Properties %B 23rd National Conference / Sheraton, Dallas Hotel, Southland Center, Dallas, Texas May 18-21 %I Society of Allied Weight Engineers, Inc. %C Dallas, Texas %P 38 %8 5/18/64 %G eng %U https://www.sawe.org/papers/0422/buy %9 7. SECTION PROPERTIES %M 0422 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE0422 %0 Conference Paper %B 23rd National Conference / Sheraton, Dallas Hotel, Southland Center, Dallas, Texas May 18-21 %D 1964 %T 438. The Dissemination of the Mass Unit as Embodied in Prototype Kilogram No. 20 %A Anderson, G B %K 07. Section Properties %B 23rd National Conference / Sheraton, Dallas Hotel, Southland Center, Dallas, Texas May 18-21 %I Society of Allied Weight Engineers, Inc. %C Dallas, Texas %P 38 %8 5/18/64 %G eng %U https://www.sawe.org/papers/0438/buy %9 7. SECTION PROPERTIES %M 0438 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE0438 %0 Conference Paper %B 21st National Conference, Seattle, Washington, May 14-17 %D 1962 %T 305. Predicting the Accuracy of Mass Property Calculations %A Ahl, W H %K 07. Section Properties %X This paper was presented at the Twenty-First National Conference of the Society of Aeronautical Weight Engineers at Seattle, Washington, May 14 – 17, 1962. This paper contains the recommendation that weight engineers should predict, well in advance of construction, by rational and practical means, the probable mass property calculation errors, manufacturing variations, and measuring tolerances of aircraft, missiles, spacecraft and any other products where mass property tolerances are of concern. Such predictions will serve to show more clearly the weight engineer what his mass property control problems will be during the design phase. They will provide more precise tolerance data than is otherwise available, thus facilitating optimum design or indicating discrepancies in tolerance requirements. These predictions also will serve to explain and justify the varying mass property values resulting from successive measurements of a series of similar products, as well as point out an erroneous measurement or faulty calculation. Equations, using the root sum square (RSS) principle, are presented, providing a solution to probable three-sigma variations (assuming a normal distribution) in mass property calculations and manufacturing. Simplified approaches are discussed along with the relative effects of the various parameters contributing to the mass properties. The benefits of subdivision of assemblies to increased accuracy are pointed out. Types and magnitudes of errors or variations are mentioned. The contents of this paper are directed to those weight engineers who are concerned with knowing before production, as well as after, what probably variations of mass property values will exist, and who will use this knowledge for a more tightly controlled design and improved overall performance for the product. %B 21st National Conference, Seattle, Washington, May 14-17 %I Society of Allied Weight Engineers, Inc. %C Seattle, Washington %P 53 %8 5/14/62 %G eng %U https://www.sawe.org/papers/0305/buy %9 7. SECTION PROPERTIES %M 0305 %1 Non-Member Price: $26.50; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 26.5 %4 SAWE0305 %0 Conference Paper %B 21st National Conference, Seattle, Washington, May 14-17 %D 1962 %T 361. Actual Mass Property Determinations for the Able Series Space Probes %A Whilden, R D C %K 07. Section Properties %X This paper was presented at the Twenty-first Annual National Conference of the Society of Aeronautical Weight Engineers at Seattle, Washington, May 14-17, 1962. Between August 1958 and December 1960, several multi-stage vehicles were launched from Cape Canaveral. They had various satellite and space probe missions. These vehicles, assembled by Space Technology Laboratories and sponsored by ARPA, the Air Force and NASA, were designated Able 1 through Able 5. They used Thor of Atlas first stages, Aerojet liquid second stages and Allegany Ballistics Laboratory solid third stages. Some of the spacecraft or payloads had propulsion units, others did not. The flight control techniques and staging methods used in these vehicles required very tight mass property and assembly tolerances. Some of the mass property tolerances were considerably smaller than had been experienced heretofore. (Mass properties in this context include weight, centers of gravity, moments of inertia and principal axes locations.) This paper examines the program requirements that necessitated actual mass properties tests and discusses how those tests performed by STL were devised and conducted to meet these requirements. No attempt is made here to discuss the overall weight control programs for these vehicles as the subject is too vast. Particular emphasis is given to methods used for mass property determinations on the upper stages and spacecraft. For some of these tests existing techniques were refined. In other cases, new methods were devised to yield the desired accuracy. The devices used in the determinations are discussed in some detail. Error analyses of the tests are also shown. The techniques and devices shown here are being refined and used on current space programs such as OGO and Program 698AM. Some are basic and highly accurate and as such should be useful in many future space generations. %B 21st National Conference, Seattle, Washington, May 14-17 %I Society of Allied Weight Engineers, Inc. %C Seattle, Washington %P 55 %8 5/14/62 %G eng %U https://www.sawe.org/papers/0361/buy %9 7. SECTION PROPERTIES %M 0361 %1 Non-Member Price: $27.50; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 27.5 %4 SAWE0361 %0 Conference Paper %B 20th National Conference, Akron, Ohio, May 15-18 %D 1961 %T 298. Derivation and Dissemination of Mass Standards %A Russell, H H %K 07. Section Properties %X This paper was presented at the Twentieth National Conference of the Society of Aeronautical Weight Engineers at Akron, Ohio, May 15 – 18, 1961. When determining the mass of an object, highly precise weighing operations are of little consequence unless the validity of the standards comprising the basis for the values determined has been established. Moreover, since the working standards --- those actually used for calibrating a weighing scale, a testing machine, a force transducer, a test weight of equal or less precision, and the like --- probably will be several steps removed from the primary standards, each step in the derivation of any standard should be properly documented so that the genealogy of the working standard can be traced to the standard of the United States. Certificates and reports issued by the National Bureau of Standards are examples of good documentation. In this country, the units of mass measurements, both metric and avoirdupois, are based on the platinum-iridium kilogram procured from the International Bureau of Weights and Measures and designated as The Standard of the United States of America. This particular standard is identified as Kilogram No. 20. Its mass, and the mass of each of the prototype kilograms of other nations signatory to the International Metric Treaty, is known; the uncertainty in every case being only a few hundredths of a milligram. As custodian of this national standard, the National Bureau of Standards is charged with the responsibility for dissemination of other mass standards, properly derived from the National Prototype, as a means for the promotion and maintenance of uniformity of mass measurements throughout the nation and in agreement with the standards of other nations. It is the purpose of this paper to set forth briefly how the National Bureau of Standards discharges this responsibility. %B 20th National Conference, Akron, Ohio, May 15-18 %I Society of Allied Weight Engineers, Inc. %C Akron, Ohio %P 9 %8 5/15/61 %G eng %U https://www.sawe.org/papers/0298/buy %9 7. SECTION PROPERTIES %M 0298 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE0298 %0 Conference Paper %B 3rd Dinner Meeting of the New Orleans Chapter of the Society of Aeronautical Weight Engineers, Inc., September 20, 1943 %D 1943 %T 28. The Calculation of Density %A Ayers, J E %K 07. Section Properties %X The purpose of this discussion is to present a method for computing specific gravity and density for alloys and certain other mixtures of chemical elements and/or compounds. Much current literature containing properties of materials often presents data on everything except that property which is of prime importance to the weight control engineer, i.e. specific gravity or density. This is particularly true in the case of the various specifications issued to control the quality of materials entering into the fabrication of articles contracted for by government procuring agencies. The method for determining specific gravity and density presented herein is not applicable to materials in which chemical elements or chemical compounds react with one another to form another chemical compound. In other words, the method is applicable only to materials which are alloys and mixtures whose uniting of constituents does not develop any chemical reaction, or develops only a negligible chemical reaction. %B 3rd Dinner Meeting of the New Orleans Chapter of the Society of Aeronautical Weight Engineers, Inc., September 20, 1943 %I Society of Allied Weight Engineers, Inc. %C New Orleans, Louisiana %P 9 %8 9/20/43 %G eng %U https://www.sawe.org/papers/0028/buy %9 7. SECTION PROPERTIES %M 0028 %1 Non-Member Price: $20.00; Member Price: $10.00 Members: First 10 product downloads are Free. %2 10.00 %3 20 %4 SAWE0028