SAWE Technical Papers

@inproceedings{3761,

title = {3761. Estimating Mass Moments of Inertia – A Quick Check Method},

author = {Damian P. Yañez},

url = {https://www.sawe.org/product/paper-3761},

year  = {2022},

date = {2022-05-21},

urldate = {2022-05-21},

booktitle = {81st Annual Conference, Savannah, Georgia},

pages = {14},

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

address = {Savannah, Georgia},

abstract = {Mass Moments of Inertia (MOI) are important and often critical components of the mass properties of a vehicle, but many Mass Properties Engineers tend to focus only on weight and center of gravity (CG), and have limited exposure to these other, rotational properties. In this paper, I present a brief overview of MOI, why they are important, and a method for quickly estimating the MOI of a part, subassembly, or assembly. This method is particularly useful when reviewing CAD calculations or a supplier’s mass properties reports in which you don’t have visibility into the details to ensure that the results are reasonable. You can also use this technique to make a quick MOI estimate for trade studies. While there are some limitations to this method which are described in this paper, this technique will get you in the ballpark and increase your confidence that the rotational properties of your vehicle are properly represented.},

keywords = {05. Inertia Calculations, 25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3715,

title = {3715. Negligible Weight Quantification for Surface Ship Weight Surveys},

author = {Greg Roach},

url = {https://www.sawe.org/product/paper-3715},

year  = {2019},

date = {2019-05-01},

booktitle = {78th Annual Conference, Norfolk, VA},

pages = {12},

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

address = {Norfolk, Virginia},

abstract = {Shipboard weight surveys are routinely performed for surface vessels across the spectrum of marine industries from small pleasure craft to large surface combatants. These surveys are typically part of a vessel's stability test (weight survey & inclining experiment) usually required as part of the vessel's delivery/acceptance or during its service life to confirm the safety of the vessel and/or crew/passengers has not been compromised from post-delivery modifications or inevitable weight & KG growth. These stability tests may take a few days to a few weeks, with a large portion of the effort attributed to the weight survey itself. Further, a large portion of the survey consists of inventorying smaller items which typically constitute a relatively small portion of the overall weight nor may have any appreciable impact to the overall results of the stability test.To date (to the author's knowledge), no official guidance or recommendation(s) exists on what or how to quantify as negligible weight(s) for the purposes of a weight survey. This guidance, if available, may reduce the time required for survey and save considerable time and resources without appreciably changing the end result and/or conclusion.With limited availability/diversity of actual ship survey data, the analysis will focus on the required precision of the stability test based on accepted requirements documentation. This analysis will consider the size of the vessel which directly impacts the design's sensitivity to weight, as well as the practicalities associated with the existing practices of shipboard surveys such as availability of the vessel or qualified personnel. In addition, industry guidance on human engineering design will be used to establish 'rules of thumb' for determining item weights and/or their potential impact to the results to aid in shipboard surveys.},

keywords = {13. Weight Engineering - Marine, 25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3692,

title = {3692. Aircraft Systems Physics-Based Weight Estimation Methods for Conceptual Design},

author = {Ali Tfaily and Dr. Susan Liscouët-Hanke},

url = {https://www.sawe.org/product/paper-3692},

year  = {2017},

date = {2017-05-01},

booktitle = {76th Annual Conference, Montreal, Canada},

pages = {12},

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

address = {Montreal, Canada},

abstract = {During the conceptual design phase of an aircraft, details regarding aircraft systems such as the detailed architecture and parts lists are not available. However, weight estimates for aircraft systems are needed very early for aircraft design and performance calculation. Several methods exist to predict system weights and most of these methods are empirical models correlated to top level aircraft parameters such as take- off weight, wingspan, etc. Even if the empirical methods have been sufficiently accurate in the past, they are not suitable for a more sophisticated multidisciplinary design optimization (MDO) approach implemented today in Bombardier's Advanced Design group. In addition, the empirical methods are not valid to predict the effect of new technologies. So called 'physics-based methods' are proposed, leading to a better understanding of technology and system architecture choice impact on the aircraft weight.The new weight estimation methods are implemented as integral part of a conceptual aircraft systems sizing framework. This framework enables the development of more mature aircraft concepts without comprising the calculation runtime. The proposed physics based models showed minimal errors when compared to actual data while capturing additional sensitivities that did not exist in previous methodologies. This paper illustrates the methodology for the example of the hydraulic power system.},

keywords = {11. Weight Engineering - Aircraft Estimation, 25. Weight Engineering - System Estimation, 34. Advanced Design},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3596,

title = {3596. Estimation of Electrical Cable Length and Centers of Gravity},

author = {Robert Chitwood},

url = {https://www.sawe.org/product/paper-3596},

year  = {2013},

date = {2013-05-01},

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

pages = {10},

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

address = {Saint Louis, Missouri},

abstract = {This paper presents methods for performing electrical cable length and center of gravity determination early in marine vehicle design. Early in the design process, little is known about electrical cable lengths and the routing location of the cable. Cable length is a function of how and where it is routed. Routing of the cable depends on many factors: equipment location, cable hanger location and hanger loading, cable separation requirements, maximum allowable cable length, etc. This information is not usually known until later in the ship's design process. Because the total amount of cable weight can be significant, and the effect on ships list and trim need to be tracked and monitored (possibly resulting in changes to the design), the mass properties engineer needs to be able to create a weight and moment estimate for cable in the early stages of design. There is rarely sufficient information available at this point to support such an estimate. While tailored towards marine vehicles, the methods described here can be applied to other vehicles if the assumptions are modified.},

keywords = {25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3562,

title = {3562. Parametric Estimation Of Anchor Handling / Towing Winches},

author = {Stein Bjòrhovde and Runar Aasen},

url = {https://www.sawe.org/product/paper-3562},

year  = {2012},

date = {2012-05-01},

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

pages = {13},

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

address = {Bad Gögging, Germany},

abstract = {Anchor Handling Tug vessels (AHT) are ships built to handle anchors for oil rigs, in addition to towing the platforms into position and in some cases operate as Emergency Rescue and Recovery Vessel (ERRV). Compared to ordinary offshore supply vessels, AHTs are characterized by large winches for towing and anchor handling, open stern for landing of anchors and a large bollard pull. 

The winch packages for anchor handling tug vessels are large and heavy constructions with weight that varies from 150 to 900 tonnes and may represent as much as 15% of the lightship weight for the vessel. In addition to significant weight, it also influences a lot on the vertical center of gravity (VCG) og thereby the stability of the ship. Also the longitudinal center of gravity (LCG) is significantly influenced by the layout and positioning of this equipment. 

Experience shows that it might be difficult to identify reliable weight and center of gravity (CoG) for this special made equipment from fabricators and suppliers in an early design phase. Based on this we want to study which parameters are relevant for estimating weight and CoG for anchor handling / towing winches, and how these parameters can be combined in mathematical formulas that can be used in regression based estimation. 

The advantage of using regression is among others the quantification of uncertainty (standard deviation) related to each specific estimation method and thereby the possibility to decide which methods that are the most precise, and to evaluate whether parametric estimation can be used at all. An evaluation of the uncertainty requirements will be performed as well. 

Stein Bjòrhovde is one of the founders and head of development of BAS Engineering. Mr. Bjòrhovde has a Master of Science Degree in Ship Design, and has been developing the weight engineering software ShipWeight since 1993. He has also been involved in development of other weight control software, in addition to being a consultant doing weight estimation and monitoring in the offshore industry. He has more than 15 years experience in weight estimation of new ship designs for several Norwegian and international ship designers and yards. 

Runar Aasen is one of the founders and technical sales manager of BAS Engineering, a SAWE corporate member. Mr. Aasen has a Master of Science Degree in Ship Design, has been extensively involved in the development of weight engineering software and user support for the last fourteen years, and became a SAWE Fellow Member in 2006. Since 1996, BAS Engineering has provided ship designers and builders around the world with naval architecture and mass properties support. BAS Engineering's ShipWeight software entered the US market for the first time in 1998 and has since been adapted by major US shipyards and designers.},

keywords = {25. Weight Engineering - System Estimation, 35. Weight Engineering - Offshore},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3479,

title = {3479. Managing and Controlling Weight and Center of Gravity for Combat Ground Vehicle Development Programs},

author = {Scott Kaiser},

url = {https://www.sawe.org/product/paper-3479},

year  = {2009},

date = {2009-05-01},

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

pages = {16},

address = {Wichita, Kansas},

abstract = {BAE Systems Inc. is the U.S, subsidiary ofBAE Systems pIc, an intcmational company engaged in the development, delivery and support of advanced defense and aerospace systems in the air, on land, at sea and in space. US Combat Systems, one of BAE Systems Inc.'s Land & Armaments lines of business is a leader in designing, rapidly prototyping and manufacturing protected fighting vehicle plattbrms and survivability solutions that support and protect the current and future forces. Improving and increasing military transformation capabilities, that is increasing the speed with which the military forces deploy and engage by reducing the logistics tail is directly related to the successes of managing and controlling the development and fielded weight of combat ground vehicles. This paper discusses methods of controlling and managing weight of complex design combat vehicle solutions tbr the customer that has various design constraints such as high level of component commonality, low cost, high reliability, speed to market, and increased performance capabilities over the current force systems. The mass properties control and management methods presented in this paper focus on developing an accurate estimate, reconciling this estimate with the customer's requirements, advocating a program mass properties and control plan, establishing and enforcing weight allocations/targets, monitoring and mitigating development weight, organizing and presenting data. The final conclusions of this paper will include lessons learned based on implementation ofthese methods.},

keywords = {17. Weight Engineering - Procedures, 25. Weight Engineering - System Estimation, 31. Weight Engineering - Surface Transportation},

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{3207,

title = {3207. Where There's a Will, There's a Weigh},

author = {Ian O. MacConochie},

url = {https://www.sawe.org/product/paper-3207},

year  = {2002},

date = {2002-05-01},

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

pages = {14},

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

address = {Virginia Beach, Virginia},

abstract = {The extensive studies of advanced space transportation systems at NASA-Langley Research Center were ?jump started? with codes that were established many years ago for the current Space Shuttle. However, in view of the wide range of items now being studied it seems to be appropriate to change to a more general system ? one such system is used by the Navy in shipbuilding wherein 100 to 199 is structure, and 200 to 299 is propulsion, etc. In this system many types of structure or propulsion can be embraced or deleted without disrupting the highest hierarchy of the numbering sequence in the code. Vehicle examples are shown with the new coding system applied. Its appropriate to use a coding system that suits the particular project ? where there?s a will there?s a ?weigh.},

keywords = {25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3154,

title = {3154. Electrical Power Generation and Distribution System Estimation},

author = {Robert M. Bond},

url = {https://www.sawe.org/product/paper-3154},

year  = {2001},

date = {2001-05-01},

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

pages = {18},

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

address = {Arlington, Texas},

abstract = {It is important to be able to influence the design of aircraft electrical systems in the definition phase. This makes it possible to influence weight at a lower cost than is possible in the design or production phases. A method is described that synthesizes an approximate part-level design from a combination of airplane level configuration data, fundamental engineering theory, cross-functional design/analysis practices, and refinement of results as more detailed real data becomes available. Automated knowledge based engineering (KBE) up front provides the initial characterization of the electrical system. 

Electrical power generation and distribution system designs are evaluated from five viewpoints. These are weight, body station center of gravity, dependability cost, reliability, and maintainability. Calculation of multiple attributes allows rapid trade study capability using a variety of measures. This cuts cycle time in the risk assessment process. This software tool is useful to both weights and electrical power system engineers. 

Sizing generation-associated components relies upon data extracted from the loads and architecture modules. The load module dictates the required capacities and the architecture module specifies the quantities of the various components. 

Feeder wire sizing involves determination of feeder heating effects as a function of current, altitude, ambient temperature of the feeder's location, wire type, and bundle configuration derating. System voltage distortion due to harmonics is estimated as a function of frequency. 

The method is user friendly, robust, and documented in an understandable manner. Default values for all parameters are constructed from two inputs: number of engines and maximum take-off weight. An on-line help function is provided and includes a feature that displays all equations used in the calculations. Detailed weight and body station center of gravity reports are provided in several formats.},

keywords = {25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3158,

title = {3158. Weight & Balance - Innovative Weight Engineering Solutions},

author = {Stephane Sicard},

url = {https://www.sawe.org/product/paper-3158},

year  = {2001},

date = {2001-05-01},

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

pages = {13},

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

address = {Arlington, Texas},

abstract = {Presentation},

keywords = {25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2286,

title = {2286. Benefits of Parametric Mechanical Design Weight Scaling Decks for Advanced Aircraft Turbomachinery},

author = {J W Rudder},

url = {https://www.sawe.org/product/paper-2286},

year  = {1995},

date = {1995-05-01},

booktitle = {54th Annual Conference, Huntsville, Alabama, May 22-24},

pages = {19},

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

address = {Huntsville, Alabama},

abstract = {To allow rapid turnaround of weight prediction for advanced aircraft programs, there is a need to be able to down-select concepts with little or no design effort. This improvement comes from application of lessons learned from past deigns and an understanding of how the design is affected by changes in performance. The development of weight decks improve the Weapon System Contractor?s capability to estimate the propulsion system weight effects to meet their mission and performance requirements. The deck allows for a wide range of parameters to be addressed with less time and expense. It also expands the ability to evaluate near and far term technologies on a variety of engine baselines. This paper will discuss the requirements and structure of an Advanced Aircraft Turbomachinery Weight Scaling Parametric with the utilization of a Mechanical Design Routine that establishes the baselines. The following subjects will be discussed in detail to familiarize the reader with the methodology and benefits of Advanced Aircraft Turbomachinery Weight Scaling Decks. What is a Weight Parametric Deck? Mechanical Design Routine Scaling Factors and Switches Technology Methodology and Parametric Integration Effective Deck Flow Benefits to the Deck User and Developer Specific comparisons will be made to the current decks that are being used on advanced programs like JAST and STOVL. This will gave an actual program input/output and program structure as a reference tool.},

keywords = {25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{2222,

title = {2222. Executive and Luxury Interior Modifications},

author = {C H Stufflebeam II},

url = {https://www.sawe.org/product/paper-2222},

year  = {1994},

date = {1994-05-01},

booktitle = {53rd Annual Conference, Long Beach, California, May 23-25},

pages = {29},

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

address = {Long Beach, California},

abstract = {Most Mass Properties Engineers in the aircraft industry work to produce aircraft in quantities numbering in the hundreds or thousands. Some Mass Properties Engineers are involved in the predesign efforts that may lead to the next model of aircraft produced at their company. A relative few are involved in the modification of new and used aircraft. The purpose of this paper is to give a brief overview of the weight and balance procedures and methodology for executive and luxury modification programs. Since each aircraft modification program is tailored to meet the needs and tastes of the customer(s), only a general guide can be given to show some of the estimation methods, weight calculation methods, and procedures for each phase of a modification program. Actual weights and material unit weights have been included for many items.},

keywords = {25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{1252,

title = {1252. Spacelab Mass Evolution and Consolidation},

author = {M Baune and J Schils},

url = {https://www.sawe.org/product/paper-1252},

year  = {1978},

date = {1978-05-01},

booktitle = {37th Annual Conference, Munich, West Germany, May 8-10},

pages = {33},

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

address = {Munich, West Germany},

abstract = {This report displays the mass evolution of representative Spacelab configurations, both combined and broken down in to functional subsystems, such as module structure (pressurized), pallet structure (unpressurized), environmental control (atmosphere and thermal control), avionics (data/power handling and distribution) and Orbiter/Spacelab interface hardware (retention beams and transfer tunnel). 

The underlying mass data analysis aims at identifications, separation, and distinct display of mass variations resulting from changes in mission requirements. For example; environment predictions, payload provisions, orbiter interface evolution (supplies, utilities, controls), safety provisions, as well as from design process changes (in sufficiency of mass estimations, make work actions). 

Since the Spacelab program has advanced to a point where system and subsystem designs are essentially frozen, a projected mass for the date of Spacelab completion is defined including suggested extrapolation to cover upcoming changes as will result from Spacelab integration and test phases.},

keywords = {25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{1164,

title = {1164. Weight Estimation of Composite and Monolithic Spherical Pressure Vessels},

author = {C K McBaine},

url = {https://www.sawe.org/product/paper-1164},

year  = {1977},

date = {1977-05-01},

booktitle = {36th Annual Conference, San Diego, California, May 9-12},

pages = {43},

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

address = {San Diego, California},

abstract = {This paper presents the principal results of a weight estimation methodology for spherical filament wound composite and conventional monolithic pressure vessels. The estimating technique used was one of first determination of the weight of an 'Ideal' closed spherical shell by the classical hoop tension method. This weight determination was then modified by applying 'Non-Ideal' factors for bosses, weld lands, tolerances and material build-up at specified locations for fatigue. These non-ideal factors were derived from empirical and actual weight data obtained directly from an actual verification test program. These data were then used in establishing the Shuttle Orbiter pressure vessel design and weight. The result is what is called the vessel 'Real' weight and represents the vessel usable weight estimate. The non-ideal factors were equated mathematically by a computer program using a regressive polynomial curve-fit technique. This was done so that the whole pressure vessel weight estimating equation might be adapted to computer aided design programming. In addition to weight estimating equations and curves for the composite pressure vessel, curves are given comparing the weight of composit vessels to the monolithic vessel. By the analysis of the composite and monolithic vessel weight, and pressure/ volume zone selective graph was developed showing when one should choose a composite over a monolithic vessel based on the pressure/volume relationship. In general, for design burst pressures above 3000 psi (2068 N/cm2), the 'composite vessel is lighter in weight than the monolithic vessel at volumes above approximately 350 cubic inches (5735 cu cm). As the design burst pressure is lowered below 3000 psi (2068 N/cm ), larger vessel volumes are necessary for the weight to favor the composite vessel. After obtaining the actual weight on three types of the Orbiter qualified vessels, the accuracy of the weight estimating technique was found to 3 to 5 percent on the conservative side. As a result of the composite pressure vessel analysis and test program, they were chosen for al17 gaseous pressure-vessels in the Orbiter propulsion pressurization and life support systems. The total weight being 1346 pounds (610.4 Kg) representing a weight reduction 4o2f6 pounds (193.2 Kg) over the more conventional monolithic vessel design, or approximately 30 percent.},

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

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

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{1181,

title = {1181. Influence of Mechanical Transmission Concepts on a Navy Type A Operational Aircraft Weight},

author = {R S St. John and F G Wyatt},

url = {https://www.sawe.org/product/paper-1181},

year  = {1977},

date = {1977-05-01},

booktitle = {36th Annual Conference, San Diego, California, May 9-12},

pages = {28},

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

address = {San Diego, California},

abstract = {Current requirements envisioned for Type 'A' V/STOL are placing unique demands on design ingenuity. The usual demands on cost, reliability, maintainability, etc., are complicated by a variety of conflicting mission and special performance requirements. 

- Range and endurance requirements suggest the need for highly efficient fuel consumption concepts such as turboprop designs. 

- Vertical takeoff and landing requirements demand high thrust efficient power plants. 

- Engine out emergency landing requirements necessitate propulsive system interconnect for power transfer. 

- Planned Navy Vertical Support Ships place stringent size limitations in terms of weight and spotting factors. 

Numerous other requirements such as dash mach number, cruise altitude and alternate mission capability further complicate the design task. 

Studies to date indicate that the most efficient balance in terms of cost/size/weight/ilities will be obtained by a concept employing a common propulsive system for both vertical lift and cruise. The common propulsive system implies a configuration with at least two thrust generators (fans, propellers or jet thrust) and some sort of thrust vectoring (deflector nozzles, tilt nacelles, tilt wing, etc .). 

One of the most significant factors in the development Type 'A' V/STOL is the power transmission concept employed to transfer power the engine to the thrust generators and the attendant system interconnect necessitated by engine out emergency landing requirements. A transmission system cannot amplify the horsepower output of the engines nor contribute any lifting thrust. Therefore, the transmission weight must be considered dead weight necessary to achieve the desired thrust balance. Elementary rules of design dictate that this dead weight must be held to a minimum and it will be a prime driver in the gross weight of the aircraft. 

The most prominently mentioned power transmission scheme is the traditional mechanical design involving gears, shafts, clutches and bearings. This paper addresses the weight, size and to some extent, the complexity for a variety of Type 'A' V/STOL mechanical transmission configurations. Although the paper emphasizes the mechanical transmission weight and size, overall aircraft characteristics are summarized for the various configurations to illustrate how the transmission weight influences the total aircraft weight. Growth sensitivities and transmission system design criteria effects are also addressed.},

keywords = {25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{1100,

title = {1100. Survivable Fuel Systems},

author = {A J Holten and R R Sorrells},

url = {https://www.sawe.org/product/paper-1100},

year  = {1976},

date = {1976-05-01},

booktitle = {35th Annual Conference, Philadelphia, Pennsylvania, May 24-26},

pages = {75},

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

address = {Philadelphia, Pennsylvania},

abstract = {The trend in aircraft design is to maximize survivability. Aircraft Fuel Systems provide one of the primary areas applicable to survivability enhancement. This paper analyses the non-nuclear threats which are encountered most often during combat situations and the most common damage responses to these threats. The Predominate failure modes for particular design configurations ane the concepts to protect these designs are examined. Methodology has been developed to evaluate the weight and volume effect of survivable design enhancements. The methods developed here present a significant advancement in the capability to access and evaluate survivable fuel systems.},

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

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

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{1102,

title = {1102. Fuselage Analytical Weight Estimation Method},

author = {A D G Bayly},

url = {https://www.sawe.org/product/paper-1102},

year  = {1976},

date = {1976-05-01},

booktitle = {35th Annual Conference, Philadelphia, Pennsylvania, May 24-26},

pages = {20},

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

address = {Philadelphia, Pennsylvania},

abstract = {Much time and energy has been spent into the investigation of fuselage weight prediction methods. Most of these methods have been established by the use of statistical data derived from past and existing aircraft. It is the authors' opinion that a more accurate and convenient method is required for use during the contract definition phase of a program where more detailed information is readily available to the weight engineer. 

This paper presents an analytical method of weight prediction for the basic shell of any fuselage. It assumes that the shear loads are absorbed b the skin and stringers and the bending loads are taken out by frames and longeron. Basic loads are required to be known in order to determine the shear and bending material of the shell structure. The method also takes into account cutouts, pressurization and shape penalties. 

The resulting basic shell weight can then be used along with statistical data for specific design features to arrive at a total fuselage weight.},

keywords = {25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{1120,

title = {1120. A Method for Estimating the Weight of Aircraft Transmissions},

author = {A H Schmidt},

url = {https://www.sawe.org/product/paper-1120},

year  = {1976},

date = {1976-05-01},

booktitle = {35th Annual Conference, Philadelphia, Pennsylvania, May 24-26},

pages = {24},

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

address = {Philadelphia, Pennsylvania},

abstract = {In the design phase of vertical take-off aircraft, it is necessary to estimate the weight of the transmissions in the drive system as accurately as possible since it comprises a significant portion of the total aircraft weight. The method of determining transmission weight presented in this paper, is based on the size of the gears in the transmission. The gear size is not used directly to derive the weight, instead, the more easily obtained values of surface compressive stress index, design horsepower, and gearbox input speed are used along with various other factors for special features, etc. Also included are the weight effects of; bearing supports, output shaft, combining stages of gearing and special features such as clutches. The use of graphs enables the rapid selection of the factors needed for the application of this weight determination method. The means for deriving the weight of accessory gearboxes is also presented, along with several examples of the application of the weight estimating method for typical gearboxes. Diagrams and sketches depicting some of the basic gear facts and some of the various types of gearboxes used in aircraft are presented as an aid in this weight determination method. A plot of the statistical accuracy of this method is also presented.},

keywords = {25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{1047,

title = {1047. Weight Estimation of Manned Spacecraft Metabolic Requirements},

author = {C K McBaine},

url = {https://www.sawe.org/product/paper-1047},

year  = {1975},

date = {1975-05-01},

booktitle = {34th Annual Conference, Seattle, Washington, May 5-7},

pages = {28},

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

address = {Seattle, Washington},

abstract = {One of the new problems confronting the weight engineer is the material and energy balance 

of the human system loop in the manned spacecraft. 

This paper presents methods of estimating weight of the crewman's metabolic material 

requirements for a balanced system. The methods are further clarified by an example problem 

being carried through the analysis for a 50 percentile crewman with a certain daily activity 

and diet composition. 

The analysis begins with the problem description of the crewman metabolic material requirements 

and material balance. Fundamental to the problem solution is the determination of the metabolic 

energy requirements and the metabolic input/output materials to satisfy these requirements. 

This paper presents methods for estimating the crewman's metabolic energy based on his physical 

characteristics and activity. Graphs are presented for the crewman's weight and height while 

equations are presented for the determination of body surface area which is fundamental to the 

metabolic energy determination. 

Food weight estimating equations are presented based on metabolic energy and food composition. 

Independent chemical oxidation equations of the food constituent (protein, fat and carbohydrate) 

are presented and used in the determination of oxygen requirement and carbon dioxide and metabolic 

water production. Limits in the use of these equations, in regard to Basal Metabolic Rate (EMR) 

and Respiratory Quotient (RQ) are given. The water balance is presented in weight equations as a 

function of metabolic energy. The metabolic material weight determinations and system balance is 

concluded with the determination of fecal waste. 

Certain weight sensitivity parameters, such as food composition,percentile and metabolic energy and 

their effect on the metabolic requirements and waste products, are discussed. 

The discussion concludes with the presentation of a recently patented closed ecological system for 

extended missions as justification of the importance of this analysis for future missions. Cursory 

study indicating that completely closed ecological systems would be required for mission over 

approximately 3-3/4 years, from a weight and economic standpoint.},

keywords = {25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{1002,

title = {1002. Methodologies for Predicting Avionic System Capability and Weight in CTOL and VTOL Fighter/Attack Aircraft - 1975 to 1995},

author = {W A Falkenstein},

url = {https://www.sawe.org/product/paper-1002},

year  = {1974},

date = {1974-05-01},

booktitle = {33rd Annual Conference, Fort Worth, Texas, May 6-8},

pages = {37},

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

address = {Fort Worth, Texas},

abstract = {There is a continuing need in advanced conceptual studies for tools and techniques that extend or provide methodologies for useful application in design of fighter/attack aircraft. This paper presents two methodologies for predicting avionic system gross capability and weight in these military aircraft in the 1975 to 1995 time frame. 

An historical background is presented that illustrates the nature of technological advances in electronic circuitry. The effect has been a tremendous reduction in size and weight of individual circuit elements. Unfortunately for the weights engineer, no weight saving has been achieved in the overall avionic systems of conventional takeoff and landing (CTOL) fighter/attack aircraft. This is due to the ever growing demand for increased capability. The consequent functional proliferation is responsible for maintaining design weight of the avionic system in fixed proportion to the design weight empty of the aircraft. This is established empirically. A methodology is developed for determining the increased functional growth or capability that will prevail in the time period 1975 to 1995. Generalizations are established for expected transformation of these future functions into gross system features. Extrapolation of a current avionic system capability is accomplished at constant weight by this methodology. An example is given. 

A second methodology is suggested by the first and is developed to allow extrapolation of avionic system weight, assuming capability is unchanged. Application to conventional takeoff and landing (CTOL) aircraft avionic systems is contrary to the established evidence that supports the previous methodology. However for vertical takeoff and landing (VTOL) aircraft, higher weight sensitivity may result in capability restrictions on the avionic system. Using this methodology, then, the advanced system designer can determine weight savings expected in an avionic system having constant capability with time. An example is given. 

Other areas, such as cost and performance, are suggested for future work to expand the utility of those two methodologies.},

keywords = {25. Weight Engineering - System Estimation},

pubstate = {published},

tppubtype = {inproceedings}

}