SAWE General https://www.sawe.org Society of Allied Weight Engineers, Inc. Thu, 06 Aug 2026 14:07:57 +0000 en-US hourly 1 https://wordpress.org/?v=7.1.3 231197347 3843 Digital Exposure of Mass Properties Data https://www.sawe.org/product/3843-digital-exposure-of-mass-properties-data/ Fri, 29 May 2026 17:05:19 +0000 https://www.sawe.org/?post_type=product&p=11475 Paper
Nick Thies: 3843. Digital Exposure of Mass Properties Data. 2026.
 

Abstract

Providing mass properties data for the consumption of others is, and may always be, a deliberate act. Whether that data takes the form of a periodic data deliverable, like a status report, or a specific response to a customer question, Mass Properties Engineers must frequently mine and manipulate data to satisfy the needs of others. The data maintained within any mass properties database has a breadth that far exceeds simple numerical values of weight, center of gravity, and inertia. Most often, a database includes a labyrinth of codes and descriptors necessary to sort, parse, and aggregate those core numerical values in a meaningful way. Few people other than the Mass Properties Engineers tasked with maintaining that data have any real success gathering/assessing the data sufficiently well to satisfy specific data requests. As a result, both Mass Properties Engineers and customers persist in a request/provide, request/provide paradigm. Even when considering periodic data deliverables, this cycle is preserved (with an implied request). Establishing methods by which mass properties data can be openly exposed, in a meaningful way, serves to break down this cycle. Many data requests need not be asked again; the data is always available without request. In some cases, periodic data deliverables are challenged, relegated to historical practices, as they are replaced by real-time or near-real-time data. However, realizing such a paradigm-breaking scenario cannot occur without one thing – a deliberate act to do so. This paper presents fundamental changes which enable digital exposure of mass properties data.]]> Paper
Nick Thies: 3843. Digital Exposure of Mass Properties Data. 2026.
 

Abstract

Providing mass properties data for the consumption of others is, and may always be, a deliberate act. Whether that data takes the form of a periodic data deliverable, like a status report, or a specific response to a customer question, Mass Properties Engineers must frequently mine and manipulate data to satisfy the needs of others. The data maintained within any mass properties database has a breadth that far exceeds simple numerical values of weight, center of gravity, and inertia. Most often, a database includes a labyrinth of codes and descriptors necessary to sort, parse, and aggregate those core numerical values in a meaningful way. Few people other than the Mass Properties Engineers tasked with maintaining that data have any real success gathering/assessing the data sufficiently well to satisfy specific data requests. As a result, both Mass Properties Engineers and customers persist in a request/provide, request/provide paradigm. Even when considering periodic data deliverables, this cycle is preserved (with an implied request). Establishing methods by which mass properties data can be openly exposed, in a meaningful way, serves to break down this cycle. Many data requests need not be asked again; the data is always available without request. In some cases, periodic data deliverables are challenged, relegated to historical practices, as they are replaced by real-time or near-real-time data. However, realizing such a paradigm-breaking scenario cannot occur without one thing – a deliberate act to do so. This paper presents fundamental changes which enable digital exposure of mass properties data.]]> 11475 3842 Modernizing SumMassProps https://www.sawe.org/product/3842-modernizing-summassprops/ Fri, 29 May 2026 16:36:45 +0000 https://www.sawe.org/?post_type=product&p=11473 Paper
Robert Zimmerman: 3842. Modernizing SumMassProps. 2026
 

Abstract

In 2003 I created the initial version of SumMassProps, an Excel Add-In that created a macro-based Excel solution for correctly summing the 10 basic mass properties (Mass, 3-axis Centers of Gravity, 3-axis Moments of Inertia, and 3-axis Products of Inertia). This was released as SAWE Paper 3310. This solution had a bare-bones Graphical User Interface (GUI) that only created the necessary header lines required to run the Add-In, all the “guts” of the solution were accessed using Excel’s built-in Paste Function) to access each of the Add-In’s summing functions. This was not ideal. Although the original 2003 version of SumMassProps did ensure that the consistent equations were used to sum mass properties, in 2012 a major update was issued as SAWE paper 3574. This update included a full GUI utilizing menus to access the various functions, as well as adding additional functionality to the Add-In. This version also included corrections to the summing of mass properties uncertainties as covered in SAWE paper 3360 “Are You Sure?”. In 2009 Microsoft created a different way to access functions and macros, calling this new method the Ribbon. Later, access to functions and macros using menus was discontinued within Visual Basic for Applications, the language used to create the SumMassProps Add-In, and the Add-In would fail to load. This forced either a return to the 2003 method or a re-write of the program to encompass the new Ribbon paradigm versus a menu driven paradigm. This paper describes the necessary steps to implement a Ribbon-based Add-In, and will also be a release for SumMassProps Version 10 (2026) that utilizes a Ribbon-based paradigm, which necessitates a re-write of the Tutorial and the User Guide to walk the user through the Add-In.]]> Paper
Robert Zimmerman: 3842. Modernizing SumMassProps. 2026
 

Abstract

In 2003 I created the initial version of SumMassProps, an Excel Add-In that created a macro-based Excel solution for correctly summing the 10 basic mass properties (Mass, 3-axis Centers of Gravity, 3-axis Moments of Inertia, and 3-axis Products of Inertia). This was released as SAWE Paper 3310. This solution had a bare-bones Graphical User Interface (GUI) that only created the necessary header lines required to run the Add-In, all the “guts” of the solution were accessed using Excel’s built-in Paste Function) to access each of the Add-In’s summing functions. This was not ideal. Although the original 2003 version of SumMassProps did ensure that the consistent equations were used to sum mass properties, in 2012 a major update was issued as SAWE paper 3574. This update included a full GUI utilizing menus to access the various functions, as well as adding additional functionality to the Add-In. This version also included corrections to the summing of mass properties uncertainties as covered in SAWE paper 3360 “Are You Sure?”. In 2009 Microsoft created a different way to access functions and macros, calling this new method the Ribbon. Later, access to functions and macros using menus was discontinued within Visual Basic for Applications, the language used to create the SumMassProps Add-In, and the Add-In would fail to load. This forced either a return to the 2003 method or a re-write of the program to encompass the new Ribbon paradigm versus a menu driven paradigm. This paper describes the necessary steps to implement a Ribbon-based Add-In, and will also be a release for SumMassProps Version 10 (2026) that utilizes a Ribbon-based paradigm, which necessitates a re-write of the Tutorial and the User Guide to walk the user through the Add-In.]]> 11473 3851 Roll and Horizontal Axis Moment of Inertia (MOI) Measurements using a Gravity Pendulum https://www.sawe.org/product/3851-roll-and-horizontal-axis-moment-of-inertia-moi-measurements-using-a-gravity-pendulum/ Fri, 29 May 2026 16:20:43 +0000 https://www.sawe.org/?post_type=product&p=11468 Paper
James Blair: 3851. Roll and Horizontal Axis Moment of Inertia (MOI) Measurements using a Gravity Pendulum. 2026.
 

Abstract

Customers with long cylindrical parts have had difficulty measuring the inertia about the roll axis on systems that require the part to be mounted vertical in order to conduct the measurement. This has led to issues with the requirement of a variety of fixtures and risky handling of parts in order to orient the part. Raptor Scientific has developed a measurement system that measures inertia about the roll axis in a horizontal manner using an air bearing fixture and universal rings to measure the time period, and when combined with center of gravity measurements from a KSR instrument and mass measurements, determines the inertia about this axis. This paper examines the goals of the end user, the process used in designing the fixture, final results and accuracy requirements / what is achievable, and lessons learned along the way for the design and build of the final deliverable instrument.]]> Paper
James Blair: 3851. Roll and Horizontal Axis Moment of Inertia (MOI) Measurements using a Gravity Pendulum. 2026.
 

Abstract

Customers with long cylindrical parts have had difficulty measuring the inertia about the roll axis on systems that require the part to be mounted vertical in order to conduct the measurement. This has led to issues with the requirement of a variety of fixtures and risky handling of parts in order to orient the part. Raptor Scientific has developed a measurement system that measures inertia about the roll axis in a horizontal manner using an air bearing fixture and universal rings to measure the time period, and when combined with center of gravity measurements from a KSR instrument and mass measurements, determines the inertia about this axis. This paper examines the goals of the end user, the process used in designing the fixture, final results and accuracy requirements / what is achievable, and lessons learned along the way for the design and build of the final deliverable instrument.]]> 11468 3846 Vendor Guarantee Weights in Product Development https://www.sawe.org/product/3846-vendor-guarantee-weights-in-product-development/ Fri, 29 May 2026 16:17:18 +0000 https://www.sawe.org/?post_type=product&p=11467 Paper
Doug Fisher: 3846. Vendor Guarantee Weights in Product Development. 2026.
 

Abstract

Aircraft OEMs outsource significant design and build scope to vendors/suppliers. A Guarantee weight (often termed a Guaranteed-Not-to-Exceed weight) is the maximum allowable delivered weight of a supplier’s item. This paper outlines key considerations for establishing Guarantee weight agreements between design/manufacturing suppliers and aircraft OEMs in the civil aviation industry. Contractually binding Guarantee weights are critical to meeting aircraft performance and safety goals. Because suppliers face penalties for non-compliance, Guarantee weights must be realistically achievable within program cost and schedule constraints. Guarantees are often set early in development, before the design is stable. Early unknowns create weight risk that must be accounted for (via management reserve, weight-growth allowance, or other countermeasures) to reach an agreement acceptable to both parties.]]> Paper
Doug Fisher: 3846. Vendor Guarantee Weights in Product Development. 2026.
 

Abstract

Aircraft OEMs outsource significant design and build scope to vendors/suppliers. A Guarantee weight (often termed a Guaranteed-Not-to-Exceed weight) is the maximum allowable delivered weight of a supplier’s item. This paper outlines key considerations for establishing Guarantee weight agreements between design/manufacturing suppliers and aircraft OEMs in the civil aviation industry. Contractually binding Guarantee weights are critical to meeting aircraft performance and safety goals. Because suppliers face penalties for non-compliance, Guarantee weights must be realistically achievable within program cost and schedule constraints. Guarantees are often set early in development, before the design is stable. Early unknowns create weight risk that must be accounted for (via management reserve, weight-growth allowance, or other countermeasures) to reach an agreement acceptable to both parties.]]> 11467 3845 The Earned Value Evolution of the Plan to Perform https://www.sawe.org/product/3845-the-earned-value-evolution-of-the-plan-to-perform/ Fri, 29 May 2026 16:04:48 +0000 https://www.sawe.org/?post_type=product&p=11465 Paper
Patrick Brownh: 3845. The Earned Value Evolution of the Plan to Perform. 2026.
 

Abstract

Earned Value Management (EVM) is a widely recognized project management technique for objectively measuring project performance by integrating scope, schedule, and cost. The Mass Properties Plan to Perform (PtP) is used in the total product lifecycle Program Development phase for managing and communicating status empty, target, and not-to-exceed (NTE) weights. This paper explores the possibility of superimposing the EVM techniques onto the PtP process. And by leveraging the EVM vernacular, the author hopes to achieve the following results:
  • PtP with ‘earned weights’ (status and NTE as compared to target weights)
  • Improved Program, Chief Engineer, and Integrated Team communication (performance indices and variance analysis)
  • Wider understanding within non-technical disciplines e.g. Business Management team, Global Supply Chain, etc. (conceptual commonality with established EVM and relationships)
While the concepts presented in the paper are practical, and loosely follow both EVM and PtP methods, the application and examples provided are hypothetical.]]> Paper
Patrick Brownh: 3845. The Earned Value Evolution of the Plan to Perform. 2026.
 

Abstract

Earned Value Management (EVM) is a widely recognized project management technique for objectively measuring project performance by integrating scope, schedule, and cost. The Mass Properties Plan to Perform (PtP) is used in the total product lifecycle Program Development phase for managing and communicating status empty, target, and not-to-exceed (NTE) weights. This paper explores the possibility of superimposing the EVM techniques onto the PtP process. And by leveraging the EVM vernacular, the author hopes to achieve the following results:
  • PtP with ‘earned weights’ (status and NTE as compared to target weights)
  • Improved Program, Chief Engineer, and Integrated Team communication (performance indices and variance analysis)
  • Wider understanding within non-technical disciplines e.g. Business Management team, Global Supply Chain, etc. (conceptual commonality with established EVM and relationships)
While the concepts presented in the paper are practical, and loosely follow both EVM and PtP methods, the application and examples provided are hypothetical.]]> 11465 3840 The Learjet 85: Historical Evolution, Critical Challenges and Lessons from a Misguided Program https://www.sawe.org/product/3840-the-learjet85-historical-evolution-critical-challenges-and-lessons-from-a-misguided-program/ Thu, 21 May 2026 15:14:42 +0000 https://www.sawe.org/?post_type=product&p=11462 Paper
Darrin McCloud: 3840. The Learjet 85: Historical Evolution, Critical Challenges and Lessons from a Misguided Program. 2026.
 

Abstract

The story of the Learjet 85 (LJ85) starts with the Learjet 60 (LJ60). In 2004 the LJ60 was the largest Learjet in production, however it suffered from many problems that were causing it to lose valuable market share. Foremost was that the LJ60 used the same basic wing and main landing gear (MLG) design that traced its lineage all the way back to the Learjet 23 in the early 1960’s. Based off the original Swiss fighter jet wing design, this design was thin, very strong, high speed optimized and originally came equipped with tip tanks for additional fuel storage. It was now being used on a plane that weighed twice as much, had winglets instead of tip tanks and was limited to the same small size wheels. The following issues were the result: 1. Poor landing performance due to high landing speeds and undersized brakes 2. Large fuselage tank required due to small wing fuel volume 3. CG issues due to short MAC length and large fuel moment change By the Summer of 2005, Learjet was ready for an internal launch of our new project. It was a design that would have instantly been recognized as a Learjet in both the performance and the external lines. Heritage aluminum structure and classic manual flight control systems would be used in line with all previous models. Newer LJ45 style systems and wing aerodynamics would be combined with a lengthened LJ60 fuselage to create a low-cost successor to the long in the tooth LJ60. It was called various official program names over the next year, but many of the employees liked to call it the Learjet 65.]]> Paper
Darrin McCloud: 3840. The Learjet 85: Historical Evolution, Critical Challenges and Lessons from a Misguided Program. 2026.
 

Abstract

The story of the Learjet 85 (LJ85) starts with the Learjet 60 (LJ60). In 2004 the LJ60 was the largest Learjet in production, however it suffered from many problems that were causing it to lose valuable market share. Foremost was that the LJ60 used the same basic wing and main landing gear (MLG) design that traced its lineage all the way back to the Learjet 23 in the early 1960’s. Based off the original Swiss fighter jet wing design, this design was thin, very strong, high speed optimized and originally came equipped with tip tanks for additional fuel storage. It was now being used on a plane that weighed twice as much, had winglets instead of tip tanks and was limited to the same small size wheels. The following issues were the result: 1. Poor landing performance due to high landing speeds and undersized brakes 2. Large fuselage tank required due to small wing fuel volume 3. CG issues due to short MAC length and large fuel moment change By the Summer of 2005, Learjet was ready for an internal launch of our new project. It was a design that would have instantly been recognized as a Learjet in both the performance and the external lines. Heritage aluminum structure and classic manual flight control systems would be used in line with all previous models. Newer LJ45 style systems and wing aerodynamics would be combined with a lengthened LJ60 fuselage to create a low-cost successor to the long in the tooth LJ60. It was called various official program names over the next year, but many of the employees liked to call it the Learjet 65.]]> 11462