Preliminary Design Mass Properties Estimation Forum March 26, 2021

The SAWE is continuing its series of virtual, Zoom-based Mass Properties Forums with the fourth installment, “Preliminary Design Mass Properties Estimation”. This Forum topic was the most requested topic in a survey of SAWE membership and prior Forum attendees.

A panel of industry Subject Matter Experts will start the discussions by expounding on how they would approach deriving the initial mass properties upon presentation of an RFP, ultimately resulting in delivery of preliminary mass properties to their proposal customer. These mass properties would include Not-To-Exceed mass, a preliminary analysis of Center of Gravity bounds, and if applicable, initial estimation of Moments and Products of Inertia. Following these introductory remarks by the panel, the Forum will proceed to questions, comments, and further examples from the audience.

The Forum will be conducted on Friday March 26th, 2021, commencing at 9:00 AM MDT (11:00 AM EDT, 16:00 CET) and will run for 90 minutes.

Registration for this Forum will open on Monday, March 15th.

SAWE RP O-3 Generic Weighing Procedure for Assemblies and Modules in the Offshore Oil Industry has been published.

Weight Control of offshore installations is critical to ensure that any Assembly, Module or Topsides may be installed using the proposed method, with minimum hook-up, and that the overall design caters for the most severe operating criteria identified.  RP O-3 establishes the requirements for weighing Assemblies, Modules or a complete Topsides facility.  It presents methods for preparation before a weighing and reporting results after a weighing has been completed and establishes methods employed to determine the center of gravity from a weighing process.

I’d like to thank the Offshore committee for the hard work in getting this document ready for publishing.  A special thanks goes out to Dave Bennett for providing his leadership for this document with respect to being a major author and editor during the development process

Upcoming SAWE Workshop!

UPCOMING SAWE WORKSHOP: January 29th, 10:00 – 11:00 am CST

Do you feel there are “Mass Properties 101” basics that every Mass Properties engineer should be knowledgeable about regardless of industry?
The SAWE Mass Properties Engineer Certification Committee is hosting an exam question brainstorming workshop where you can help shape the questions included on an Associate-Level Certified Mass Properties Engineer exam.  This exam will be non-industry specific, and will be geared toward members who have either a Bachelor’s degree and 2 years of experience OR 5 years of applicable MPE experience.

The workshop will be virtual with breakout “rooms” for different Mass Properties topics.

Not only is this an opportunity to help shape the knowledge base required for future Certified Mass Properties Engineers, this is also an opportunity to get to know your mass properties colleagues in an interactive setting.

If you are unable to attend the workshop but still want to submit questions, please submit them to Anjie.L.Emmett@NASA.gov

Keep an eye out for emails and updated blog posts on how to sign up!


The facilitators will send out topics, an agenda, and materials on January 20th.

Persuading Leaders and Peers of the Value of Mass Properties

The SAWE has been holding virtual forums using Zoom since the Tech Fair on various mass properties topics.  We are now in the initial phases of creating the third on the series.  The topic will be Persuading Leaders and Peers of the Value of Mass Properties, which will be presented on Friday, January 15th.  Nominally, we are looking for the Forum to run for an hour and a half starting at 9:00 AM MST (11:00 AM EST).

This forum will be somewhat different than previous forums in the following way – rather than a Forum leader and a host for the meeting, there will be a forum host and a panel of mass properties experts, who have now moved on to other positions in their organizations. We have identified people who have moved up to group lead and then to higher management levels, people who have risen to lead mass properties groups, people who oversee mass properties, and people who have experienced both well run and poorly run mass properties organizations.  Each have a tale to tell.

What we envision is  supplying a short PowerPoint template for each panelist to use to expound on their “secret sauce” on how to enable a well functioning mass properties effort, and more importantly, what the overall value of having such an organization (which could even be a single person) is to their group, company, and nation.  Each panelist will have a short period of time (approximately 3-4 minutes) to present their case.  After all the panelists have spoken, we will open up the floor for our audience to comment, ask questions, and discuss what they have just witnessed.  Then there we will conduct a short wrap-up with the opportunity for discussions to continue off-line.

Be on the look out for more information as the details are finalized, but now is the time to get this on your calendar to make sure you are part of this great virtual forum!

Give us Your Best Engineering Joke!

One thing I think everyone can agree on:  it has been a heck of a year, and everyone could use a bit of comic relief. 

So, for the Winter 2021 issue of “Weight Engineering”, we will be featuring a selection of favorite engineering jokes from the membership!  Please send your submissions to me at nmarickovich@gmail.com.  Along with the funny stuff, please send your name, SAWE chapter, and (if you’d like) a picture of yourself and why you find the joke meaningful to you. 

Please get your submissions in by 1/10/21 to be considered.  You can type your joke up in an email or send an MS Word or PDF file.  And let’s keep it classy folks:  jokes considered racist, sexist, or otherwise offensive will not be published.  Should not be a problem from such a fine bunch of Mass Properties Professionals such as yourselves!  Jokes at management’s expense would be considered par for the course, naturally. 

Thank you for your continued support of the SAWE through these challenging times. 

Nick Marickovich, VP Publications

MORE VIRTUAL TRAINING COMING IN JANUARY 2021

Two more classes have been added to the SAWE 2020-2021 Virtual Training schedule. Vendor Weight Control and Marine Vehicle Weight Estimating Methodology will be offered on January 22 and 23, 2021. Both classes are eight hours long, taught in two four hour sessions (Friday 1/22/21 and Saturday 1/23/21). The Cost for each class is $ 500.

The Vendor Weight Control class discusses the various items included in RP100 Vendor Weight Control for the Aircraft Industry as well as RP 15/M-4 Vendor Weight Control for the Marine Industry. These two RPs share many common requirements from vendors. Although some of the acronyms and definitions may vary, the data request is of a similar nature. The course will cover the major sections of the two RPs. Examples of what sort of data that is required in these sections will be presented accompanied by in class discussions, which will provide a means to ask specific questions that may address problems or clarification of requirements. Topics that will be covered are: Introduction and Purpose, Equipment and Supply Chain, Weight Control, Mass Properties Requirements, Weight Reduction programs, Actual weighing and verification, and Weight Reporting. Other topics may be discussed time permitting. The goal of this course is to introduce vendor weight control, detail the different phases and types of deliverables that may be required and also provide guidance on how to achieve these requirements. SAWE Fellow Whidy Kiskunas will be the Instructor.

The Marine Vehicle Weight Estimating Methodology class discusses the fundamentals of Marine Vehicle Weight Estimating. The weight estimating methods described in SAWE Recommended Practice 14 “Marine Weight Estimating & Margin Policy Guideline” will be reviewed. The class will cover the theory, and application of these methods on specific examples and for whole ship design. The appropriateness of each method for each stage of ship design, construction and operation will be discussed. The students will work examples to estimate the weight of a vessel using multiple methods. Historic examples of weight estimating errors will be discussed as an example of practices to be avoided. Classroom materials and exercises will be provided. SAWE Fellow Davy Hansch will be the instructor.

Registration details coming soon.

Dan Rowley
SAWE Vice President, Training

Fatigue Life vs Weight Virtual Forum Coming November 20th

Designing for the lightest weight conflicts with the reality that our products have to be usable over their lifetime.  Flexure, friction, rolling resistance, and impact resistance all need to be considered before a product is released for production.  Combating these forces and movements often requires additional or larger structure to ensure a product’s survival out in “the world”.  How do we, as mass properties engineers, accurately predict structural and dynamic systems weight based on system life requirements?

Answering this question is the subject of the second SAWE Virtual Forum.  The Society of Allied Weight Engineers is holding a one-hour Virtual Forum on Fatigue Life vs Weight on Friday, November 20th at 8 AM PST (11 AM EST, 4PM CEST) to discuss this looming problem. Join us and let the SAWE know your experiences and opinions on how best to account for component life requirements in the weight of structural and dynamic components.

Join Forum Leader Josh Elmore of the Army’s Combat Capabilities Development Command, Aviation and Missile Center, and the SAWE Leadership in this 2020-2021 SAWE Virtual Forum via Zoom (link below) and let your voice be heard.  Be involved in solving a problematic aspect of mass properties engineering that impacts not only our ability to control weight, but our relationships with our management and customers.

Zoom Instructions

To join the meeting, first you must register using the link below.

https://us02web.zoom.us/meeting/register/tZMvf-6pqzwsGdBR46NzUL9fLJQZ5kgcXhA1

After registering, you will receive an email from Bill Boze (SAWE Executive Director) with the subject “Tech Forum – Fatigue Life vs Weight Confirmation”. Save this email, as it has the information required to actually join the meeting. Please note that to join the meeting, you MUST use the Zoom desktop client or mobile app. You will not be able to join using the web client.

Questions Anyone? MPE Certification Committee needs help!

The Mass Properties Engineering (MPE) Certification Committee is seeking help from SAWE members to formulate questions for the Associate-Level MPE exam.  This exam will be non-industry specific, and will be geared toward members who have either a Bachelor’s degree and 2 years of experience OR 5 years of applicable MPE experience.  The committee is building a repository of questions spanning various facets of mass properties engineering from which to pull exam content.

The multiple choice questions will cover topics such as:

  • Experience
  • Safety
  • Leadership
  • MPE Fundamentals
    • Design Development
    • Validation
    • Verification
    • MP Measurement
    • Design of Fixtures
    • Customer and Contract Requirements
  • Engineering Knowledge
    • MP Engineering Knowledge
    • Systems Engineering Knowledge
    • Sub System Engineering Knowledge
    • Fundamentals
  • Process
  • Systems
  • Software
  • Analysis
  • Reporting

References from which to pull questions may include but are not limited to:

  • The Weight Engineers’ Handbook
  • Introduction to Aircraft Weight Engineering Textbook
  • Marine Vehicles Weight Engineering Textbook
  • SAWE Papers

Please submit your questions, along with the multiple choice options  and answers, to Anjie Emmett at Anjie.l.emmett@nasa.gov or Dirk Petersen at dirk.petersen@gmx.net.  Your help will ensure that our unique knowledge and critical discipline and continue to thrive!

Reminder “Barbeque Roll of a Near Axisymmetric Spacecraft” – Virtual Presentation 10/29

SAWE members you have seen the email invitation to the SAWE-Hampton Roads (10/29 12:00PM Eastern U.S ) virtual chapter meeting. This is just a reminder that the presentation, the first half of the meeting, is open to all members. But the Zoom link is sent privately as only 100 slots are available and we are avoiding the phenomena of “zoom bombing”.

Contact Jeffrey.a.cerro@nasa.gov if you would like to attend and still need the meeting invitation/link.

Note that for anyone who is unable to download the ZOOM application. You can click on the meeting link, then select “Launch Meeting”, and then select “Join from your browser”.

Carlos M. Roithmayr is a senior aerospace engineer in the Systems Analysis and Concepts Directorate at the NASA Langley Research Center in Hampton, Virginia. He earned a Bachelor of Aerospace Engineering degree at the Georgia Institute of Technology, both an M.S. and a Degree of Engineer in Aeronautics and Astronautics from Stanford University, and a Ph.D. in Aerospace Engineering from the Georgia Institute of Technology. He began his career with NASA at the Johnson Space Center in Houston, Texas. His research interests include dynamics of multibody mechanical systems, spacecraft attitude dynamics and control, and orbital mechanics, and he has contributed to a wide variety of Agency projects and missions. He is author or coauthor of one book and numerous refereed journal papers. Dr. Roithmayr is a senior member of the American Institute of Aeronautics and Astronautics.

Virtual Training Classes – Register Now!

We are two weeks out from our first Fall Training weekend! The classes being held October 23-24 are Developing Basic Parametric Methods & Ship Inclining Experiment. It is not too late to sign up! Classes will be held via zoom from 10:00am – 2:00 PM Eastern Time both days.

Developing Basic Parametric Methods – Instructor: Andy Walker

Have you ever been asked to predict the future? With a little information, you can explore the solution-space around the problems you encounter on the job as a Mass Properties engineer.
The course will cover:
• Parametric estimation and rapid aircraft mass properties assessments.
• Feasibility studies on detail design projects
• Conceptual trade studies based on very limited information
• Quantify predictive and descriptive uncertainty around your predictions
• Calculate the benefits of next-generation technologies
Agenda items will include basic statistical terminology, statistical correlation processes, parametric estimation pitfalls, and a parametric fighter aircraft wing weight correlation example.

Ship Inclining Experiment – Instructor: William A. Fox

This class will discuss the inclining of a vessel in order to determine its displacement (weight) and centers of gravity. The primary emphasis will be on inclining in water, but inclining in air will also be covered. The theory, procedure, and results of inclining will be discussed. Students will view a recording of an actual Ship Inclining Experiment, narrated by the Instructor (the Director’s Cut).
The objectives of the class are to provide the student with an introduction to the principles of naval architecture and to marine terminology, and to discuss and demonstrate the inclining of a vessel to determine its weight and center of gravity. ASTM F 1321-90, Standard Guide for Conducting a Stability Test, will be used as a text for this class. After a brief introduction to the principles of naval architecture, the theory and purpose of the inclining experiment will be presented. The lightweight survey will be described and then the inclining experiment itself will be discussed. Preparations required aboard the vessel and ashore will be described, and plans and equipment required will be discussed and demonstrated. Inclining procedures, data, and calculations will be reviewed and examples from an actual inclining will be examined in detail. Troubleshooting the results of the inclining, and matters of bias and accuracy, will be covered. Inclining of a small vessel in air will be discussed.

Registration link: https://www.sawe.org/registration/