SAWE Technical Papers

@inproceedings{3802,

title = {3802. The Mass Growth Factor – Snowball Effects in Aircraft Design},

author = {John Singh Cheema and Dieter Scholz},

url = {https://www.sawe.org/product/2802-the-mass-growth-factor-snowball-effects-in-aircraft-design/},

year  = {2024},

date = {2024-05-22},

urldate = {2024-05-22},

booktitle = {83rd International Conference, virtual (2024)},

pages = {64},

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

abstract = {Purpose – This project work shows a literature survey, clearly defines the mass growth factor, shows a mass growth iteration, and derives an equation for a direct calculation of the factor (without iteration). Definite values of the factor seem to be missing in literature. To change this, mass growth factors are being calculated for as many of the prominent passenger aircraft as to cover 90% of the passenger aircraft flying today. The dependence of the mass gain factor on requirements and technology is examined and the relation to Direct Operating Costs (DOC) is pointed out.



Methodology – Calculations start from first principles. Publically available data is used to cal-culate a list of mass growth factors for many passenger aircraft. Using equations and the result-ing relationships, new knowledge and dependencies are gained.



Findings – The mass growth factor is larger for aircraft with larger operating empty mass ratio, smaller payload ratio, larger specific fuel consumption (SFC), and smaller glide ratio. The mass growth factor increases much with increasing range. The factor depends on an increase in the fixed mass, so this is the same for the payload and empty mass. The mass growth factor for subsonic passenger aircraft is on average 4.2, for narrow body aircraft 3.9 and for wide body aircraft (that tend to fly longer distance) 4.9. In contrast supersonic passenger aircraft show a factor of about 14.



Practical implications – The mass growth factor has been revisited in order to fully embrace the concept of mass growth and may lead to a better general understanding of aircraft design. Social implications – A detailed discussion of flight and aircraft costs as well as aircraft de-velopment requires detailed knowledge of the aircraft. By understanding the mass growth fac-tor, consumers can have this discussion with industry at eye level.



Originality/value – The derivation of the equation for the direct calculation of the mass growth factor and the determination of the factor using the iteration method for current aircraft was not shown in the examined literature.},

keywords = {Aircraft},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3805,

title = {3805. Measuring Reaction Points during Aircraft Weighing using an Inexpensive Laser},

author = {Damian P. Yañez },

url = {https://www.sawe.org/product/3805-measuring-reaction-points-during-aircraft-weighing-using-an-inexpensive-laser/},

year  = {2024},

date = {2024-05-22},

booktitle = {83rd International Conference, virtual (2024)},

pages = {12},

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

abstract = {Maintaining an aircraft's weight and balance within specified limits throughout all phases of its lifecycle is critical to its performance and the safety of its crew, passengers, and maintenance personnel. Measuring the weight and center of gravity (CG) of the aircraft in its Empty Weight configuration is typically the starting point for all subsequent weight and balance calculations. This procedure is often accomplished by placing load cells on jacks underneath the aircraft at three (or more) known locations relative to the aircraft coordinate system, raising and leveling the aircraft, measuring the weights on each cell, and calculating the moments and resultant CG. If the load cells are positioned at fixed reaction points on the airframe, the locations of the cells are easily known. If the load cells are positioned beneath the landing gear, the reaction points must be measured since the gear typically moves with an increase or decrease in load. Finding the true dimensions of these reaction points can be difficult, time consuming, and prone to error. This paper describes a method for quickly and accurately determining the reaction locations for the jacks under gear (JUG) method using an inexpensive laser distance meter. All aircraft designs are unique, so the process may not work exactly as described here, but the hope is that this paper will stimulate discussion and ideas for extending the concept as needed to fit your situation.},

keywords = {Aircraft},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3811,

title = {3811. Parametric Weight Substantiation And Uncertainty Quantification For Aircraft Design},

author = {Andy Walker},

url = {https://www.sawe.org/product/3811-parametric-weight-substantiation-and-uncertainty-quantification-for-aircraft-design/},

year  = {2024},

date = {2024-05-22},

booktitle = {83rd International Conference, virtual (2024)},

pages = {46},

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

organization = {SAWE},

abstract = {Creating and substantiating weight estimation methods for future aircraft design has been completed using open-source data. Legacy best-practices were explored in corelating weight estimating relationships for configurations relating to manned fighters, carrier-based fighters, jet transports, business jets, military intelligence/ surveillance/ reconnaissance (ISR), and general aviation. Statistical methods were used to validate that each parametric method follows a normal, Gaussian distribution. This paper also makes some novel observations regarding statistical weight regressions, including: the fallacy of removing data points in regressions, the good and bad side of adding weight growth margins, employing detailed vs coarse weight method calibration factors, and how legacy aircraft validation helps in the big picture but hurts in the details.},

keywords = {Aircraft, Other Engineering},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3794,

title = {3794. The Mass Properties Function during The Aircraft Interior Outfitting},

author = {Luis A. Lopez},

url = {https://www.sawe.org/product/paper-3794},

year  = {2023},

date = {2023-05-20},

urldate = {2023-05-20},

booktitle = {82nd Annual Conference, Cocoa Beach, Florida},

pages = {20},

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

address = {Cocoa Beach, Florida},

abstract = {Outfitting is defined as the introduction and physical addition of custom furnishings, cabin entertainment systems, cabin insulation, acoustics materials, seats, and others to a “green aircraft”, a plane without interiors or other components at a completion center facility per customer definition. 

By its nature, outfitting will vary from one aircraft to another, depending on number of seats, degree of function or luxury elements and location of interior components. Mass properties are the physical properties of an object that describe all its mass, center of gravity, and moment of inertia. These properties are impacted when outfitting interiors are introduced in the aircraft as they are typically the last step of the manufacturing build on an aircraft, however they will influence and define the final performance and handling of an aircraft. 

The intention of this paper is to explore the aircraft interiors outfitting activity as it relates to the Completions Mass Properties Engineer function and its effects at the final build. 

We briefly explore areas that are related to the completions function from the mass properties perspective. We will use simple terms to highlight the important responsibility of the Mass Properties Engineer in the outfitting final phase’s role on a typical OEM (Original Equipment Manufacturer). A discipline that is not well understood by colleagues and the public in general due to the specialized nature of the work.},

keywords = {Aircraft},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{3795,

title = {3795. Aerostructural Weight Estimation for a Transonic Truss-Braced Wing Using the Higher-Fidelity Conceptual Design and Structural Optimization Tool},

author = {Zachary Windous and Jesse R. Quinlan},

url = {https://www.sawe.org/product/paper-3795},

year  = {2023},

date = {2023-05-20},

urldate = {2023-05-20},

booktitle = {82nd Annual Conference, Cocoa Beach, Florida},

pages = {11},

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

address = {Cocoa Beach, Florida},

abstract = {Continued development and enhancements of the Higher-fidelity Conceptual Design and structural optimization (HCDstruct) tool have been driven largely by advanced aircraft concepts of interest to NASA. While previous versions of HCDstruct were limited to hybrid wing body (HWB) and generalized tube and wing (TW) aircraft concepts, the latest version of HCDstruct supports the analysis of Truss-Braced Wing (TBW) aircraft concepts, enabling users to model both high and low wing configurations as well as strut and jury geometries parametrically. Additionally, new methods for modeling advanced composite materials within HCDstruct have been implemented. These recent tool enhancements were demonstrated for an independent assessment of the NASA/Boeing SUGAR Phase VI Mach 0.8 Transonic Truss-Braced Wing (TTBW) concept.},

keywords = {Aircraft},

pubstate = {published},

tppubtype = {inproceedings}

}