QUICK ESTIMATE of the Skin Mass of a Lifting Surface : a Phyton tool developed by CEC Members

Many factors are involved in estimating the mass of the skin of a lifting surface, such as the geometry, the loads , its structural configuration, the materials, etc ….
All these factors determine the preliminary dimensioning of the skin. And all of them contribute to the mass that the skin will have once it is designed and manufactured.
Quickly analyzing the mechanical properties (sizing) of the skin in very preliminary phases will help us not only to have a first and quick estimation of the mass, but also to evaluate the effect of the main factors that influence it.
The method described here serves these purposes : E-MASS

E-MASS tool has being developed with Pyhton including Microsoft Excel and txt files for both : Input and Output Data and includes a set of Graphical outputs . If you want to now more : contact.us

Recent Central European PAPERS

# S3787 Small Satellites Launcher Mass Properties Estimation for Design Efficiency
Improvement in Preliminary Conceptual Phase

Ruben Gonzalez Gonzalez, Universidad Politécnica de Madrid


BEST STUDENT PAPER at COCOA BEACH International Conference

Massimiliano Gobbi, Gianpiero Mastinu, Giorgio Previati,University of Milan

The reconstruction of car accidents is a critical step in understanding the causes of an accident and, in case, for attributing responsibilities. Therefore, the reconstruction must be realized by considering all of the possible sources of error and misrepresentation. Since such activity relies on dynamic models of the colliding vehicles, mass properties (mass, centre of gravity location, inertia tensor) play a crucial role.The present papers aims to quantify the requirements in the knowledge of the inertia properties for a proper reconstruction of car accidents. The analysis is performed with reference to the case of two colliding vehicles. After a detailed description of the model employed for the reconstruction, dynamic simulation are utilized to assess the required accuracy, with particular reference to the effects of the uncertainty in mass, longitudinal location of the centre of gravity and yaw moment of inertia. It turns out that even relatively small errors in the definition of such parameters can lead to large errors in the reconstruction of the state of the colliding vehicles before the accident. Also, the variation in the inertia properties of the vehicles due to the crash is investigated. Engineers involved in car accident reconstruction should be aware of the importance of correctly estimate the inertia properties of vehicle, both before and after the accident, to obtain a correct estimation of the actual dynamic of the accident.

# S3793 Effects of Mass and Pitch Moments of Inertia on Vehicle Suspension Design with Race Car Example
Pietro Stabile,  Federico Ballo, Giorgio Previati, University of Milan

The present paper addresses the topic of studying the influence of the main vehicle inertia parameters on the suspension design. A simple four degrees-of-freedom half-car model is used to describe the dynamic behaviour of vehicles running on randomly profiled roads. The response of the system is analysed by evaluating three performance indexes, namely driver discomfort, road holding and working space, referring to the standard deviations of driver seat vertical acceleration, force at ground and relative displacement between wheels, respectively. The effect of varying wheel mass, vehicle mass, centre of gravity longitudinal location and pitch moment of inertia on the three performance indexes is investigated. The proposed approach is applied to the design of the suspension system of a vehicle conceived for efficiency-based competitions. Based on these results, considerations on the best location for battery pack and ballast are drawn.

# 3780 Analysis of Risk and Opportunities Concerning Effects on Cost and Mass Properties
Claudia Rosenberger, usb – Munich

# 3768 Mass Properties Reporting , Ma,Yiyuan,Yan Jin, and Elham Ali, 2021 SAWE Tech Fair
This paper presents the development of a semi-empirical method for the weight estimation of TF aircraft in the initial sizing stage. A physics-based wing weight estimation method is improved for higher aerodynamic analysis fidelity and composite materials, which is used in the design of experiments and the results are applied for regression analysis to establish a semi-empirical method. Eventually, the established semi- empirical weight estimation method is integrated into a TF aircraft conceptual design and performance analysis framework, and a mid-range TF aircraft and a long-range TF aircraft are designed and sized to illustrate its application and efficiency in rapidly estimating the TF aircraft weight breakdown.

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# 3735. Weight and Balance Challenges for Hybrid Electric Propulsion system, Paula Vera and Dr. Vogel Florian , 2020 SAWE Tech Fair

In the last years electric propulsion systems became increasingly interesting and thanks to many of the technological breakthroughs from automotive companies this technological change is now entering the aviation industry and raises questions about the feasibility, advantages and challenges of the new technologies. In this context, the HEPS weight receives a special attention. The HEPS takes advantage of both electric motor and internal combustion engine and enables the system to be switched on the electrical component of the propulsion for specific flight phases (takeoff and landing).This proposed system has not only the benefit in fuel saving but also a reduction in takeoff noise, emission levels and cost.  It also enables to open spaces and can contribute for safety increase, depending on application. This potential benefits are explored by manufacturers for future aircrafts, helicopters, drones and Urban Air Mobility vehicles.

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# 3536 : Horizontal Tailplane Weight Drivers Analisys ( by Ruben Gonzalez )
Presented during the 70th Annual Conference in Houston,2010


This Paper provides an overview of the horizontal tailplane design, identifying all the weight drivers and explaining their weight impact based on a multidisciplinary aproach…The typical horizontal tail plane desing process in early phases is explained and the main weight drivers are evaluated .

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# 3749 One Fits All ? A Comparison of weight Estimation Methods for Preliminary Aircraft, Kluendr Arthur and Gobbin Andreas, 2020 SAWE Tech Fair

The overall objective of this paper is to evaluate, whether there is a method that precisely calculates all relevant masses or else, which one delivers the most accurate results for various aircraft types. In order to differentiate even further, the set of required input parameters is considered. In early design phases, typically only a few of those are known. Hence, a method that leads to accurate results with minimal input is favorable for preliminary design. The study indicates that none of the methods covers all the aircraft types. However, tendencies show that some approaches suit certain aircraft types better than others. Most of them provide satisfactory results for an average, jet-engine propelled, single aisle, medium range aircraft in conventional twinjet configuration. Regarding more unusual configurations, for example with turboprop engines, the outcome differs noticeably. Also, for long range aircraft, only a few methods produce realistic numbers. According to this exploration, guidelines on when to use which method are provided. This is followed by an outlook, giving recommendations on the development of new methods. Ultimately, a suggestion on how to consider new technologies and implement them into existing methods of weight estimation is given.

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CEC Best Paper Awards

1974  Paper-No. 1021

A Procedure for Calculating the Weight of Wing Structures with increased Service Life

Author: Wolfgang Schneider – VFW-Fokker GmbH

1978  Paper-No. 1242

The Impact of Active Control Technology on Structures

Authors: Helmut Zimmermann – VFW-Fokker GmbH ; Otto Sensburg – MBB GmbH

1995  Paper-No. 2283

Wing Primary Structure Weight Estimation of Transport Aircraft in the Pre-Development Phase

Authors: Roland Kelm – Daimler Benz Aerospace Airbus GmbH ; Martin Läpple – Daimler Benz Aerospace Airbus GmbH ; Michael Grabietz – Grabietz Engineering

1997  Paper-No. 2406

Advanced Fuselage Weight Estimation for the New Generation of Transport Aircraft

Authors: Roland Kelm – Daimler Benz Aerospace Airbus GmbH ; Martin Läpple – Daimler Benz Aerospace Airbus GmbH ; Michael Grabietz – Grabietz Engineering 

2007  Paper-No. 3430

Systems Weight Estimation Enhanced Method for Early Project Phases

Author: Isabel Banel-Caule – Airbus France

2012  Paper-No. 3547

Implementation of a Tool Chain for extended physics-based Wing Mass Estimation in Early Design Stages

 Authors: Felix Dorbath, Björn Nagel, Volker Gollnick – German Aerospace Center (DLR)