# OPerA - Optimization in Preliminary Aircraft Design

Aim of OPerA was to apply formal optimization to aircraft preliminary design and preliminary aircraft cabin design. In this way OPerA was extending the Lecture and the Short Course Aircraft Design of Prof. Scholz by also building on the results of PreSTo and CARISMA. The follow-on-project is SAS.

### Introduction to OPerA

Problem Statement:
Aircraft design parameters like aspect ratio, maximum lift coefficients, ... are the engineer's choice. Especially for inexperienced users it is difficult to choose all required design parameters in a sensible way. The challenge is to find the best combination of design parameters leading to an optimum design.

The Solution:
The best combination of design parameters can be found by formal optimization of the aircraft design and by presenting these optimized values to the user as a starting point for further investigations in aircraft design.

Application of a Formal Optimization Program:
The Optimus software platform by Noesis Solutions (Belgium) was connected to the Excel preliminary sizing sheet from PreSTo. This made it possible to optimize any design output parameter for any combination of design input parameters. A variety of optimization algorithms could be tested. Differential Evolution was found to be a suitable algorithm for aircraft design problems. The original PreSTo spread sheets were simplified for use in optimization. PreSTo was also extended in order to incorporate both benefits (L/D, SFC...) and penalties (structural mass, drag...) to the design coming from parameter variations.

Stand-alone Optimization with Code Written in VBA:
Today OPerA is independent of any other commercial optimization software. OPerA requires only Microsoft Excel 2007 and makes use also of Excel's Solver.

Result (Example):

Bubble plot from Optimus relating three input values (T/W, C_L,max, m_ML/m_MTO) to the maximum take-off mass of the aircraft (m_MTO) as output.

### Organisation

Dipl.-Ing. Mihaela Niţă (today: Dr.-Ing. Mihaela Man) was working on OPerA as part of her cooperative dissertation with Hamburg University of Applied Sciences. Her work was financed through a grant from Pro Exzellenzia. She was registered for her PhD studies at the Universitatea Politehnica din Bucuresti (UPB). The results of OPerA are part of her dissertation together with her results from CARISMA. OPerA was looking at the theory of optimization applied to aircraft design and aircraft cabin design. CARISMA on the other hand was taking up this general knowledge, applying it to practical questions in an industrial cabin design environment.

Publications related to OPerA
Reports from OPerA (Work details: Memos)

NIŢĂ, Mihaela Florentina: Contributions to Aircraft Preliminary Design and Optimization. München : Verlag Dr. Hut, 2013. - ISBN 978-3-8439-1163-4, Dissertation, Download: https://purl.org/aero/NITA_DISS_2013

Data set at DNB: http://d-nb.info/1042877904

As hard copy, the dissertation is available also from the libraries of these universities:
HAW Hamburg, TU Hamburg Harburg, TU Braunschweig, TU Berlin, TU Dresden, TU Darmstadt, U Stuttgart, TU München, Uni BW München, FH Aachen.

Library catalog entries:

NITA_Abstract_Teza_de_Doctorat_A-C_Preliminary_Design_and_Optimization.pdf (Abstract: Romanian / English)

Paper and Presentation at the German Aerospace Conference, Berlin, 10. - 12. September 2012:

NIŢĂ, Mihaela; SCHOLZ, Dieter: Estimating the Oswald Factor from Basic Aircraft Geometrical Parameters. In: Publikationen zum DLRK 2012 (Deutscher Luft- und Raumfahrtkongress, Berlin, 10. - 12. September 2012). - URN: urn:nbn:de:101:1-201212176728. DocumentID: 281424. Download: http://OPerA.ProfScholz.de

OPerA_PUB_DLRK_12-09-10.pdf     Size:  941K

How well does the method match the Oswald factor of all the aircraft in TAB. A2 of the paper? See here:

Presentation related to the paper: Only the method is covered (without literature review)

OPerA_PRE_DLRK_12-09-10_MethodOnly.pdf     Size:  1.2M

Presentation at the European Workshop on Aircraft Design Education, 24. - 27. May 2011:

NIŢĂ, Mihaela; SCHOLZ, Dieter: Parameter Optimization for an Interactive Aircraft Design, EWADE 2011 (10th European Workshop on Aircraft Design Education, University of Naples "Federico II", Italy, 24. - 27. May 2011 ). - Download: http://OPerA.ProfScholz.de

Poster and Presentation during Aerodays 2011, Madrid, 30. March - 01. April 2011:

NIŢĂ, Mihaela; SCHOLZ, Dieter: Parameter Optimization for an Interactive Aircraft Design (Aerodays 2011, Madrid, 30. March - 01. April 2011). - Poster for the Student Participation Program. Download: http://OPerA.ProfScholz.de

OPerA_PUB_Aerodays_11-03-30.pdf     Size:  1.4M

Publication of the DGLR Conference Contribution:

NIŢĂ, Mihaela; SCHOLZ, Dieter: From Preliminary Aircraft Cabin Design to Cabin Optimization - Part 1. In: University Politehnica of Bucharest, Scientific Bulletin. Series D, Vol. 75 (2013), Iss. 3, pp. 59-72. - ISSN: 1454-2358. Download: http://www.scientificbulletin.upb.ro/rev_docs_arhiva/rezac2_305981.pdf

OPerA_PUB_UPB-Sci-Bull-D-75-3_13-07-01.pdf     Size:  368K

NIŢĂ, Mihaela; SCHOLZ, Dieter: From Preliminary Aircraft Cabin Design to Cabin Optimization - Part 2. In: University Politehnica of Bucharest, Scientific Bulletin. Series D, Vol. 75 (2013), Iss. 4, pp. 27-46. - ISSN: 1454-2358. Download: http://www.scientificbulletin.upb.ro/rev_docs_arhiva/rez074_347413.pdf

OPerA_PUB_UPB-Sci-Bull-D-75-4_13-10-01.pdf     Size:  813K

Paper and Presentation at the German Aerospace Conference, Hamburg, 31. August - 02. September 2010:

NIŢĂ, Mihaela; SCHOLZ, Dieter: From Preliminary Aircraft Cabin Design to Cabin Optimization. In: DGLR: Deutscher Luft- und Raumfahrtkongress 2010 : Tagungsband - Manuskripte (DLRK, Hamburg, 31. August - 02. September 2010). - ISBN: 978-3-932182-68-5. DocumentID: 161168. Download: http://OPerA.ProfScholz.de

OPerA_PUB_DLRK_10-08-31.pdf     Size:   13M