Project Department of Automotive and Aeronautical Engineering Aircraft Design Studies Based on the ATR 72 Author: Mihaela Florentina Niţă Examiner: Prof. Dr.-Ing. Dieter Scholz, MSME Delivered: 13.06.2008 Abstract This project gives a practical description of a preliminary aircraft design sequence. The sequence starts with a preliminary sizing method. The design sequence is illustrated with a redesign study of the ATR 72 turboprop aircraft. The requirements for the redesign aircraft are those of the ATR 72. The ATR 72 serves also as the reference during the redesign. The Preliminary sizing method was available (at the university) only for jet-powered aircraft. Therefore the method was adapted to work also with propeller driven aircrafts. The sizing method ensures that all requirements are met: take-off and landing field length, 2nd segment and missed approach gradients as well as cruise Mach number. The sizing method yields the best (low) power/weight ratio and the best wing loading. The redesign process covers all the aircraft components: fuselage, wing, empennage and landing gear. The aircraft design sequence defines the cabin layout, the wing parameters, the type of high lift system, the configuration and surface of the empennage. A mass distribution analysis is made, the position of the CG is calculated and the wing position determined. Finally the Direct Operating Costs (DOC) are calculated. DOCs are calculated applying the method from the Association of European Airlines (AEA). The DOCs serve for an aircraft evaluation. In order to meet requirements, the redesigned ATR 72 had to be slightly modified compared to the original ATR. E.g. the redesigned high lift system shows added slats. In general, the resulting parameters of the redesigned aircraft came out similar with the original ATR 72. Since data of the original ATR 72 is not completely available in public, one of the challenges was to discover the driving factors and secret parameters from the original design. 1 DEPARTMENT FAHRZEUGTECHNIK UND FLUGZEUGBAU Aircraft Design Studies Based on the ATR 72 Project work towards a thesis at Universitatea Politehnica din Bucuresti (PUB) Background Aircraft design studies at universities seem to concentrate quite often at civil transport jets. In this respect, Hamburg University of Applied Sciences is no exception. In order to cover a little bit of new ground in aircraft design teaching, it was decided to pay more attention to propeller driven aircraft, starting with passenger aircraft (certified based on CS-25) and subsequently considering the whole field of propeller aircraft certified based on CS-23, CS-VLA and to ul- tra light aircraft. Emphasis should be given to the respective methods for preliminary sizing of the respective category of aircraft. Furthermore, effects that have to be handled differently from jets should be considered carefully and in depth. Task An ATR 72 should be redesigned. If time allows, preliminary sizing according to CS-VLA should be considered. ATR 72 redesign should comprise of: • Parameter studies: power, propeller efficiency and glide ratio as a function of operational and geometric parameters. • Data collection and evaluation for the ATR 72. • Preliminary sizing of turboprop aircraft for CS-25 – general approach and application to ATR 72. • Sizing of cabin / fuselage, wing (including high lift devices) empennage and landing gear. • Calculation of mass, drag polar and DOC. The report has to be written in English based on German or international standards on report writing. 4 Table of Content Page Abstract ................................................................................................................................. 2 Table of Content......................................................................................................................... 4 List of Figures ............................................................................................................................ 7 List of Tables.............................................................................................................................. 9 List of Symbols ........................................................................................................................ 10 Greek Symbols ......................................................................................................................... 11 Indices ............................................................................................................................... 12 Indices for flight phases ........................................................................................................... 12 Indices for Aircraft Components.............................................................................................. 12 Indices of the Wing .................................................................................................................. 13 Other Indices ............................................................................................................................ 13 List of Abbreviations................................................................................................................ 16 1 Introduction ......................................................................................................... 17 1.1 Motivation ............................................................................................................. 17 1.2 Definitions............................................................................................................. 17 1.3 Task ....................................................................................................................... 18 1.4 Literature ............................................................................................................... 19 1.5 Structure of Work.................................................................................................. 19 2 ATR 72 Parameters ............................................................................................ 20 3 Preliminary sizing................................................................................................ 23 3.1 Landing distance.................................................................................................... 23 3.2 Take-off Distance.................................................................................................. 25 3.3 Climb Rate during 2nd Segment............................................................................. 28 3.4 Climb Rate during Missed Approach.................................................................... 30 3.5 Cruise..................................................................................................................... 31 3.5.1 Power to weight ratio ............................................................................................ 31 3.5.2 Estimation of Lift to Drag Ratio during Cruise..................................................... 32 3.5.3 Estimation of Power Variation with Height.......................................................... 35 3.5.4 Wing Loading........................................................................................................ 39 3.5.5 Propeller Efficiency............................................................................................... 40 3.5.6 Results ................................................................................................................... 41 3.6 Matching Chart...................................................................................................... 42 3.7 Maximum Take-off Mass...................................................................................... 43 3.7.1 Relative Fuel Mass ................................................................................................ 43 3.7.2 Relative Operating Empty Weight ........................................................................ 47 5 3.7.3 Payload .................................................................................................................. 47 3.8 Design Parameters................................................................................................. 48 3.9 Comparing values.................................................................................................. 49 4 Fuselage Design.................................................................................................... 50 4.1 Fuselage cross section ........................................................................................... 50 4.2 Cabin Layout ......................................................................................................... 53 4.3 Cargo compartments.............................................................................................. 55 4.4 Emergency Exits.................................................................................................... 56 4.5 Water line .............................................................................................................. 57 5. Wing Layout ........................................................................................................ 59 5.1 Wing Parameters ................................................................................................... 61 5.2 Position of the wing............................................................................................... 62 5.3 Design Mach Number ..........................................................................................