Aircraft Design Studies Based on the ATR 72
Author: Mihaela Niţă
Project / Thesis at Universitatea "Politehnica" din Bucuresti (PUB)
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.