Optimization of High lift device system deployment for takeoff performance

Author(s): 
Filipe Giacomelli, José Roberto Clark Reis, Adson Agrico De Paula and Luiz F. Tibério Fernandez (Technological Institute of Aeronautics, Embraer)

CHALLENGE - High lift devices are widely used in modern civil and military aviation as they allow the reduction of aircraft stall speed and the increase of MTOW (maximum takeoff weight). The proposal of this work is to provide an optimization framework for such devices to improve aircraft performance given track and weight restrictions, taking into account the criticality of the flight phase. This paper addresses the first phase of a work aimed at a complete tool of high lift devices.

SOLUTION - The overall goal of this work is, given a runway length, to find out the most efficient high lift configuration (surface deflection in degrees for flaps and slats) that provides the highest (MTOW), according to user specification.  The proposed framework can be used with multiple fidelity data such as physics-based models, CFD models and semi-empirical ones, in order to accommodate the learning curve that exists in any product development timeline. For an initial approach, the take-off performance calculation is conducted using statistical models constructed from wind tunnel test data and then optimized, having as the main design goal the maximization of the MTOW for a certain runway and having 2nd segment gradient as the main constraint.   Different meta-modeling techniques were tested and evaluated in modeFRONTIER.

BENEFITS - For each flight condition a specific and optimized solution (maximum flap-slat deflection) was obtained, reducing as much as possible the runway length while keeping compliant with FAR 25 requirements for a safe takeoff, implemented in the check module. It worth to mention that all climb gradients complwith the FAR 25 requirements aforementioned, that establishes a minimum climb gradient of 2.4% for single engine operation in dual engine aircraft.