Cruise Range Optimization of a Propeller-Driven Light Aircraft Using a Direct Transcription Method with a Regularization Term

[EN] The problem of maximizing the range of a propeller-driven aircraft in a level flight cruise is analyzed within the framework of optimal control. The specific fuel consumption and propeller efficiency of its propulsive system are characterized by functions of the velocity and engine power (full...

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Bibliographic Details
Authors: Delgado Marcos, Adrián, Rubio Sierra, Carlos, Domínguez Fernández, Diego, Escapa García, Luis Alberto
Format: article
Status:Published version
Publication Date:2024
Country:España
Institution:Ajuntament de Barcelona
Repository:BULERIA. Repositorio Institucional de la Universidad de León
OAI Identifier:oai:buleria.unileon.es:10612/22846
Online Access:https://www.mdpi.com/2226-4310/11/10/794
https://hdl.handle.net/10612/22846
Access Level:Open access
Keyword:Ingeniería aeroespacial
Propeller-driven aircraft
Maximun range
Flight optimization
Optimal control
Direct transcription method
Regularization
3301.15 Sistemas de Propulsión
3319.10 Hélices
3301.06 Estructuras de Aeronaves
Description
Summary:[EN] The problem of maximizing the range of a propeller-driven aircraft in a level flight cruise is analyzed within the framework of optimal control. The specific fuel consumption and propeller efficiency of its propulsive system are characterized by functions of the velocity and engine power (full model), in contrast to previous works, where they were considered to be constant. To conduct the study, a notional Piper Cherokee PA-28 is selected as representative of light aircraft, defining both the airplane and mission features. Two simplified models are also derived: the Von Mises model, with constant specific fuel consumption and propeller efficiency, and the Parget and Ardema model, defined by constant specific fuel consumption and propeller efficiency depending on the velocity. The problem is solved numerically by means of a direct transcription method. Since the optimal problems of the Von Mises and Parget and Ardema models are singular, it is necessary to incorporate a regularization term. Such a numerical algorithm is validated against the analytical solution given by the Breguet formulation. In this context, the velocity and mass (state variables), the power throttle (control), and the best range are determined. The full model provides a maximum range of 1492 km. The differences between the Von Mises and Parget and Ardema models are about 24 km and 1 km, respectively. A non-optimal steady cruise is also analyzed, providing a significant reduction in the flight time, with a decrease of about 2% of the range. The evolution of the state variables and control in the steady cruise, however, separates from the full model. On the other hand, the Parget and Ardema model almost reproduces the full model results, leading to a clear image of the physics involved: the best range comes from maximizing the product of the propeller and aerodynamic efficiencies with respect to the velocity, which determines the optimal arc.