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Takeoff optimisation of coaxial compound helicopter with uncertainty quantification
This paper focuses on the optimal takeoff of a coaxial compound helicopter, considering the possibility of engine failure. When one engine fails during takeoff, a twin-engine helicopter must either reject the takeoff (RTO) before reaching the takeoff decision point (TDP) or continue the takeoff (CTO) after the TDP. This study aims to determine the theoretical TDP by striking a balance between CTO and RTO while considering uncertainties that arise during takeoff. To achieve this goal, a multistep optimisation structure that involves uncertainty quantification is proposed. Firstly, an aircraft with a developed engine power dynamics model is established for the one-engine-inoperative problem. The entire takeoff procedures, from all-engine-operating (AEO) takeoff to CTO/RTO, are formulated as nonlinear trajectory optimisation problems. A typical takeoff is analysed to illustrate the takeoff characteristics and the conventional procedure to determine the TDP of a coaxial compound helicopter. It is found that the interference between the coaxial rotor results in an inevitable height increase during landing, with each 1-m increase in failure height resulting in 2.28 m of additional height rising. Then a robust TDP and AEO takeoff are identified by applying a multistep optimisation structure, where the influences of uncertainties are discussed. Results indicate it is feasible to define TDP as a single speed or height indicator despite the uncertainties. The recommended speed indicator is slightly lower than the takeoff safety speed, and the speed ensures a short runway length and successful CTO regardless of the AEO takeoff. In addition, an AEO takeoff path is recommended, which shortens the runway length by 10%, and the corresponding liftoff speed is slightly lower than the TDP speed. Overall, the proposed multistep optimisation structure and uncertainty quantification approach help to achieve a robust takeoff performance for a coaxial compound helicopter with consideration of engine failure.
Takeoff optimisation of coaxial compound helicopter with uncertainty quantification
This paper focuses on the optimal takeoff of a coaxial compound helicopter, considering the possibility of engine failure. When one engine fails during takeoff, a twin-engine helicopter must either reject the takeoff (RTO) before reaching the takeoff decision point (TDP) or continue the takeoff (CTO) after the TDP. This study aims to determine the theoretical TDP by striking a balance between CTO and RTO while considering uncertainties that arise during takeoff. To achieve this goal, a multistep optimisation structure that involves uncertainty quantification is proposed. Firstly, an aircraft with a developed engine power dynamics model is established for the one-engine-inoperative problem. The entire takeoff procedures, from all-engine-operating (AEO) takeoff to CTO/RTO, are formulated as nonlinear trajectory optimisation problems. A typical takeoff is analysed to illustrate the takeoff characteristics and the conventional procedure to determine the TDP of a coaxial compound helicopter. It is found that the interference between the coaxial rotor results in an inevitable height increase during landing, with each 1-m increase in failure height resulting in 2.28 m of additional height rising. Then a robust TDP and AEO takeoff are identified by applying a multistep optimisation structure, where the influences of uncertainties are discussed. Results indicate it is feasible to define TDP as a single speed or height indicator despite the uncertainties. The recommended speed indicator is slightly lower than the takeoff safety speed, and the speed ensures a short runway length and successful CTO regardless of the AEO takeoff. In addition, an AEO takeoff path is recommended, which shortens the runway length by 10%, and the corresponding liftoff speed is slightly lower than the TDP speed. Overall, the proposed multistep optimisation structure and uncertainty quantification approach help to achieve a robust takeoff performance for a coaxial compound helicopter with consideration of engine failure.
Takeoff optimisation of coaxial compound helicopter with uncertainty quantification
Optim Eng
Zhao, Yanqin (author) / Yuan, Ye (author) / Chen, Renliang (author)
Optimization and Engineering ; 25 ; 999-1024
2024-06-01
26 pages
Article (Journal)
Electronic Resource
English
Coaxial compound helicopter , Takeoff decision point , Trajectory optimisation , Uncertainty quantification , Sensitivity analysis Mathematics , Optimization , Engineering, general , Systems Theory, Control , Environmental Management , Operations Research/Decision Theory , Financial Engineering , Mathematics and Statistics
Takeoff optimisation of coaxial compound helicopter with uncertainty quantification
Springer Verlag | 2024
|Online Contents | 1998
Online Contents | 1998
Online Contents | 1999
Online Contents | 1998