Investigating trim algorithms for a utility helicopter

Download

index.pdf

Date

2019

Author

Demirel, Anıl.

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

239
views

85
downloads

Obtaining trim positions of an aircraft is an issue of importance. In this thesis, the aim is to develop a procedure that can achieve the trim points with reasonable assumptions for the entire flight of a helicopter. In order to achieve this goal an autopilot is used to determine the trim points. A high-fidelity flight model is used. The structure is based on GENHEL model. Helicopter trim states are calculated for specified flight conditions. The parameters that are sensitive to trim convergence are determined. A simplified set of trim equations are solved to generate a proper input set for fast convergence of Nelder-Mead (NM) Simplex runs. A NM Simplex algorithm is used to find accurate trim points. The procedure is tested for the UH-60 helicopter model in hover and forward flight conditions. A comparison of the trim results with flight test data available in literature is used to. Thereby the utility of the procedure is demonstrated, the reliability of the assumptions and the practicality of the model are shown.

Subject Keywords

Helicopters., Keywords: Helicopter, Trim, Simplex, GENHEL, Autopilot .

URI

http://etd.lib.metu.edu.tr/upload/12624812/index.pdf
https://hdl.handle.net/11511/45260

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Modeling of the dynamic delamination of L-shaped unidirectional laminated composites Gozluklu, Burak; Çöker, Demirkan (2012-03-01) One of the widely used geometrically complex parts in advanced commercial aircraft is the L-shaped composite. Due to the sharp curved geometry, interlaminar opening stresses are induced and delamination occurs under considerable mode-mixities in L-shaped beams. Dynamic phenomena during delamination initiation and propagation of L-shaped beams are investigated using dynamic (explicit) finite element analysis in conjunction with cohesive zone methods. The 2-D model consists of 24 plies of unidirectional CFRP ...
Design and evaluation of a helicopter main rotor electrohydraulic control system Düzağaç, Hasan Ali; Çalışkan, Hakan; Balkan, Raif Tuna; Department of Mechanical Engineering (2022-8-26) Helicopters are widely used aircrafts for several purposes. Main Rotor of a Helicopter creates necessary flight forces for performing flight operation. Orientation of a Helicopter Rotor System is determined and controlled manually by pilot and automatically by automatic control system via hydraulically operated flight control actuators. In this research, a novel electrohydraulically operated helicopter main rotor control system is mathematically designed and developed to improve overall performance of contr...
Generic trim analysis and simulation algorithm creation for design and optimization of the fixed wing aircraft Özdemir, Mustafa; Kurtuluş, Dilek Funda (2021-09-10) In order to design a fixed wing aircraft, certain phases are needed to perform. From these phases, trim analysis and simulation are very crucial for design process. Trim and simulation analysis enable to calculate performance and stability characteristics of the aircraft. After aerodynamic, weight and engine database creation, the next step is trim analysis and simulations. However, database creation phase requires a huge amount of computing time, and for the preliminary design phase it is needed to perform...
Assessment of the Performance of a Cruise Missile Wing Depending on Design Parameters at Various Flight Conditions Ertürk, Burak; Yaman, Yavuz (2019-09-03) The design of a cruise missile wing is a multidisciplinary work, since the wing has to provide enough aerodynamic forces while being structurally safe. In order to meet the design requirements and achieve a successful design, several parameters of the wing need to be investigated at various flight conditions. In this paper, lift forces and flutter speeds are obtained for different wing geometries, at various altitudes and speeds. The design of experiments is constructed by changing the several variables of ...
An algorithm for designing nonlinear springs, or nonlinear dampers, using a mechanical force generator and its application to an aircraft landing gear Yıldız, Fatih; Soylu, Reşit; Department of Mechanical Engineering (2021-12-03) The landing gear system is one of the most critical aircraft sub-systems that takes part in the landing, taxi and take-off phases of every aircraft. Its main function is the absorption of part of aircraft's kinetic energy during landing. There are different types of shock absorbers to perform this task. The performance of the shock absorbers has developed a lot after the invention of air-oil type shock absorbers. However, increasing the performance of these shock absorber elements is still a field of resear...

Citation Formats

A. Demirel, “Investigating trim algorithms for a utility helicopter,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Aerospace Engineering., Middle East Technical University, 2019.