This document summarizes a final year project and start-up project for an AT-1 helicopter. The project involves design and analysis of the rotor system, transmission system, and fuselage/airframe structure. For the rotor system, blades were designed and CFD was used to analyze flow. Gearboxes and shafts were modeled and numerically/structurally analyzed. The fuselage was modeled in CAD, underwent CFD analysis to optimize shape, and the airframe was structurally and modally analyzed. The project is currently finalizing documentation.

1. AERITRANS COMPANY
Abstract of a
Final year project & start-up project
By
Students : Supervisors :
Marouan Selmi Mme Wafa Ben Yahia
Nader Khattabi Mr Fathi Djemal
Wsifi Bassem Mr Hedi EL-Hamdi
AT-1 HELICOPTER
27 May 2016
National
Engineering
School of Gabes
ENIG
Tunisia
Mechanical
Engineering
Departement

2. Subjects involved in thisprojectare:
Finite element methods, fluids mechanical, Computational fluid dynamic CFD, thermodynamics,
hydraulic systems, technical design, materials properties, project management,
SOLIDWORKS,ANSYS Workbench…
main parts :
Part1.CFD analysisof a rotor system fora helicopter:
Designof the rotor bladesbasedonNACA0012 airfoil
CFD simulationof a2 bladesrotorusingAnsysWorkbench
Part2.Studyanddesignof a transmission system for a helicopter:
Designof gearboxesandshaftsusingSolidWorks
Numerical analysisof gearboxes
Stressanalysisof gearboxesusingAnsysWorkbench
Part3.Design andanalysisof a helicopter fuselageandairframestructure:
Designof a helicopterfuselageandairframe structure usingSolidWorks
CFD analysisof a helicopterfuselage
Structural and modal analysisof a helicopterairframe

3. Current achievements in the project:
Part 1 . CFD analysis of a rotor systemfor a helicopter:
Design of the blades based on NACA0012 airfoils :
 Completed task
After carefulStudies the design of the helicopter blade was made based on the
NACA0012 airfoil, then using Momentum theory and Blade element theory the
blade shape was finally designed. The figure below shows thefinal CAD of the
blade.
CFD simulation of a teetering rotor using Ansys Workbench
 Completed task
Using Ansys Workbench softwaretheprevious design of blade was put under
severalsimulations to predict the interaction between the air flow and the blade
structureincluding : turbulence, velocity magnitude, pressure…
Some promising results was also withdrawn fromthe CFD simulations including:
Lift coefficient, drag coefficient, moment…
the figurebelow shows a sample of one of the simulations using Fluent tool in
Ansys Workbench.

4. Contours of pressure coefficient and history convergence of the CFD simulation

5. Part 2.Study and design of a transmissionsystem for a helicopter:
Design of gearboxes and shafts using SolidWorks:
 Completed task
After designing the fuselage, a design of the transmission systemwas the
second part of this project. The figures below shows theCAD model of
gearboxes and shafts using SolidWorks.
Numerical analysis of gearboxes:
 Completed task
The gearboxes and shafts was then numerically analyzed to make surethey resist
the torques and loads applied during several cases (hover, forward flight…). The
figures below shows thenumerical analysis process using MicrosoftExcel and
hand calculations.

6. Numerical analysis using Microsoft Excel
Stress analysis of gearboxes using Ansys Workbench:
 Completed task
Adding to the numerical analysis, the transmission components wentthrough
stress analysis to predict the possibledeformations. The stress analysis was made
using transient structuraltool in Ansys Workbench.Thefigurebelow shows the
results of the simulation.
Deformation of a bevel gear using transient structural tool in Ansys Workbench

7. Deformation of a gearboxes using transient structural tool in Ansys Workbench
Part3.Design andanalysisof a helicopter fuselageandairframestructure:
Design of a helicopter fuselage and airframe structure using
SolidWorks:
 Completed task
The idea was to design a robustand aerodynamic fuselage that can resist the
applied loads. The NASA ROBINfuselage was the basic startas it gives a great
reference in order to be able to comparethe results of the CFD simulations of
the desired fuselage with the ROBINfuselage results. You can see in the figure
below the preliminary shapeof the AT1 helicopter in compareto the ROBIN
fuselage.
ROBIN fuselage
AT1 fuselage

8. CFD analysis of a helicopter fuselage:
 Completed task
After designing the AT1 fuselage severalCFD simulations took place in order to
predict the air flow around the fuselagetherefore improving the aerodynamic
shapeif needed. The figure below shows oneof the CFD simulations process
frommeshing to results using Ansys Workbench.

9. Contours of turbulence using 𝐾 − 𝜀 model
in Fluent (Ansys Workbench)
After running the CFD simulations the shapeof the fuselage needed to be
improved in order to reduce turbulence and drag load. The figure below shows
the final shapewhich was validated later with further simulations.
Structural and modal analysis of a helicopter airframe:
 Completed task
After designing the fuselage, the airframeof the AT1 was designed based on the
shapeand dimensions of the fuselage. The airframe was then under several
simulations to predict it’s behaviors under static loads. Finally the airframewent
through modal analysis to withdraw the firstmodes that could cause resonance

10. under specific loads. The figures below shows the different states of both static
and modal analysis fromCAD to mesh to simulations.
Airframe design using SolidWorks
Static deformation of the airframe under loads using static structural tool in Ansys
Workbench

11. Modal analysis of the airframe using modal tool in Ansys Workbench
Current work in the project: (27 May 2016)
Currently it is the final step in the project which is the documentation and the
essay preparation of the project.