ETD

• Airbus
• Airbus Helicopters
• antitorque
• downwash
• empennage
• Eurocopter
• fenestron
• fenestron blade pitch
• fin
• generalized wake model
• helicopter
• horizontal stabilizer
• interactions
• Landgrebe
• mast moment
• swirl
• tail
• tail rotor
• tip vortex
• UTRC
• vertical stabilizer
• vortex
• wake
• wake contraction
• wake deformation
• wake model
• wake modeling

Simulation of aerodynamic and flight mechanic characteristics is essential to
predict helicopter flight behaviour. One of the most important features is certainly
the interactions between the main rotor wake and different helicopter components.
This Master Thesis focuses on an analytical model able to predict and evaluate
main rotor wake interactions with tailboom, empennage and fenestron. This was
implemented in a more general flight mechanical simulation code. The first version
was created in a former master thesis by Airbus Helicopters. Further development
have been requested in order to have a better estimation of computed quantities in
trimmed conditions for a higher range of speeds. The previous model, indeed, was
suitable only for hover and low velocity steady forward flight.
For this purpose, has been fundamental a better estimation of lateral forces and of
wake geometry. Researches about influence of different factors have been conducted
and new physical models considering fin and fenestron interactions and wake
distortion have been derived and implemented.
Two main variables have been considered as quality indicators: mast moment and
fenestron blade pitch. Nevertheless, other quantities like forces and velocities have
always been taken into account as well. Computed results have been compared
with flight test data in order to verify the reliability of the improved simulation
model. Moreover, CFD analysis have been used to clearly understand the wake
behaviour.