If you are interested only in the HBEL model, the codes to dounlowds are:
#########################################################################################################################
"try11.m"
"hbem_model.m"

"hbem_model.m" takes in the relative velocity vector of the vehicle ([10,0,-10]) in m/s, and required thrust
in Newtons i.e., "hbem_model(6,[10,0,-10])". The model provides mutiple outputs including the rotor RPM. Also
it is noted that the rotor geometry is defined inside the function "hbem_model.m".

If you are intersted in performing flight simulation using HBEM model:
#########################################################################################################################
You should download all of the codes in your working directory. The simulink flight simulation model
is "M_6DoF_BS_Full_backup_11_25_2018.slx" and the simulation can be managed/initialized using 
"Main_run.m" including the geometry/characterstics of quad-copter.

Through "M_6DoF_BS_Full_backup_11_25_2018.slx", you can choose your desired wind model (No wind, LES or Dryden).
Also you can choose your desired trajectory as well the aerodynamic model. Please download these papers to know more about
the capabalities built into this flight simulation module:
https://www.researchgate.net/publication/330898595_Quad-rotor_Flight_Simulation_in_Realistic_Atmospheric_Conditions
https://www.researchgate.net/publication/333429439_A_Hybrid_Blade_Element_Momentum_Model_for_Flight_Simulation_of_Rotary_Wing_Unmanned_Aerial_Vehicles


More question, feel free to ask! you can directly email Behdad Davoudi, davoudi@umich.edu