engleski

About the influence of the atmosphere over the wildfire on the flight dynamics for the helicopter simulator application

The scope of this paper is modelling of the atmosphere over the wildfire and analysis of its influence on the helicopter flight dynamics in defined conditions. To achieve realistic simulation of helicopter flight over the wild land fire it is required to take into account the influence of the fire on the atmosphere conditions. The work presented here is in the framework of the project of helicopter simulator for Mi-171Sh, a modernized variant of the Mi-8/17 helicopter, which is used in the Croatian Air Force for both military and civil applications, especially for its specific use for the firefighting purposes. The influence of fire atmosphere environment on rotor aerodynamics and the whole aircraft flight dynamics can be significant. For the flight training device the results for the spread of the fire are not required, but it is necessary to calculate the aerodynamic forces and moments using density and wind in the atmosphere influenced by wildfire. This aerodynamic calculation is applied with many hypotheses. Presented work is oriented to the determination of the influence of the atmosphere over the wildfire on the helicopter performances under the same hypotheses. Because of this reason we are looking for the atmosphere model under the same hypotheses as for the aerodynamic calculation and only problems relevant to the evaluation of the aerodynamic forces and moments will be taken into account. For the investigation of the specific effects it is required to have reliable mathematical models both of the wildfire and helicopter. Aerodynamic model of the rotor based on the blade element theory is analysed with presented model of atmosphere model over the wildfire. Results of influence of atmosphere over the wildfire on helicopter required power in forward flight and available power are also presented. For these analyses a generic example helicopter similar to Mi-8/17 has been used. Visualization aspects of fire and smoke atmosphere for the helicopter simulator project are also covered in the paper. Helicopter data approved by the manufacturer are required for mathematical models of the future simulator what leads to a successful certification process both for military and civil operational use. Although there are already present several different simulators for this type of helicopter, specifics of this project are fulfilments of the requirements for the development for the training for the missions with external load, aerial firefighting, search-and-rescue operations with landings in near-fire areas etc.

multirole helicopter simulator ; aerial fire fighting ; atmosphere over the wildfire ; rotor aerodynamics ; flight dynamics

nije evidentirano