”’The following Python code is intended to analyze an aircraft on the simplest possible physical basis. Please comment on any errors in formulation or approach. ”’
PropulsionEfficiency = 0.9 # Efficiency of propulsion system
PropulsionEffectiveness = 20 # N/kW
EnergyGravimetricDensity= 205 # Wh/kg
VehicleEfficiency = 20 # L/D = CL/CD
# in steady level flight:
# L = W , D = T
# therefore
# L/D = W/T
# therefore
# T = W*D/L = W*(1/LOD)
# W = T*L/D = T*(1*LOD)
Battery_WH = 500*1000
Battery_Mass = Battery_WH/EnergyGravimetricDensity # Wh / (Wh/kg) = kg
Battery_Mass_frac = 0.5
Empty_Mass = Battery_Mass/Battery_Mass_frac # kg
Aircraft_Mass = Empty_Mass + Battery_Mass # kg
Weight = Aircraft_Mass*9.81 # kg -> N
Thrust = Weight*(1/VehicleEfficiency) # N * ( N/N ) = N
print(Thrust,’N thrust’)
print(Weight,’N weight’)
print(Aircraft_Mass,’kg mass’)
print(Thrust/Weight,’TWR’)
PropPower =Thrust/(PropulsionEffectiveness/1000) # N/(N/W) = W
PropPower +=(PropPower*(1-PropulsionEfficiency)) # W + W = W
print(PropPower,’W power’)
PropEndurance=Battery_WH/(PropPower)
print(PropEndurance,’hrs endurance’)
Jonny Hyman 