def propeller_range_endurance_speeds(analyses, altitude, CL_max, up_bnd,
delta_isa):
# setup a mission that runs a single point segment without propulsion
def mini_mission():
# ------------------------------------------------------------------
# Initialize the Mission
# ------------------------------------------------------------------
mission = SUAVE.Analyses.Mission.Sequential_Segments()
mission.tag = 'the_mission'
# ------------------------------------------------------------------
# Single Point Segment 1: constant Speed, constant altitude
# ------------------------------------------------------------------
segment = SUAVE.Analyses.Mission.Segments.Single_Point.Set_Speed_Set_Altitude_No_Propulsion(
)
segment.tag = "single_point"
segment.analyses.extend(analyses)
segment.altitude = altitude
segment.temperature_deviation = delta_isa
# add to misison
mission.append_segment(segment)
return mission
# This is what's called by the optimizer for CL**3/2 /CD Max
def single_point_3_halves(X):
# Update the mission
mission.segments.single_point.air_speed = X
# Run the Mission
point_results = mission.evaluate()
CL = point_results.segments.single_point.conditions.aerodynamics.lift_coefficient
CD = point_results.segments.single_point.conditions.aerodynamics.drag_coefficient
three_halves = -(CL**(
3 /
2)) / CD # Negative because optimizers want to make things small
return three_halves
# This is what's called by the optimizer for L/D Max
def single_point_LDmax(X):
# Modify the mission for the next iteration
mission.segments.single_point.air_speed = X
# Run the Mission
point_results = mission.evaluate()
CL = point_results.segments.single_point.conditions.aerodynamics.lift_coefficient
CD = point_results.segments.single_point.conditions.aerodynamics.drag_coefficient
L_D = -CL / CD # Negative because optimizers want to make things small
return L_D
# ------------------------------------------------------------------
# Run the optimizer to solve
# ------------------------------------------------------------------
# Setup the a mini mission
mission = mini_mission()
# Takeoff mass:
mass = analyses.aerodynamics.geometry.mass_properties.takeoff
# Calculate the stall speed
Vs = stall_speed(analyses, mass, CL_max, altitude, delta_isa)[0][0]
# The final results to save
results = Data()
# Wrap an optimizer around both functions to solve for CL**3/2 /CD max
outputs_32 = sp.optimize.minimize_scalar(single_point_3_halves,
bounds=(Vs, up_bnd),
method='bounded')
# Pack the results
results.CL32 = Data()
results.CL32.air_speed = outputs_32.x
results.CL32.value = -outputs_32.fun[0][0]
# Wrap an optimizer around both functions to solve for L/D Max
outputs_ld = sp.optimize.minimize_scalar(single_point_LDmax,
bounds=(Vs, up_bnd),
method='bounded')
# Pack the results
results.L_D_max = Data()
results.L_D_max.air_speed = outputs_ld.x
results.L_D_max.value = -outputs_ld.fun[0][0]
return results
