def cl2lift(
Cl,
eas,
wing_area,
speed_units=default_speed_units,
lift_units=default_weight_units,
area_units=default_area_units,
):
"""
Returns the lift, given coefficient of lift, equivalent airspeed, and wing
area.
"""
eas = U.speed_conv(eas, from_units=speed_units, to_units='m/s')
wing_area = U.area_conv(wing_area, from_units=area_units,
to_units='m**2')
lift = (((0.5 * Rho0) * eas ** 2.) * wing_area) * Cl
if lift_units == 'kg':
lift = U.force_conv(lift, 'N', 'lb')
lift = U.mass_conv(lift, 'lb', 'kg')
else:
lift = U.force_conv(lift, 'N', lift_units)
return lift
def cd2drag(
Cd,
eas,
wing_area,
speed_units=default_speed_units,
area_units=default_area_units,
drag_units=default_weight_units,
):
"""
Returns the drag, given coefficient of drag, equivalent airspeed, and wing
area.
Example:
>>> cd2drag(.138, 100, 10, speed_units='km/h', area_units='m**2',\
drag_units='N')
652.19907407407425
"""
eas = U.speed_conv(eas, from_units=speed_units, to_units='m/s')
wing_area = U.area_conv(wing_area, from_units=area_units,
to_units='m**2')
drag = (((0.5 * Rho0) * eas ** 2) * wing_area) * Cd
drag = U.force_conv(drag, from_units='N', to_units=drag_units)
return drag
def cd2drag(
Cd,
eas,
wing_area,
speed_units=default_speed_units,
area_units=default_area_units,
drag_units=default_weight_units,
):
"""
Returns the drag, given coefficient of drag, equivalent airspeed, and wing
area.
Example:
>>> cd2drag(.138, 100, 10, speed_units='km/h', area_units='m**2',\
drag_units='N')
652.1990740740742
"""
eas = U.speed_conv(eas, from_units=speed_units, to_units='m/s')
wing_area = U.area_conv(wing_area, from_units=area_units, to_units='m**2')
drag = (((0.5 * Rho0) * eas**2) * wing_area) * Cd
drag = U.force_conv(drag, from_units='N', to_units=drag_units)
return drag
def eff2thrust(eff, bhp, TAS, power_units="hp", speed_units="kt", thrust_units="lb"):
"""
Returns thrust, given prop efficiency, true airspeed and brake power.
Matches the results from the Hartzell prop map program fairly closely.
"""
TAS = U.speed_conv(TAS, from_units=speed_units, to_units="m/s")
bhp = U.power_conv(bhp, from_units=power_units, to_units="W")
thrust = eff * bhp / TAS
return U.force_conv(thrust, from_units="N", to_units=thrust_units)
def ct2thrust(Ct, Rho, rpm, dia, thrust_units="lb", density_units="lb/ft**3", dia_units="in"):
"""
Returns the thrust, given thrust coefficient, Ct, density, rpm and prop
diameter.
"""
Rho = U.density_conv(Rho, from_units=density_units, to_units="kg/m**3")
dia = U.length_conv(dia, from_units=dia_units, to_units="m")
# convert rpm to revolutions / s
n = rpm / 60.0
thrust = Ct * Rho * n ** 2.0 * dia ** 4.0
return U.force_conv(thrust, from_units="N", to_units=thrust_units)
def cl2lift(
Cl,
eas,
wing_area,
speed_units=default_speed_units,
lift_units=default_weight_units,
area_units=default_area_units,
):
"""
Returns the lift, given coefficient of lift, equivalent airspeed, and wing
area.
"""
eas = U.speed_conv(eas, from_units=speed_units, to_units='m/s')
wing_area = U.area_conv(wing_area, from_units=area_units, to_units='m**2')
lift = (((0.5 * Rho0) * eas**2.) * wing_area) * Cl
if lift_units == 'kg':
lift = U.force_conv(lift, 'N', 'lb')
lift = U.mass_conv(lift, 'lb', 'kg')
else:
lift = U.force_conv(lift, 'N', lift_units)
return lift
def eff2thrust(eff,
bhp,
TAS,
power_units='hp',
speed_units='kt',
thrust_units='lb'):
"""
Returns thrust, given prop efficiency, true airspeed and brake power.
Matches the results from the Hartzell prop map program fairly closely.
"""
TAS = U.speed_conv(TAS, from_units=speed_units, to_units='m/s')
bhp = U.power_conv(bhp, from_units=power_units, to_units='W')
thrust = eff * bhp / TAS
return U.force_conv(thrust, from_units='N', to_units=thrust_units)
def ct2thrust(Ct,
Rho,
rpm,
dia,
thrust_units='lb',
density_units='lb/ft**3',
dia_units='in'):
"""
Returns the thrust, given thrust coefficient, Ct, density, rpm and prop
diameter.
"""
Rho = U.density_conv(Rho, from_units=density_units, to_units='kg/m**3')
dia = U.length_conv(dia, from_units=dia_units, to_units='m')
# convert rpm to revolutions / s
n = rpm / 60.
thrust = Ct * Rho * n**2. * dia**4.
return U.force_conv(thrust, from_units='N', to_units=thrust_units)
def test_02(self):
Value = U.force_conv(444.82216, from_units='N', to_units='lb')
Truth = 100
self.failUnless(RE(Value, Truth) <= 1e-7)
def test_01(self):
Value = U.force_conv(100, from_units='lb', to_units='N')
Truth = 444.82216
self.failUnless(RE(Value, Truth) <= 1e-7)
def test_02(self):
Value = U.force_conv(444.822, from_units='N', to_units='lb')
Truth = 100
self.failUnless(RE(Value, Truth) <= 1e-5)
def test_01(self):
Value = U.force_conv(100, from_units='lb', to_units='N')
Truth = 444.822
self.failUnless(RE(Value, Truth) <= 1e-5)
def test_02(self):
Value = U.force_conv(444.82216, from_units='N', to_units='lb')
Truth = 100
self.assertTrue(RE(Value, Truth) <= 1e-7)
def test_01(self):
Value = U.force_conv(100, from_units='lb', to_units='N')
Truth = 444.82216
self.assertTrue(RE(Value, Truth) <= 1e-7)
