def eval_pre_design_vtp(aircraft):
"""
VTP predesign
"""
design_driver = aircraft.design_driver
fuselage = aircraft.fuselage
nacelle = aircraft.turbofan_nacelle
engine = aircraft.turbofan_engine
vtp = aircraft.vertical_tail
vtp.taper_ratio = 0.40 # Design rule
vtp.aspect_ratio = 1.7 # Design rule
vtp.t_o_c = 0.10 # Design rule
wing_sweep = 1.6 * max(0,
(design_driver.cruise_mach - 0.5)) # Empirical law
vtp.sweep = wing_sweep + unit.rad_deg(10) # Design rule
# if(HQsizing==0): # Statistical sizing
vtp.volume = 0.4 # Design rule
vtp.lever_arm = 3.4e-4 * fuselage.length**2 + 0.42 * fuselage.length
vtp.area = vtp.volume * (1e-3 * engine.reference_thrust *
nacelle.y_ext) / vtp.lever_arm
# else: # HQ sizing
# vtp.lever_arm = VtpLarm0 - dXwing ;
# vtp.area = VtpArea0 + dVtpArea ;
# vtp.volume = (vtp.area*vtp.lever_arm)/(1e-3*aircraft.reference_thrust*nac_y_ext_i) ;
vtp.net_wetted_area = 2.01 * vtp.area # Factor 2.01 accounts for carmans
vtp.height = numpy.sqrt(vtp.aspect_ratio * vtp.area)
vtp.c_root = 2 * vtp.area / (vtp.height * (1 + vtp.taper_ratio))
vtp.c_tip = vtp.taper_ratio * vtp.c_root
vtp_x_wise_anchor = 0.825 # Locate VTP versus end fuselage length
vtp.x_root = fuselage.length * (
1 - fuselage.tail_cone_length / fuselage.length *
(1 - vtp_x_wise_anchor)) - vtp.c_root
vtp.x_tip = vtp.x_root + 0.25 * (
vtp.c_root - vtp.c_tip) + vtp.height * numpy.tan(vtp.sweep)
vtp.z_root = fuselage.height
vtp.z_tip = vtp.z_root + vtp.height
vtp.mac = vtp.height * (vtp.c_root**2 + vtp.c_tip**2 +
vtp.c_root * vtp.c_tip) / (3 * vtp.area)
vtp.x_mac = vtp.x_root + (vtp.x_tip - vtp.x_root) * vtp.height * (
2 * vtp.c_tip + vtp.c_root) / (6 * vtp.area)
return
def vtp_aero_data(aircraft):
"""
WARNING : output values are in Wing reference area
"""
vtp = aircraft.vertical_tail
# Helmbold formula
cyb_vtp = vtp_lift_gradiant(
aircraft
) # (numpy.pi*vtp.aspect_ratio)/(1+numpy.sqrt(1+(vtp.aspect_ratio/2)**2))*(vtp.area/wing.area)
# Position of VTP center of lift
xlc_vtp = vtp.x_mac + 0.25 * vtp.mac
# Maximum angle of attack allowed for VTP
aoa_max_vtp = unit.rad_deg(35)
# VTP induced drag coefficient
ki_vtp = 1.3 / (numpy.pi * vtp.aspect_ratio)
return cyb_vtp, xlc_vtp, aoa_max_vtp, ki_vtp
def htp_aero_data(aircraft):
"""
WARNING : output values are in Wing reference area
"""
wing = aircraft.wing
htp = aircraft.horizontal_tail
# Helmbold formula
cza_htp = (numpy.pi * htp.aspect_ratio) / (
1 + numpy.sqrt(1 + (htp.aspect_ratio / 2)**2)) * (htp.area / wing.area)
# Position of HTP center of lift
xlc_htp = htp.x_mac + 0.25 * htp.mac
# Maximum angle of attack allowed for HTP
aoa_max_htp = unit.rad_deg(9)
# HTP induced drag coefficient
ki_htp = 1.2 / (numpy.pi * htp.aspect_ratio)
return cza_htp, xlc_htp, aoa_max_htp, ki_htp
def eval_pre_design_wing(aircraft):
"""
Wing predesign
"""
design_driver = aircraft.design_driver
fuselage = aircraft.fuselage
vtp = aircraft.vertical_tail
nacelle = aircraft.turbofan_nacelle
weights = aircraft.weights
wing = aircraft.wing
wing.t_o_c_t = 0.10
wing.t_o_c_k = wing.t_o_c_t + 0.01
wing.t_o_c_r = wing.t_o_c_k + 0.03
wing.sweep = 1.6 * max(0,
(design_driver.cruise_mach - 0.5)) # Empirical law
wing.dihedral = unit.rad_deg(5)
if (wing.morphing == 1): # Aspect ratio is driving parameter
wing.span = numpy.sqrt(wing.aspect_ratio * wing.area)
elif (wing.morphing == 2): # Span is driving parameter
wing.aspect_ratio = wing.span**2 / wing.area
else:
print("geometry_predesign_, wing_morphing index is unkown")
# Correlation between span loading and tapper ratio
wing.taper_ratio = 0.3 - 0.025 * (1e-3 * weights.mtow / wing.span)
# Factor 1.64 accounts for the part of HTP ref area hidden in the fuselage
wing.net_wetted_area = 1.64 * wing.area
wing.y_kink = nacelle.y_ext
wing.y_root = 0.5 * fuselage.width
wing.y_tip = 0.5 * wing.span
if (15 < unit.deg_rad(wing.sweep)): # With kink
Phi100intTE = max(0, 2 * (wing.sweep - unit.rad_deg(32)))
tan_phi100 = numpy.tan(Phi100intTE)
A = ((1 - 0.25 * wing.taper_ratio) * wing.y_kink +
0.25 * wing.taper_ratio * wing.y_root - wing.y_tip) / (
0.75 * wing.y_kink + 0.25 * wing.y_root - wing.y_tip)
B = (numpy.tan(wing.sweep) - tan_phi100) * (
(wing.y_tip - wing.y_kink) *
(wing.y_kink - wing.y_root)) / (0.25 * wing.y_root +
0.75 * wing.y_kink - wing.y_tip)
wing.c_root = (wing.area - B * (wing.y_tip - wing.y_root)) / (
wing.y_root + wing.y_kink + A *
(wing.y_tip - wing.y_root) + wing.taper_ratio *
(wing.y_tip - wing.y_kink))
wing.c_kink = A * wing.c_root + B
wing.c_tip = wing.taper_ratio * wing.c_root
else: # Without kink
wing.c_root = 2 * wing.area / (
2 * wing.y_root * (1 - wing.taper_ratio) +
(1 + wing.taper_ratio) * numpy.sqrt(wing.aspect_ratio * wing.area))
wing.c_tip = wing.taper_ratio * wing.c_root
wing.c_kink = ((wing.y_tip - wing.y_kink) * wing.c_root +
(wing.y_kink - wing.y_root) * wing.c_tip) / (
wing.y_tip - wing.y_root)
tan_phi0 = 0.25 * (wing.c_kink - wing.c_tip) / (
wing.y_tip - wing.y_kink) + numpy.tan(wing.sweep)
wing.mac = 2.*(3*wing.y_root*wing.c_root**2 \
+(wing.y_kink-wing.y_root)*(wing.c_root**2+wing.c_kink**2+wing.c_root*wing.c_kink) \
+(wing.y_tip-wing.y_kink)*(wing.c_kink**2+wing.c_tip**2+wing.c_kink*wing.c_tip) \
)/(3*wing.area)
wing.y_mac = ( 3*wing.c_root*wing.y_root**2 \
+(wing.y_kink-wing.y_root)*(wing.c_kink*(wing.y_root+wing.y_kink*2.)+wing.c_root*(wing.y_kink+wing.y_root*2.)) \
+(wing.y_tip-wing.y_kink)*(wing.c_tip*(wing.y_kink+wing.y_tip*2.)+wing.c_kink*(wing.y_tip+wing.y_kink*2.)) \
)/(3*wing.area)
x_mac_local = ( (wing.y_kink-wing.y_root)*tan_phi0*((wing.y_kink-wing.y_root)*(wing.c_kink*2.+wing.c_root) \
+(wing.y_tip-wing.y_kink)*(wing.c_kink*2.+wing.c_tip))+(wing.y_tip-wing.y_root)*tan_phi0*(wing.y_tip-wing.y_kink)*(wing.c_tip*2.+wing.c_kink) \
)/(3*wing.area)
wing.x_root = vtp.x_mac + 0.25 * vtp.mac - vtp.lever_arm - 0.25 * wing.mac - x_mac_local
wing.x_kink = wing.x_root + (wing.y_kink - wing.y_root) * tan_phi0
wing.x_tip = wing.x_root + (wing.y_tip - wing.y_root) * tan_phi0
wing.x_mac = wing.x_root+( (wing.x_kink-wing.x_root)*((wing.y_kink-wing.y_root)*(wing.c_kink*2.+wing.c_root) \
+(wing.y_tip-wing.y_kink)*(wing.c_kink*2.+wing.c_tip))+(wing.x_tip-wing.x_root)*(wing.y_tip-wing.y_kink)*(wing.c_tip*2.+wing.c_kink) \
)/(wing.area*3.)
if (wing.attachment == 1):
wing.z_root = 0
else:
wing.z_root = fuselage.height - 0.5 * wing.t_o_c_r * wing.c_root
wing.z_kink = wing.z_root + (wing.y_kink - wing.y_root) * numpy.tan(
wing.dihedral)
wing.z_tip = wing.z_root + (wing.y_tip - wing.y_root) * numpy.tan(
wing.dihedral)
# Wing setting
#-----------------------------------------------------------------------------------------------------------
g = earth.gravity()
gam = earth.heat_ratio()
disa = 0
rca = design_driver.ref_cruise_altp
mach = design_driver.cruise_mach
mass = 0.95 * weights.mtow
pamb, tamb, tstd, dtodz = earth.atmosphere(rca, disa)
cza_wo_htp = frame_aero.cza_wo_htp(mach, fuselage.width, wing.aspect_ratio,
wing.span, wing.sweep)
# AoA = 2.5° at cruise start
wing.setting = (0.97 * mass * g) / (0.5 * gam * pamb * mach**2 * wing.area
* cza_wo_htp) - unit.rad_deg(2.5)
return
def eval_pre_design_htp(aircraft):
"""
HTP predesign
"""
design_driver = aircraft.design_driver
fuselage = aircraft.fuselage
wing = aircraft.wing
vtp = aircraft.vertical_tail
htp = aircraft.horizontal_tail
htp.taper_ratio = 0.35 # Design rule
htp.aspect_ratio = 5 # Design rule
htp.t_o_c = 0.10 # Design rule
wing_sweep = 1.6 * max(0,
(design_driver.cruise_mach - 0.5)) # Empirical law
htp.sweep = wing_sweep + unit.rad_deg(5) # Design rule
htp.dihedral = unit.rad_deg(5) # HTP dihedral
# if(HQsizing==0): # Statistical sizing
htp.volume = 0.94 # Design rule
if (htp.attachment == 1): # Classical
htp.lever_arm = vtp.lever_arm - 0.20 * numpy.tan(
vtp.sweep) * vtp.height
elif (htp.attachment == 2): # T-tail
htp.lever_arm = vtp.lever_arm + 0.80 * numpy.tan(
vtp.sweep) * vtp.height
else:
print("airframe_predesign_, HtpType value is out of range")
htp.area = htp.volume * (wing.area * wing.mac / htp.lever_arm)
# else: # HQ sizing
# htp.area = HtpArea0 + dHtpArea ;
# htp.lever_arm = HtpLarm0 - dXwing ;
# htp.volume = (htp.area*htp.lever_arm)/(wing.area*wing.mac)
if (htp.attachment == 1): # Classical
htp.net_wetted_area = 1.63 * htp.area
elif (htp.attachment == 2): # T-tail
htp.net_wetted_area = 2.01 * htp.area
else:
print("airframe_predesign_, htp.attachment value is out of range")
htp.span = numpy.sqrt(htp.aspect_ratio * htp.area)
htp.c_axe = 2 * htp.area / (htp.span * (1 + htp.taper_ratio))
htp.c_tip = htp.taper_ratio * htp.c_axe
htp.y_tip = 0.5 * htp.span
htp.mac = htp.span * (htp.c_axe**2 + htp.c_tip**2 +
htp.c_axe * htp.c_tip) / (3 * htp.area)
htp.y_mac = htp.y_tip**2 * (2 * htp.c_tip + htp.c_axe) / (3 * htp.area)
x_tip_local = 0.25 * (htp.c_axe - htp.c_tip) + htp.y_tip * numpy.tan(
htp.sweep)
x_mac_local = htp.y_tip * x_tip_local * (htp.c_tip * 2. +
htp.c_axe) / (3 * htp.area)
htp.x_mac = vtp.x_mac + 0.25 * vtp.mac - vtp.lever_arm + htp.lever_arm - 0.25 * htp.mac
htp.x_axe = htp.x_mac - x_mac_local
htp.x_tip = htp.x_axe + x_tip_local
htp_z_wise_anchor = 0.80 # Locate HTP versus end fuselage height
if (htp.attachment == 1): # Classical
htp.z_axe = htp_z_wise_anchor * fuselage.height
elif (htp.attachment == 2): # T-tail
htp.z_axe = fuselage.height + vtp.height
else:
print("airframe_predesign_, htp.attachment value is out of range")
htp.z_tip = htp.z_axe + htp.y_tip * math.tan(htp.dihedral)
return