/
horizontal_tail.py
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/
horizontal_tail.py
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" horizontal tail "
import numpy as np
from gpkit import Model, Variable
from tail_aero import TailAero
from gpkitmodels.GP.aircraft.wing.wing import AeroSurf
from gpkitmodels.GP.aircraft.wing.constant_taper_chord import c_bar
from gpkitmodels.GP.aircraft.wing.wing_interior import WingInterior
from gpkitmodels.GP.aircraft.wing.wing_skin import WingSkin
class HorizontalTail(Model):
"horizontal tail model"
def setup(self, N=3, lam=0.8):
Vh = Variable("V_h", "-", "horizontal tail volume coefficient")
W = Variable("W", "lbf", "horizontal tail weight")
lh = Variable("l_h", "ft", "horizontal tail moment arm")
CLhmin = Variable("(C_{L_h})_{min}", 0.75, "-",
"max downlift coefficient")
mh = Variable("m_h", "-", "horizontal tail span effectiveness")
mfac = Variable("m_{fac}", 1.1, "-", "horizontal tail margin factor")
cb, eta, deta, cbarmac = c_bar(lam, N)
subdict = {"\\lambda": lam, "\\bar{c}": cb, "\\eta": eta,
"\\bar{c}_{ave}": (cb[1:]+cb[:-1])/2, "\\tau": 0.08,
"\\bar{c}_{MAC}": cbarmac, "d\\eta": deta, "C_{L_{max}}": 1.5}
self.surf = AeroSurf(N=N)
self.surf.substitutions.update(subdict)
self.skin = WingSkin()
self.skin.substitutions.update({"\\rho_{CFRP}": 0.049})
self.foam = WingInterior()
self.foam.substitutions.update({"\\bar{A}_{jh01}": 0.0548})
self.foam.substitutions.update({"\\rho_{foam}": 0.024})
self.components = [self.skin, self.foam]
constraints = [
W/mfac >= sum([c["W"] for c in self.components]),
mh*(1+2.0/self.surf["AR"]) <= 2*np.pi,
self.skin["W"] >= (self.skin["\\rho_{CFRP}"]*self.surf["S"]*2
* self.skin["t"]*self.skin["g"]),
self.foam["W"] >= 2*(
self.foam["g"]*self.foam["\\rho_{foam}"]
*self.foam["\\bar{A}_{jh01}"]*self.surf["c_{ave}"]**2
* (self.surf["b"]/2)*self.surf["d\\eta"]).sum()
]
return constraints, self.surf, self.components
def flight_model(self, state):
return TailAero(self, state)