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},
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"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 14: Airframe loads"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 14.1 Pg.No.407"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"import math\n",
"\n",
"W=45 #weight of aircraft (kN)\n",
"m=45/9.8 #mass of aircraft(k-kg)\n",
"a=3*9.8 #deceleration due to cable (ms^-2)\n",
"m1=4.5/9.8 #weight of aircraft after AA in Diagram (k-kg)\n",
"v0=25 #touch down speed (m/s)\n",
"alpha=10 #center line angle with ground (degree)\n",
"\n",
"T=m*a/math.cos(math.radians(alpha))\n",
"print \"tension in cable = %3.1f kN\\n\"%(T)\n",
"\n",
"R=W+T*math.sin(math.radians(alpha))\n",
"print \"load on each undercarriage strut = %2.1f kN\\n\"%(R/2/math.cos(math.radians(20)))\n",
"\n",
"N=T+m1*9.8*math.sin(math.radians(alpha))-m1*a*math.cos(math.radians(alpha))\n",
"S=m1*a*math.sin(math.radians(alpha))+m1*9.8*math.cos(math.radians(alpha))\n",
"print \"N and S forces are shown in Fig 14.4 N=%2.2f kN S=%2.2f kN\\n\"%(N,S)\n",
"\n",
"s=v0**2/2/a\n",
"print \"length of deck covered = %2.2f m\\n\"%(s)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"tension in cable = 137.1 kN\n",
"\n",
"load on each undercarriage strut = 36.6 kN\n",
"\n",
"N and S forces are shown in Fig 14.4 N=124.57 kN S=6.78 kN\n",
"\n",
"length of deck covered = 10.63 m\n",
"\n"
]
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 14.2 Pg.No.409"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"import math\n",
"\n",
"g=9.8\n",
"W=250 #weight of aircraft(kN)\n",
"m=250/g #mass of aircraft (K-kg)\n",
"I_CG=5.65*10**8 #inertia about center of mass(N.s^2.mm)\n",
"v0=3.7 #vertical velocity of undercarriage(m/s)\n",
"R_h=400 #horizontal reaction (kN)\n",
"R_v=1200 #vertical reaction (kN)\n",
"l=1 # nose wheel distance from ground (m)\n",
"d=2.5 # distance of CG from ground (m)\n",
"\n",
"#horizontal equilibrium\n",
"ax=R_h/m\n",
"\n",
"#vertical equilibrium\n",
"ay=(R_v-W)/m\n",
"\n",
"\n",
"alpha=(R_v*l+R_h*d)*10**6/I_CG\n",
"print \"angular acceleration of aircraft = %2.1f rad/s^2 \\n\"%(alpha)\n",
"\n",
"#v=v0+ay*t\n",
"t=v0/ay\n",
"print \"time taken for vertical velocity to become zero = %1.3f s\\n\"%(t)\n",
"\n",
"#w=w0+a*t\n",
"w=a*t\n",
"print \"angular velocity of aircraft = %1.2f rad/s \\n\"%(w)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"angular acceleration of aircraft = 3.9 rad/s^2 \n",
"\n",
"time taken for vertical velocity to become zero = 0.099 s\n",
"\n",
"angular velocity of aircraft = 0.39 rad/s \n",
"\n"
]
}
],
"prompt_number": 20
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 14.3 Pg.No.414"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"import math\n",
"\n",
"W=8000 #weight of aircraft (N)\n",
"n=4.5 # wing loading\n",
"S=14.5 #wing area (m^2)\n",
"V=60 #speed (m/s)\n",
"rho=1.223 #density (kg/m^3)\n",
"alpha=13.75 #from Fig 14.8 (a)\n",
"C_Mcg=0.075 #from Fig 14.8 (a)\n",
"c=1.35 #mean chord (m)\n",
"\n",
"\n",
"L=n*W\n",
"C_L=L/(0.5*rho*V**2*S)\n",
"print \"lift coefficient of aircraft = %1.3f \\n\"%(C_L)\n",
"\n",
"#from Fig 14.8 (b)\n",
"l=4.18*math.cos(math.radians(alpha-2))+0.31*math.sin(math.radians(alpha-2))\n",
"print \"length of tail arm = %1.3f m \\n\"%(l)\n",
"\n",
"\n",
"C_L=C_L-c/l*C_Mcg\n",
"print \"lift coefficient =%1.3f \\n\"%(C_L)\n",
"\n",
"alpha=13.3\n",
"l=4.18*math.cos(math.radians(alpha-2))+0.31*math.sin(math.radians(alpha-2))\n",
"print \"Now tail arm length = %2.3f m\\n\"%(l)\n",
"\n",
"L=0.5*rho*V**2*S*C_L\n",
"print \"Lift = %5.1f N\\n\"%(L)\n",
"\n",
"P=n*W-35000\n",
"print \"Tail Load = %5.1f N\\n\"%(P)\n",
"\n",
"D=0.5*rho*V**2*S*0.0875\n",
"print \"Drag = %5.1f N\\n\"%(D)\n",
"print \"Forward inertia force = %5.1f N\\n\"%(D) #eqn 14.13"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"lift coefficient of aircraft = 1.128 \n",
"\n",
"length of tail arm = 4.156 m \n",
"\n",
"lift coefficient =1.103 \n",
"\n",
"Now tail arm length = 4.160 m\n",
"\n",
"Lift = 35222.3 N\n",
"\n",
"Tail Load = 1000.0 N\n",
"\n",
"Drag = 2793.0 N\n",
"\n",
"Forward inertia force = 2793.0 N\n",
"\n"
]
}
],
"prompt_number": 31
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}
|
