Question

Consider a large jet airplane which has the following characteristics: Maximum gross weight = 130000 N General • Fuel weight = 50000 N Wing 2 Wing area = 50 m Wing aspect ratio (AR) = 6.5 Wing span efficiency factor (e) = 0.87 Aerodynamics . = MARE • Zero-lift drag coefficient = 0.032 Drag Cp = Cpo + kc where k = kı + kz kı = 0 and k3 Lift CLmax = 1.4 during flight Two turbojet engines. (thrust changes with altitude) • Each engine produces thrust = 40 kN at sea level. • Thrust-specific fuel consumption is 1 h Maximum structural load factor = 4. Propulsion Structure Calculate: i. maximum speed at altitude = 10 km, ii. maximum rate of climb at altitude = 10 km. iii. absolute ceiling of the aircraft if maximum rate of climb at sea level is 50 m/s. iv. range and endurance of the aircraft at altitude = 10 km. (10) (10) (10) (10)

Answer 1

te (AR) MXO&#X65 solution maximum googs weight (W) –130000N fuel weight (WP) = 50 100N Net weight ( W) = W-Wp- 130000-50000 = 80 OVON Wing Area (8)=50m2 Aspect ratio (AR)=65 e =0.87, CD20 =0.032, Emery ol4 Comax = Coot I may Comax = 0.032 t -X1.42 0.1424 Maximum Structural loud factors (nmay] =4 Now density of air at 10km height, so 70.41 35 kg / m3 o nmax = 12 Sa Va Aman W/ 4= X0.4135X Va Xloy Vo = 189.55 m/s Maximum speed at allitude 10km is 189.55 m/s. NOW, G & Polos = 0.35 AX 087865 0:0389 Regurred Torque ot lokm altitude. WR) = 2 (BODOgo) 10 W 1 30000 X0.4135x (18953)2X50 (p=0.032+ (0.38)2 W TR = 130000 0:35 8.0389 =14448.57N

Maximum rate of climbat 10km altitude (B/C) max = TRVO 14448.97X189.55 W 130000 (B/C) max =21.067 m/s (B/C) may= 21067 m/s Assuming We) meny Varies linearly with altitude (P() mux zahtb- hiven at sea level (h=0), (B/C) max=20m/s At h=10ooom (B/C) max =21.067 m/s 50=4 (0) th - 21.067 = a (10orr) +belli from and , b=30, 0 = -0.0028933 meix = -0.0028933h+50 To obterin absolute ceiling, (/) mes=0 0=-0.0028933h+50 h=17281.305m. Absolute ceiling, Permax = 17281.309 m For Jet Airplane hiven TSFC (CA) = 1 ht - 2.77x104 See (13 Cote AR) (12) max = 15:462 (R/C) mex N) Yu 1972 ( \X0.032X19XO.87X 18*X6 43 X 0.032 To may -W3 Co

GB 2 ISOS W/ ww/ 4 CD may 2 2.77X10 4 X 1.78 Range (R)=2 R = 2 10-4138850 (2-47X16-4 X(15:46) (12.000 280000 100%) R = 269.15X104 m = = 2691.5km Por endurance С. 6)mey = (rear Coo) (1x KxLxx003 = 11.78 28 0.032 of Jet aircraft tota la o muy dn( Was) CD may 2000 Endurance 130000 80000 E=20647.22 sec =573 ho