Fighter jet design and performance calculations by using the case studies.
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The document presents a comprehensive configuration study of a multirole fighter aircraft designed by Naga Manikanta Kommanaboina at Kaunas University of Technology. It includes performance specifications and parameters for four aircraft models—F-22, F-16, Rafale, and SU-35—along with details on design considerations such as wing configuration, stealth technology, and engine selection. Overall, the study aims to ensure optimal performance characteristics across various flight modes and operational requirements.
Fighter jet design and performance calculations by using the case studies.
- 1. Fighter Jet Design Name: Naga Manikanta Kommanaboina Master Science – Aeronautical Engineering Kaunas University of Technology
- 2. Configuration Study: Parameters/ Aircrafts F-22 F-16 Rafale Su-35 Role Multirole Air superiority Multirole Air superiority fighter Multirole fighter Multirole Air superiority Status In service In service In service In service Crew 1 1 1 1 Performance Study: Parameters/ Aircrafts F-22 F-16 Rafale Su-35 G-limits -3 to +9 +9 +9 to -3.6 +9 Thrustto weight ratio 1.08 1.095 0.988 0.92 Max. Speed (at Sea level) (Mach No.) 1.8 1.2 1.1 1.15 Max. Speed (at altitude) (Mach No.) 2.25 2 1.8 2.25 Service Ceiling (feet) 65000 50000 50000 59100 Range (Km) 2960 3223 3700 3600 Wing Loading (Kg/m2) 375 431 328 428
- 3. Specification Study: Parameters/ Aircraft F-22 F-16 Rafale Su-35 Length 18.9 15.06 15.27 21.9 Height 5.08 4.88 5.34 5.90 Wing area 78.04 27.87 45.7 62 Wing span 13.56 9.96 10.8 15.3 Empty Weight(KG) 19700 8570 9850 18400 Max. takeoff weight (Kg) 38000 19200 24500 34500 Payload (Kg) 8000 7700 9500 8000 Fuel capacity (Gal) 3050 710 1240 3040 No.of engines 2 1 2 2
- 4. CONFIGURATION SELECTION WING Am going to design a Multi role Fighter aircraft so we need good performance of the wing at both subsonic and supersonic speed. Hence analyzing various configurations simple swept wing will be suit for multirole fighter aircraft that will be operate in both subsonic and supersonic because it will create more vortex lift. ELEVATOR AND RUDDER Since it is swept wing aircraft so there will be two elevators, but there is a need of two rudders each in each vertical stabilizer, so it can give more longitudinal stability and highly maneuvering capability. INLET AND NOZZLE From the available configuration of inlets and nozzles for supersonic operations circular configuration seems easy and suitable for supersonic operations. STEALTH The aircraft needs to be stealthy and stealth can be obtained by following methods they are 1.stealth by shape 2.stealth by material 3. stealth by surface paints A stealth aircraft is made up of completely flat surfaces and very sharp edges. When a radar signal hits a stealth plane, the signal reflects away at an angle. Radio absorbent materials are used to absorb the radio waves rathe than deflect it in other direction Material used in this method are MAGRAM, Absorbing Honeycomb Structure.
- 5. By using of special kind of surface paints that will have a capacity of absorbing the radio waves emitted by radar. Hence radio waves will be absorbed instead of reflecting back to Radar receiver. PRELIMINARY DESIGN Am going to design a Multi role Fighter aircraft so we need good performance of the wing at both subsonic and supersonic speed. Hence analyzing various configurations simple swept wing will be suit for multirole fighter aircraft that will be operate in both subsonic and supersonic because it will create more vortex lift. ELEVATOR AND RUDDER Since it is swept wing aircraft so there will be two elevators, but there is a need of two rudders each in each vertical stabilizer, so it can give more longitudinal stability and highly maneuvering capability. INLET AND NOZZEL From the available configuration of inlets and nozzles for supersonic operations circular configuration seems easy and suitable for supersonic operations. The wing loading is simply weight of the aircraft divided by the area of the reference wing. Wing loading affects stall speed, Climb rate, take-off and landing distances and turn performance. The wing loading determines the design lift coefficient and impacts drag through its effect upon wetted area and wing span. TAKE OFF PERFORMANCE 1.Takeoff distance: Sg =1.21 (W/S) /g ρ Cl max (T/W) Sg = 436.3 m Take off distance = Sg + Sa
- 6. 2. Airborne Distance: Sa= 𝑅 sin 𝜃 𝑂𝐵 Flight path radius (R)= 6.96(𝑉𝑠𝑡𝑎𝑙𝑙)2 𝑔 = 2666m Flight path Angle (𝜃𝑂𝐵) = cos−1 1 − 𝐻𝑜𝑏/𝑅 = θOB = 6.129° Airborne Distance: Sa= 𝑅 sin 𝜃 𝑂𝐵 = 2666 Sin6.129° = 284m Take off distance = Sg + Sa = 720.9m Total Landing Distance, Ld = 2242.85m Weight Unit(Kg) Unit(N) Empty Weight 6247.5 61287.97 Fuel Weight 3421.25 33562.46 Overall Weight 18159.54 178145.08 Weight of Crew 100 981 Payload weight 8300 81423 AIRFOIL SELECTION: Airfoil will be selected by following calculations, NACA 64A204 V approach=1.3 V stall V approach=155knots V stall =61.3 m/s 𝐶𝑙 max = 2 ∗ 𝑤𝑜 2 ∗ 𝑤𝑜 𝑉𝑠𝑡𝑎𝑙𝑙)2 ∗ ρ ∗ S CL max =1.45 CL max (wing) = (CLmax/0.95) =1.52
- 7. CL max (gross) =1.68 CL max (net)=1.2 W/S=340.19Kg/m^2 W/S (TO)=6534.6 Kg/m^2 W/S(Landing) = 5554.46 Kg/m^2 Wing Area: 𝑆 = 𝑊𝑜 𝑊/𝑆 = 53.38 𝑚^2 Wing Span: b = (AR ×S)^0.5 b = 12.26 m Root Chord C root = 6.803m Tip Chord C tip = 1.90m Wing Aerodynamic Chord (C) C= 4.35 WING SELECTION Mach No. = 2.08 Mach angle, μ = 28.73 ° Swept back wing angle is (Ʌ) = 73.52 ° Effective Chord length of Swept wing C eff = 3.52 m Leading edge Swept Back (Ʌ LE) = 74.39° Half of the chord Ʌ c/4 = 71.45°
- 8. Oswald Span efficiency, η = 0.7 POWERPLANT SELECTION Thrust required to propel the Aircraft: T= Takeoff Weight × Thrust Loading T = 18536.25 Kg Hence Thrust required for Two Engines is T= 181.841 KN Each Engine contributes 90.920 KN of Thrust ENGINE SELECTED As per requirements Engine selected for Multirole Fighter Aircraft is General Electric F414- GE400. GENERAL CHARACTERISTICS Type: Afterburning turbofan Length: 154 in (391 cm) Diameter: 35 in (89 cm) Dry weight: 2,445 lb (1,110 kg) max weight COMPONENTS Compressor: Axial compressor with 3 fan and 7 compressor stages Combustors: annular Turbine: 1 low-pressure and 1 high-pressure stage
- 9. PERFORMANCE Maximum thrust: 13,000 lbf (57.8 kN) military thrust 22,000 lbf (97.9 kN) with afterburner Overall pressure ratio: 30:1 Thrust-to-weight ratio: 9:1 air mass flow: 77.1 kg/s LIFT ESTIMATION L=1652661.4N or L = 1.65 MN Lift at Take-Off L=1.688(Flap extended and kept at take-off position of) Lift at Landing L = 299.75 kN Drag at takeoff D = 24 KN Drag at Landing D = 63.38 KN velocity at minimum thrust required V_TR (min) = 92.57 m/s (L/D) max = 5.38 Velocity at Max. Lift to drag ratio V (L/D) max: V (L/D) max = 92.57m/s T_r min = 33.11kN
- 10. Power Required minimum (Pr): P_r = 20.34 MNm/s Thrust Available: T_A = 196KN (From Engine selections) POWER AVAILABLE P_A = 120.43 MN m/s Max Rate of Climb (R/C) max (R/C) max = 190.38m/s Velocity at max. rate of climb: V(R/C) max= 262.39 m/s Level Turn: Turn Radius R= 4263.33m NACA 64-206 AIRFOIL CHARACTERISTICS 1.Maximum coefficient of Lift(CLmax)= 1.45 2. Maximum Coefficient of Lift Wing (CLmax)W= 1.52 3.Gross maximum Lift coefficient (CLmax)gross= 1.68(FLAP DOWN) 4.Net Maximum Lift Coefficient=1.72
- 11. PERFORMANCE CURVES Constrai n Numb er of crew and passen ger Engin es Max. takeoff weight (N) Turn load / speed / height Rate- of climb at SL Take off run / speed Cruise speed / height Magnitu ed 1 2 18159. 54 KG +9.0- 3.0g 254m /s 286.88k m/h 1963k m/h Constrai n Servic e ceiling AR of wing CD min, Rolling drag coeff Take -off CLT O Take- off CDTO Landin g speed Magnitu ed 65,000 ft 2.81 0.284 - 5,658kg/ m 0.8 0.46 95.32m /s
- 14. Fig: Matlab performance curves
- 15. Aircraft 3 views