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Tsl Thrust to Weight ratio and Aspect Ratio
Tsl Thrust to Weight ratio and Aspect Ratio
Tsl Thrust to Weight ratio and Aspect Ratio
Tsl Thrust to Weight ratio and Aspect Ratio
Tsl Thrust to Weight ratio and Aspect Ratio
Tsl Thrust to Weight ratio and Aspect Ratio
Tsl Thrust to Weight ratio and Aspect Ratio
Tsl Thrust to Weight ratio and Aspect Ratio
Tsl Thrust to Weight ratio and Aspect Ratio
Tsl Thrust to Weight ratio and Aspect Ratio
Tsl Thrust to Weight ratio and Aspect Ratio
Tsl Thrust to Weight ratio and Aspect Ratio
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Tsl Thrust to Weight ratio and Aspect Ratio

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  • 1. TSL_Oct2010<br />Thrust to weight Ratioand Aspect Ratio <br />NguyễnAnhTuấn<br />Naval Architecture and Marine Engineering tuanshipland@gmail.com<br />(+84) (0) 944 113 787<br />
  • 2. T/W Ratio<br />T/W ratio estimates:<br />Part of the takeoff distance<br />Rate of climb<br />Maximum velocity<br />http://www.centennialofflight.gov/essay/Theories_of_Flight/Performance_Class2/TH25G1.htm<br />
  • 3. Takeoff distance = sg+ sa = 2500 ft<br />According eq. [6.95] (see [1]), Ground Roll sg<br />For Flap<br />Plain Flap deflection 20ofor takeoff (see table 5.3 [1])<br />Section maximum lift coeffient∆(cl)max of45o flap deflection is 0.9 (see Fig.5.28, [1])<br />∆(cl)max= 0.9 (20/45) ~ 0.5 (For linear changes)<br />For the whole of wing, average (cl)max= 1.7 + 0.5 = 2.2<br /> <br />Raymer, Ref [25] of [1]<br />3D- effect of the finite aspectratio<br />
  • 4. Flight path radius<br />=<br />Flight path angle<br />= 50 ft : obstacle height<br />Airborn distance<br />Takeoff distance = sg+ sa = 2500 ft<br />Velocity of airplane<br />Gross takeoff weight = 5,158lb <br />The liftoff velocity<br />Requirement powerPA =<br />Shaft brake power<br />Note: 550ft.lb/s = 1hp<br />Power of the takeoff constraint ≥ 119 hp<br />
  • 5. P<br />PR = PA<br />T/W ratio <br />and Aspect ratio<br />Effects<br />T/W<br />V∞<br /> <br />Wo<br />sg<br />sa<br />𝜃𝑂𝐵<br /> <br />R<br />Vstall<br />VLO<br />T/W<br />W/S<br />(Cl)max<br />(cl)max<br />
  • 6. Maximum Rate of climb (R/C)max = 1000ft/min = 16.67 ft/s at sea level<br />Single-engine general aviation airplanes<br />The ratio of wetted area to the wing referenece area Swet/Sref= 4 (See fig. 2.54, [1])<br />The skin –friction coefficent (for early jet fighters) Cfe = 0.0043 corressponds to Reynolds number Re = 107 (See fig 2.55, [1])<br />
  • 7. The zero-lift drag coefficient (the zero-lift parasite drag coefficient)<br />The drag polar for airplane<br />The drag due to lift (downwash and so on)<br />The span efficiency factor to account for a nonelliptical lift distribution along the span of the wing e<br />The coefficient<br />=<br />= 0.075<br />Based on data from famous existing airplanes, estimating a reasonable first approximation for maximum of Lift to Drag ratio for 4-6 peoples aircraft (See p.403 [1])<br />A reasonable estimate The Oswald efficiency eo for a low-wing general aircrafts is 0.6 (See p.415 [1])<br />=7.07<br />
  • 8. Maximum rate of climb for a propeller-driven airplane<br />Shaft Brake Power for the constraint of rate of climb<br />W/S<br />K<br />Wo<br />Aspect Ratio<br />
  • 9. Themaximum velocity V∞ = Vmax = 250 mi/h = 366.7 ft/h at midcruise weight and level flight 20,000ft<br />In level flight T=D<br /> <br />The weight at maximum velocity is less than the weight at takeoff stage<br />The midcruise weight WMC<br />Estimating the weight fraction <br />
  • 10. Gross takeoff weight = 5,158lb <br />For a propeller-driven aircraft, we use power to weight ratio<br />For a jet aircraft, we use thrust to weight ratio<br />T/W and P/W are same mean<br />
  • 11. Thank you!<br />
  • 12. References<br />[1] John D. Anderson, Jr. 1999. Aircraft Performance and Design. McGraw-Hill<br />[2] E. L. Houghton and N. B. Carruthers. 1986. Aerodynamics for Engineering Students. 3rd edition. Thomson Press<br />

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