0
Upcoming SlideShare
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Standard text messaging rates apply

# Tsl Thrust to Weight ratio and Aspect Ratio

1,439

Published on

0 Likes
Statistics
Notes
• Full Name
Comment goes here.

Are you sure you want to Yes No
Your message goes here
• Be the first to comment

• Be the first to like this

Views
Total Views
1,439
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
43
0
Likes
0
Embeds 0
No embeds

No notes for slide

### Transcript

• 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 />