• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
Tsl Thrust to Weight ratio and Aspect Ratio
 

Tsl Thrust to Weight ratio and Aspect Ratio

on

  • 1,618 views

 

Statistics

Views

Total Views
1,618
Views on SlideShare
1,618
Embed Views
0

Actions

Likes
0
Downloads
32
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

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

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