I’ve been trying to draw a wing with data such as

Ctip, Croot, b, lambda (Taper ratio) and S

What I’m struggling with is how to actually start with this if we don’t know the angle created by the fuselage with the as trailing or leading edge shown in my picture

So when we first draw the Croot and a Ctip a distance away from each other, how far to the left or right would I draw Ctip?

enter image description here

  • $\begingroup$ What is lambda in this particular case? Leading edge sweep, 25% chord sweep or what? $\endgroup$
    – Jpe61
    Mar 29, 2022 at 9:03
  • $\begingroup$ Is that diagram intended to represent a wing? $\endgroup$ Mar 29, 2022 at 15:11
  • $\begingroup$ @MichaelHall Yes, that is how you graphically determine the mean aerodynamic chord. See this for an explanation. $\endgroup$ Mar 29, 2022 at 15:54
  • $\begingroup$ @PeterKämpf, thank you. Your diagram is MUCH better, and I see a wing now. All I saw this morning was a messed up looking Roman numeral twelve... $\endgroup$ Mar 30, 2022 at 0:19

2 Answers 2


If you have c_tip, c_root, b and S and assume a trapezoidal wing (straight taper), you have one too many values prescribed, i.e. you can omit one of the four. If lambda is indeed taper ratio, then it's the same as c_tip/c_root, again redundant. But then you don't know anything about sweep.

If Lambda is sweep angle, on the other hand, then you know everything you need. For subsonic aircraft, sweep angle usually denotes the sweep of the quarter-chord line, so you can start drawing the root chord along the fuselage, draw a perpendicular (to the fuselage axis -> spanwise) line from this point, and then draw a line at the sweep angle to this perpendicular one. This will be your quarter chord. At the semispan, draw a line parallel to the root chord with length c_tip, extending 1/4 c_tip forward from the quarter chord line you just drew, and 3/4 back.


$C_{tip}$ is at a distance of ½b away from $C_{root}$. Placement left or right in the drawing follows from the quarter chord sweep angle.


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