## Can't connect all the dots with a line

### Kevin Tai (view profile)

on 29 Oct 2019
Latest activity Commented on by Kevin Tai

on 29 Oct 2019

### Rik (view profile)

Hi there, still learning here. I have a small question where how do I connect all the points with a line? I can't seem to get it even after using different functions.
Any help is greatly appreaciated!
c = 0.2;
Re = 386639;
V = 27.78;
b = 0.8:0.02:1.2;
alpha_Lmax = 17.2;
alpha_Lzero = -4.3;
C_lmax = 1.508306;
C_lzero = 0.4527213;
c_d0 = 0.01188282;
rho_0 = 1.225;
rho = 1.202;
R = 287.057;
mew_0 = 1.789e-5;
mew = 1.7284e-5;
alpha = 0;
v = 1.4370e-5;
a_airfoil = C_lmax/(alpha_Lmax-alpha_Lzero);
for i = 1:length (b)
a_wing = a_airfoil/(1+(57.3*a_airfoil)/(pi*0.7*(b(i)/c)));
C_L = a_wing*(alpha-alpha_Lzero);
L = 0.5*rho*(V^2)*b(i)*c*C_L;
C_Di = (C_L^2)/(pi*0.7*(b(i)/c));
C_D = c_d0 + C_Di;
ratio = C_L/C_D;
plot (b(i),ratio,'x')
hold on
end
grid on
xlabel('Span (m)')
ylabel('CL/CD')
title('CL/CD vs Span')

Rik

on 29 Oct 2019
Kevin Tai

### Kevin Tai (view profile)

on 29 Oct 2019
Oh thank you very much. There's more for me to learn here it seems cause this is my first question posted to here.

on 29 Oct 2019
Edited by Rik

### Rik (view profile)

on 29 Oct 2019

Store the ratio in an array:
ratio=zeros(size(b));
for i=length(b)
ratio(i) = C_L/C_D;
end
plot(b,ratio,'-x')

Kevin Tai

### Kevin Tai (view profile)

on 29 Oct 2019
Thank you very much!