# Can't connect all the dots with a line

3 views (last 30 days)
Kevin Tai on 29 Oct 2019
Commented: Kevin Tai on 29 Oct 2019
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 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.

Rik on 29 Oct 2019
Edited: Rik 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')

#### 1 Comment

Kevin Tai on 29 Oct 2019
Thank you very much!