LD HAACK Calculation for MATLAB & Octave =advanced=

[Ozymandias]

I got to do a pretty cool project for my Computing for Engineers class. I wrote two simple scripts that will calculate the shape for HAACK series nose cones. Below is the script for the popular LD-HAACK (aka. Von Karmann Ogive). I have it set up for a 15" long, 3" diameter nose. If you would like a nose of a different size, simply change L (nose length) and R (nose radius @ base) accordingly. This script will work in MATLAB as well as GNU Octave. You could also plot it on a graphing calculator with a little reverse engineering. I hope this helps someone out there. Script follows:

%LD-HAACK Cone Calculator
%Written by David A. Roy

C = 0;
L = 15;
R = 1.5;
x = linspace(0, 15);

theta = acos(1-(2*x)/(L));
y = R*sqrt((theta-sin(2*theta)/2+C*(sin(theta)).^3))/(sqrt(pi));

plot(x,y)
hold on
plot(x,-y)
axis('equal');
xlabel('length')
ylabel('radius')
title('Nose Profile')

 

[DynaSoar]

Originally posted by Ozymandias
I have it set up for a 15" long, 3" diameter nose. If you would like a nose of a different size, simply change L (nose length) and R (nose radius @ base) accordingly.

And if you'd like a a minimum drag Haack for a given volume (LV) instead of for a given diameter (LD; ie. Von Karmaan) set C = 1/3.

But the only reason I can think to do so is if you have a payload of a given size inside your nose cone.

 

[mike_bar]

Originally posted by Ozymandias
I got to do a pretty cool project for my Computing for Engineers class. (Snip.)

That is a cool project. It must be fun to incorporate your hobby into your schoolwork. Great job!

I am not an engineer and I do not know the software you mentioned. I am a finance geek (and closet, wanna-be, rocket scientist). I know Microsoft Excel, inside and out, so I worked on your formulas there. I even made a graph of the cone profile. (Check it out below.) I created a 4:1 cone with a shoulder. Note, the graph is not scale, but the geometry looks good. That was a fun project for me too.

I must credit Kemal Payza who wrote an excellent Microsoft Excel workbook to create nose cone profiles. His workbook can create ogive, parabola, ellipse, and weighted average profiles.

This Microsoft Excel workbook can be found at Rocketry Online’s INFOcentral.

I was wondering how to do a LD-Haack cone, and now I can! Thanks again.