Design a Rocket Nose Cone (with Software)

If you are designing an amateur rocket or a big rocket to place a satellite in orbit, one of the most important parts of a rocket is the nose cone. The nose of a rocket determines the amount of drag that the air is going to generate in your launch. So this also determines the amount of fuel you need to reach the altitude you want and the amount of cargo you can deliver to that altitude.

Yesterday I was looking for some software to make better Nose Cones and I can't find anything useful, so I decide to look up for the formulas and make my own with Matlab code and SolidWorks. Here I share what I end up with.

Hope you like it.

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When you are designing a rocket nose cone you need to know some things.

• The diameter of your rocket body
• The Nose Long
• and the type of Nose you want to build

As you can see in the first image there are other thing that are important but the software is going to calculate those for us. If you want to read more about nose cone design I recommend this wikipedia page: rocket nose cone design

( I take the formulas for the software from there.)

Conical:

A very common nose shape is a conical. In the first rockets that I have the opportunity to take part we have this shape because it is the easiest to manufacture. you just need to make a paper cone and fill it with epoxy or make a straight line in the lathe and that's it, you have your first rocket nose cone.

Parabolic:

When you here parabolic nose you think of a blunt nose like a parabola, but in real the parabolic nose is just a part of a parabola rotated in an axis, so it end up been a curved nose that ends up in a sharp point. there are various types f parabolas, the most common are the full parabola, the 1/2 parabola, and the 3/4 parabola.

Matlab:

I know that downloading files sometimes is annoying, so I´m going to paste here the matlab come to generate the conical and the parabolic nose cones.

%***************************************************%

clear all
close all

clc

%*********************data*************************%

nose_long=12;

rocket_wide=4; %diameter

x_resolution=.1;

k=0;

C=1;

%************Para parabolic y cone*********%

%formula r=(2*x-K*(x)^2)/(2-K)

%C=0; %for cone

%C=1; %for parabolic nose

%C=.75; %for 3/4 parabolic nose

%C=.50; %for 1/2 parabolic nose

for I = 0:x_resolution:nose_long

k = k + 1 ;

x=I/nose_long;

r(k)=((2*x)-(C*(x)^2))/(2-C);

r(k)=r(k)*(rocket_wide/2);

end

%***********************************%

plot(r)

the Power Series is really close to the parabolic nose cone, but in this case the point doesn't end up in a sharp end, but ends up in a round shape. If you increase the value of n in the formula you will be getting a more sharp nose like a parabolic ending up in a cone. By the other side is you make n 0 the nose is going to be a cylinder or blunt.

Matlab:

clear all
close all

clc

%*********************data*************************%

nose_long=12;

rocket_wide=4; %diameter

x_resolution=.1;

k=0;

n = 0.5;

%*********For Power Rockets********%

%Formula

%r=x^n

%When

%n = 1; %for a cone

%n = 0.75; %for a 3/4 power

%n = 0.5; %for a 1/2 power (parabola)

%n = 0; %for a cylinder

for X = 0:x_resolution:nose_long

k = k + 1 ;

x=X/nose_long;

r(k)=x^n;

r(k)=r(k)*(rocket_wide/2);

end

%***********************************%

plot(r)

This are the most efficient Nose Cones for rockets. They are the hardest to build but with some cnc lathe or a 3d printer you can easily make them with the help of this code.

Matlab:

clear all
close all

clc

%*********************data*************************%

nose_long=12;

rocket_wide=2; %diameter

x_resolution=.1;

k=0;

C=0.333333;

%*********Von Karman y L-V Haack********%

%C = 0.333333 %for L-V Haack nose cones

%C = 0 %for Von Karman nose cones

for X = 0:x_resolution:nose_long

k = k + 1 ;

x=X/nose_long;

h=acos(1-2*x);

r(k)= sqrt((h-(1/2)*sin(2*h)+(C*((sin(h))^3)*h))/pi);

r(k)=r(k)*(rocket_wide*2);

end

%***********************************%

plot(r)

Matlab to .txt file:

1. First you need to double click the r variable and it will open a "excel like" screen on matlab. Copy all the row.
2. Paste the row on a column on excel (use de B column)
3. you need to create a series of numbers in the A row, start at 0 and add .1 until you end in your rocket long, this A column is your x values in solidworks.
4. On the column C just add 0's, this are your Z's in solidworks
5. Change the format to numbers with 4 decimals. this is important!
6. Open a new text file and paste the 3 columns. Save the file

.txt to Solidworks

1. open a new part file
2. select insert>curve>curve by x,y,z points
3. then open your txt file and you should see a table filled with your data
4. click on accept or insert and you now have your points in solidworks

There are just 3 steps to make the part from there.

1. Make a new drawing
2. then transform the entities to a line and close the drawing
3. Go to solid by revolution and now you have your nose cone

Finally, you can manufacture your new Nose Cone. Right now I only have conical nose cones, and they work ok. I'm looking for a way to get a 3d printer so I can make more rockets and more projects, but right now I think is going to take me 5 or 6 more years to get one for real. I hope you can make your own and share with the community.

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