Easiest way to balance a model rocket?

Hello,
What is the best way to balance a model rocket? Some of my designs require some nose weight. I want to check the balance before I launch.

Brian

 

[rocketkid88]

personaly i've used every thing from a knife blade to my finger. naturaly the thinner the balancing point the more accurate your 'reading' is going to be, but if your rocket is already finished you may not want to be sitting it on the edge of a knife. there are so many ways to balance your rocket, just do what ever you want

 

[powderburner]

The edge of a scrap piece of balsa sheet (1/16 or 1/8 inch) will be plenty 'sharp' to give you an indication of where the balance point falls, and will not damage your model rocket.

If you want to double-check your work and calculate where the longitudinal C.G. should be, check out this old TRF thread:

https://www.rocketryforum.com/showthread.php?threadid=3379&highlight=CG+CP+101

And feel free to email or PM me if you have questions.

 

[swimmer]

Here is what I do: I tie a slip knot in a piece of 36" to 48"string. Tape or attach the string to the top of a door frame. I usually duct tape it to the trim. Slip it over your rocket and slide the string until your rocket is balanced. Be sure to find the CG with the heaviest motor you will use. I got some modeling putty, weighed out the same weight as the heaviest motor I will be flying and put it between the fins over the motor tube. CG could move aft, toward the CP, to the point you may have to add some noseweight. Again, use modeling clay and form it over your nosecone until your CG is correct in relation to your CP. Not complicated at all and your rocket will be balanced.

 

[Fore Check]

Originally posted by Swimmer
Here is what I do: I tie a slip knot in a piece of 36" to 48"string. Tape or attach the string to the top of a door frame. I usually duct tape it to the trim. Slip it over your rocket and slide the string until your rocket is balanced. Be sure to find the CG with the heaviest motor you will use. I got some modeling putty, weighed out the same weight as the heaviest motor I will be flying and put it between the fins over the motor tube. CG could move aft, toward the CP, to the point you may have to add some noseweight. Again, use modeling clay and form it over your nosecone until your CG is correct in relation to your CP. Not complicated at all and your rocket will be balanced.

I use the string-and-loop method too, but why bother with the modelling clay to simulate an engine? Slap one in there!

 

[jetra2]

Simply put, sometimes the motor is a reloadable and you can't load it to put it in the rocket!

But I agree with you if it was a SU engine - slap one on in there!

Jason

 

[sandman]

why bother with the modelling clay to simulate an engine? Slap one in there!

The only real engine failure I ever had on an Estes Engine was with an engine I was using as a "tool" to balance rockets on my work bench.

Finally I decided to take a few spent engines 13mm, 18mm two 24mm sizes;

First peal a layer of paper off so they go in and out easier.

Paint them a nice bright color and mark each with "Tool" on the side.

Fill each one with lead and clay until they ballance the identical engine they represent. Or at least the heaviest like a C6-7 or an E9-8.

You can drop them on the floor a few times and they will still work!

sandman

 

[swimmer]

Fore Check,

If the motor is a reload, I use clay. If it is a SU, I'll install it if I have one. The clay allows me to continue if I don't have the motor at that time whether reload or SU.

 

[rocketkid88]

Originally posted by powderburner
The edge of a scrap piece of balsa sheet (1/16 or 1/8 inch) will be plenty 'sharp' to give you an indication of where the balance point falls, and will not damage your model rocket.

i usualy use a ruler... i was just giving examples the extremes
I've also used the string method... i've also balanced the model with the same peice of string i was going to do the 'swing test' with, a few moments latter. you have to tie that string around the CG any way.