CENTER OF PRESSURE CALCULATOR

[RPM ROCKETRY]

I have found center of pressure calculators (automatic after info re: rocket measurements have been entered) but the one I found calls for a "transition". My rocket does not have a "transition". It just has a nose cone going into a straight body. Body does not get large or smaller, it remains the same size with no transition. If I enter "0" for "length of transition" the calculator will not work. Does anyone have any suggestion as to an automatic center of pressure calculator to be found on the web?:shock::shock::shock:

 

[Cl(VII)]

Open rocket. Free and effective.

 

[blackbrandt]

+1 on Openrocket. Free, and it will let you design the rocket on the computer before you even start cutting parts.
https://openrocket.sourceforge.net/

Matt

 

[rocketgeek101]

+2 on OpenRocket. They now even have 3D views of your model... And it's free!

 

[blackbrandt]

Some screenshots from it, just so you can see the pure awesomness:

 

[RPM ROCKETRY]

What is "open rocket" or "operocket". Plus "1" or "plus 2" what are we talking about here?

 

[blackbrandt]

Openrocket is a simulation program for rockets. I posted a link to download it in my first post in this thread. +1 and +2 are just saying "I agree" in a short hand manner.

Matt

 

[Area66]

What is "open rocket" or "operocket". Plus "1" or "plus 2" what are we talking about here?

best way to know it's to download it and try it, it's free


https://openrocket.sourceforge.net/

 

[jaymeister99]

+1 again on Open Rocket. This has got to be one of the best free programs ever for anything. Great.

 

[goldlizard]

Open rocket has everything you need. Good luck and happy flying!!!

 

[PhlAsh]

Yeah... Not so much
Pic

 

[soupwizard]

Yeah... Not so much
Pic

Well, ok, OpenRocket doesn't cover *every* possible rocket design...

 

[SteveA]

Pic

LIKE! A lot!

 

[samb]

Perhaps the OP wasn't after a full blown design tool. There are (or used to be) spreadsheet-style CP calculators that implement the Barrowman equations. How well some of these work (if at all) in todays desktop/laptop/handheld computing environment is a question for the user. A search on "barrowman stability calculations" resulted in some info, among them:

https://v-serv.com/vcp/

https://my.execpc.com/~culp/rockets/Barrowman.html


So RPM, what were you using and what do you want ?

 

[PhlAsh]

LIKE! A lot!

Thanks!
Now if I could recover it in a reasonable number of pieces...

 

[bill_s]

If I enter "0" for "length of transition" the calculator will not work. Does anyone have any suggestion as to an automatic center of pressure calculator to be found on the web?:shock::shock::shock:

You should be able to enter very small numbers and/or the start and end diameters of the transition the same. I do this with RASP when simming CHAD staging, the booster weight can't be zero but .001 works. What calculator are you using? My computer won't run Open Rocket.

 

[RadManCF]

If you're willing to crunch numbers by hand, one of the apendices in G Harry Stine's Handbook of Model Rocketry gives the formulas used for the Barowman Method of CP calculation. It looks nasty, but it isn't really that bad. You just have to plug in your numbers and go.

 

[SteveNeill]

Thank you gentlemen!

 

[samb]

Perhaps the OP wasn't after a full blown design tool. There are (or used to be) spreadsheet-style CP calculators that implement the Barrowman equations. How well some of these work (if at all) in todays desktop/laptop/handheld computing environment is a question for the user. A search on "barrowman stability calculations" resulted in some info, among them:

https://v-serv.com/vcp/

https://my.execpc.com/~culp/rockets/Barrowman.html RIP


So RPM, what were you using and what do you want ?

Thanks for resuscitating this thread Steve. Allows me to correct a dead link.

https://www.rocketmime.com/rockets/Barrowman.html

 

[SteveNeill]

You bet. I was up late playing with this easy to use intuitive program. It's a dream come true for someone returning to rockets and needing to check my 10 year old builds before I fly them. Better yet to help in future designs I have planned.

 

[SteveNeill]

And thanks for reposting the Barrowman link! This should be printed out poster size for the shop.

 

[BeyondEarth]

For non-standard components and quick checks, you can also use the CP cardboard cut-out method.
https://www.apogeerockets.com/education/downloads/Newsletter18.pdf