multiple bore holes?

[Tristan]

Hello everyone this is my first post so please excuse and obvious mistakes i make as i am still new to rocketry (9 months) anyways...

I was wondering if there would be any benefits to adding more than 1 bore hole in a rocket motor would increase the speed that the motor burns at? I've done some testing and it did show that the fuel was burned faster but that might just be the removed fuel...

 

[rfjustin]

Welcome to TRF... and good luck to you.

 

[Steve Shannon]

Hello everyone this is my first post so please excuse and obvious mistakes i make as i am still new to rocketry (9 months) anyways...

I was wondering if there would be any benefits to adding more than 1 bore hole in a rocket motor would increase the speed that the motor burns at? I've done some testing and it did show that the fuel was burned faster but that might just be the removed fuel...

Modifying a motor by drilling additional cores can cause a motor to burn faster, right up until the case bursts explosively due to the extra pressure. Anything you do that increases surface area will cause the motor to burn in a shorter time AND raise pressure inside the motor. Without fully understanding the relationship of surface area, burn time, and internal pressure you’re flirting with disaster and if you’re ignorant of safe test practices you’re also possibly placing your health at risk. I would strongly urge you to find a local Tripoli Prefecture which has members who participate in research Rocketry and learn from them. It can be a fascinating facet of our hobby.
Also, discussion of modifications to motors is limited to a special area of TRF.

 

[heada]

Burn rate is related to surface area. Increase the surface area and you increase the burn rate (all else being the same). Surface area is not the only factor in controlling burn rate. This is an advanced topic and if you want to talk about details, you'll probably need to join the restricted "research" section of this forum.

Or just read what Steve wrote, its better than my response.

 

[tim cubbedge]

Discussion of motor modifications is limited to research forum. Access is granted if you meet the requirements listed in this thread:
https://www.rocketryforum.com/threads/research-forum-access.17943/

 

[OverTheTop]

If you have extra holes there is also the possibility of a piece of unsupported propellant becoming separated from the main bulk and then blocking the nozzle. Burn rate is exponentially proportional to pressure, so a CATO is the result.