Moon Grain Build for High Altitude Second Stage

[JoshAllen]

Hi,

I'm new to the forums, but I'm working on a project on which we are trying to build a two stage to hit a very high altitude. The first stage is going to be a commercial motor and the second is a research motor. My colleagues and I feel as though a moon grain is the best option for the long burn time, but we are concerned about core size and erosive burning. Does anyone have any tips or tricks?

We're working with a 76 mm outer diameter, 70 mm inner diameter, upwards of 30 to 36 inches long and packing as much total Isp as possible into this thing.

 

[rharshberger]

First of all welcome to TRF. Research/EX motors are only discussed in depth in the Restricted Research, the main forum is mostly commercial motors. Also to be more helpful a new member asking about a complex project/EX motors really needs to provide more information. If this is a college project that is good to know as well.

 

[JoshAllen]

Hey Rich, Thanks for the welcome. It is for a college project. I have been researching motors for a little while now and we are about to move into the testing phase. I know that there is a big issue with erosive burning for motors that have a high length / diameter ratio and I've found through research and simulation that creating a transient or translating core from larger near the nozzle to smaller at the fwd end may help slightly.

Can I get access to the restricted research section?

 

[tim cubbedge]

They have certain criteria to access that forum. You must be US citizen, Level 2 or higher and over 18 and I think I read something about being a senior member. Need to contact one of the Admins.

 

[Nytrunner]

Your best bet may be to contact a Tripoli club in your state and try and introduce your project to them formally.

 

[RocketFeller]

Your best bet may be to contact a Tripoli club in your state and try and introduce your project to them formally.

This is probably the best thing you can do. College teams attend the OROC (Oregon Rocketry) meetings almost every month and get lots of face-to-face advice from experienced people.

 

[djs]

Can you tell us where you are located? There might be someone nearby on the forum that can support you (and your college).

 

[JoshAllen]

Cool, thank you. I think I'll do that. Managed to get my level two a few weeks ago.

We have definitely been in contact with the OROC guys. They are awesome and helped our club get over twenty level ones the weekend of the 12th.

 

[Incongruent]

They have certain criteria to access that forum. You must be US citizen, Level 2 or higher and over 18 and I think I read something about being a senior member. Need to contact one of the Admins.

There's instructions if you click on the link in the research forum's description on sending an email for access.

I'll post it here:
https://www.rocketryforum.com/showthread.php?17943-Research-Forum-Access