Reddit mentions of Rocket Propulsion Elements, 7th Edition

A few things should be noted in case people are looking for more information:

• The throat area sets the mass flow rate (for a given chamber pressure). So if you want a certain mass flow rate, this tells you how big or small to make the throat -- you can only shove so much fluid through an opening.
  
  
• The throat-exit area ratio sets the exit Mach number which for a given exit fluid and temperature sets the gas exhaust speed, Ve. The exit fluid properties are set by the combustion process which is determined by the fuel and oxidizer (and lots of other things you can't calculate so easily).
  
  
• This is an IDEAL equation. There are losses associated with underexpansion (see the blue lines that bow out). These are tiny velocity vectors and it amounts to an efficiency term. For easy to build conical nozzles, this efficiency can be pretty low (~80%%) if the nozzle angle is high. This is why bell nozzles are attractive if you can afford to make one.
  
  
• The bell nozzle shape is classically determined by the Method of Characteristics (allowing smooth ideal expansion) but in practice this results in very long (heavy) nozzles. The nozzle shown here is probably a "Rao" Nozzle named for the engineer that developed the approximation to make a nozzle very short and still get as much efficiency as possible.
  
  If you want to really dive head-first into the subject, Rocket Propulsion Elements is the text we all have on our bookshelves.

For a textbook, try and find a copy of Sutton.

NASA's technical reports server will throw more data at you than you can possibly use, but if you can narrow the search terms enough it's useful.

You can google for particular engines or propellant combinations and find reasonable, but not necessarily authoritative data. The best sources will be from the manufacturers.

Please be aware that if you are in the USA, and make too good a simulation, it can fall under the "International Traffic in Arms Regulations" (ITAR) and be export-controlled. Launch to orbit and long range ballistic missiles are essentially the same problem, so any associated technology can be classed as military. "Export" includes passing a copy to a grad student who is not a US citizen, or posting the code on GitHub where anyone can copy it.

It's a bit dumb, because computers, aerodynamics, and Newtonian mechanics are all public, but I'd rather you didn't get in trouble accidentally. When I worked at Boeing, all our good trajectory simulators were export-controlled, and you had to be a US citizen to work in those areas of the company.

I have read that book. I actually did design a simple rocket a long time ago (10 years now, wow!), but never had access to machine tools to build it.

I was using KNO3 sugar fuel, and there was this great website where a guy had all the performance characteristics of the fuel which was helpful. I wish I could remember that site. It was a terrible geocities style site, but the info was good.

The definitive basic text on rocketry if you're interested

the basic idea you can get from wikipedia pages and the first result of google search. this book is also good http://www.amazon.com/Rocket-Propulsion-Elements-7th-Edition/dp/0471326429

Did something very similar to you OP. Built a rocket engine with KNO3 fuel, and added Fe3O4. Tested small scale with aluminum nozzles, screwed in with three screws 60deg around. The tests resulted in a decent burn, but the aluminum showed sligns signs of melting/shearing at the throat. Not terribly bad, but on a larger scale it would affect flight path quite a bit.

I do think that aluminum would be a good starting point for the nozzle though, then if it doesn't turn out too well, moving to graphite.

Also, check out "Rocket Propulsion Elements." It has fantastic details on solid and liquid propellents, nozzle theory, different analysis process, and tons of other stuff. If you look hard enough you can find a pdf of it on Google.