My Homemade Propane+O2 Rocket Engine Design

[MaverickSawyer]

The fingerprints left behind in the combustion chamber by your handling it are what we are concerned about. Handling the construction with gloves should remove most of that risk, and a thorough cleaning after completion might be in order to take care of the rest.

 

[Veterok]

The fingerprints left behind in the combustion chamber by your handling it are what we are concerned about. Handling the construction with gloves should remove most of that risk, and a thorough cleaning after completion might be in order to take care of the rest.

Non-rocket scientist here. Why would some oils being burned off the chamber walls during firing be a concern?

 

[Urwumpe]

Non-rocket scientist here. Why would some oils being burned off the chamber walls during firing be a concern?

It isn't just the rocket chamber but practically all those parts, in which oxygen, temperature and pressure are in the right mixture to permit such contaminations to start a fire. Imagine for example a valve that is eroded and damaged by such combustions. Or a seal, that gets temperatures that it can not withstand.

Next, even at much lower temperatures, fat and oxygen can result in nasty corrosive acids. You could also have moisture in a cryogen line, for example in real rockets, that plugs valves and pipes. In liquid oxygen pumps, cavitation can actually result in ice forming on the pump impeller.

Finally, once you have the temperatures high enough at the surface eroded, even the most oxygen resistant metal will eventually start to burn itself. The Russians mastered oxygen rich preburner technology, but that does not mean that their engines are oxygen fire-proof, it simply has different temperature limits that can be prevented.

 

[Kaito]

Behold, the final design: http://dl.dropbox.com/u/50093375/Engine3.jpg

Unless there is a fundamental flaw, such as this arrangement making a black hole in the center of the sun, I will proceed with this design. I feel it is simple enough to do, with very few places for error. I might make the chamber a nozzle, as RisingFury has suggested.

The brown stick in the middle is a punk that I'll use as my ignition source. The streams of propellants will directly intersect with this (there may be a cluster of them), almost ensuring a proper start. The black cylinder is just wire holding up the punk.

As far as propellant management goes, Im going to install a ball valve (properly cleaned with solvent and acetone) along the line headed from the storage container to the engine. My plan is to turn on the O2 first (to get the punk really hot), then less than a second later, introduce the propane. I plan on having a friend/family member time the burn of the engine, so I dont get "distracted" by the pretty flame :lol:

Hope you all like this

 

[RGClark]

Much better choice, but you have to remember that it is self-pressurizing at a fairly high steam pressure.

Good point. As Scaled Composites learned, nitrous under some conditions can be explosive.


Bob Clark

 

[Urwumpe]

Good point. As Scaled Composites learned, nitrous under some conditions can be explosive.

Exactly, it isn't harmless, but for amateurs easier to handle than pure oxygen. The car tuning scene already has a lot of "trail-and-error" experience what you can do and use for working with it, and what you should better not do for the sake of your health.

 

[Loru]

Also I'd go for advice to profesional welder that works with O2. They've got quite good experience with Fuel/O2 burning and know details about valves you may need for your rocket.

http://en.wikipedia.org/wiki/Oxy-fuel_welding_and_cutting

 

[Urwumpe]

I would also recommend downloading the latest edition of the NASA Systems Engineering Handbook, because, while it aims at complete spacecraft missions as its target, it explains a lot of about engineering project management and quality assurance, that can sure save you a lot of money and reduce the risk of your fingers reaching first cosmic velocity in the process.

[ame="http://en.wikipedia.org/wiki/Systems_engineering"]Systems engineering - Wikipedia, the free encyclopedia[/ame]

http://education.ksc.nasa.gov/esmdspacegrant/Documents/NASA SP-2007-6105 Rev 1 Final 31Dec2007.pdf

 

[mike65401]

Have you considered a high pressure water mist injector? This would help cooling as well as add to the thrust as the water was vaporized.