A Pile of Steel & Gas

[Swigert]

I used to be highly into model rocketry. I had always wondered how difficult it would be to make a model rocket without a kit or factory-produced parts; how difficult it would be to make a homemade rocket.

Myself, I don't think it would be very hard at all. The most difficult thing is to make the body of the spacecraft durable enough so that if it smacks something during the flight, it won't be severely damaged. I was thinking that propane would be a great fuel because it is available almost anywhere from Wal-Mart to your local gas station and would cost a lot cheaper, at anywhere from $50-$120 for a nicely sized canister than a high-grade fuel at the same size. I doubt that one could build an engine capable of producing enough thrust to lift a 20lb tank of gas, however, so maybe it wouldn't work so well. :lol:

Perhaps exert some of the fuel from the tank to a smaller, lighter canister would be a better idea.:yes:

 

[Urwumpe]

Wouldn't it be simpler to start with solid propellants first, which are a known technology at that scale and fired a few billion times per year...

 

[Ghostrider]

Unless you know what you're doing, be massively careful. I've blown up my fair share of stuff back in my teenage years and even then I always did it under supervision.

As a rule of thumb, if you think anything isn't difficult when you have no practical experience on it, then you're wrong. Very wrong.

The most difficult thing is not making the body of the rocket, it is containing the explosion that will happen inside the combustion chamber in order to produce thrust. Then you have the guidance problem.

And then Homeland Security will probably send in a flight of B-52s to carpet bomb your home because they've heard there might be a terrorist in it, and your whole neighborhood so they won't be killed by the terrorist they just bombed.

 

[Swigert]

I wasn't planning anything fortunately...The last thing I want is the police to show up to my door responding to the claim of a canister of propane exploding! :rofl:

But yeah, it would be easier to make solid fuel rather than liquid/gas.

 

[Pablo49]

I was thinking that propane would be a great fuel because it is available almost anywhere from Wal-Mart to your local gas station and would cost a lot cheaper, at anywhere from $50-$120 for a nicely sized canister than a high-grade fuel at the same size.

Probably a totally fine idea, bro

​

 

[Ghostrider]

Rocket candy is a fine solid propellant for, er, rockets. Start with it. If you want to build a propane-fueled rocket, build a SMALL engine first and test it somewhere it won't blow up the 'hood. Use a remote control. You don't like it when propane goes BOOM.

 

[Urwumpe]

Rocket candy is a fine solid propellant for, er, rockets. Start with it. If you want to build a propane-fueled rocket, build a SMALL engine first and test it somewhere it won't blow up the 'hood. Use a remote control. You don't like it when propane goes BOOM.

And especially read about the wisdom of the elders. At least those elders, who discovered phenomena like screeching and wrote warnings for the pilots to detect it as soon as you can still shut the engine down or eject, and for engineers to provoke conditions that can lead to screeching and how to make engines immune to it.

You can do everything right from a purely static point of view - your structure can hold the static pressure and your pumps and valves are designed to keep a static firing condition controlled. And then the dynamic behaviour breaks your neck.

So don't commit old errors again. Learn about the errors that had already been done and find your own errors to commit.

(That is all why I didn't yet found my own spacecraft engine manufacture - while I really dream of such a business, the investments into the needed testing gear and safety are huge if you also want to work professional)

If you want to start learning:

http://ftp.rta.nato.int/public/PubFullText/RTO/AG/RTO-AG-AVT-039/AG-AVT-039-01.pdf

(Don't worry, you won't get visited by men in black for reading NATO science bulletins)

 

[Swigert]

Or better yet, I could go to an empty place, like a small desert...But that may be tricky in Illinois.

 

[BruceJohnJennerLawso]

Probably a totally fine idea, bro

​

mmhmm :yes:

One of my relatives out in the country near Guelph has a fairly large propane tank (2-3 m long ?) in the backyard for cooking and heating. He mentioned that back in the fifties a similar tank was supposed to have ruptured and destroyed a good chunk of a small town. I wouldn't mess around with propane.

Rocket candy and other solid fuels make a lot more sense for you, although you do need to be somewhat careful in preparing and handling any of those too.

Remember, lost time wont matter much, lost appendages will.

Best of luck