Hybrid O2/styrofoam engine project

[Johansson]

For some time I have been tempted to throw together a small hybrid engine just for fun, and yesterday I spent a few hours making one from some scrap parts I had at home.

With small I mean really small, the fuel grain is no longer than 5 cm so I am not expecting any impressive thrust figures. The oxygen bottle is from a survival kit and I had to remove some parts inside the regulator to increase the flow quite a bit.

I tried it last night and got it to ignite with a sawed off piece from a broom stick as fuel, but since I had used the bottle earlier it ran out of gas just a few seconds later. I have found a new bottle so I will do another test tonight with melted styrofoam as fuel, hoping for some flame and lots of noice! :-)

Pics will come as soon as my brother has returned my camera...

//Anders

[Jim Berquist]

Johansson:

One day I was at the lake and punched hole in the bottom of my aluminum boat...This old boy took a styrofoam cup and placed it in a can. He then added about 20 drops of gasoline. It tuned into a glue/past that we repaired the boat with..

Could you make a grain with that??

Jim

[Johansson]

Damn that´s one hot engine!

After a couple of unimpressive tests with wood and melted styrofoam as fuel I found that a hydraulic rubber hose inside a metal tube fitted perfectly inside the casing, and that did the trick. After 4-5 seconds of full thrust the oxygen feed hose blew off so I quickly shut it down to inspect the damage.

The metal tube was partially melted and the brass nozzle was completely destroyed by the heat, so I will have to make a new nozzle from steel before the next test. The local villagers reported later that it was pretty loud, they are quite used to my noisy experiments by now... ;-)

The ignition source is the crudest possible, a lit match stuck into the exhaust. My guess it that the fuel starts to burn from the bottom and up instead of the opposite, but in this case it doesen´t matter much.

I will take some pics of the damaged parts along with the highly advanced test rig, and hopefully a video of the next run with a full O2 bottle. Oh boy this is fun!

Jim: That is how I melted the styrofoam, but I used acetone instead. I ran it before it had hardened completely so that might be the reason why it didn´t work well.

//Anders

[Jim Berquist]

I was thinking of using one of those wantabee ox bottles used for the propane/ox torch sets. You can by a bottle here for around $12.00. They only hold like 14 oz or so.

Did you use the o2 gas or invert the bottle?


Kiddies Do Not Do This At Home!!

Ox is mean stuff. If your holding a match to start it, and the fuel is consumed, IE the match , the Ox will be more then happy to consider your finger as fuel.

Yep your going to need something better then brass. Even some of the pipe was consumed I bet. After the 4 or 5 second, you had exhosted the fuel and it was using what was available.....The engine....

This one looks fun!

Jim

[Johansson]

Did you use the o2 gas or invert the bottle?

O2 is as far as I know compressed gas, not like nitrous oxide which is liquid under pressure.

Here are the pics, it is obvious that I have spent many hours perfecting this masterpiece... *LOL*

//Anders

[Jim Berquist]

I like it!!

Looks like you may need some way to insulate/isolate the grain from the metal case.

I like that bottle you have. That is for breathing I would assume. The ones I was talking about are for braz and small welding jobs.. When you shake one, you can feel it rolling around inside so I assume it is semi liquid state.

Like a cutting torch. Once the metal is energized, red hot, it becomes fuel and blowes away.

Check this out: http://www.intertlan.com/cohetes/hybrids/fuel.html


Go ahead and laugh! I was thinking of using a Condum inplace of the balloon within a rocket body...

Jim

[Jim Berquist]

I would like to try the same thing using gaseous 02...With a metered jet system.

I want to use a condom in place of the balloon. Go ahead laugh!! Rocket fuselage of compress 02.

Fuel is the issue. It would not weight not! Balloon, Grain, Casing, and Nozzle material. Not!!!

If you did it wrong it could CATO on you! But if it worked it would zoom!

Jim

[marksteamnz]

[quote="berquistj@peoplepc.com"]I like it!!

Looks like you may need some way to insulate/isolate the grain from the metal case.

I like that bottle you have. That is for breathing I would assume. The ones I was talking about are for braz and small welding jobs.. When you shake one, you can feel it rolling around inside so I assume it is semi liquid state.

Sorry Jim you assume wrong you can not liquify oxygen at room temp by compressing it

[Johansson]

I made a new nozzle in mild steel since I didn´t have any stainless at home, lets just say that it wasn´t the brightest idea I´ve had...

After many attempts trying to light it I filled it with alcohol and lit it at the tail, it ran perhaps 0.5 second before the nozzle started to melt giving off a rain of sparks, nice show though. I didn´t take it apart for inspection since it was to hot to handle, but since the nozzle is almost completely gone I guess that the inside is pretty messed up too.

The video will soon be uploaded at http://www.youtube.com/watch?v=ap98ktPWoCo, don´t mind the stupid yelling at the end... ;-)

//Anders

[Jim Berquist]

Markstreamz: Yep your right! No liquid available from the bottle . I bought one today and it feels like something is rolling around it when you slosh it. But no liquid will come out. Thank You!

Johansson: WoooooooooooHooooooo !! from this end too! All of that sparking bee thing? Was that your nozzle or does the rubber hose have metal braiding in it?

A question for you rocket people?

I wonder if you could get the same thrust if you tame down on the 02. The fuel can only utilize so much I would think....

Jim

[Zippiot]

Each fuel burns with a different amount of air, unless you use a common known fuel your best bet is trial and error!!

Liking the fireworks, I would throw one of these together if I didnt honestly believe it would explode.

[Jim Berquist]

I liked the idea of using the balloon. I would not have thought it would provide enough oxidizer.

Zipp: I see more chance of a wild fire then explosion. I know it could happen but with the right precautions I see it safer then solid fuels. LOX would be a different matter. I seen what happened when a Airman was filling breathing tanks on a plane and incurred a spill. Walking around in the tarmac he had fuel, oil, jp4 what not on the soles of his boots. He then stepped in the boiling LOX he spilled and his boot and foot ignited. He lost his foot almost up to the ankle.

Jim