Home made rocket engine

[JonClarke]

And a view the other way, into the combustion chamber.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

An outside view of the engine head.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[bobw]

Those last pictures leave me with more questions than answers. How about a picture containing all three with the parts labeled? I'll take a wild guess.<br /><br />It looks like the fuel goes in the tubes sticking out of the combustion chamber, the way they are angled will produce a swirl pattern clockwise as we look down on the bolts.<br /><br />That would leave the two parallel pipes on the head for oxygen. Probably the curved "Y" pipe with the solenoids for that, too.<br /><br />Is the small hole in the center of the head for a pressure sensor and the tube at the extreme end of the combustion chamber (in the photo from your second post)for a thermocouple? Also, this is a dumb one, but do the nuts get removed from the bolts on the combustion chamber prior to assembly or is the center ring of the head tall enough to seal the joint?<br /><br />That thing looks like fun. Thanks for the photos. I wish I knew enough about rocket motors to know what I am looking at. Where's the spark plug? <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

I just post the pictures, I didn't build the thing! <img src="/images/icons/smile.gif" /> But I will forward your questions.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[bobw]

<font color="yellow">I didn't build the thing!</font><br /><br />Lucky you. The inside of the combustion chamber looks like it is made of about a million pieces!<br /><br />I was thinking the pipes on the combustion chamber would be for cooling but if you count the 12:00 bolt, then between the third and fourth bolt clockwise it looks like an oval hole on the inside of the flange that lines up with the pipe coming out by the 12:00 bolt.<br /> <div class="Discussion_UserSignature"> </div>

 

[racer7]

To those that find this interesting, you need to check out the news reports at Armadillo Aerospace if you haven't already. Pretty much take the project in the OP and rachet it up several notches. Not to take anything away from the people in the OP of course. Cool stuff.

 

[trailrider]

DEFINITELY keep us updated! And post as many photos as you have bandwidth! BTW, I'm not up on some of the old measurements...is a "bar" = 1 atmosphere, i.e., 14.7 psi? Or am I off by an order of magnitude? I seem to recall that 1000 milibars = 1 std. atm at sea level, but, again, it's been a loooong time.<br /><br />Also, could you have them show some dimensions on the "beast"? For example, what's the diameter of the throat? Since we see no signs of an igniter in the injector, am I presuming correctly that the igniter is inserted through the nozzle or at least has a jet of flame to ignite the propellants? I worked on a laboratory rocket that ran on GO2/CH4 (gox/methane) or sewer gas. It had a glowplug for an igniter, but the rocket only had 1 lbf thrust.<br /><br />Best of luck to your friend! Godspeed Atlantis!<br /><br />Ad Luna! Ad Ares! Ad Astra!

 

[spacester]

<font color="yellow">I'm not up on some of the old measurements...</font>According to www.convertit.com, 1.0 bar = 0.986923 atm<br /><br />What a great little rocket motor! With a development program planned and all the knowledge here, this could turn into a truly great thread. I'm sure updates will be eagerly awaited and much appreciated by many. Thanks!<br /> <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

I will ask for dimensions. I am not sure how it was started except it was done remotely from a control position 30 metres away via a lap top, which was also intended to record data (there were some problems with the sensors, I understand, so this did not pan out as well as planned). So I assume that ignition was electrical.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

Kerosene and nitrogen valves <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

The control trench <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[bobw]

racer7 <br />Interesting stuff at your link. It was nice of Armadillo to post those pictures. I especially liked the water test ones.<br /><br />Like Rybanis, this whole thread makes me want to melt something myself. Trailrider wrote about building a rocket with 1 lbf thrust. Kerosene, an air compressor and one of those oxygen tanks for a cutting torch is within my budget for a small one but leaves me wondering... <br /><br />Is there a definition for "rocket motor"? Is it the constriction at the nozzle which accelerates the gas? The existence of above ambient pressure in the combustion chamber? There must be a difference between a 1 lbf rocket and an oxyacetylene torch turned up full blast.<br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

Side view of the engine while being set up.<br /><br /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

A rocket engine uses liquids, a rocket motor solids. I am not sure what you call a hybrid <img src="/images/icons/smile.gif" /><br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[bobw]

So if I build a little thing and put a strain gauge on the test stand I can call it a rocket engine if it generates thrust? <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

Yep! <img src="/images/icons/smile.gif" /> Attached is a photo of the load cell that provided an analogue measure of thrust. <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[earth_bound_misfit]

Is that a modified bottle jack? <div class="Discussion_UserSignature"> <p> </p><p> </p><p>----------------------------------------------------------------- </p><p>Wanna see this site looking like the old SDC uplink?</p><p>Go here to see how: <strong>SDC Eye saver </strong>  </p> </div>

 

[bobw]

It is a great idea with the electrical pressure transducer on the tee with the dial gauge. <div class="Discussion_UserSignature"> </div>

 

[spacester]

ROTFLMAO!<br /><br />That is awesome! I've used bottle jacks for many things - they are a complete, self-contained hand-powered hydraulic system and are available in a wide selection and mass produced. But never as a load cell! That's effing brilliant! This guy must be a rocket scientist or something. <img src="/images/icons/laugh.gif" /><br /> <div class="Discussion_UserSignature"> </div>

 

[rocketman5000]

I love it too. For a do it yourself test stand I can't think of a more accurate device. Even has the ability for a digital readout. much easier than the typical spring scale.

 

[rybanis]

The area looks kind of dry and grassy, you must have to be careful when its run! <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

It's proably the biggest safety concern. Obviously the engine can't be tested during a summer fire ban and there has to to fire fighting equipment to hand even in spring.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[nyarlathotep]

Well, it's winter, so that helps. I'm sure the Rural Fire Service was knocking back a slab just out of frame. You don't light a candle that big without a tanker.

 

[JonClarke]

I caught up with my friend last week end and have a few more pictures and info to share. He also gave a paper on his engine at the Australian Mars Society Conference.<br /><br />First some details.<br /><br />The aim of the engine was as a learning tool intended to develop an understanding of the technical and practical issues in rocket engine design and testing. To this end the engine needed to be large enough to gain useful experience and be a reliable benchmark for future scaling of the elements. thus the engine was made as large as possible.<br /><br />It had a throat diameter of 60 mm & 120 mm chamber ID chosen as fitted in the author’s lath. <br /><br />Maximum operating pressure 10 bar (150 psi) enabled the<br />purchase of cheap off the shelf valves. <br /><br />He chose kerosene and oxygen gas mix due to simplicity and ease of supply. Propellants were fed using tank pressure, eliminating pumps. He chose mild steel as a construction material to keep the cost down. Mild steel is not a good choice for engines. but is good enough. he also used broze brazing to fill fill the gaps.<br /><br />The engine test site attributes: <br />Location within 30 minutes drive from home;<br />Location to be distant from habitation.<br /> to minimize noise impact and explosion damage.<br />Water to quench noise and fires;<br />Low cost rent;<br />Electrical power available. <br /><br />He adopted a horizontally fired engine test rig to minimize concrete mass and avoiding flame direction issues.<br /><br />The test rig has ‘3.5 tonne’ thrust engine capacity - the largest practical structure with foundations that could<br />be made by the team.<br /><br />The picture shows the engine as it is at present, partly disassembled with the head off and the cable winding largely removed. My friend is reboring the fuel injector holes to improve performance.<br /><br />Jon<br /><br /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

The engine was controlled from a laptop using ‘Visual Basic’ Software.<br /><br />The Ignition lighter, O2 in-feed valves Kerosene in-feed valves and N2 purge valve was controlled sequentially.<br /><br />In essence O2 is fed into the combustion chamber first before the kerosene fuel to prevent a ‘hard start’ or explosion. <br /><br />Shut down was automatic (with an emergency stop override) that did the above operations in reverse.<br /><br />The lighter worked by heating a nickel wire through a 9 volt curent to incandescence. <br /><br />The photo shows the lap top control screen.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>