Step 4: Make the Rotor Shaft

-Mark the length of the steel rotor shaft.  Mark it 1 inch shorter than the center tube (the center tube should be 2" longer than the combustion chamber) and put marks on the shaft where the center tube will be cut. Cut it at the length you marked. Grind the last inch or so to a point.

-Shave the middle part of the shaft that will be between the bearings down to 1/4" to take off some weight. Then drill a 1/4 inch diameter hole about 1 inch deep into the end of the shaft in the front.

-Put the rest of the 1/2 inch diameter steel rod in the lathe and take a 3/4 inch long section at the end of it down to just under 1/4 inch in diameter. This will be a pin to slide into the hole in the front of the shaft. Then cut the rod off 2 inches behind the pin you just made and smooth off the end. If you are using an electric starter, drill a hole into the end of this piece that will accept the motor's rotor shaft. If not then you can grind the front of this piece to a point.
<p>Oh,I think it is great,</p><p>This is my turbine engine</p><p>http://www.instructables.com/id/Turbine-engine-2/</p>
<p>First I don't see how this can work with the kind of bearings used. The shaft needs to be on bearings relative to the combustion chamber a long shaft on each end protruding out of the main engine chambers is one way to do that the other is to have small ones internally and a way to hold the internal bearings outer race in some way that allows the input and output gases to pass through the engine.</p><p> <br>Suggestions: </p><p>Up scale because that will reduce the precision needed for a smaller scale prototype. If this is going to work at high rpm's you should give some thought to making it as balanced as possible. </p><p>Don't use a fan for starting torque because when you take it away the turbojet will quickly have different input/output air flow. US a DC motor instead. That way you can gradually remove the extra power needed for startup by gradually reducing the power to the motor using a rheostat or combo transistor rheostat control or silicon rectifier control.</p><p>Use a small universal joint or a gears with spokes on the turbo shaft to connect the motor to the turbo shaft. This will help reduce any lateral drag on the bearings. You could also use two or three motors instead of one on shaft gear to further reduce lateral drag. If you use three motors properly mounted you can get rid of the front bearing. </p><p>Reduce the size of the spark plug igniters. That will reduce drag in the combustion chamber. Use High Voltage wire from an old CRT TV or Monitor drill a small hole in the Combustion Chamber and inset the wire. Use epoxy to both hold and insulate the wire or use or make a small piece of porcelain to insert the wire threw and then epoxy. You will want to a make this as close to the fuel injector as possible. If you palace the igniter wire up stream and bent down stream toward the fuel injector that should be the best spot for re ignition should the turbo fan flame out. </p><p>Replace the piezoelectric sparkers with a continuous or almost continuous high voltage spark from automotive ignition or gas appliance electric ignitions. This will allow re light the fuel air mixture quickly should you flame out. </p><p> I don't think you can have good air/fuel ratio control with a valve from a propane torch. If the valve is electrically controlled instead of mechanically controlled that opens the way to using an oxygen sensor in a feedback circuit to control fuel input. </p>
Not yet for pics, I'm still putting the materials together and drawing it out - its to be used at the end of a long string of piped water to power a drill to put down a geothermal well - think a 100' of 1 1/4&quot; polyprop pipe ending in maybe a 2' piece of 3&quot; pvc pipe with a row of axial blades turning on a shaft inside with water pumped in at maybe 50 psi/ 50 gpm at one end with the blades driving a 4&quot; dia earth bit at the outlet of the 3&quot; pipe - this is all a maybe! but hell I now have an easy way to make a bunch of blades. Jets have static blades that deflect the flow back to a better angle for each seceding row of rotary blades but I'm hoping I don't have to do that. I'll send a pic when I get there
A geothermal well, what is that exactly? One that is deep enough to never freeze or something? I am just hoping you are not actually trying to put a geothermal power plant in your yard! But if you do then that is very ambitious of you. <br> <br>You will need to have some stator blades to hold the axel, so why not put them between each turbine blade?
Hello Jaycub and congratulations on a great attempt at an axial flow jet. One of the comments added that its really difficult to come up with a working axial compressor.<br> I think you did well with the tools you had - learning to tig weld would be a great help to you.<br> I had been looking for a week for a simple way to build an axial water turbine short of CNC machining - the blades had me stumped til I came across your instructible - it gave me your idea on how to make the blades simply - so thanks!!
Cool, I'm glad there was some benefit to this other than just what I learned. Do you have pictures of your water turbine? <br> <br>I can tig weld but it has been a couple years now since I've done it. But since this instructable I purchased a cheap flux wire welder, and I have an oxyhydrogen torch partway made.
You have done an excellent job, it looks like you you put a quite decent amount of work into this bit of engineering. You have got some inventors potential :)
. Your design unfortunately has zero chance of working. Even if the compressor stage was perfectly designed and the combustor correctly dimensioned you can not get enough pressure rise in the compressor to over come the drag of the bearings etc. Axial Gas turbines need multiple compressor blades stacked with stators and the blades need to be aerodynamically perfect and unfortunately this gets worse the smaller the turbine is.<br><br>Thumbs up for trying but by your lack of responses recently I guess you have found it won't spin up.<br>Don't give up, just take a step back. You need to go to a gas turbine forum and talk to experienced builders and perhaps start with a bigger engine with a centrifugal compressor and an axial exhaust turbine. Get your eye in. and slowly sneak up on a pure axial, it's a monster of a mission
I didn't realy expect it to work, at least not very well. I just wanted something that would look cool to submit to the epilog challenge and the makerbot contest. Thanks for the advice.
Hi Jaycub<br>I am agree with marksteamnz as i tried the project and found it not working. to get it working i increase the size of compressor so that more intake air can flow into combustion chamber. and this worked. also i opened the ball bearing covers and washed the excess grease which make them run smoother.
You actually got it running with a bigger compressor?
Yes it worked and runs fine.. but now trying to add a turbo prop to make cooler.
You need to clarify. You can not have got this design to run with a bigger axial fan compressor. With out many compressor stages of vastly improved sophistication the design will not run. As far as I can determine no amateur builder had ever got a home made axial turbine to run certainly not in the small sizes this instructable refers to. If you have used a centrifugal fan that is quite possible but that is not what is under discussion. Pictures or a youtube video would help clear up the confusion
Awesome! I'll have to re-work mine to have a better compressor. Can you post a video on youtube or some pictures?<br><br>Is there anything else you changed from what I show on this intructable that I would need to change to make mine work?
Argh! Don't cut the tubing with tin snips! Use a pipe cutting tool, the one that clamps down and spins around.
Hello Jaycub.. Great work ... your way of design is very simple and will definately runs.. I am waiting for your last steps.. I have already build till the step discribed.. <br><br>Please get well soon and help us to finish this project.
Thanks. I can't guarantee it will work but I think it will. The only steps left are to braze the back of the combustion chamber to the center tube, and attatch the fuel lines ans igniter wires. You could be done before me! Be carefull if you test it. <br> <br>I am already well but it is spring break so I can't use the high school's welders for a week.
I got most of the parts to build the engine. It sure would be nice to get the plans on how to finish it.
I'm working on it.
Video? This work deserves it.
There will be a video by the end of the week if everything works out as planned.
OK, thanks. Please, then send me a PM.
Hi nice job, is there more? As how it is the tube attached to the pipe ? Could the blades be silver soldered in place? All of that wire does not look like it will be balanced to well.
This is not quite finnished, I had to post it like this to enter it in the epilog challenge. I have pretty sick since Friday. This instructable should be finnished within the next few days.
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