The Great Ramjet Challenge!!!

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redneck
Posts: 89
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Re: The Great Ramjet Challenge!!!

Post by redneck » Fri Oct 11, 2013 2:13 am

I know this is quite the thread resurrection, but this is such an awesome thread didnt think anybody would mind.

So years have gone past, but I havent forgotten this and still have my engine. I recently dug it out, and fired it up. This time though, I decided to run it off of old used up burnt motor oil. Hottest run I have ever had. Very impressive. I need a better nozzle though. One that can spray oil and not just drip it out. I may hook up a power steering pump to an electric motor to pressurize the fuel. I need a nozzle that can handle this. Any help?
hooowee that was loud! do it again!

redneck
Posts: 89
Joined: Tue Dec 26, 2006 10:32 am

Re: The Great Ramjet Challenge!!!

Post by redneck » Sun Oct 13, 2013 12:17 am

So a quick visit to ace hardware hooked me up with a nice small brass spray nozzle. It has some sort of synthetic O ring in it, but hopefully the fuel flow through it will keep the ring from melting. If I can get a good spray of oil out this thing, the next step in fuel delivery is going to be a power steering pump fuel pump coupled with an electric motor for fuel delivery. Throttling will be done with a valve in the fuel line, or with varying the speed of the pump. I would like to just use a fuel pump but I dont think it can handle the thick oil compared to the thinner than water gas it was designed for.
After the fuel system is worked out, I need to figure out how die a spray pattern to make ( its an adjustable spray nozzle ) and how far to position it into the CC compared to the flame holder. I imagine the closer it is to the flame holder the better. If anybody is reading this forum anymore, any thoughts?
hooowee that was loud! do it again!

redneck
Posts: 89
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Re: The Great Ramjet Challenge!!!

Post by redneck » Sun Oct 13, 2013 3:37 am

Well, I tried the fuel nozzle just doing an outside engine spray test. Just a solid week spray stream. I need more pressure than what my propane pressure system will deliver. So, I will be boosting the pressure with a pump next, soon as I find a suitable motor to power my pump. May use an electric motor, or gas weed eater. I may hook up to my band saw motor, its 1 HP.... Not sure how much power I need but I know I dont have enough yet.

As I think on this, I also believe that the very thin and long fuel delivery line may be reducing the pressure to the engine as well.
hooowee that was loud! do it again!

tufty
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Re: The Great Ramjet Challenge!!!

Post by tufty » Sun Oct 13, 2013 9:04 am

redneck wrote:Well, I tried the fuel nozzle just doing an outside engine spray test. Just a solid week spray stream. I need more pressure than what my propane pressure system will deliver. So, I will be boosting the pressure with a pump next, soon as I find a suitable motor to power my pump. May use an electric motor, or gas weed eater. I may hook up to my band saw motor, its 1 HP.... Not sure how much power I need but I know I dont have enough yet.
There's 2 things you need to consider. Pressure and flow rate. Oil burner nozzles flow rates are usually given for 10 bar of pressure, and, depending on nozzle, you're probably looking at between 3 and 15 kilos/hr of flow (this really isn't very much). You really need to know the specifications for your nozzle.
redneck wrote:As I think on this, I also believe that the very thin and long fuel delivery line may be reducing the pressure to the engine as well.
Nah, pressure will be the same regardless of line length or diameter (look at the brake lines on your car, which are dealing with hundreds of bar in pressure), but it /will/ affect flow rate, which is affected by both line diameter and viscosity. If you can't get enough flow through your pump / line, you will get a trickle out of the other end.

As far as pumps go, a power steering pump should do the trick - hell, even a fridge compressor provides ample pressure (I get around 25 bar from my danfoss unit, and you don't have to worry about external motors 'n' stuff) *if* you can get the flow you need, especially with viscous oils (you'll be lucky to get more than 1cfm of diesel through a fridge compressor, I dread to think how low it would go with the sort of sludge that drops into your oil drain pan).

I'd suggest cutting your oil with diesel and having a go with that.

redneck
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Re: The Great Ramjet Challenge!!!

Post by redneck » Sun Oct 13, 2013 4:57 pm

Thank you for the reply tufty. If I had thought on it a little harder I would have remembered that pressure in a hydraulic system is equal through all components. So I am looking at a flow rate problem because I am using a skinny metal line to push the fuel to the engine. So I need a larger line for better flow rate. Thanks for the tip there.

As to the specs of my nozzle, I dont know, I was just hoping to boost pressure and flow rate until I had a nice spray out of it. Then I was going to modify the combustion chamber and flame holder to match the nozzle. Backwards I know, but I am working on unknowns here so....

Using an air conditioning compressor is something I had thought of, but they dont pump liquid, they are designed to pump gas, then right after the pump the gas is cooled into a liquid. I dont think that would work because of that. But that doesnt mean I couldnt use a motor from an old fridge unit to power my power steering pump.

I hadnt thought of cutting the oil with diesel to thin it down. I like that idea and will give it a try. Thanks again for the reply.
hooowee that was loud! do it again!

tufty
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Re: The Great Ramjet Challenge!!!

Post by tufty » Sun Oct 13, 2013 6:55 pm

redneck wrote:Using an air conditioning compressor is something I had thought of, but they dont pump liquid, they are designed to pump gas,
D'oh! My bad. You're right, of course.

What about a cheapo pressure washer? Loads of pressure and flow there, all in a self-contained unit.

redneck
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Re: The Great Ramjet Challenge!!!

Post by redneck » Sun Oct 13, 2013 9:00 pm

Thats an interesting idea.... Have too look into that. Thanks for the idea....
hooowee that was loud! do it again!

redneck
Posts: 89
Joined: Tue Dec 26, 2006 10:32 am

Re: The Great Ramjet Challenge!!!

Post by redneck » Tue Oct 15, 2013 3:10 am

Well I just remembered that I have a skill saw.... Bet i can take the blade and guard off, then mount a pulley and do a belt drive to the skill saw motor....

Wait, wtf is wrong with me, I could use an oil pump off a car and run it up to full speed. They run all the way up too 120 psi and are high flow and small.... I wonder....
hooowee that was loud! do it again!

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