Giant "thermalpulse" chinese valveless LIQUID CARB

[Eric]

With the recent success of finally being able to provide enough fuel to the giant Chinese Valveless to get it to run, and the articles about the original Chinese Valveless liquid carburetion I decided that It was finally warm enough out to screw around with making a liquid fuel system for it.

First I took a milk jug and filled it with water, ran a brass "fuel" line and bent it at a 90 degree angle to simulate the perpendicular fuel injector. I got the engine running on propane and stuck the injector in to the intake at various positions to see if it would draw fuel.

To my total surprise it would draw water up at an alarming rate even over 1' elevation. The engine still ran with massive flow of water entering the engine, and a huge stream of condensing water vapor shoots from the back of the engine. I would imagine some power could be gained by this, but that will be for another topic.

I moved the injector probe in and out of the intake finding the point of lowest pressure. It was a little surprising how much the gas velocity varied in the intake at different lengths, giving some real world data of how the standing waves may be. Once I found the spot that draws the fuel the best, I quick marked it and turned off the engine.

After drilling a hole in this spot I made a stainless fuel injector to be inserted into the engine perpendicular to the intake. I turned on the propane and gave it a quick buzz and fuel rushed through the pipe and into the engine much faster than the dynajet ever could, and it was pulling it from about 10" below. In fact it was pulling fuel so well that I had to put a pair of vice grips on the fuel line and use it as a crude needle valve, for full power the vice grips need only to be cracked open slightly by the twist of the adjustment knob.

I got it running on propane and kerosene at the same time, slowly turning down the propane and increasing the kero until the engine was running entirely on liquid fuel. Unfortunately the fuel sprays out of the engine during the exhaust phase, and forms a huge white cloud of vapor. I have a feeling if I put the injector back farther it would not pull fuel as well, but probably would not eject it as much either. Either way pure carburetion will be obsolete when I perfect the new system, the tests proved it will work quite well. I will post the video once I get some supper and get it compressed to size. The engine runs really hot on kerosene, and puts out a hell of a lot more power.

The new system injects the fuel almost into the combustion chamber, with a pressure tube at the point of highest gas speed in the intake. The injector is at a low pressure point, and the pressure tube is situated facing into the exhaust, the difference between the two provide enough pressure to use proper fuel spray nozzles, and should entirely eliminate wasted fuel. Today was a big success, now that its actually getting warmer things will really start to get exciting around here, maybe this weekend I can post some of the big engines. Here is a quick sketch of the new and improved pressurized system with no need for one way valves or anything of the sort..

Eric

[larry cottrill]

Eric -

Absolutely beautiful.

Just the way I like it - utterly simple without being obvious.

Great work!

L Cottrill

[Eric]

Ok heres the video. I should mention that the fuel was a mix, about 80% methanol 20% kerosene. Notice how the cloud behind the engine changes shape and seems to repeat at extreme speed as if it were somehow affected by the pressure swings around the engine, or it could just be pure chaos. The new fuel system should also eliminate the cloud entirely, and save fuel.

Eric

[steve]

HOLY CRAP!!

if that dosn't attract the fire department, nothing will!

I really want to try that with a linear FWE now. Could you send some detailed photos of the exact fuel probe location? (to give me an idea of where to start)

BTW, I bet that engine would look spectacular at night with those huge cloude backlit by flame and glowing steel (hint hint)

[skyfrog]

I have seen your video it seems that you let the engine run on gaseous fuel say propane a while then turn on the throttle valve of the liquid fuel to let it take over the fueling, so it is rely on gaseous fuel still. If it could start all by itself then it would be perfect.

To use such a fueling system on a gas turbine would be possible as starter motor drives the compressor, then use this pressurized air to squeeze the liquid fuel say kerosine to injet into the combustor. All we need is electric power to start the engine.

[Mike Everman]

Eric, you little b*****d! You beat me to trying this by a day! LOL. I have to work this weekend, anyway... I'm going to try an LH type. Nice work. Doubt I'd see that vapor in 65 degree weather here. Too tired to look it up, but is the exhaust of kerosene more full of water than propane?

here's a plot of every 25mm in a 150mm long intake. the royal blue is 25mm in, the teal color is the joint with the CC. was your magic spot in the inner or outer half of the CC?

[Mark]

That was very macho.
Mark

[Mark]

I wonder if there is a method to introduce fuel deeper inside the engine? Maybe some sort of aerodynamic winglet placed in the combustion chamber would form an eddy of low pressure or just lower than the average ambient and helped along with the positive pressure bleed as already being shown to work.
I remember my tiny Logan developing a hammer effect in the fuel line if I made it too long, but on the other hand, the speedy up and down reving was quite comic. The seizure effect is the funniest thing to hear.
Again, neat stuff Eric.
Mark

[Mark]

I was thinking once the engine started heating up, you could boil some of the fuel and use that pressure to drive the fuel into the deeper recesses of the engine. Tricky to do but not insurmountable. The more this is explored, the more it seems to me the pulsejet starts to approach a rocket in philosophy. Why even a Gluhareff uses the heat of the engine to drive the fuel feed reaction.
And as Larry brought up, if you have compressed air, your engine doesn't have to run, because you can make it run. I have an early document reported by William Schubert where his Schubert shaped engine only runs with forced air, developing a meager 10.5 pounds of thrust at 340 MPH and 13.5 pounds of thrust at 420 MPH. At 480 MPH, it "would not resonate properly." He used propane for fuel and a ram air pipe situated a few feet from the intake to simulate forward air speed. "Air pressure, of course, is required for this motor's operation, but would be readily available in applications to the aircraft already traveling at high speeds." Humble beginnings!
Mark

[Eric]

wtf, i thought i wrote a pretty big post answering everyones questions and stuff but now its gone!? I know I wasnt imagining it..... I think.

Eric

[Mike Everman]

Yeah, I read that post. WTF indeed.

You know I meant b*****d in the most endearing way, of course!

[Mark]

After a second viewing of the video Eric, I have to say it carefully shows all the steps you went through, and a nice touch killing the engine before it drank all the fuel. Keen.
Mark

[Eric]

I know Mike, I took it as a compliment :)

Mark, I actually didnt shut off the engine, It was only a total coincidence that the engine shut off when it did. There was only a little dribble of fuel left in the can, it wasnt totally full to begin with though. The smoke really shows how much wind the engine produces, there was enough flow to keep pushing the smoke away for quite a while.

Anyone know where the heck a post could dissapear to? Its as if the black hole in my closet has somehow transfered to the pulse-jets server.

Eric

[Mark]

Well Eric, I saw you toying with the vise grips and the engine stopped. What was I to think? I really thought your liquid fuel system sucked. Or as Mike would say, I meant that in an endearing sort of way. ha ha
Or as Luc would say, "he he." Ah, the differences a border makes.
Mark

[Eric]

Yea Mark,
The fuel system sucks, and the engine blows, so I must be doing something right. :)

Im going to try to rewrite the message that dissapeared.

Skyfrog,
The engine can be started on liquid fuel, but you need 3 hands to do it, when it starts up for a second the air gun gets blown out and screws things up while you are trying to adjust the fuel flow with the 3rd hand you dont have. Until I get a starting air probe on there it will be difficult to do by hand.

Steve,
I live in the middle of nowhere, you could set off nuclear weapons without the fire department noticing. For the FWE you would have to test the pressure in the intake and find the best spot, just make a probe with a 90 degree bend that you can stick into the intake and have a rubber hose running into a container with water to test the flow.

Ben,
Hopefully the fuel wont be ejected when its injected almost into the CC.

I know there was a lot more but oh well.

Eric