running trouble

Sedgewick · Post by **Sedgewick** » Sat Aug 11, 2007 9:01 pm

All right, all the problems on my pulsejet seem to be worked out now. The engine is making a distinct rumbling sound that is loud enough to hurt my ears without protection, and everything seems to be working great .Except for when I pull my vacuum away which causes the pulsejet to die. Any help would be greatly appreciated thanks.

hagent · Post by **hagent** » Sun Aug 12, 2007 1:45 pm

Hi Sedgewick,

It would greatly help the rest of us if you could upload pictures of your new PJ or some sort of construction drawings.

If you not 100% sure that you PJ has started then it hasn't.

These things are so loud that there is no mistake when they are running.

You mentioned that when you take away the vaccum?

Do you mean that you are using compressed shop air?

Also show us your fuel setup. Most of the time people make the mistake of not give their PJ enough fuel. Make sure there are not restrictions in your fuel setup. Are you using propane? What type of fuel injector are you using?

We need more info.

Welcome to the forum by the way.

Cheers,

Sedgewick · Post by **Sedgewick** » Sun Aug 12, 2007 4:23 pm

Here are two pictures of my pulse jet and setup. I am using propane for the fuel ,and a Mapp torch for the igniter. I tried using my air compressor, but it seemed to powerful for my pulsejet and snuffed out the flame. I watched a couple of pulse jet videos on youtube and I seem to be getting the same sort of rumbling and growling sound when I try to start it.
Thanks for the welcome to the forum. It is definitely an interesting place.

Post by **Mike Everman** » Mon Aug 13, 2007 3:46 am

Sedge,
The first thing that leaps out at me is the CC is too long. The plan calls for a 2.5" long nipple between reducers. Also, this rough a jet will not run from blowing a flame from outside into the intake. You honestly need a spark plug. You can drive it with any cheap BBQ piezo clicker, but you really must get it in there for this to work.
Mapp should be OK, but I doubt you're going to get enough out of that cannister. Again, a BBQ tank without regulator is prescribed.
All that being said, shorter CC, fully tight, spark going, your vac/blower should be OK.

Eric · Post by **Eric** » Mon Aug 13, 2007 3:46 pm

Welcome back Mike

How resistant is the engine to leaks? Would it still run well if he drilled a 1/16" hole in the center of the combustion chamber and then held a flame to the hole?

Eric

Ah... just realized this is the same engine as the other thread where he already has a spark plug installed....

Sedgewick · Post by **Sedgewick** » Mon Aug 13, 2007 5:04 pm

Um, I am new here and have absolutely no idea what a CC is. I was using a spark plug powered by a weed whacker magneto, but unfortunately, I did not see a sharp piece of metal on the drive shaft, which destroyed my drill chuck. Is there a way I can run the magneto on battery power? I filled my pulsejet with water to test for any leaks, and think that it is airtight.

Post by **Mike Everman** » Mon Aug 13, 2007 5:22 pm

OK, CC is Combustion Chamber. So that nipple (2" dia straight piece between reducers) is the thing that needs to be shorter. If you want to pitch your spark assembly, Eric makes a good suggestion, drilling a 1/16" hole at the mid length of the CC, and hitting that with your torch to get combustion started in the CC. This little hole should make no problems for running.

Again, this will need a lot of fuel to run, so a bigger tank will be necessary.

I've bought several BBQ tank hose assemblies from Home Depot. Once you cut off the end that would screw into a camp stove, you need to check it for flow. Some will only allow a trickle to come out, even after drilling out the feed hole at the tank end of the hose assembly. If it's low flow, you may need another brand. I have had only one of 5 or so that just wouldn't send enough fuel.

You should be able to really blast propane out when opening the valve.

Sedgewick · Post by **Sedgewick** » Mon Aug 13, 2007 8:45 pm

All I can cut of is 1 1/2 in. from the CC .Would that be small enough to get the jet running?

Post by **Mike Everman** » Mon Aug 13, 2007 8:51 pm

Worth a try.

Sedgewick · Post by **Sedgewick** » Tue Aug 14, 2007 12:40 pm

Well, I acidently cut the threads at a angle, and ruined the pipe.How long of a CC should I buy for my pulse jet?.

Post by **Mike Everman** » Tue Aug 14, 2007 2:21 pm

2.5" Refer to the plan:
http://www.pulse-jets.com/phpbb2/download.php?id=7231

Sedgewick · Post by **Sedgewick** » Wed Aug 15, 2007 12:55 pm

I noticed that your plan said to round off the pipe ends.Is this important to do with a lockwood design?

Post by **Mike Everman** » Wed Aug 15, 2007 3:58 pm

It's important on this one.

www.pulse-jets.com

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