School Project-- GOT QUESTIONS on -- K-PT 07X --

[mk]

The injector, which I presented in the blueprints, is mostly referred to as a radial "swizzle-stick" injector.

It simply consists of a pipe, which has been closed on one end, so that injection orifices could be drilled radially, most likely, near that closed end. There really is not anything special to it. (That is why that four-hole injector can by no means considered as optimal or advanced, but it works good enough for propane vapour fueling.)

You can now...:
(a) ...insert a long, straight (and small diameter) pipe via the inlet.
(b) ...let the pipe point upstream, just as shown in the blueprint, by bending it so that it protrudes the combustion chamber a little.

Make sure that the whole injector (pipe) is approximately centered and fixed to its location in both of the above cases (a) and (b). This includes the longitudinal location of the radial hole array, i.e. in either case, (a) or (b), the same distance from headplate referrence has to be applied. I would suggest the measurement depicted in the blueprint schematics, which is not in brakets.

[snakeye]

allright,

I am making improvement, but the PJ aint working optimal I think.
I've drawn my setup in paint (pretty simple put clear).

So I get my propane in the combustion chamber trough a small copper wire, and I've got a leave blower in front of the air intake instead of an air-compressor.
the small burner at the end is to ignite the whole thing cause I aint got no spark plug built in.

The engine works I thing cuase there's a blue like very loud and fast flame at the end, but as soon as I stop the leaveblower, the engine stops to and the flame becomes slow, big, and orange.

PLEASE HELP ME

[mk]

Okay, I assume you stated the tailpipe measurements in centimeters, correct?

So, first thing I have to note is that you did not build exactly to spec, which could be a problem. Especially the largely oversized intake cone could cause some trouble.

Anyway, without a spark plug you will have some hard times to start the engine.
For the time being, I can only suggest, that you try to blow the flame from the inlet plane downstream "into the engine". In earlier experiments of mine (with small Hiller-Lockwood-shaped ducts) this always worked way better than waiting for a suitable upstream burn from the tailpipe.

Due you would rather need four hands instead of even three; How did you try to get the engine running? Together with an assistant?

From the information you provided, I would definitely encourage you to get an combustor-internal, "hands-off" ignition source.

[leo]

Snakeye first off all did you remove the pressure regulator?, you don’t mention it in your posts.
With one you never get enough propane to get your pulsejet going, unless you have a high pressure / high flow regulator.
Probably your pulsejet is running in blowtorch mode, if its running good you will now, and have no doubts about it, when you only have the slightest doubts about it running or not, its not running for sure.
For a ignition you can use sparklers (sterretjes (Dutch translation)), light one and throw it in the combustion chamber.
Please post pictures of your fuel injector and other parts so we can help you better.

[snakeye]

I removed pressure regulator.

yes I work with an assistant....
I just open the propane valve... turn on the leaf blower... and then ignite the jet at the exhaust pipe..,then I turn down the propane level untill I hear a bang and the flame turns into a fast going sort of toch like flame..with very hard sound.
the problem is... WHEN I TURN THE LEAFBLOWER OFF, the engine stops running.

can anybody PLEASE help me...
gotta fix this for SCHOOL.. in 2 weeks or so.

Jimmy

[snakeye]

hey guys.. I need some quick help.. here's a link to my movie I made...

click here

[mk]

Wrt. the video: The engine was only running in "howling mode", locally restricted to the tailpipe (expansion) parts.
Therefore, as I said before, you will have trouble starting the engine without igniting the F/A-mixture instantaneously from inside the combustion chamber.

Without doing further changes, you might be lucky in regulating fuel flow and air delivery simultaneously in order the flame front could travel upstream into the combustion chamber at first. Then further tweaking (fuel flow and air delivery variations) might be necessary.

[Jason]

Sorry to bother you sir but with the regulator on LPG cylinder, i cant get enough fuel in my engine cause i want my engine to move forward and for this i need a lot of pressure and fuel flow.

The problem is this that many people told me that without the regulator on, i will get the LPG container blow up as there will be a flashback from the engine......Please i need a little HELP!!!

[Mike Everman]

Most of us take the regulator off. In my experience and engineering opinion, there is no possibility of flashing up the fueling hose, there's no air in the hose. I'm trying to think of a possible way the tank could get dangerous. I suppose if you live in a place that is so cold, and your tank were so empty, and you opened the valve and it actually sucked air inside with the fuel, and somehow was in a combustable mix, and then you closed the valve and waited until there was a heatwave, and actuall had some pressure develop and then touched it off in your motor...

FYI, the average pressure in a running pulsejet hovers around 5psi.

Disclaimer:
No one here has anything but opinions and experience when it comes to safety. No one here, especially myself are recommending you play with noise and fire and tanks of combustable material, no matter how much fun we are having! If you are nervous, GOOD! But we are usually only losing arm hair.