Can't find blue shim sheets, but got strips, so...

[skyfrog]

A special coil-spark plug combination isn't needed. But a motorcycle coil is good. You just need a switch (or a relay if you are good in electrical stuff), a 12V (=) power supply, maybe a battery, and a ~0.22 10e-6F capacitor.
Connect the switch, the coil and the power supply to a closed "circle". Finally place the capacitor (reduces self induktion sparks in the switch) parallel to the switch.

You should get a nice spark at every switch then.
Note: A relay would do the switching process for you, maybe much faster, too.

Thanks, this is what I really needed. I'm not so good at electric engineering, the greatest electric stuff I've ever built is merely a rectifier. I think, I shall continually treat electric stuff as blackbox for the rest of my life. hehe

[skyfrog]

I have two pulsejet projects proceeding at the same time, one is valved which is in half way before its birth, while the other one, a valveless. Due to the best thing I can do is welding for the time being, my valveless is now under construction too : welding the body. Perhaps the valveless will be delivered first.

[mk]

A special coil-spark plug combination isn't needed. But a motorcycle coil is good. You just need a switch (or a relay if you are good in electrical stuff), a 12V (=) power supply, maybe a battery, and a ~0.22 10e-6F capacitor.
Connect the switch, the coil and the power supply to a closed "circle". Finally place the capacitor (reduces self induktion sparks in the switch) parallel to the switch.

You should get a nice spark at every switch then.
Note: A relay would do the switching process for you, maybe much faster, too.

Here is the drawing.

[Al Belli]

Hi Marten,

The relay coils in series with the ignition coil, will not allow sufficient current to flow through the coil thereby giving a very weak spark ( or none at all ). I would use a two pole relay, and isolate the ignition coil from the relay coils.

Al Belli

[Mark]

http://www.steamengine.com.au/ic/engines/buzzcoil/

http://www.steamengine.com.au/ic/engine ... zcoil.html

http://www.lindsaybks.com/arch/spark/

Just some buzz coil info.

Mark

[mk]

Here's an updated version.

The transitor must handle about 6 to 10 A.
The resistor sets the voltage for the relay (eventually unnecessary).

[skyfrog]

Hi Marten,

Good job, and thanks again.

[Viv]

Here's an updated version.

The transitor must handle about 6 to 10 A.
The resistor sets the voltage for the relay (eventually unnecessary).

Needs a big diode across the transistor to buck the EMF fromt he coil or the thransistor will get destroyed.

Viv

[skyfrog]

Needs a big diode across the transistor to buck the EMF fromt he coil or the thransistor will get destroyed.

This circuit will end up something like the one posted on Bruce Simpson's website, I think.
It's becoming more and more complicated.

Regarding Marten's original circuit, I have seen someone else used it too.
I'll try to find the drawings and have it posted.

EDIT : here it is.

[mk]

Ooops!
Maybe a mistake in the transistorized version...
The base-collector (transistor) voltage, being at 12 V by using a 12 V relay, is a bit too high, I think.

The most simple version should be a double relay then.

Transistorized version is recommend for high spark frequenzies only.
Both capacitors are 0.22 10e-06 F.

[scottkm]

Hello,

I'm Scott, and new to this forum, as you might guess :-}

I have a question about propane as a fuel, I noticed that earlier in this thread Steve posted a picture of a design with the injection going in the side, I'm thinking it's propane and looks to be 1/4 inch tube.

What's on the inside? Does the tube just end?

How are the rest of you dealing with propane injection?

And I gota tell you all, this is harder than you make it look! I've made some really spectacular torches but no running engine.

Thanks - Scott

[scottkm]

Sorry, replied to the wrong thread :-O

[scottkm]

Okay now I now why I can't get it running! I'm dumb. This is the right thread, I just never looked at the bottom!